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Environment Friendly Composite Materials: Biocomposites and Green Composites

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Abstract

Biocomposites can supplement and eventually replace petroleum-based composite materials in several applications. Several critical issues related to bio-fiber surface treatments is to make it a more suitable matrix for composite application and promising techniques need to be solved to design biocomposite of interest. The main motivation for developing biocomposites has been and still is to create a new generation of fiber reinforced plastics material competitive with glass fiber reinforced ones which are environmentally compatible in terms of products, use and renewal. There is an immense opportunity in developing new biobased products, but the real challenge is to design suitable bio-based products through innovation ideas. Green materials are the wave of the future. Bionanocomposites have very strong future prospects, though the present low level of production, some deficiency in technology and high cost restrict them from a wide range of applications.

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... Besides, in general, the obtained composites cannot be reprocessed or recycled. Therefore, it becomes necessary to find alternative raw materials to produce WPC-like parts (Mitra, 2014;Netravali and Chabba;2003). Nowadays, there is a great interest in developing green composites using sustainable, biodegradable, environment friendly and renewable fibers and resins, particularly derived from biomass. ...
... Nowadays, there is a great interest in developing green composites using sustainable, biodegradable, environment friendly and renewable fibers and resins, particularly derived from biomass. A wide variety of biodegradable matrices, such as starch, cellulose and proteins, mixed with natural fibers, such as flax, ramie, kenaf, jute, sisal and wood fines, have been used to fabricate green composites or biocomposites (Netravali and Chabba, 2003;Mitra, 2014). An attractive alternative are the eco-composites where both the matrix and the reinforcement are obtained from renewable resources that are completely biodegradable, thus achieving environmental and ecological advantages over conventional composites (Mitra, 2014;Bogoeva-Gaceva et al., 2007). ...
... A wide variety of biodegradable matrices, such as starch, cellulose and proteins, mixed with natural fibers, such as flax, ramie, kenaf, jute, sisal and wood fines, have been used to fabricate green composites or biocomposites (Netravali and Chabba, 2003;Mitra, 2014). An attractive alternative are the eco-composites where both the matrix and the reinforcement are obtained from renewable resources that are completely biodegradable, thus achieving environmental and ecological advantages over conventional composites (Mitra, 2014;Bogoeva-Gaceva et al., 2007). In this regard, wood fiber based ecocomposites or biocomposites, also known as WBPCs (Wood Bio-Plastic Composites), are of particular interest. ...
Article
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The influence of the processing conditions and composition on the properties of biocomposites made of a bioplastic matrix from soybean protein, crosslinked with glutaraldehyde, reinforced with lignocellulosic material from wood sawdust (Wood Bio-Plastic Composite, WBPC) was investigated. The WBPCs were obtained by thermocompression applying a pressure of 70 bar at 100 and 120 °C for 30 or 60 minutes. Several test pieces were prepared varying the crosslinker/protein and protein/sawdust ratios. The samples obtained were characterized by scanning electron microscopy (SEM), flexural and hardness tests, and water absorption and swelling, according to international ASTM standards. The crosslinking of the protein improves the mechanical properties of the biocomposites, especially when contents of bioplastic matrix and crosslinker are low. It was also verified that the WBPCs prepared in this work recover their original shape and dimensions after immersion in water and subsequent drying. The results were explained considering crosslinker-protein and protein-sawdust interactions.
... The NFRCs are also referred to "green composites," "ecocomposites" and "biocomposites" where natural fibres are embedded with the thermosetting or thermoplastic polymers to fabricate the composites [9][10][11]. The NFRCs are composed of a polymer matrix (consisting of either a petroleum-based source or a natural biopolymer) and a reinforcing material (in the form of fibres or particles) [17]. The NFRCs can be classified into three groups, green, semi-green and hybrid composites, depending on the ratio of natural materials used as the reinforcing medium [17][18][19][20]. ...
... The NFRCs are composed of a polymer matrix (consisting of either a petroleum-based source or a natural biopolymer) and a reinforcing material (in the form of fibres or particles) [17]. The NFRCs can be classified into three groups, green, semi-green and hybrid composites, depending on the ratio of natural materials used as the reinforcing medium [17][18][19][20]. Green composites are when both the polymer matrix and reinforcing materials are procured from natural or renewable sources (e.g., PLA and hemp) [17,21,22]. ...
... The NFRCs can be classified into three groups, green, semi-green and hybrid composites, depending on the ratio of natural materials used as the reinforcing medium [17][18][19][20]. Green composites are when both the polymer matrix and reinforcing materials are procured from natural or renewable sources (e.g., PLA and hemp) [17,21,22]. The semi-green composites are composed of natural and synthetic polymers-with more natural materials [17][18][19][20]. ...
Article
Full-text available
The increasing global environmental concerns and awareness of renewable green resources is continuously expanding the demand for eco-friendly, sustainable and biodegradable natural fibre reinforced composites (NFRCs). Natural fibres already occupy an important place in the composite industry due to their excellent physicochemical and mechanical properties. Natural fibres are biodegradable, biocompatible, eco-friendly and created from renewable resources. Therefore, they are extensively used in place of expensive and non-renewable synthetic fibres, such as glass fibre, carbon fibre and aramid fibre, in many applications. Additionally, the NFRCs are used in automobile, aerospace, personal protective clothing, sports and medical industries as alternatives to the petroleum-based materials. To that end, in the last few decades numerous studies have been carried out on the natural fibre reinforced composites to address the problems associated with the reinforcement fibres, polymer matrix materials and composite fabrication techniques in particular. There are still some drawbacks to the natural fibre reinforced composites (NFRCs)—for example, poor interfacial adhesion between the fibre and the polymer matrix, and poor mechanical properties of the NFRCs due to the hydrophilic nature of the natural fibres. An up-to-date holistic review facilitates a clear understanding of the behaviour of the composites along with the constituent materials. This article intends to review the research carried out on the natural fibre reinforced composites over the last few decades. Furthermore, up-to-date encyclopaedic information about the properties of the NFRCs, major challenges and potential measures to overcome those challenges along with their prospective applications have been exclusively illustrated in this review work. Natural fibres are created from plant, animal and mineral-based sources. The plant-based cellulosic natural fibres are more economical than those of the animal-based fibres. Besides, these pose no health issues, unlike mineral-based fibres. Hence, in this review, the NFRCs fabricated with the plant-based cellulosic fibres are the main focus.
... The NFRCs are also referred to "green composites," "ecocomposites" and "biocomposites" where natural fibres are embedded with the thermosetting or thermoplastic polymers to fabricate the composites [9][10][11]. The NFRCs are composed of a polymer matrix (consisting of either a petroleum-based source or a natural biopolymer) and a reinforcing material (in the form of fibres or particles) [17]. The NFRCs can be classified into three groups, green, semi-green and hybrid composites, depending on the ratio of natural materials used as the reinforcing medium [17][18][19][20]. ...
... The NFRCs are composed of a polymer matrix (consisting of either a petroleum-based source or a natural biopolymer) and a reinforcing material (in the form of fibres or particles) [17]. The NFRCs can be classified into three groups, green, semi-green and hybrid composites, depending on the ratio of natural materials used as the reinforcing medium [17][18][19][20]. Green composites are when both the polymer matrix and reinforcing materials are procured from natural or renewable sources (e.g., PLA and hemp) [17,21,22]. ...
... The NFRCs can be classified into three groups, green, semi-green and hybrid composites, depending on the ratio of natural materials used as the reinforcing medium [17][18][19][20]. Green composites are when both the polymer matrix and reinforcing materials are procured from natural or renewable sources (e.g., PLA and hemp) [17,21,22]. The semi-green composites are composed of natural and synthetic polymers-with more natural materials [17][18][19][20]. ...
Article
Full-text available
The increasing global environmental concerns and awareness of renewable green resources is continuously expanding the demand for eco-friendly, sustainable and biodegradable natural fibre reinforced composites (NFRCs). Natural fibres already occupy an important place in the composite industry due to their excellent physicochemical and mechanical properties. Natural fibres are biodegradable, biocompatible, eco-friendly and created from renewable resources. Therefore, they are extensively used in place of expensive and non-renewable synthetic fibres, such as glass fibre, carbon fibre and aramid fibre, in many applications. Additionally, the NFRCs are used in automobile, aerospace, personal protective clothing, sports and medical industries as alternatives to the petroleum-based materials. To that end, in the last few decades numerous studies have been carried out on the natural fibre reinforced composites to address the problems associated with the reinforcement fibres, polymer matrix materials and composite fabrication techniques in particular. There are still some drawbacks to the natural fibre reinforced composites (NFRCs)-for example, poor interfacial adhesion between the fibre and the polymer matrix, and poor mechanical properties of the NFRCs due to the hydrophilic nature of the natural fibres. An up-to-date holistic review facilitates a clear understanding of the behaviour of the composites along with the constituent materials. This article intends to review the research carried out on the natural fibre reinforced composites over the last few decades. Furthermore, up-to-date encyclopaedic information about the properties of the NFRCs, major challenges and potential measures to overcome those challenges along with their prospective applications have been exclusively illustrated in this review work. Natural fibres are created from plant, animal and mineral-based sources. The plant-based cellulosic natural fibres are more economical than those of the animal-based fibres. Besides, these pose no health issues, unlike mineral-based fibres. Hence, in this review, the NFRCs fabricated with the plant-based cellulosic fibres are the main focus.
... However, due to rising environmental concerns, depletion of petroleum reserves, strict environmental regulations and costly processes of both incineration and dumping in land-fills, and health hazards, e.g. allergic irritations (Naghdi et al. 2009;Naghdi et al. 2013;Thakur et al. 2014), there is recently a dramatic shift in developing novel composites from plants (Mitra 2014). A good few properties of fully bio-based composites such as biodegradability, acceptable specific strength, low density, cost-effectiveness, abundance and easy accessibility, reprocessibility, acceptable toughness and stiffness, limited toxicity, good thermal, acoustic and insulation properties, low tool abrasion, non-allergic, and low energy consumption have introduced them as a versatile alternative for future environmentally benign, industrial applications (Thakur et al. 2014). ...
... Micro-organisms, e.g. bacteria and fungi, can decompose the bio-based fibre/natural polymer constituents of green composites and then convert them into carbon dioxide and water molecules gradually absorbed by plant structure (Nadali et al. 2010;Mitra 2014;Nadali and Naghdi 2020). The pivotal reasons for producing green composites are the huge amounts of agricultural wastes globally produced per year and the economically and environmentally safe possibility to use them in biocomposites. ...
... Acetate-modified starch matrix/cellulose-fibrereinforced composites were manufactured and Table 1. Mechanical properties and chemical composition of natural and synthetic fibres (Mitra 2014;Nair and Joseph 2014;Thakur et al. 2014;Satyanarayana 2015) Wong et al. (2000) Chemical ...
Article
The present environmental limitations and also the depletion of oil-based resources have resulted in greater thrust for the development of environmentally friendly and energy-saving biocomposites termed as green composites. The unique combined properties of biofibres have introduced this new class of biocomposites as a versatile alternative to the present petrochemical composite materials. Considerable efforts are now underway to effectively take advantage of the synergistic effects of combining natural reinforcements and plant-derived polymers for high-performance green composites and nanocomposites. This paper reports the most recent advances in characterization and multifunctional properties of different agro-waste fibres and polymers. The structural properties and functions of the resulting green composites along with their applications are also discussed in details in each section. The current research trends for modification of natural fibres, processing techniques of the given composites as well as their future prospects and challenges are addressed.
