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Natural fiber henequen/unsaturated polyester (UPE) composites were fabricated by means of a compression molding technique
using chopped henequen fibers treated at various electron beam (EB) dosages. The interfacial shear strength (IFSS), dynamic
mechanical properties, and thermal expansion behavior were investigated through a single fiber microbond...
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Citations
... Chloro-silanes generate mainly hydrogen chloride as a byproduct during coupling reactions,hence, are generally less utilized. Pang et al., (2005) argued that the good mechanical, chemical, and weather resistant properties of unsaturated polyester resins (UPE) when reinforced with fibers, makes them most widely used thermosetting matrix in NFRPs. However, poor interfacial bonding between the polymer and natural fillers has remained an increasing area of research interest among researchers. ...
This research work investigated the effect of alkoxy silane (ethoxy silane) on the mechanical properties of polyethylene/ dried powdered pine apple peels composite. The pine apple peels was washed in distilled water, sun dried for about eight hours and later oven dried at a temperature of 60oC for about three hours. The dried pine apple peels was pulverized and sieved using a mechanical sieve arranged in descending order of fineness. The alkoxy-silane (ethoxy-silane) coupling agent (2%) was first hydrolyzed in ethanol to deliver the alkoxy functional silane to the interior of the pineapple peels and ion-free water at room temperature for 6 hours. This was followed by addition of the dried powdered pineapple peels into the hydrolyzed coupling agent solution in a reactor at a temperature of about 80 ◦C for 20 minutes. The formed product was oven dried at 110 ◦C for 3 hours and pulverized using a locally made grinding machine and sieved using a set of sieves arranged in descending order of fineness in accordance with BS1377:1990 standard as was reported by Rajan et al., (2007) to obtain pineapple peels coated with the coupling agent (150mμ). The recycled polyethylene waste was washed using distilled water, sun-dried and shredded in a shredding machine. The pineapple peels powder coated with alkoxy silane and the shredded recycled polyethylene waste were blended using a two-roll rheo-mixer at 50°C and a rotor speed of 60 rpm. The percentage of the powdered pineapple peels coated with coupling agent in the recycled polyethylene matrix was varied from 10% to 40% to produce four different compositions. A hydraulic pressing machine was used to compress the produced composites for about ten minutes applying a pressure of about 25 tons at 130°C. The produced composite samples were allowed to cool to room temperature under sustained pressure before being removed from the hydraulic press for various mechanical tests. The impact tests were performed according to ASTM D256 standard using Impact testing machine model EXT94064/6705CE, 300 J. Flexural test was performed using Universal Testing Machine model TUE-C-100, according to ASTM D790. The hardness tests were performed according to ASTM D785 standard using Rockwell Scale K hardness testing machine. The results showed that maximum flexural strength of 10.8MPa and 384Hv were recorded at 40wt.% reinforcement. The developed composite can be used applications where moderate strength will be required.
... Figure 19. The structure of orthophthalic UPR [83]. ...
Thermosetting resins are used in many applications due to their great mechanical properties, chemical resistance, and dimensional stability. However, the flammability of thermosets needs to be improved to minimize fire risk and meet fire safety regulations. Some commercially available flame retardants have an adverse effect on people’s health and the environment. Thus, the development of novel, more sustainable flame retardants obtained or derived from biomass has become an objective of contemporary research. The objective of this study is to summarize recent progress on bio-based flame retardants for thermosetting resins so as to promote their prompt development. Groups of biomass compounds with a potential for flame retardant industrial applications were introduced, and their thermal degradation was investigated. The authors focused mostly on the thermal degradation of composites containing bio-based flame retardants determined by thermogravimetric analysis, their tendency to sustain a flame determined by a limiting oxygen index, and fire behavior determined by a cone calorimeter test. The results showed that the mode of action is mostly based on the forming of the char layer. However, in many cases, there is still a necessity to input a high amount of additive to achieve significant flame retardancy effects, which may adversely impact mechanical properties.
... Henequen fiber has been extensively utilized to make twines, ropes, carpets, and cordages for a long period of time. In addition, it has often been used as reinforcement for making NFRP with thermoplastic or thermosetting polymers, due to its high specific stiffness and strength [5][6][7]. Henequen is composed of approximately 77% cellulose, 4-8% hemicellulose, 13% lignin, 2-6% pectin, and waxes [8,9]. it has often been used as reinforcement for making NFRP with thermoplastic or thermosetting polymers, due to its high specific stiffness and strength [5][6][7]. ...