... Green marketing, cleaner production, sustainability, and change of cognitive values of consumers and lawmakers have led to environment-friendly production. Composite materials are being developed and redesigned to improve and adapt conventionally manufactured products while also bringing new products to market sustainably and responsibly [2]. These multifunctional materials have been developed to match the needs of a certain application and offer remarkable physicomechanical properties. ...
... Natural renewable resources that reduce carbon footprint are green composites. While materials that have one of the constituents, either fiber or matrix, from norenewable resources are partly eco-friendly composites [2]. Non-biodegradable predominant fiber-reinforced plastics such as glass, carbon, and aramid fibers reinforced with synthetic thermoplastic and thermosetting resins are hazardous to the environment since they are derived from finite resources [5]. ...
... Hence, Bamboo can emerge as a naturally sustainable material for high-end applications and value-added products. In recent years, the development of eco-friendly green composites using natural fibres has attracted significant interests because of their biodegradability and non-emission of any toxic or harmful components [5][6][7]. Bamboos occupy an area of 36 million hectares worldwide which is equivalent to 3.2 per cent of the total forest area globally, with 11.40 million hectares or 16.8 per cent of the total forest area [8]. Bamboo attains its maximum size in 60-90 days and completely matures in 3-6 years in comparison to the 20-60 year growth cycle of timber. ...
... Although very few researchers have reported specific work like Puri et al. reported Bamboo reinforced prefabricated wall panels for low-cost housing [3]. Mitra, reported Environment-friendly composite materials: biocomposites and Green Composites [5]. Srebrenkoska [19]. ...
Article
Full-text available
The present work reports a novel process for developing advanced chemically designed materials by utilizing both bamboo stem and fly ash's inherent chemical and complementary properties. The process involves forming unique heterogeneous tailored precursor material using treated bamboo stem and Class F-fly ash to develop advanced chemically designed material in a Panel form. In the process, the bamboo stem plays a dual role by helping in the in-situ formation of chemicals like sodium silicates; sodium lignates etc. which are essential for the formation of geo polymeric moieties during the reaction processing in the developed product. The other is the so formed cellulosic derived fibers are used as natural reinforcement fibres.
... To make the LLDPE/PVOH matrix easier to degrade, natural fibers can be added to its composition. In addition to being economical and lightweight, natural fibers provide biodegradability to the polymer matrix (Moriana et al. 2010;Mitra 2014). One of the natural fibers that has gained popularity among researchers is kenaf fibers (John et al. 2010;Ramesh 2016). ...
Article
In recent decades, natural fibers have become widely used with petroleum based polymers such as polyethylene (PE) and polypropylene (PP) because of their light weight, lower cost, and inherent biodegradability. In the present work, linear low-density polyethylene/polyvinyl alcohol (LLDPE/PVOH) composites with untreated kenaf and silane-treated kenaf at filler loadings of 0, 10, and 40 phr were prepared via the melt mixing process. The soil burial test was used to evaluate the degradability of the composites for different durations (90 and 180 d). The tensile properties, surface morphology, chemical composition, percentage of weight loss, and crystallinity of the composites before and after degradation were evaluated. With increased kenaf loading and soil burial duration, all the composites showed a decrease in tensile properties. This was further confirmed by the changes in surface morphology and chemical structure of the buried composites. The increase in weight loss percentage and crystallinity after soil burial indicated that the longer burial duration had increased the degradation of composites. Composites with silane-treated kenaf exhibited lower degradability than that of composites with untreated kenaf after being buried for 90 and 180 d. This may be attributed to the improved adhesion of kenaf to the LLDPE/PVOH matrix via silane treatment.
... SPI has a relatively complex and stable polymer structure. The forces supporting the protein structure include hydrogen bonds, disul de bonds, and electrostatic bonds (Hsieh et al. 2014;Mitra et al. 2014;Garrido et al. 2013;). However, this stable structure can be handled by chemical modi cation methods. ...
Preprint
Full-text available
In an effort to control dust pollution in open-air environments such as pit coal mines and coal transportation systems, a new dust suppressant with a cross-linked network structure was prepared. Graft copolymerization of soy protein isolate (SPI) and methacrylic acid (MAA), using potassium persulfate (KPS) as the initiator and hexametaphosphoric acid (SHMP) as the cross-linking agent, formed the network structure. The optimal MAA/SPI mass ratio for the dust suppressant was determined through a single factor experiment to be 3:4, with 0.8 and 0.2 g of SHMP and KPS, respectively. The grafting reaction required 30 min at 60 ℃. Scanning electron microscopy, energy-dispersive x-ray spectroscopy, Fourier-transform infrared spectroscopy, and differential scanning calorimetry were used to characterize the structure and application performance of the dust suppressant. The experimental results showed that the graft copolymerization reaction successfully formed the desired cross-linked network, and that when the cross-linked network material was sprayed on coal dust it formed a dense, solidified shell, which effectively resisted wind erosion and served as a dust suppressant. The average reduction of the total suspended particulate matter of an open-air coal pile reached 79.95%, demonstrating effective dust suppression.
... SPI has a relatively complex and stable polymer structure. The forces supporting the protein structure include hydrogen bonds, disul de bonds, and electrostatic bonds [33][34][35]. However, this stable structure can be handled by chemical modi cation methods. ...
Preprint
Full-text available
In an effort to control dust pollution in open-air environments such as pit coal mines and coal transportation systems, a new dust suppressant with a cross-linked network structure was prepared. Graft copolymerization of soy protein isolate (SPI) and methacrylic acid (MAA), using potassium persulfate (KPS) as the initiator and hexametaphosphoric acid (SHMP) as the cross-linking agent, formed the network structure. The optimal MAA/SPI mass ratio for the dust suppressant was determined through a single factor experiment to be 3:4, with 0.8 and 0.2 g of SHMP and KPS, respectively. The grafting reaction required 30 min at 60 ℃. Scanning electron microscopy, energy-dispersive x-ray spectroscopy, Fourier-transform infrared spectroscopy, and differential scanning calorimetry were used to characterize the structure and application performance of the dust suppressant. The experimental results showed that the graft copolymerization reaction successfully formed the desired cross-linked network, and that when the cross-linked network material was sprayed on coal dust it formed a dense, solidified shell, which effectively resisted wind erosion and served as a dust suppressant. The average reduction of the total suspended particulate matter of an open-air coal pile reached 79.95%, demonstrating effective dust suppression.
... The development of polymeric composites materials from lignocellulose raw fibre resources have advantages over synthetic materials in possessing high strength, biodegradable and sustainable green material, lightweight, low in cost and energy production, environment friendly, thermal resistance [6][7][8]. Furthermore, the combination of organic natural fibers and inorganic or organic polymers as a hybrid composites tend to increase the mechanical performances, and expanding the areas of application such in constructions, automotive and food packaging sector [9][10][11]. ...
Article
The effect of 2%v/v silane and 4%v/v hydrogen peroxide treatment on mechanical, physical and morphological characterization of oil palm empty fruit bunch (OPEFB) and sugarcane bagasse (SCB) fiber reinforced bio-phenolic hybrid composites has been evaluated in this work. The treated OPEFB and SCB fibers has been prepared with different ratio while maintaining 50%wt fiber loading, and then incorporated with the bio-phenolic resin by hand layup technique to produce pure and hybrid composites. Universal testing machine INSTRON has been used for tensile, flexural, and compressive strength analysis. Water absorption and thickness swelling are determined after 24 h. Fracture behaviour, void and fiber pull out of the specimen was observed by using scanning electron microscope in morphological analysis. The hybridization of silane treated 7OPEFB:3SCB fiber indicates better highest performance on tensile strength and modulus with 11.67 MPa and 1348.43 MPa. The silane treated 5OPEFB:5SCB hybrid composites show highest flexural and compressive strength, 16.82 MPa and 6.53 MPa, respectively. Obtained result showed silane treated 3OPEFB:7SCB hybrid composites displays lowest water absorption and thickness swelling after 24 h analysis and show less void content. This study indicated that 2%v/v silane coupling agent gives better enhancement of mechanical properties compared to 4%v/v hydrogen peroxide treatment. Silane treated 5OPEFB:5SCB fiber reinforced bio-phenolic hybrid composites fulfil requirement of the mechanical and physical properties needed for insulation board as per standard. It can be concluded from this study that silane treatment improve the performance of agriculture residue and the hybridization of bio-composites have potential to develop new class of eco-friendly thermal insulation and sustainable wall building materials.
... In the recent years, the awareness of environmental and consumer's awareness towards new products subjected to strictly regulation and law enforcement, the environmentally friendly used materials adopting natural fibers become more popular [1] [2]. Natural fiber offered good properties and environmental user friendly compared to synthetic one when developing a new product which aiming quality and sustainable values [3]. The growth of natural fiber applications in composites industries are considerably fast over 5 years (2011 -2016) by 10% worldwide [4]. ...
Article
Full-text available
Study on new composite materials in engineering products with promising physical and mechanical properties has been considered as one of the fields of concern in recent decades. Strength, hardness and fatigue properties make engineering structural more flexible. They are extensively used in the aerospace industry, mechanical engineering applications and parts, electronic packaging, vehicle and aircraft structures, process industry equipment, as well as in biomedical equipment. Disposing of composite wastes however, are very difficult because of its structure and compositions. Hence, composite materials recycling has become one of the major measures of the future. This study seeks to analyse the present state of engineering plastics using natural fibers in their properties and manufacturing techniques. The effects of various chemical treatments on natural fibres’ mechanical and thermal properties have been studied in strengthening thermosetting and thermoplastics composites. The mix ratio of polymer waste used from the industry sector with natural fiber is expected to rise in the future, thus issues regarding recycling need to be tackled. It concluded that chemically treated natural fibre improved the adhesion between fibre surface and polymer matrix, which gradually increased the properties of natural fibres incorporated composites.
... Generally, most of the research published related to composite materials concern on developing and redesigning with the aim to improve and to adapt traditional products and introduce new products in a sustainable and responsible way [1]. In the last few years, there have been a stringent consumer's awareness towards new products from renewable sources. ...
Article
In this study, the impact properties of kenaf fibre reinforced hybrid fiberglass/Kevlar polymeric composite was investigated. In this study, a new fiber arrangement based on kenaf bast fiber as reinforcement to the hybrid fiberglass/Kevlar fiber and polyester as matrix used to fabricate the hybrid polymeric composite. Five different types of samples with different of kenaf fiber content based on volume fraction (0, 15, 45, 60 and 75%) to hybrid fiberglass/Kevlar polymer composites were manufactured. 0% of kenaf fiber has been used as control sample. The results showed that hybridization has improved the impact properties. These results were further supported through SEM micrograph of the manufacturing defects of the polymer composite. Based on literature work, manufacturing defects that occurs in composite system reduced the mechanical properties of the material. Therefore, in this research the correlation of impact behaviors and manufacturing defects of kenaf fiber reinforced hybrid fiberglass/Kevlar polymeric composite has been successfully done. As conclusion, the highest manufacturing defects determined in the composites during the fabrication significantly lowest the results of impact behavior.
... SPI has a relatively complex and stable polymer structure. The forces supporting the protein structure include hydrogen bonds, disulfide bonds, and electrostatic bonds (Hsieh et al. 2014;Mitra 2014;Garrido et al. 2013;Ma et al. 2020a, b). However, this stable structure can be handled by chemical modification methods. ...
Article
Full-text available
In an effort to control dust pollution in open-air environments such as pit coal mines and coal transportation systems, a new dust suppressant with a cross-linked network structure was prepared. Graft copolymerization of soy protein isolate (SPI) and methacrylic acid (MAA), using potassium persulfate (KPS) as the initiator and hexametaphosphoric acid (SHMP) as the cross-linking agent, formed the network structure. The optimal MAA/SPI mass ratio for the dust suppressant was determined through a single-factor experiment to be 3:4, with 0.8 and 0.2 g of SHMP and KPS, respectively. The grafting reaction required 30 min at 60 °C. Scanning electron microscopy, energy-dispersive x-ray spectroscopy, Fourier-transform infrared spectroscopy, and differential scanning calorimetry were used to characterize the structure and application performance of the dust suppressant. The experimental results showed that the graft copolymerization reaction successfully formed the desired cross-linked network, and that when the cross-linked network material was sprayed on coal dust, it formed a dense, solidified shell, which effectively resisted wind erosion and served as a dust suppressant. The average reduction of the total suspended particulate matter of an open-air coal pile reached 79.95%, demonstrating effective dust suppression. Graphical abstract
... Biocomposites are the composite materials in which either one or both the constituents of the composite material are biodegradable while green composites contain both the biodegradable components. Figure 1 shows the various categories of biocomposites in which either the matrix is biopolymer and fiber is synthetic , fiber is natural and matrix is synthetic or both the constituents are biodegradable (Mitra, 2014). There are few issues with natural fibers which need to addressed, like poor adhesion and compatibility with hydrophobic polymer matrix, thermal stability, tendency to aggregates and poor resistance to moisture. ...
Chapter
Academicians and researchers are exploring new opportunities in the field of natural fiber-based green composites because of excellent properties of natural fibers like lightweight, easy availability, sustainability and environment-friendly tendency. Cost effectiveness, diversity and renewability of natural fibers are also added advantages which attract scientific community and industrialists. Being lignocellulosic, natural fibers are hydrophilic in nature, and their poor adhesion with hydrophobic polymer matrix is one of the major issues which can create hurdles for the commercialization of their finished composites. Extensive research on different treatment methodologies has been done on these natural fibers and their reinforced polymer composites to get the improved properties. Various chemical, physical and biochemical methods have been suggested to get the excellent finished products. A detailed compilation of the existing treatment methodologies including traditional methods like alkali treatment, silanization, graft copolymerization and along with less common ways like enzymatic, radiation, ionic liquid treatment have been discussed. Emphasis has been given to add recent findings in the field of surface treatment of natural fibers to get the optimized green composites.
... Les nanocomposites permettent de pallier ces inconvénients. Les nanocharges améliorent les propriétés mécaniques sans compromettre la ductilité du matériau car la faible taille des particules ne crée pas de concentrations de contrainte [127]. La diminution de la taille des renforts insérés dans la matrice conduit à une augmentation très importante de la surface des ...
Thesis
Les protéines isolées végétales sont une source renouvelable de matière première, disponible en grande quantité. Malgré des propriétés mécaniques faibles par rapport aux polymères traditionnels, elles possèdent d’autres spécificités intéressantes comme leur biodégradabilité, leur filmabilité et leur absence de toxicité. Cette étude s’est focalisée sur l’influence du procédé d’élaboration, la compatibilité et l’ajout de nanocharges sur les propriétés de mélanges poly(butylène succinate - co - adipate)/protéines de soja isolées plastifiées (PBSA/PISP). Dans un premier temps, les protéines de soja sont plastifiées et mélangées au poly(butylène succinate - co - adipate), dans des proportions différentes et extrudées simultanément en une étape d’extrusion. Ensuite, l’effet de l’ajout du poly(2-éthyl-oxazoline) comme compatibilisant a été étudié. L’addition de ce compatibilisant permet d’améliorer l’interface et les propriétés thermiques. En outre, l’addition de nanotubes d’halloysite permet d’améliorer certaines propriétés mécaniques et thermiques. Enfin dans le cas de films préparés avec une composition PBSA/PISP égale (50/50), le compatibilisant améliore les propriétés optiques, tandis que l’ajout des nanotubes d’halloysite améliore les propriétés de barrière à la vapeur d’eau et retarde la dégradation du film enfoui dans un sol. L’ensemble des résultats donne de premières indications sur l’usage potentiel de ces films dans le domaine de l’emballage et éventuellement dans le biomédical.
... It would not be feasible to totally replace 100% of hydrocarbon-based materials. A feasible solution [32] would be to introduce different characteristics and advantages with both crude and natural resources to manufacture consistent materials, that is, biocomposites with cost-effectiveness for commercial applications. ...
Chapter
Materials play a significant role in daily life and have contributed greatly to the technoeconomic advancement of the modern era. Biocomposites are considered newly developed fourth-generation materials that are considerably high performance and desirable in the light of environmental sustainability and full end-use consumer product degradability. Biocomposites derived via renewable resources offer very interesting potential to benefit manufacturers, the surrounding environment, and consumers as petroleum resources are deteriorating rapidly. This chapter presents an overview of some basic concepts of biocomposite materials and their potential applications in automotive industries. It also addresses the recent advances, current initiatives, and key limitations to be tackled for the implementation of biocomposites at the commercial scale. Moreover, the economic and environmental consequences of biocomposites in the automotive sector are also highlighted in detail. A retrospective review of market trends and forecast analysis of biocomposites has also been addressed and discussed. The study also highlights the potential of natural fibers and biopolymers for commercial applications in the interior and exterior components of cars and a few other applications as well.
... On the other hand, the non-wood fibers are categorized into five classes such as bast fibers (jute, flax, and hemp), straw fibers (corn, wheat, and rice), leaf fibers (sisal, banana, and pineapple), seed/fruit fibers (coir and cotton), and grass fibers (bamboo and elephant grass) (Dixit et al. 2017;Pennells et al. 2020;Syduzzaman et al. 2020). The animal-based fibers are mostly obtained from hair sources (e.g., sheep, alpaca, and cashmere) and silk fibers (Mitra 2014;Wang et al. 2020a). The mineral-based fibers are sourced from different mineral sources like asbestos (Pickering, Aruan Efendy, and Le 2016). ...
Article
Full-text available
Due to the increased public awareness in ensuring a sustainable and long-lasting world, both academic and industrial researchers are trying to use eco-friendly and biodegradable materials in every sphere of life. Petroleum-based synthetic materials are nonrenewable, hazardous, and costly. In contrast, natural fibers are mainly derived from plant-based sources, which are recyclable, renewable, sustainable, abundantly available, and cheap. Hence, the use of natural fibers in the fabrication of composite materials is increasing dramatically. These are used as a reinforcement with the polymer matrix to fabricate the composites. Although a massive amount of research works has been performed to develop green composites, until now the composite fabrication process is facing some terrific problems such as the lower adhesion tendency of the composites, due to the presence of the hydrophilic natural fibers and hydrophobic polymer matrix. Researchers are trying to find out the optimum combination of the composites that can be able to exhibit excellent mechanical properties for the application areas where greater strength is a must. This review is focusing on the composite materials fabricated from the bast fibers, a branch of the natural fibers, with various thermoplastic and thermosetting polymers, and their potential application areas.
... The carbon fibres which act as a reinforcement carry most of the load. The resin helps to maintain the relative position of the fibre within the composite, and transfer load from the bottom fibre to the inner fibre [5]. These strengthen the interfacial properties of the fibre/resin composites. ...
Article
Full-text available
This study is based on readily available materials within the locality. The extraction of carbon fibre from periwinkle shell is to reduce the high cost of processing carbon fibre from petroleum pitch and to serve as reinforcement to the natural rubber resin. The fibre was activated using potassium hydroxide (KOH) followed by characterization through XRF, tensile test, hardness and impact test. On forming the composite, the reinforced material was calculated on percentages: 10%, 20% and 30% and added differently to 220grams of natural rubber resin. The samples were then prepared for various tests analysis based on ISO and ASTM standard,(ISO 527 for tensile test, ISO 179 for impact test and ASTM D2240 for hardness test) to determine the composite strength in comparison with the natural rubber for vibration isolation. The basis for this comparison is because natural rubber is widely used as a vibration isolator. The result shows an increased in tensile strength of the composite to 0.20 mega Pascal as against 0.09 mega Pascal of natural rubber resin, good strain rate for improved isolator life and high resistance to thermal expansion
... The a polymer matrix are collected in NFRCs consisting of moreover a petroleum based source otherwise a natural bio-polymer as well as a reinforcing materials in the form of fibres otherwise particles. [5]. ...
Conference Paper
Our research work is based on the use of natural and synthetic fibers within the replacement of plastic in automobile instrumental panel. The incorporation of jute and the composites of glass fiber are gained improving the purposes in the field of engineering. These composites are subjected to give high strength and light weight fiber composite material. Our aim of this research is to compare the difference of two material which have different properties and conditions, namely the first one Acrylonitrile Butadiene Styrene [ABS] and the materials of composite of Jute as well as glass fiber by means of epoxy resin. The experiment outcome demonstrates so as to the mixture composites contain increased the properties of mechanical. In this research a real time component model of instrumental panel is fabricated with jute and glass fiber and due to limited resource, this component model needs further improvements.
... Perkembangan material komposit dalam kurun waktu dua dekade terakhir diutamakan untuk menggunakan bahan alami baik yang bersumber pada tumbuhan, binatang, serta mineral Mitra (2014) Serat alami, meliputi serat daun nanas, serat pisang, serat sabut kelapa, serat jute, serat rami adalah jenis-jenis serat alam yang banyak dipergunakan sebagai penguat Mohd Nurazzi dkk. (2017). ...
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... The incorporation of new materials such as those that can be obtained from plants, crops, animals, or other sources is one of the alternatives to reduce some outstanding problems. These materials are characterized by being environmentally safe, easy to recycle, and available in abundance from renewable natural sources [25]. The mechanical properties of the PMMA composite can be improved by interacting between the oil palm empty fruit bunch fiber and matrix. ...
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The current paper focuses on studying the mechanical and tribological properties of Polymethyl methacrylate (PMMA) reinforced by natural materials. Two different natural powders, corn cobs, and miswak particles were used with different loading fractions, 2.0, 4.0, 6.0, 8.0, and 10 wt.%. The results showed a good enhancement in the mechanical properties of PMMA composites comparing with pure PMMA. The improvement in mechanical properties is accompanied by an improvement in tribological properties. Experimental results illustrated that PMMA composites with weight fractions of 8.0 % corn cobs and 6.0 % miswak recorded the optimal tribological and mechanical characteristics among other weight fractions. Furthermore, the microscopic results showed a change in the wear mechanism of the PMMA due to the incorporation of the natural materials.
... Natural fibers are eco-friendly, low cost and the most important renewable source of biodegradable structural materials. The utilization of natural fibers to develop fully biodegradable novel green materials is need for today's ecological and environmental problems (Anandjiwala and Blouw 2007;Mitra 2014;Ramesh, Palanikumar, and Reddy 2017). Natural fiberbased materials are low-cost, lightweight, biodegradable, and exhibit good mechanical properties (Mohammed et al. 2015;Prasad, Saini, and Kumar 2019;Saheb and Jog 1999;Negi et al.). ...