... Henequen is composed of approximately 77% cellulose, 4-8% hemicellulose, 13% lignin, 2-6% pectin, and waxes [8,9]. it has often been used as reinforcement for making NFRP with thermoplastic or thermosetting polymers, due to its high specific stiffness and strength [5][6][7]. Henequen is composed of approximately 77% cellulose, 4-8% hemicellulose, 13% lignin, 2-6% pectin, and waxes [8,9]. The chemical compositions may be varied to a greater or lesser extent, depending on the henequen plant. ...
In the present study, novel natural fiber composites, consisting of untreated and alkali(NaOH)-treated chopped henequen fibers and polyamide 6 (PA6), were produced by the hopper feeding and side feeding of henequen fiber, upon the extrusion process, and then by an injection molding process, respectively. The effects of the alkali treatment and fiber feeding route on the heat deflection temperature, tensile, flexural, and Izod impact properties of henequen fiber/PA6 composites were investigated. The composite properties were increased by alkali treatment and further increased, considerably, by side feeding of the henequen fiber, being supported by inspecting the fiber length distribution and the fracture surface of resulting composites. It was clarified that the side feeding of chopped henequen fibers was preferable to increase the composite properties, compared to hopper feeding. This study may be worthy of processing and manipulating the properties of novel natural fiber composites, consisting of agave plant-derived henequen fiber and engineering plastic PA6.
... Electrical discharge methods are more efficient in modifying non-active polymer surfaces such as polypropylene (PP), polystyrene (PS), and polyethylene (PE). Corona method is an electrical discharge method applied to surface energy of natural fiber at atmospheric pressure using electric current that changes the surface energy of the natural fiber (Pang et al., 2005). Corona treatment can modify the fiber structure and Ahlbad and Kron, 1994) the mechanical properties of the resulting composites. ...
... Electrical discharge methods are more efficient in modifying non-active polymer surfaces such as polypropylene (PP), polystyrene (PS), and polyethylene (PE). Corona method is an electrical discharge method applied to surface energy of natural fiber at atmospheric pressure using electric current that changes the surface energy of the natural fiber (Pang et al., 2005). Corona treatment can modify the fiber structure and Ahlbad and Kron, 1994) the mechanical properties of the resulting composites. ...
Nowadays, sustainable and eco-friendly products are gaining more attention in various engineering industries owing to their considerable strength-to-weight ratio, abundant availability, and recyclability. The properties of biofibers depend on the cultivation method, environmental conditions, and extraction method. Biofibers are hauled out by dew retting, water retting, and mechanical decortication methods. The properties of natural fiber–reinforced composites can be enhanced by proper physical and chemical treatments. The aim of this study is to propose a complete evaluation of the different extraction methods applied on natural fibers. Various physical and chemical treatment methods were used to ascertain the properties of optimized natural fiber-reinforced composites for various industrial applications. The key findings derived from various existing data and the chemical treatment results of the biofiber-reinforced composite are specifically highlighted with critical assessment. The properties and use of natural fiber-reinforced composites in the various fields of applications have made them candidates of choice over synthetic petroleum–based fibers.
... In contrast, for the 90:10/40MCC-10kGy sample, the absorption peak of the carbonyl group was pronounced. Therefore, it is likely, a higher i-rPP content had formed harder domains in the rPP through the formation of greater crosslinking, thereby increasing the [20][21]. ...
The unconventional electron beam (EB) irradiation route in preparing microcrystalline cellulose (MCC) fiber reinforced recycled polypropylene (rPP) composites was studied. In this route, the rPP was first subjected to EB irradiation at various doses (10-50kGy) and was then used as a compatibilizer. Unirradiated and irradiated rPPs were blended at two different ratios (90:10; 50:50) and added with MCC at contents of 5, 20 and 40wt%. Dynamic mechanical analysis (DMA) and water absorption tests were carried out. The DMA spectra exhibited high stiffness and damping behaviour. As the content of MCC increased, the water resistance of composites dropped slightly as compared to the controlled rPP. However, some compositions (50:50/40MCC-10kGy and 50:50/5MCC-50kGy) had shown opposite results. The improvement in the studied properties proved the existence of the compatibility effect that occurred at low irradiation doses, and also depended on the ratio (unirradiated and irradiated rPP) and MCC contents.