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Jatropha residue (shells and de-oiled cake) is a waste product from the oil processing industries and is toxic. Jatropha shell powder (JSP) was used as filler to fabricate an epoxy glass fiber hybrid composite material. The effect of different wt.% (10, 15 and 20%) and Jatropha shell powder sizes (150, 150–250, and 250–300 µm) on physical-mechanical characteristics of hybrid composites were studied. It was discovered that the tensile strength of the hybrid composite (79.6 MPa) improved significantly with 15 wt % JSP loading of size 150–250 µm as compared to epoxy glass fiber composite (35.7 MPa). The hybrid composite specific wear rate (0.079 mm3/Nm) reduced significantly (89%) as compared to the glass fiber composite material. The impact strength of the hybrid composite material is increased by 4 times of simple composite. The SEM images revealed that the fibers pull out from the lamina due to a lack of interfacial bonding between glass fiber, epoxy, and JSP. Additionally, the TOPSIS method was used to predict the best hybrid composite material using the experimental results. It can be concluded that JSP powder can be used for epoxy glass fiber composite, which would reduce environmental pollution by increasing the green building resource base.
... T he need of environment friendly composite [1,2] materials has triggered the researchers to explore several lingo cellulose based natural fibers for automobile applications [3]. The synthetic fibers are been replaced by natural fibers due to its severe environmental damages. ...
Conference Paper
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The dependence on bio-friendly composite has triggered researchers to explore several natural lignocellulose fibers. The promising properties of the fibers resulted in natural fibrils to be used as sustainable alternate for artificial man-made fibrils. The present work deals with exploration of physio-mechanical and chemical characteristics of coconut inflorescence fibers. The coconut inflorescence fibers are extracted by the process of retting and then the fibers are subjected to surface modification with KOH. The amorphous constituents present in the fibers were eroded and significant improvements in properties of the fibers were observed. XRD and FTIR analysis confirmed the removal of functional groups and crystallinity improvement were also confirmed. Single fiber tensile test confronted the improvement in tensile nature of the fibrils. Increase in fiber diameter was also observed as a result of surface modifications done on the fiber surfaces. Finally SEM analysis confirmed the elimination of wax and other oil covering materials existing on the surface of the fibers.
... The a polymer matrix are collected in NFRCs consisting of moreover a petroleum based source otherwise a natural bio-polymer as well as a reinforcing materials in the form of fibres otherwise particles. [5]. ...
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An experimental investigation on machinability of aluminium metal matrix composite Al6061 reinforced with SiC through wire electrical discharge machining (WEDM) Abstract. Our research work is based on the use of natural and synthetic fibers within the replacement of plastic in automobile instrumental panel. The incorporation of jute and the composites of glass fiber are gained improving the purposes in the field of engineering. These composites are subjected to give high strength and light weight fiber composite material. Our aim of this research is to compare the difference of two material which have different properties and conditions, namely the first one Acrylonitrile Butadiene Styrene [ABS] and the materials of composite of Jute as well as glass fiber by means of epoxy resin. The experiment outcome demonstrates so as to the mixture composites contain increased the properties of mechanical. In this research a real time component model of instrumental panel is fabricated with jute and glass fiber and due to limited resource, this component model needs further improvements.
Thesis
L’objectif de cette thèse est la caractérisation du comportement mécanique et de l’endommagement d’un composite tissé jute/polyester. Les fibres végétales constituent en effet une alternative écologique intéressante à l’utilisation des fibres synthétiques, en particulier les fibres de verre qui sont les plus utilisées pour les pièces composites de grande diffusion. Le composite est développé au sein du laboratoire LMNM à l’IOMP, Sétif, Algérie. Deux orientations ([0]8 et [+45/-45]2S) sont considérées. La caractérisation mécanique est effectuée en traction et compression monotones ainsi qu’en fatigue cyclique. Les caractérisations mécaniques et microstructurales sont réalisées au sein du laboratoire MATEIS. L’étude de l’endommagement des composites est réalisée en combinant cinq techniques : l’évolution des paramètres mécaniques via des essais cyclés et de fatigue, la microscopie, l’émission acoustique (EA), la corrélation d’images et la micro-tomographie RX. L’étude de l’évolution des paramètres mécaniques accompagnée de l’analyse globale de l’EA fournit des premiers indicateurs quant au développement de l’endommagement lors des essais. Les analyses microstructurales permettent d’identifier finement les différents mécanismes d’endommagement qui surviennent lors des sollicitations mécaniques (décohésions fibre/matrice, fissurations matricielles et rupture de fibres). Pour la segmentation des signaux d’émission acoustique en traction et en compression monotones, une classification non-supervisée est utilisée en mettant l’accent sur le choix des descripteurs et sur la labellisation des classes obtenues. Des essais de traction instrumentés par corrélation d’images ainsi que des essais de traction in-situ sous tomographe permettent d’identifier la chronologie d’apparition de l’endommagement. Ces résultats permettent également de labelliser les classes obtenues. Les signaux labellisés servent ensuite à créer une bibliothèques pour identifier la chronologie d’évolution des modes d’endommagement en fatigue cyclique réalisée par classification supervisée. Enfin, toutes ces analyses ont permis d’établir des scénarios d’endommagement pour les différents modes d’endommagement et pour les deux orientations. Il est ainsi possible de reconsidérer l’élaboration pour optimiser les propriétés mécaniques.
Article
As a way to save petroleum resources, considerable efforts were made in the last three decades to develop green composites. Green composites are a category of composite materials in which at least one phase (reinforcement or matrix) is made from renewable resources. An attempt was made to present a simple fabrication process to produce hollow integrally woven sandwich composites. In addition, the potential of jute fibers to be utilized as piles in the core of an integrally woven sandwich composite was assessed and compared to the counterparts made using glass fibers. The crashworthiness performances of integrally woven sandwich composite samples considering the effect of relative density, pile material and the presence of polyurethane foam were investigated through performing quasi-static flat-wise compression tests. Based on the findings, the foam-filled integrally woven sandwich composites exhibited stable compression load-displacement response and better energy absorption properties over pure foam, which make them appropriate for automobile interior components. Moreover, a computational cost-efficient finite element modeling was presented and subsequently validated with experimental results.
Chapter
The use of traditional plastics poses a major threat to the environment due to their non-biodegradability, which is also responsible for increasing human health risks. The majority of the traditional plastics are produced from fossil fuel-based non-renewable resources. It is estimated that more than 350 million tons of plastics are produced every year globally for versatile applications. In contrast, the production of bioplastics is still in the infancy stage. Further, the reservoir of fossil fuel is also getting exhausted over time. Due to these two main problems associated with traditional plastic, it is quite mandatory to look for new materials, eventually solving both purposes. From a social and economic viewpoint, unless an alternative is discovered, it is difficult to permanently escape from using these plastics because of the way they have ingrained in our daily lives. However, the environmental degradation caused by the accumulation of non-biodegradable plastic materials on our earth has been well documented. Several measures have also been taken to mitigate this damage but switching to purely bioplastics could essentially be a wise approach for sustaining our environment. Bioplastics are sourced from renewable raw materials found in nature, but it does not necessarily mean that all bio-based plastics are biodegradable. Therefore, a more thorough investigation is urgently required to identify bio-resourced plastics, which are eventually biodegradable. Moreover, keeping in mind the misconception of bioplastics, in this book chapter, we clearly defined all the terminologies related to plastics and bioplastics. Further, we reviewed in detail the most important raw materials, namely, polylactic acid, polyglycolic acid, polylactic-co-glycolic acid, and polyhydroxyalkanoates for the production of bioplastics in terms of their syntheses, properties, and degradation mechanisms. In addition, a futuristic sustainable model was also discussed as a probable solution to have a safer and greener environment.
Chapter
Raising global attention towards environmental problems has gained a drastic emergence of environmentally friendly and sustainable green materials based on renewable resources and tends to be biodegradable and recyclable. Such green materials may be either cement-based or polymer-based. The cement-based ones require new addition of binders which includes the recycled and geo-polymer aggregators. The effective application of renewable/recycled resources assures the reduction in consumption of various minerals and also petrochemical products which certainly leads to depletion of natural resources, whereas, in polymer-based materials, the selected natural fibres like jute, hemp, kenaf, sisal and flax have been recommended to replace/substitute the synthetic fibres. Whereas bio-resins have grown up to a large extent and these are absolutely derived from vegetable oil, protein as well as starch to overcome the use of petroleum-based products. Hence, commercial products along with its sophisticated applications are emerging nowadays for such green composites. The tremendous development of green composites must be a competitive alternate for glass fibre reinforced composite material which is a broad focus of research in the present era.
Chapter
There is an increasing interest worldwide in the use of Pineapple Leaf Fibers (PALF) as reinforcements in polymer composites, since this type of natural fiber exhibit attractive features such as superior mechanical, physical and thermal properties, thus offer potential uses in a spectrum of applications. PALF contains high cellulose content (between 70-82%) and high crystallinity. However, being hydrophilic, it posed a compatibility issue particularly in a hydrophobic polymeric matrix system. Thus, their shortcoming need to be addressed to ensure good interfacial bonding at the fibers/matrix interphase before their full potential can be harnessed. This chapter summarized some of the important aspects relating to PALF and its reinforced composites, particularly the main characteristics of the fiber, extraction and pre-treatment process of the fibers. Following this, discussions on the available fabrication processes for both short and continuous long PALF reinforced composites are presented.
Chapter
Composite Material which are different from common heterogeneous materials come to the forefront of manufacturing a few decades ago because of their superior specific mechanical properties. The reduction of the non-renewable resources and increment in environmental pollution inspired investigators to emphasis on the improvement of environment friendly bio-based materials from renewable resources. The centrality of this investigate is related to critical judgment data to policy makers and prospective manufacturers within the commercialization stage of this modern bio composites as sustainable and green building materials. Studies specify that a vehicle weight reduction of 10% leads to reduction in fuel consumption up to 3%–7% for automotive industry. It was concluded that Poly Methyl Methacrylate (PMMA) bio composite may well be effectively reinforced by seashell Nano powder with superior properties at 12% seashell Nano powder substance taken after by 8% filled composite. This audit is planning to supply a brief outline of work that’s beneath way within the range of bio-composite inquire about and advancement, the logical hypothesis behind these materials, zones in which this investigate is being connected, and future work that is awaited.
Chapter
Green materials are an emerging solution for reducing waste and pollution. Various studies show that Green materials have reached every aspect of product design which covers the entire life cycle of a product from conceptual design to disposal causing a minimal adverse impact on the environment by the optimized use of resources. Green materials based products have the target to minimise the effects of human actions on the environment and ecosystem. Nevertheless, the production of biocompatible composites with the necessary hydrophobicity and hydrophilicity, adhesion, affinity and mechanical properties pose significant challenges. These issues have, to an extent, been addressed through nanotechnological interventions. Nanobiopolymers have shown immense potential in the biomedical, food and electronic industries and it may be justly expected that further research into advanced green nanocomposites may be the solution to waste management, pollution control and lower cost of production. This book chapter highlights the future aspects and prospects of green materials towards sustainable production and - recycling. To save the environment and reduce the product cost , green materialsare essential for sustainable development for the current global issues
Article
In this work, PHBV composites were prepared by melting extrusion using triethyl citrate (TEC) as a biodegradable plasticizer and sugarcane bagasse fibers (SBF) as reinforcement. The plasticizer TEC played a crucial role in the preparation of the formulations by extrusion, reducing the viscosity of the melt and minimizing the thermomechanical degradation of PHBV. Moreover, TEC was an efficient plasticizer for the composites, reducing the glass transition and melting temperatures of PHBV and making the specimens ductile. The increase in the concentration of TEC led to an enlargement of the interlamellar spacing and larger PHBV spherulites without changing the cell parameters. In contrast, the introduction of the SBF elevated the viscosity of the molten during extrusion, leading to thermomechanical degradation of PHBV. The SBF acted as a nucleation agent for the PHBV crystallization and oriented the growth of the PHBV crystals due to the transcrystallization, which contributed to the matrix‐filler adhesion, the increase in the lamellae thickness, and changes in the thermal properties of PHBV. The SBF acted as a reinforcing agent, increasing the tensile properties of the matrix. Therefore, TEC and SBF had antagonistic effects on the properties of the formulations, opening opportunities to tune their properties by varying the composition.
Article
Bagasse raw materials were filled with recycled polyvinyl chloride composites via compounding and compression molding. In this research, unmodified, soda treated, and oxidized bagasse fibers were combined in different concentrations (5%, 10%, 15%, and 20%) with pure PVC/recycled PVC (30:70 wt). The composites surfaces were examined as well as their mechanical properties, crystallization behavior, and biodegradation properties. It was found that uniformity in the distribution of the bagasse fibers in the microstructure of the polymer composites was a major factor affecting the mechanical properties. The oxidized bagasse fiber loaded composite matrix gives the best mechanical and biodegradation properties compared with the untreated and soda treated bagasse fibers. In addition to increasing modulus and tensile strength, fiber loading also reduced hardness. X‐ray diffraction investigation illustrated that introducing fiber to a p‐ PVC/r‐PVC matrix did not affect characteristic peak positions. Packaging applications can be further developed with these composite materials.
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In recent years, natural fibers incorporation in polymeric resin has received huge attention among the research community. The reasons of demand are multiple that includes its light weight, environmental friendly nature; non-toxic, low cost, easy availability, low processing cost and most importantly they possess characteristics which are comparable to conventional material. With this approach, present work comprises of fabrication of new category of natural fiber reinforced composites with polymer as base matrix. Sisal fiber is selected as reinforcing phase with epoxy matrix. Four different combination of composites are prepared with sisal fiber loading varies from 2.5 wt. % to 10 wt. % using well-known hand lay-up method. Sisal fibers were treated with NaOH at varied concentration to observe the effect of surface modification and its concentration on the developed material. Three different concentration of NaOH is used i.e. 2 mole, 4 mole and 6 mole for preparing three sets of composites. One set is prepared with raw sisal fiber to make total of four sets of composites. Mechanical properties under investigation are tensile behaviour, compressive behaviour and flexural behaviour. The experimental results obtained are compared for optimizing the concentration of NaOH. From the analysis it is seen that composite with surface modified sisal fiber yield better results and further fiber treated with 2 mole NaOH concentration is superior among their counterpart. The maximum tensile strength, compressive strength and flexural strength obtained are 31.5 MPa, 72.5 MPa and 37.8 MPa respectively. All these values are obtained for fiber treated with 2 mole NaOH aqueous solution.
Article
Any new product that we develop for the world should undergo a life cycle analysis (LCA) from birth to death. Environmental impact can be enhanced by lowering reliance on the resources derived from naphtha. The challenges accompanying the generation of plastic-derived waste can be substantially reduced by employing biodegradable polymers. Green composites have gained significance over traditional petroleum-based products because they are derived from natural resources, environment friendly, recyclable, non-toxic, and biodegradable. In addition, the fabricated composites should exhibit optimized weight and required mechanical properties to meet the performance requirements. Green composites comprise two phases: a bio-based polymer matrix integrated with natural fiber reinforcements like jute, hemp, sisal, flax, banana fiber (abaca), etc. Owing to the inherent benefits of natural fiber reinforcements such as low density (synthetic fibers like carbon and E-glass fibers exhibit density values ranging from 1.8 to 2.1 g/cm3 and 2.54 g/cm3, respectively as opposed to natural fibers spanning from 1.25 to 1.6 g/cm3) and higher acoustic damping in composites, they can be widely used in interior automotive applications. Potential applications in the automotive sector include interior structures such as door panel inserts, armrests, seatback lining, seat bottoms, and under-floor body panels. Green composites formulated from soy protein, polylactic acid (PLA), starch, cellulose, and chitin and along with their processing techniques and applications have been discussed here.
Chapter
In last few decades, the manufacturing and application of natural fiber reinforced polymeric composites have remarkable achievements to replace the non-bidegradable petroleum based materials. The demand for natural composites is drastically increasing, and became a notable material to use for extensive range of applications such as automotive, aviation, consumer products, and civil engineering, etc. Many investigations and studies have been reported to expand the mechanical and durability performance of biocomposites to compete with conventional composites. Comparatively enormous number of failure mechanisms occurs in fibre reinforced composite arises, and the fatigue life distributions of composites at various constant stress levels are determined using various models. In this chapter, the different methodologies adapted to determine the fatigue life of biocomposites were discussed. The fatigue behavior of biocomposites when subjected to different aging mechanisms under various service conditions and environments were reviewed. Further the chapter also detailed the long-term durability of biocomposites in different dynamic and static stresses under various environments namely corrosive stresses, mechanical stresses, electric stress, thermal stress and photo stress.
Chapter
Sustainability has become the prime focus nowadays for scientific strategies; hence researchers are keen on developing more sustainable materials displaying properties that may be comparable to conventional materials. Owing to their environmental-friendly nature, sustainability and good specific properties natural fibers have succeeded in attracting many researchers and industries to utilize them as reinforcements in the production of Polymer Matrix Composites (PMCs). However, PMCs reinforced with man-made fibers like carbon, glass, and aramid have exhibited better performance in comparison with PMCs strengthened with cellulosic fibers. One of the reasons for PMCs reinforced with natural fibers displaying lower mechanical properties is the inadequate interfacial adhesion between a hydrophobic matrix and hydrophilic natural fibers. Hence in order to achieve good interfacial bonding among fiber and matrix, a lot of research has been taking place in the direction of achieving hierarchical nature into the composites by incorporating nanomaterials in any of the constituents. In the view of maintaining sustainability, this book chapter emphasizes the detailed description of various natural fibers and green nano reinforcements. A detailed description of inducing hierarchical nature into the biocomposites via incorporating reinforcements at different scales such as Micro Crystalline Cellulose (MCC), Cellulose Nanocrystals (CNC), and Bacterial Cellulose (BC) and recent studies in this area has been reported in the latter part of this chapter.
Chapter
Due to the environmental and sustainability issues, the interest in biobased composite materials is rapidly growing, both in terms of their industrial applications and fundamental research. However, in addition to numerous advantages, natural composites have some serious drawbacks when compared to synthetic composites. Higher moisture absorption, inferior fire resistance, lower mechanical properties, and durability are some of them. The properties of biocomposites are influenced by a number of variables, including the fiber type, environmental conditions, processing methods, and the type of fiber modifications. Due to the positive economic and environmental outlook of biocomposites, there are numerous studies dedicated to the surface treatment of fibers and improvement of the fiber/matrix interface. This chapter focuses on the characteristic idea of biocomposites, discussing the role of their components, biomatrix and biofillers, as well as challenges impeding their advancement into wider applications.
Chapter
In these times of climate change and increasing emissions in the environment, lightweight structures have made their way into the majority of industries. Governments and authorities, mainly in the automotive industrial sector, formulate endlessly decreasing targets in emission reductions. Because gradually stringent emissions can be reduced through weight reduction, an ideal structural design completed with lightweight materials is a principal tendency in the current improvement of passenger cars. This chapter reviews the findings in the literature to date in this evolving field, specifically the classification of natural fibers, the matrix of green composites, and the mechanical properties and chemical compositions of the various types of green composites that have been proposed. It also presents details of the typical applications of green composites in the automotive area and highlights its challenges.
Chapter
Bio-composite materials, which are a serious alternative to synthetic-based fibre and matrix materials due to their high characteristics and biodegradability, cause difficulties and uncertainties for usage conditions due to their high sensitivity to climatic conditions. Scientific studies have shown that climatic factors such as temperature, humidity, radiation, UV rays, and acid rain that act synergistically in natural weathering conditions, cause degradation and changes in the bio-composite material's characteristics. Examining the material's behaviour under natural weathering conditions provides the most realistic and reliable results in terms of determining the shelf life of the material and knowing its behaviour in the usage environment. In this study, changes in thermal, mechanical, and aesthetic properties of bio-composite materials exposed to natural ventilation conditions were investigated. It has been observed that natural weathering induces dramatic decreases in thermal and mechanical properties of bio-composite materials, especially with the effect of prolonged exposure times, and causes changes in colour, surface deterioration and changes in shape.
Article
Natural fibers such as rice straw (RS) are widely available in abundance and these residues are predominantly burned off in open fields. The burning of these rice straws, by the virtue of incomplete combustion, emits detrimental pollutants (greenhouse gases) and particulate matters (inhalable particles), which contribute to global warming and air pollution. Moreover, PET (Polyethylene terephthalate) bottles which are used as soft drinks or water bottles, are said to be the biggest contributors to plastic waste. This study aims to investigate the tensile strength of rice straw reinforced recycled polyethylene terephthalate rPET (RS-rPET) composite material. In addition, the effect of fiber content, fiber size, and fiber modification on the tensile strength of RS-rPET composites were investigated. The modification of fiber was characterized by the FTIR spectroscopic. It was observed that the tensile strength of RS-rPET composite decreased with fiber content and fiber size. The urea treatment of fibers enhanced the tensile strength of the RS-rPET composite. However composite materials based on rice straw fiber treated with a higher concentration of urea showed a lower value of tensile strength.