ABSTRAK: Kaedah sinaran gelombang elektron secara bukan konvensional dalam penyediaan komposit polipropilena kitar semula (rPP) bersama serat selulosa mikrohablur (MCC) telah dikaji. Dalam kaedah ini, rPP telah didedahkan kepada sinaran gelombang elektron dengan dos yang berbeza (10-50kGy) dan kemudiannya digunakan sebagai penserasi. rPP tidak tersinar dan tersinar telah dicampur dengan nisbah (90:10; 50:50) dan ditambah dengan MCC pada kandungan 5, 20 and 40wt%. Analisis dinamik mekanikal (DMA) dan ujian penyerapan air telah dijalankan. Spektrum DMA menunjukkan sifat kekakuan dan pengenduran yang tinggi. Apabila kandungan MCC bertambah, kerintangan komposit terhadap air berkurang sedikit berbanding rPP terkawal. Bagaimanapun sebahagian komposisi (50:50/40MCC-10kGy and 50:50/5MCC-50kGy) telah menunjukkan keputusan sebaliknya. Penambahbaikan sifat bahan dalam kajian ini membuktikan kewujudan kesan keserasian yang berlaku pada dos sinaran rendah, dan juga bergantung kepada nisbah (rPP tidak tersinar dan tersinar) dan kandungan MCC.
... Oxygen plasma improves fiber/matrix adhesion and interlocking due to an increase in roughness and by the fact that plasma treatment removes cellulose and hemicellulose, leaving lignin behind on the fiber surface which contributes in increasing fiber/matrix adhesion [93]. Electron-beam irradiation is an eco-friendly, clean and energy saving process to improve the surface properties of fibers, composite, films, and polymers [94]. Ji et al. [95] studied the effects of electron-beam irradiation on the mechanical and physical properties of jute fibers; 0-100 kGy (kiloGray) of electron-beam doses were used. ...
The popularity of jute-based bio and hybrid composites is mainly due to an increase in environmental concerns and pollution. Jute fibers have low cost, high abundance, and reasonable mechanical properties. Research in all-natural fibers and composites have increased exponentially due to the environment concerns of the hazards of synthetic fibers-based composites. Jute based bio and hybrid composites have been extensively used in number of applications. Hybrid jute-based composites have enhanced mechanical and physical properties, reasonably better than jute fiber composites. A detailed analysis of jute-based bio and hybrid composites was carried out in this review. The primary aim of this review paper is to provide a critical analysis and to discuss all recent developments in jute-based composites. The content covers different aspects of jute-based composites, including their mechanical and physical properties, structure, morphology, chemical composition, fiber modification techniques, surface treatments, jute based hybrid composites, limitations, and applications. Jute-based composites are currently being used in a vast number of applications such as in textiles, construction, cosmetics, medical, packaging, automobile, and furniture industries.
... It was reported that EB irradiation of natural fibres can lead to dehydrogenation, destruction of anhydroglucose and crosslinking of cellulose depending on the applied doses (Han et al., 2006(Han et al., , 2007. This treatment can result in enhanced interfacial adhesion of natural fibres and polymer matrix as compared with untreated fibres (Choi et al., 2009;Pang et al., 2005). The advantages of EB irradiation are no use of chemicals and it offers a dry process at room temperature. ...
Polylactide (PLA) composites containing flax fibre strands (20 wt%) and various content of triallyl isocyanurate (TAIC) as crosslinking agent were prepared by extrusion and injection moulding processes. The composites were modified by electron beam (EB) irradiation at dose values of 0, 10, 20, 30 and 40 kGy. The effects of EB and TAIC on the mechanical and structural properties of the composites were studied using tensile and impact tests, dynamic mechanical analysis (DMA), gel fraction measurement, differential scanning calorimetriy (DSC) and thermogravimetry (TG). However, the main attention was paid to biodegradation effects. Composites were biodegraded by means of enzymatic treatment and industrial composting. The composites were examined using mass loss analysis, DSC and photoelectron spectroscopy (XPS) in order to determine structural changes induced by biodegradation. Application of TAIC and EB at dose of 40 kGy led to the increase of tensile strength of about 20%. Besides crosslinking branching of PLA macromolecules was of significant importance. EB irradiation intensified enzymatic and composting degradation, however, when TAIC was applied, the composite was much more resistant to these processes.