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Nanofiber (NF) polymeric composites have received more interest nowadays. The majority of the study focuses on characterizing NF and comparing them to traditional composites in terms of mechanical behavior and usage efficiency. There are different varieties of NFs, each with unique possessions that influence whether or not they are used in particular industrial usage. Because of the natural source of these materials, they have an extensive variety of characteristics that are largely dependent on the gathering position and conditions, assembly it tough to choose the right fiber for precise usage. This study aims to map where every form of fiber was located in numerous assets by providing a detailed analysis of the characteristics of NF employed as composite-based materials reinforcement. Recent research on emerging forms of fibers was also discussed. A bibliometric analysis of NF composite applications is discussed. A future trend analysis of NF applications, as well as the essential innovations to extend their uses were also addressed. Introduction Even though organic resins are being used as a gluing material, the creation of fiber composites started when researchers discovered plastics. Synthesized plastics like vinyl, polythene, phenolic, and polyester are created in the early 1900s. Even so, due to lower strength, plastics were unable to meet such applications as load shifting parts of cars, aircraft, sporting goods, wind turbine blades, and other similar technologies; as a result, reinforcements were designed to enhance the qualities. The 1 st Fiber Reinforced Composite (FRC) were produced in 1935, but due to the need for composite materials throughout World War II, fiber composites underwent a substantial evolution. Following WWII, various resins and synthetic fibers were uncovered in the 1970s, fully changing the typical material use [1]. Because of their unique mechanical characteristics in different applications, synthetic fibers such as glass, coal, and aramid fibers were the utmost communal promising adsorbent in polymer-based composites [2]. Synthetic fibers are appealing because of their material properties, but they are non-biodegradable and cause further environmental concerns [3]. In the quest for synthetic fiber alternatives, bio reinforcing NFs (NF) was discovered to be an auspicious substitute for synthetic fibers in the preparations of Fiber-Reinforced Plastic (FRP) composites because of its accessibility, renewability, cost-effective, and strong unique features [4, 5]. NF is lower in cost, density, and weight, as well as being environmentally friendly and posing few health risks. NF is assumed to be worth using in the production of composites not just in terms of environmental and economic benefits, but also because these were recycled raw processes for novel green goods. NFs' biological, chemical, ecological, and economic characteristics can greatly enhance the ending features of fiber-based composite and its use in numerous application areas. NF degradation rate will strongly help the recyclability feature of fiber composites. NF degradability will sturdily sustenance the recyclability property of fiber-based composites, thus promoting the production of NF reinforced polymer (NFRP) [6]. NFRP has a lower density, resulting in lighter composites [7]. As a consequence, there is an increasing interest throughout the commercial usage of NFRP in diverse industries. NF was collected from leaves, roots, vegetables, and seeds, among other parts of the plants. The use of the Fiber reinforced composite (FRC) has improved gradually in recent times in several applications. These composite materials were now being utilized in new fields like medicinal devices and civil structures [8]. Fiber reinforcement comes in a variety of shapes and sizes of composites. From an environmental standpoint, NF composites were larger than glass-based fiber composites [9]. NF selection is the utmost critical method in the processing of NFRP composites in particular. NF selection is affected by a variety of factors. NF is selected based on its physical characteristics. The age of floral was a key feature in evaluating NF output [10]. The chemical-based composition of the fiber differs by origin; the most common additives were cellulose, hemicellulose, and lignin; however, another additives including ash, wax, and pectin were available [11]. One of the problems with NF is the lack of consistent information and mentioned distinctions in material characteristics. The lack of expertise for both creators and consumers of these materials in terms of how to collect, consider, method, and post-process natural materials further complicates the selection criteria. These
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Thermal insulation bio-composites made of plant origin by-products as bio-aggregates are one of the ways to decrease the impact of the building and construction sector on CO2 emissions. In this study, three bio-aggregates were analysed for their potential use in the production of bio-composites with potato starch binder. Technologically important properties, such as particle size, shape and compacted bulk density, as well as properties of the resulting bio-composites were identified. The main characteristics of the aggregates are relatively similar: density of 80–100 kg/m3, thermal conductivity of 0.042–0.045 W/m∙K, specific heat capacity of 1240–1330 J/g∙K, kinetic water absorption from 456–584%. This leads to similar basic properties of the produced bio-composites: density around 200 kg/m3, thermal conductivity 0.053–0.062 W/m∙K, specific heat capacity 1250–1450 J/kg∙K, with a difference in compressive strength ranging from 0.2 to 0.8 MPa. Created starch binder and agricultural by-product filler materials could be used in the production of boards where strength is required, for example, envelope and wind barrier boards, and thermal insulation boards under floors.
Chapter
In recent years, a significant body of research has been focused on the sustainability of resources and adverse human impacts on the ecosystem. Therefore much effort has been made to potentially reprocess industrial waste and to seek a replacement for petroleum-based products with biodegradable materials. Green biocomposites are broadly recognized as composite systems with superior performance, strength and versatility, whose complete degradability of its components and composability make them comparatively attractive. Green biocomposites are generally constructed by the incorporation of a biodegradable polymeric matrix reinforced by eco-friendly and renewable fibers. These biomaterials have made an overwhelming impression on the world’s economy and found applications in diverse markets including aerospace, automobile, biomedical, etc. These products provide a viable solution to the issue of sustainability and ecological concerns surrounding plastic waste which has become the primary topic of many environmental debates. In recent years, the ecological impacts of materials and technologies seem to serve as one of the factors affecting consumers’ purchasing decisions. Additionally, there is constant pressure from environmental authorities on companies to closely monitor and manage the environmental effects of their products. Thereby, it is not surprising to see the industries seeking green replacement of the nondegradable and synthetic components used in their products. Besides the environmental incentive, the performance of many potential components for the prospective green composite systems has also been explored, and green materials in place of matrix and reinforcement materials have been tested to be recognized as a substitute which champions both adequate strength and stiffness besides being financially viable so as to be promising materials for the biocomposite systems. In this chapter, an overview of composite’s structure, history and the ecological concerns surrounding the polymer-based composites are provided. Furthermore, the use of green alternatives including natural fibers as reinforcement and biopolymers as the matrix is discussed. Lastly, some of the applications of green biocomposites, particularly biomedical applications, are outlined.
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Material selection is the process of determining which material is best suited to meet the needs of a specific application. Mechanical characteristics, chemical properties, physical properties, electrical properties, and cost are all aspects that define the selection requirements. During the material selection process, these must be weighed. Materials selection is a process used by design engineers to choose the best materials for a specific component. To find the best composite materials, a materials selection system is used to find candidate materials from various composite materials that meet all of the material selection criteria, such as strength, stiffness, cost, and aesthetics. Similarly, a materials selection system will require candidate materials to contain several forms of NFC to identify the best appropriate NFC for a specific product. Materials selection for NFC goods is a relatively recent field of study. Because of the vast number of individual constituent materials in NFC, the work of selecting the best NFC for a specific product is regarded as challenging and time-intensive (Marques T, Esteves JL, Viana J, Loureiro N, Arteiro A. Design for sustainability with composite systems. In: 15th international conference on experimental mechanics (ICEM15); 2012:1–2 pp). Whereas conceptual design is a crucial activity in the design process in modern design, it is continually highlighted that improper conceptual design can lead to extensive rework and problems after the product is produced. According to (Pugh S. Total design: integrated methods for successful product engineering. Wokingham, England: Addison-Wesley Publishing; 1991), conceptual design activity is creating and assessing design solutions to meet the PDS. Because many design features are distinct in composites, and the tailor-made nature of composites has caused the design approach to be different, conceptual design with NFC is typically different from metals. Designing with NFC is similar to designing with a traditional composite product in terms of concept. This activity entails numerous processes, including creating a design brief, information collecting, market research, and product design specifications (PDS).
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PVA/Co/Ag film has been prepared by sputtering Co followed by Ag in polyvinyl alcohol (PVA) matrix film by IBS technique, so as to get a 9 nm (thick) layer of Co metal nanoparticles followed by a protective 4 nm (thick) layer of Ag nanoparticles. Grazing incidence x-ray diffraction (GIXRD) pattern of the film reveals the formation of nanocrystalline Co with hcp phase. GIXRD pattern also indicates that there is no change in the crystalline structure of PVA even after sputtering of the metallic nanoparticles. The average particle size of Co nanoparticles as evaluated using Scherrer formula is found to be about 2.64 nm. UV visible absorption pattern of the film sample showed SPR peaks of Co and Ag metals in their nano size level embedded in the PVA matrix system. XPS study confirms the metallic nature of Co and Ag nanoparticles; and the depth profiling study reveals that both the metal nanoparticles have been embedded in the PVA matrix system. Surface morphology of such film has been studied using AFM; and the magnetic behaviour of the film studied by using MOKE shows soft ferromagnetic behaviour in this PVA/Co/Ag system.
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The application of acoustic emission (AE) measurements to locate the sources of fracture of a single high-strength fibre embedded in an epoxy matrix which is loaded in tension is described. From the micromechanical model and the fragment length distribution, interfacial shear strength values were calculated. The technique is demonstrated for small-diameter glass and graphite fibres as well as for fibres which exhibit fibrillar fracture, such as Kevlar and PBZT. Good agreement is found between the mean fragment length values obtained by optical and AE measurements for glass and graphite fibres. Values obtained for interfacial shear strength by the AE technique are comparable with those obtained using other techniques.
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Biodegradable thermoplastic starch (TPS)/clay hybrids were prepared by melt intercalation. Three organically modified montmorillonite (MMT) with different ammonium cations and one modified Na+ MMT (Cloisite Na+) were used. Cloisite Na+ showed the best dispersion in the TPS matrix. It was observed that the TPS/Cloisite Na+ hybrid showed an intercalation of TPS in the silicate layer due to the matching of the surface polarity and interaction of the Cloisite Na+ and TPS, which gives higher tensile strength and better barrier properties to water vapor as compared to the other TPS/organoclay hybrids as well as the pristine TPS. It was found that the dynamic mechanical properties of the TPS/clay hybrids were also affected by the polar interactions.
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This chapter presents one of the effective techniques to improve the mechanical properties of biodegradable polylactic acid (PLA)-based bamboo fiber composites. Commercially available microfibrillated cellulose (MFC) obtained from wood pulp was applied as an enhancer to the composite. The bamboo fibers were extracted by the steam explosion method and they were also rubbed in water to remove xylem (soft-wall cells). The liquid-based MFC, PLA, and the bamboo fiber were mixed in water for several minutes and they were filtered under vacuum pressure. To fabricate the composite, the sheets obtained were then heat pressed after drying. The three-point bending strength and Mode I fracture toughness of the composite were significantly improved, even when 10% of the MFC was added to the PLA/BF composite in weight. If a low fraction of MFC was added to the bamboo fiber composite, the tangled MFC fibers prevented the growth of microcracks along the interface between the bamboo fiber and the matrix. It was found that due to the relative difference in scale between microfibrillated cellulose and bamboo, a hierarchy of reinforcement was created where the bamboo fiber bundles were the primary load-bearing reinforcement and the cellulose created an interphase in the matrix around the bamboo fiber that prevented sudden crack growth.
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The use of synthetic and natural bioabsorbable plastics has been severely limited due to their low stiffness and strength properties as well as their strong tendency to absorb moisture. This research focused on the development of bioabsorbable polyphosphate filler/soy protein plastic composites with enhanced stiffness, strength, and water resistance. Bioabsorbable polyphosphate fillers, biodegradable soy protein isolate, plasticizer, and adhesion promoter were homogenized and compression-molded. Physical, mechanical, and water absorption testing was performed on the molded specimens. Results showed improvements in stiffness, strength, and water resistance with increasing polyphosphate filler content up to 20% by weight. Application of a coupling agent produced further mechanical property enhancements and a dramatic improvement in water resistance, interpreted by an interfacial chemical bonding model. Examination of the fracture surfaces of the materials revealed that the addition of the polyphosphate fillers changed the failure mode from brittle to pseudo-ductile. These results suggest that these materials are suitable for many load-bearing applications in both humid and dry environments where current soy protein plastics are not usable.
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Wood fiber-based composites are historically, and today, cost-driven commodity materials. This is partially a result of the low cost of wood (two to five cents per pound) and the traditional way of using wood products. Certain wood fibers have been shown to have specific tensile strengths comparable to certain nonwood engineered materials. Combining the positive attributes of wood fibers, modern thermosetting resins, and other polymeric systems with concerted research efforts may provide ample opportunities for manufacturing wood fiber and wood fiber-nonwood fiber hybrid composites for performance-designed and -driven, and cost sensitive applications. This study examines specific static flexural properties and costs of aspen wood fiber composites and compares them with glass fiber reinforced polymer matrix composites. Also presented are the characteristics of polyisocyanate thermoset resins and their potential for bonding wood fibers with nonwood materials in manufacturing hybrid composites.
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After decades of high-tech developments of artificial fibres like carbon, aramid and glass it is remarkable that natural grown fibres have gained a renewed interest, especially as a glass fiber substitute in automotive industries. Fibres like flax, hemp or jute are cheap, have better stiffness per unit weight and have a lower impact on the environment. Although automotive takes the lead in the revival of natural fibres, applications are mainly restricted to upholstery applications where acoustic and thermal insulation, low cost and an environmental image are advantages. Structural applications are rare since existing production techniques are not applicable and availability of semi-finished materials with constant quality is still a problem. But on the research and prototyping level it has been shown meanwhile that in structural applications natural fibre composites have the potential to become a substitute for glass composites. Within the Dutch R&D program 'Biolicht', production techniques with appropriate semi-finished materials were developed in order to manufacture structural components with techniques like SMC and RTM. This article describes the results of that research program.
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The idea of industrial utilization of renewable raw materials has been propagated from all sides without truly knowing its performance potential. An overview of the preparation and treatment of fibres and of the mechanical properties of plastics reinforced with natural fibres as compared with those of glass fibre reinforced plastics should help making the discussion more objective.
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Plasma polymerization of ethylene and ammonia gas mixtures is used to obtain uniform polymer coatings on the surface of AS4 graphite fibers. The polymer deposition rates were determined for processing parameters such as composition of the monomer mix, monomer flow rate, chamber pressure, and power input of the radio frequency field. Plasma formed polymers were characterized using Fourier Transform Infrared (FTIR) and X-ray Photoelectron Spectroscopy (XPS). XPS spectra were collected at 75° and 30° takeoff angles to obtain elemental composition and functional group populations at different sampling depths. Plasma deposition rate was the smallest for 100% ethylene and increased by three to four fold when ammonia was added to the monomer mixture. The polymer coatings were of uniform thickness and exhibited a complex crosslinked structure. The 100% ethylene plasma polymer was strongly hydrocarbon in nature but had some oxygen and nitrogen containing groups. Plasma polymers from ethylene/ammonia mixture were much more polar and contained reactive and polar group constituents, including carbonyl, ether, primary and secondary amines, and hydroxyl groups. The presence of oxygen and nitrogen functionalities is presumed to arise primarily from the reaction of trapped radicals with oxygen and nitrogen when exposed to air. Small amounts of silicon were also detected in the plasma formed films.
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The morphology of flax, hemp, jute, ramie, and sisal, as well as the effects of alkaline treatments (2% NaOH scouring and 18% NaOH slack mercerization) were comparatively investigated by optical and electron microscopy (TEM, SEM). The obtained morphological parameters of single fibres (shape, diameter, cell thickness), and of the fibrillar substructures (width of cellulosic fibrils and bundless) of the secondary cell wall were tabulated for all investigated natural fibres. The cross-sections of hemp and flax show a concentric lamellation of fibril bundles around the lumen which is changed by the scouring and mercerization procedure. After mercerization the surface of the natural fibres shows besides the more distinct fibrillar bundles a coarse grooving and straighting structure, which should be advantageous for an improved fibre-matrix-adhesion.
Article
This chapter presents the measurement methods for fiber-matrix adhesion in composite materials. It is clear that each of these methods for measuring fiber-matrix adhesion in composite materials requires one to make some assumptions about the material properties in the interphase and also requires that the system studied conform to the boundary conditions established for the analysis of the results. None of these techniques offers a complete and unambiguous method for measuring the interfacial shear strength between fiber and matrix. However, each method has proven to be sensitive to slight changes in adhesion in a given fiber-matrix system. The chapter reviews the three most common direct methods for measuring fiber-matrix adhesion, focusing on the sample preparation and fabrication, the experimental protocols and the underlying theoretical analyses upon which evaluation of these methods are based. In addition, finite-element nonlinear analyses and photoelastic analyses are used to identify differences in the state of stress that is induced in each specimen model of the three different techniques. To provide an objective comparison among the three different techniques to measure the interfacial shear strength for the prospective user, data and a carbon fiber-epoxy resin system is used as a baseline system throughout the chapter. However, these methods and procedures can be applied for adhesion measurements to any fiber-matrix combination.
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The present study was motivated by the desire to replace plastics produced from petrochemicals by working materials made from renewable resources. Chlorine-containing polymers are especially at issue, due to waste management problems. The polar character of these materials, which is important both for the creation of a gas barrier in packaging applications and for high frequency electromagnetic weldability, can be matched by polar biopolymers such as polysaccharides and proteins.
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α,ω-Dihydroxy terminated polyester resins in the form of macroglycols of molecular weight, on the order of ∼2 × 10 3, were synthesized by polymerization of ε-caprolactone in the presence of different glycol initiating additives. The macroglycols were characterized by physico-chemical techniques. The hydroxyl groups of such macroglycols were present as terminals while ethereal (-CH 2CH 2O-) and non-ethereal (-CH 2CH 2-) linkages, connecting the polyester segments, occupied the central part of the macroglycol molecule. The WAXD pattern indicated the presence of crystal structure in the macroglycols. The presence of non-ethereal and ethereal group played important role to influence the melting point of macroglycols. The enthalpy of melting of the macroglycols was found to remain in the range of 36 J/g to 111 J/g.
Article
Cellulose diacetate (CDA) nanocomposite films were prepared by using various plasticizer and montmorillonite nanofiller in methylene chloride/ethanol (9:1 w/w) mixed solution. The thermal property (Tg) of prepared CDA films was observed by DSC and Tg of the films was decreased with the increase in the plasticizer content. The degree of dispersion of MMT in the CDA film was observed by XRD and mechanical property of CDA film was measured by tensile strength and Young's modulus. When the plasticizer was added into the CDA film upto 30 wt%, the Young's modulus of film was decreased from 1930 MPa to 1131 MPa but was increased from 1731 MPa to 2272 MPa when the MMT was added into the film upto 7 wt%. The mechanical properties of CDA films were decreased by addition of plasticizer but strengthened by the incorporation of MMT.
Article
In this paper we report chemical modifications such as alkali treatment, diazocoupling with aniline, crosslinking with formaldehyde, p-phenylene diamine and combined crosslinking cyanoethylation imparted onto an agrowaste, "pineapple leaf fiber" (PALF). The parent and chemically modified PALF have been characterized by FTIR spectroscopy. The per cent moisture regain, mechanical strength and behavior to common chemical reagents have also been tested. The modified fibers showed significant hydrophobicity, improved mechanical strength and good chemical resistance.
Article
Quenching and annealing of polyetheretherketone (PEEK) was performed to study the changes in its physical properties and its interfacial shear strength with AS4 graphite fibers. Physical and mechanical properties of the PEEK matrix were studied using Differential Scanning Calorimetry (DSC) and tensile tests. Plasma polymer deposition of ethylene and ammonia gas mixtures was carried out on the fiber surface to improve the graphite fiber/PEEK matrix adhesion. The adhesion of treated fibers to PEEK was studied using single fiber composite (SFC) tests. Graphite fiber strength were not affected by the plasma polymer deposition process. The SFC tests showed that the interfacial shear strength (IFSS) between graphite fibers treated with ammonia/ethylene gas mixture plasma and PEEK increased by about 84%. However, 100% ethylene plasma deposition, which was strongly hydrocarbon in nature, had no effect on the IFSS. It was found that annealing increases the maximum yield stress, but has no effect on the initial modulus of PEEK. The effect of heat treatment time on the interface strength was also studied. The interface strength increased by a factor of two after the heat treatment.
Article
A compatibilized composite made of polypropylene and kenaf fibers extracted from a commercial crop is described. The material has mechanical properties comparable with those of commercial PP composites.
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The melt rheological behaviour of acetylated sisal fibre reinforced natural rubber composites was studied using a capillary rheometer. The results illustrate the effects of fibre concentration and shear stress/shear rate on melt viscosity and melt elasticity of the composites. The fibre undergoes severe breakdown during extrusion, and as the shear rate increased the breakdown also increased. The melt showed pseudoplasticity which increased with fibre loading. Incorporation of acetylated sisal fibre into natural rubber results in an increase in its melt viscosity and a decrease in its melt elasticity.
Article
A rice starch based film, reinforced with starch nanocrystals (prepared by submitting native granules of rice starch to acid hydrolysis at 40 °C) was prepared by casting film-solution on leveled trays. The influence of the content of starch nanocrystals (5 to 30%) on the mechanical, thermal and structural properties of rice starch films was investigated. The rice starch films showed an increase in tensile strength but decreasing elongation at break and water barrier properties with the addition of rice starch nanocrystals. The addition of starch nanocrystals increased the crystalline peak structure of rice starch film. However, too high starch nanocrystals content resulted in a decreased crystallinity of the resulting film. The behavior of the thermal properties of rice starch films reinforced with starch nanocrystals was investigated by means of dynamic mechanical thermal analysis, differential scanning calorimeter and thermogravimetric analysis. No endothermic peaks were observed in the glass transition temperature (Tg) of the rice starch film. However, increasing endothermic heat flow was observed when addition and increasing of starch nanocrystals in rice starch films. This can restrict the mobility of the starch chain due to the establishment of strong interactions between rice starch and starch nanocrystals. In addition, a lower content of starch nanocrystals showed smoother than high starch nanocrystals in a rice starch film matrix.
Article
Cobalt-Polymer nanocomposites have been synthesized by depositing cobalt onto polyvinyl alcohol (PVA) film underlayer by ion beam sputtering (IBS) technique. The deposition of cobalt nanoparticles has been controlled to get cobalt-bearing nanocomposite parts with thickness of 5 nm, 10 nm and 40 nm to prepare samples, designated hereafter as PC5, PC10, and PC40, respectively. Further, a 2 nm carbon overcoat was deposited by IBS technique as a protective layer in each case. The Grazing Incidence X-ray Diffraction (GIXRD) patterns of the nanocomposite samples reveal the formation of hcp polycrystalline cobalt without disturbing the structure of PVA. The average particle size of the cobalt nanostructures as calculated by Scherer formula is found to be 3.9 nm, 4.62 nm, and 7.07 nm for PC5, PC10 and PC40, respectively. The metallic character of cobalt is confirmed by XPS. The morphology of the nanocomposite surface has been studied using Atomic Force Microscope (AFM). The Magneto Optical Kerr Effect (MOKE) study establishes soft ferromagnetic behavior of these nanocomposites; the Hc values recorded are 7.7 Oe for PC5, 65.3 Oe for PC10, and 102.6 Oe for PC40. The effect of cobalt deposition on the properties of Carbon-Cobalt-PVA nanocomposites has been discussed.
Article
A numerical analysis based on polynomial interpolation was done to fit the experimental results of the mechanical characterization of a composite made of polyester resin and short natural fiber (palma samandoca-zacate). The experimental tensile strength of the composite was compared to the one obtained from a theoretical model. A correction factor, attributed to the empty spaces (voids) formed between the resin and the fibers, was necessary for fitting the experimental data. The behavior of this factor as a function of the fiber volume fraction showed that a polynomial interpolation could be used to approximate this function and then predict any point over the appropriate range.
Article
The main focus of this work is to improve the adhesion of jute fiber with polylactide (PLA). For this purpose, surface of the jute fiber was modified by alkali, permanganate, peroxide and silane treatments. The surface modified fibers were characterized by FTIR spectroscopy. Unidirectional composites were prepared with treated jute fibers and PLA matrix by hot pressing of solvent impregnated prepregs. Surface treatments resulted in enhancement of tensile and flexural properties and reduction in Izod impact strength. Dynamic mechanical analysis (DMA) results showed that, treated composites have higher storage modulus and lower tangent delta with respect to untreated composite. The degree of interfacial adhesion between the jute fiber and PLA was estimated using adhesion parameter obtained through DMA data. The results of thermogravimetric analysis (TGA) showed a higher thermal stability for silane treated composites. Experimental results on abrasive wear tests revealed that the wear resistance of composite is sensitive to fiber/matrix adhesion.