... The adhesion between the fibers and matrix was largely enhanced by the PETI-5 interphase. For evaluating the fiber-matrix adhesion of fiberreinforced plastics, interfacial shear strength and/or interlaminar shear strength (ILSS) tests can often provide very useful information [60][61][62]. Short-beam shear test results have indicated that when PETI-5 was sized at 150°C, the ILSS of a 2-directional carbon/BMI composite was markedly improved, by about 35% and 66%, respectively, in comparison to an unsized counterpart, as seen in Fig. 8. The adhesion enhancement strongly depends not only on the presence and absence of the PETI-5 sizing interphase, but also on sizing temperature, because both factors critically influence the physical and chemical state of the sizing Fig. 8. ...
In efforts to characterize and understand the properties and processing of phenylethynyl-terminated imide (LaRC PETI-5, simply referred to as PETI-5) oligomers and polymers as a high-temperature sizing material for carbon fiber-reinforced polymer matrix composites, PETI-5 imidization and thermal curing behaviors have been extensively investigated based on the phenylethynyl end-group reaction. These studies are reviewed here. In addition, the use of PETI-5 to enhance interfacial adhesion between carbon fibers and a bismaleimide (BMI) matrix, as well as the dynamic mechanical properties of carbon/BMI composites, are discussed. Reports on the thermal expansion behavior of intercalated graphite flake, and the effects of exfoliated graphite nanoplatelets (xGnP) on the properties of PETI-5 matrix composites are also reviewed. The dynamic mechanical and thermal properties and the electrical resistivity of xGnP/PETI-5 composites are characterized. The effect of liquid rubber amine-terminated poly(butadiene-co-acrylonitrile) (ATBN)-coated xGnP particles incorporated into epoxy resin on the toughness of xGnP/epoxy composites is examined in terms of its impact on Izod strength. This paper provides an extensive overview from fundamental studies on PETI-5 and xGnP, as well as applied studies on relevant composite materials.
... As mentioned earlier, mechanical properties of fiber reinforced polymer composites are controlled by stress transfer efficiency at interfaces, among other factors. 15,24,73,74 Major drawbacks of natural fibers in composites include their poor compatibility with polymeric matrix and a relatively high potential for moisture sorption. The surface OH groups attract free water, which worsens the ability of the fiber to develop adhesive binding with polymer. ...
... In addition, the waxy substances in plant fibers can also influence their wettability and matrixfiber adhesion characteristics. 15,24,73,74 Other factors including surface area, physical surface structure, and porosity of the fibers should also be taken into account as factors that control interfacial adhesion and ultimately affect the performance of composites. ...
Natural cellulose-based fibers offer low cost, low density composite reinforcement with good strength and stiffness. Because of their annual renewability and biodegradability, natural fibers have materialized as environmentally-friendly alternatives to synthetic fibers in the last two decades. They are replacing synthetic materials in some traditional composites in industrial manufacturing sectors such as automotive, construction, furniture, and other consumer goods. In this work, the use of lignocellulosic fibers in green materials engineering, particularly their application as polymeric composite reinforcement and surface treatment via ionizing radiation, are reviewed. Because these cellulose-based materials are intrinsically hydrophilic, they require surface modification to improve their affinity for hydrophobic polymeric matrices, which enhances the strength, durability, and service lifetime of the resulting lignocellulosic fiber-polymer composites. In spite of a long history of using chemical methods in the modification of material surfaces, including the surface of lignocellulosic fibers, recent research leans instead towards application of ionizing radiation. Ionizing radiation methods are considered superior to chemical methods, as they are viewed as clean, energy saving, and environmentally friendly. Recent applications of controlled ionizing radiation doses in the formulation of natural fiber – reinforced polymeric composites resulted in products with enhanced fiber-polymer interfacial bonding without affecting the inner structure of lignocellulosic fibers. These applications are critically reviewed in this contribution.