Article
Kenaf (Hibiscus cannabinus) is a fast growing annual growth plant that is harvested for its bast fibers. These fibers have excellent specific properties and have potential to be outstanding reinforcing fillers in plastics. In these experiments, the fibers and polypropylene (PP) were blended in a thermokinetic mixer and then injection molded, with the fiber weight fractions varying to 60%. A maleated polypropylene was used to improve the interaction and adhesion between the nonpolar matrix and the polar lignocellulosic fibers. The specific tensile and flexural moduli of a 50% by weight (39% by volume) of kenaf-PP composite compare favorably with a 40% by weight of glass fiber-PP injection-molded composite. These results suggest that kenaf fibers are a viable alternative to inorganic/mineral-based reinforcing fibers as long as the right processing conditions are used and they are used in applications where the higher water absorption is not critical.
Article
Ramie fiber/soy protein concentrate (SPC) polymer (resin) interfacial shear strength (IFSS) was measured using the microbond technique. To characterize the effect of plasticization, SPC resin was mixed with glycerin. Fibers were also treated with ethylene plasma polymer to reduce fiber surface roughness and polar nature to control the IFSS. Fiber surfaces after ethylene plasma polymerization, and fracture surfaces of specimens before and after the microbond tests were characterized using a scanning electron microscope (SEM). Some specimens were also characterized using electron microprobe analyzer (EMPA) to map the residual resin on the fiber surface after the microbond test. Effects of glycerin concentration in SPC and ethylene plasma fiber surface treatment time on the IFSS were investigated. Preparation of SPC resin requires a large amount of water. As expected, during drying of SPC resin, the microdrops shrank significantly. The high IFSS values indicate strong interfacial interaction in the ramie fiber/SPC resin system. This strong interfacial interaction is a result of a highly polar nature of both the ramie fiber and the SPC resin and rough fiber surface. Ethylene plasma polymerization was used to control the IFSS. The plasma polymer imparted a polyethylene-like, non-polar polymer coating on the fiber surface. As a result, the fiber surface became smoother compared to the untreated fiber. Both fiber smoothness and non-polar nature of the coating reduced the ramie fiber/SPC resin IFSS. Plasticization of the SPC resin by glycerin also decreased the adhesion strength of the ramie fibers with the SPC resin. The load-displacement plots for IFSS tests obtained for different resin and fiber combinations indicate different interfacial failure modes.
Article
The henequen fiber/poly(hydroxybutyrate-co-hydroxyvalerate) resin (PHBV) interfacial shear strength was characterized by single-fiber fragmentation (SFF) (also called the single-fiber composite test) and microbond techniques. The surface microstructure and tensile properties of henequen fibers were characterized using a scanning electron microscope (SEM) and an Instron tensile testing machine. The moisture content of the fibers was measured using a Brabender rapid moisture/volatile tester. SEM photomicrographs of the longitudinal views of the henequen fibers showed their fibrillar structure and the transverse views showed their hollow/multicellular nature and noncircular cross-section. The henequen fiber/PHBV interfacial shear strength was 6.97 MPa, as measured using the SFF test, and 5.24 MPa, as measured using the microbond test. These results are surprisingly close in spite of the different stresses experienced during the SFF and microbond tests. SEM photomicrographs showed interfacial failure. The interfacial shear strength was attributed mainly to the mechanical interlocking resulting from the fiber surface roughness, since no hydrogenbonding possibility existed for PHBV.The fiber/resin mechanical interlocking, however, may also be limited because of the high viscosity of the resin, which limits its ability to penetrate into and around the cells.
Article
Quenching and annnealing of polyetheretherketone (PEEK) was performed to study the changes in its physical properties and its interfacial shear strength with AS4 graphite fibers. Physical and mechanical properties of the PEEK matrix were studied using Differential Scanning Calorimetry (DSC) and tensile tests. Plasma polymer deposition of ethylene and ammonia gas mixtures was carried out on the fiber surface to improve the graphite fiber/PEEK matrix adhesion. The adhesion of treated fibers to PEEK was studied using single fiber composite (SFC) tests. Graphite fiber strength were not affected by the plasma polymer deposition process. The SFC tests showed that the interfacial shear strength (IFSS) between graphite fibers treated with ammonia/ethylene gas mixture plasma and PEEK increased by about 84%. However, 100% ethylene plasma deposition, which was strongly hydrocarbon in nature, had no effect on the IFSS. It was found that annealing increases the maximum yield stress, but has no effect on the initial modulus of PEEK. The effect of heat treatment time on the interface strength was also studied. The interface strength increased by a factor of two after the heat treatment.
Article
Wood-polymer composites (WPC) of 13 different Malaysian tropical hardwoods and 10 vinyl monomers and mixtures of monomers were prepared by in situ polymerisation using gamma radiation or the catalyst-heat treatment.The polymer loading achievable was found to be dependent on the wood species and the nature of the impregnated monomer. Low loadings were observed for the heavy hardwoods and for vinylidene chloride monomer. WPC showed improvement in termite and fungal resistance, dimensional stability and mechanical properties such as hardness, compression and static bending strengths. Thermal conductivities of WPC were found to be lower than the respective wood. From crib tests and oxygen indices, vinylidene chloride, bis(2-chloroethyl) vinyl phosphanate and bis (chloropropyl)-2-propene phosphonate were found to impart flame retarding properties to the WPC prepared. The dielectric constants of most of the WPC were marginally lower than that for the untreated wood.
Article
Jute fibers were investigated to verify their possible application in reinforcement of thermoplastics. A laboratory press was modified and laminates were produced using polymer films of LDPE, HDPE, PE copolymer, and PP as interlayers. Variations of the processing parameters were carried out in order to find optimal adjustment. High molding temperature leads to a decrease of mechanical properties and water absorption ability of the composites. The effect of water treatment on mechanical properties was also studied.
Article
Three different cellulosic fibers-a mechanical pulp, wood flour, and cellulose pulp-were used as filler in high-density polyethylene (HDPE). the addition of wood fiber in HDPE increased the stiffness of the composites while the tensile strength decreased. to improve the adhesion between the filler and the polymer matrix, wood fibers were pretreated with a silane coupling agent/polyisocyanate before compounding with the polymer. Tensile strength increased from 18.5 MPa (untreated fiber) to 35.2 MPa in isocyanate-treated fiber composites. Analysis of the filler cost/performance showed the advantage of wood fiber over glass fiber and mica.
Article
An epoxy-silicate nanocomposite has been prepared by dispersing an organically modified mica-type silicate in an epoxy resin (diglycidyl ether of bisphenol-A, DGEBA) and curing in the presence of nadic methyl anhydride (NMA), benzyldimethylamine (BDMA), or boron trifluoride monoethylamine (BTFA) at 100-200 degrees C. Molecular dispersion of the layered silicate within the cross-linked epoxy matrix was verified using X-ray diffraction and transmission electron microscopy, revealing layer spacings of 100 Angstrom or more and good wetting of the silicate surface by the epoxy matrix. The curing reaction appears to involve the hydroxyethyl groups of the alkylammonium ions located in the galleries of the organically modified silicate, which participate in the cross-linking reaction and result in direct attachment of the polymer network to the molecularly dispersed silicate layers. The nanocomposite exhibits a broadened T-g at slightly higher temperature than the unmodified Furthermore, the dynamic storage modulus of the nanocomposite containing 4 vol % silicate was approximately 58% higher in the glassy region and 450% higher in the rubbery plateau region compared to the unmodified epoxy.
Article
The effects of stearic acid on the physical, tensile, moisture, thermal and micro-structural properties of the soy protein isolate (SPI)-based resin have been investigated. Fully biodegradable, environment-friendly, unidirectional, ramie fiber reinforced ‘green’ composites were also successfully fabricated using SPI and stearic acid modified SPI (MSPI) resins and characterized for their tensile and flexural properties. The fiber/resin interfacial shear strength was characterized using microbond technique. The mechanical and thermal properties and moisture resistance of the MSPI resin were significantly better than the SPI resin. It was observed that part of the stearic acid crystallized in SPI resin and that the crystallizability was affected by the glycerol added as a plasticizer. The replacement of glycerol with stearic acid did not affect the fiber/resin interfacial interaction. The ramie/MSPI composites showed significantly better mechanical properties compared to ramie/SPI composites. While the Young’s modulus of ramie/MSPI composites was closer to the theoretically calculated values, both composites had lower values than predicted. The ramie fiber/MSPI resin composites may be used as ‘green’ composites for certain indoor applications.
Article
This paper presents the mechanical and thermal properties of unidirectional, degradable, environment-friendly “green” composites made from pineapple fibers and poly(hydroxybutyrate-co-valerate) (PHBV) resin. Tensile and flexural properties of the “green” composites with different fiber contents were measured in both longitudinal and transverse directions. Compared to those of virgin resin, the tensile and flexural strengths of “green” composites are significantly higher in the longitudinal direction while they are lower in the transverse direction. However, the mechanical properties are lower than those predicted by simple models. Scanning electron microscope (SEM) photomicrographs of the tensile fracture surfaces demonstrate fibers being pulled out from the matrix, the interfacial failure, fiber fibrillation, and the nonunidirectional nature of the “green” composites. The thermal behavior of the “green” composites, studied by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA), showed that the presence of pineapple fibers does not affect the nonisothermal crystallization kinetics, crystallinity, and thermal decomposition of PHBV resin.
Article
Fully biodegradable, environment-friendly 'green' composites were fabricated using glutaraldehyde (GA) modified (MSPC-1) and GA and poly(vinyl alcohol) modified (MSPC-2) soy protein concentrate (SPC) resins. The SPC modifications resulted in better thermal and mechanical properties and lower moisture absorption due to the additional cross-linking provided by GA. Flax fabrics were used to reinforce MSPC-1 resin to produce composite sheets. Flax yarns were used to fabricate unidirectional composites using MSPC-2 resin. The fabric reinforced composites showed strength values of 50 - 55 MPa and Young's modulus values around 1 GPa. The yarn reinforced composites showed strength of over 125 MPa and modulus values of about 2.25 GPa in the longitudinal direction. These results indicate that green composites may be made with useful mechanical properties. The flax yarn reinforced composites may be used in secondary structural applications in automotive, housing and packaging whereas fabric reinforced composites may be used in packaging and indoor panels.
Article
Current study presents one of effective techniques to improve mechanical properties of PLA (Poly-Lactic Acid)-based bamboo fiber composite. Commercially available Micro-Fibrillated Cellulose (MFC) obtained from wood pulp was applied as an enhancer to the composite. The bamboo fibers were extracted by steam explosion method and they were also rubbed in water to remove xylem (soft-wall cells). The liquid-based MFC, PLA and the bamboo fiber were mixed in water for several minutes and they were filtrated under vacuum pressure. To fabricate the composite, remained sheets were then hot pressed after dry. Three-point bending strength and Mode I fracture toughness of the composite were significantly improved, even when 10% of the MFC was added into the PLA/BF composite in weight. If small amount of MFC added into the bamboo fiber composite, tangled MFC fibers prevented the growth of micro crack along the interface between bamboo fiber and matrix.
Article
Biodegradable thermoplastic starch (TPS)/clay hybrids were prepared by melt intercalation. Three organically modified montmorillonite (MMT) with different ammonium cations and one unmodified Na+ MMT (Cloisite Na+) were used. Cloisite Na+ showed the best dispersion in the TPS matrix. It was observed that the TPS/Cloisite Na+ hybrid showed an intercalation of TPS in the silicate layer due to the matching of the surface polarity and interactions of the Cloisite Na+ and the TPS, which gives higher tensile strength and better barrier properties to water vapor as compared to the other TPS/organoclay hybrids as well as the pristine TPS. It was found that the dynamic mechanical properties of the TPS/clay hybrids were also affected by the polar interactions.