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Characterization of alkali treated and untreated Abutilon indicum FIBERS
... It is deemed that the low thickness of the fiber is owing to the structure of the inkberry plant fiber. Because the fiber contains a large amount of cellulose, its high density can be explained [71]. Inkberry fiber density is determined as higher than some original cellulosic fibers, such as Abutilon indicum (1170 kg/m 3 ) [71], Streblus asper (1388 kg/m 3 ) [72], Spinifex littoreus (780 kg/m 3 ) [73], and Himalayacalamus falconeri culms (1300 kg/m 3 ) [74] and lower than Hibiscus canescens (1425 kg/m 3 ) [75]. ...
... Because the fiber contains a large amount of cellulose, its high density can be explained [71]. Inkberry fiber density is determined as higher than some original cellulosic fibers, such as Abutilon indicum (1170 kg/m 3 ) [71], Streblus asper (1388 kg/m 3 ) [72], Spinifex littoreus (780 kg/m 3 ) [73], and Himalayacalamus falconeri culms (1300 kg/m 3 ) [74] and lower than Hibiscus canescens (1425 kg/m 3 ) [75]. ...
In this study, a novel cellulosic plant-based fiber was extracted from Phytolacca americana (inkberry) as a sustainable substitute natural fiber for synthetic fibers. For this purpose, an extended characterization of inkberry fibers was carried out. The elemental composition was determined as 58.27% carbon and 41.70% oxygen. Moreover, an image processing approach was presented and used for computing the average thickness of cellulosic inkberry stem fiber. Fiber diameter was estimated from the scanning electron microscope micrographs with image processing as 480.56 µm. The scanning electron microscope image indicated that inkberry fiber has a smooth surface with a channel structure. X-ray diffraction analysis revealed that the fiber has a 4 nm crystalline size with a 51.4% crystalline index. Fiber functional groups were characterized with Fourier transform infrared analysis. The mechanical behaviors of inkberry fiber were tested with a single fiber tensile test device, and tensile strength was determined as 146.5 MPa, Young’s modulus was found as 24.8 GPa, and elongation at break of fiber was obtained as 2.37%, respectively. Furthermore, the fiber was thermally stabilized up to 435.37 °C with thermogravimetric analysis. These physico-chemical behaviors confirm that inkberry fiber may be recognized as a promising reinforcement fiber in polymer matrix composites for many non-structural applications, which are interior body panels in yachts, automobiles, partition boards in buildings, and barriers.
Graphical Abstract
... Natural fiber composites exhibit several limitations, including high moisture absorption [15], poor thermal stability [16], and reduced durability, which hinder their broader industrial applications. Surface modification, especially with silane treatment, offers a solution by improving fiber-matrix bonding through the formation of chemical bridges [17]. ...
A novel stereolithography-based three-dimensional (3D) printing technique incorporating hydroxyapatite (HA) nanoparticles into dental photopolymer resin was introduced in this study. The design aimed to address the inadequate mechanical strength of conventional dental photopolymer resins by leveraging the reinforcing properties of HA. The HA concentrations of 0, 1, 3, and 5 wt.% were mixed with the resin to produce four distinct resin-HA (RHA) composites. The composites were evaluated for tensile strength, impact strength, and hardness, wear rate (K), and coefficient of friction (µ). Morphological analysis using scanning electron microscopy (SEM) provided insights into HA distribution and the resulting microstructural changes. The design approach incorporated HA nanoparticles to enhance molecular stiffness and promote a mechanical interlocking effect within the resin matrix. These mechanisms led to significant improvements in the composite's mechanical and tribological properties. The 5 wt.% RHA composite demonstrated the highest tensile strength (66.11 MPa), impact strength (35.2 kJ/m²), and Shore D hardness (79.32). Tribological tests revealed that this composite also exhibited the lowest wear rate and coefficient of friction, correlating with its superior mechanical performance. SEM analysis revealed finer debris and smoother wear tracks in HA-reinforced samples compared to HA-free samples, highlighting the role of HA in improving wear resistance. This study underscores the potential of integrating HA nanoparticles to enhance the performance of 3D-printed dental resins, providing a pathway for developing advanced materials tailored for dental and biomedical applications.
... Natural fiber composites exhibit several limitations, including high moisture absorption [15], poor thermal stability [16], and reduced durability, which hinder their broader industrial applications. Surface modification, especially with silane treatment, offers a solution by improving fiber-matrix bonding through the formation of chemical bridges [17]. ...
This study explores the feasibility of using Adina cordifolia fibers (ACFs) as reinforcements in thermoset polymer composites. ACFs are primarily composed of cellulose (58.36 ± 6.56%), hemicellulose (10.61 ± 3.38%), and lignin (14.55 ± 3.55%), which exert a unique effect on the properties of the fiber. The presence of cellulose I and II in the ACF was detected through X-ray diffraction analysis, revealing that cellulose II had a crystallinity index (CI) of 32.06% and a crystallite size (CS) of 2.23 nm. ACFs can be used in thermosetting polymer composites as their thermal stability (200ºC) and maximum cellulose degradation temperature (336ºC) are higher than the processing temperature of thermoset polymers. The elements present on the outer surface of ACFs were determined by energy-dispersive X-ray spectroscopy (EDAX) analysis, which identified the highest quantities of carbon and oxygen in the fiber, which are related to the cellulose and hemicellulose in the fiber, and minimum amount of other elements such as calcium, potassium, magnesium, and chlorine, which are linked to contamination in the fiber. The results of atomic force microscopy and scanning electron microscopy confirmed the rough surface of the ACF; however, surface modification is needed to remove contamination.
Fibers were extracted from the pseudostem of the plantain of the variety Hartón, belonging to the order Zingiberales, family Musaceae, genus Musa, species Musa paradisiaca. The fibers were exposed to alkaline treatment to improve their physicomechanical properties for use as reinforcement in green composites. NaOH solutions of 4 %, 5 %, and 6 % by weight were prepared. The fibers were immersed for 2 h in each solution. Fibers were washed with acetic acid to remove NaOH residues and dried at room temperature. Weight loss and lignin, cellulose, and hemicellulose content were evaluated. FTIR, tensile, and elongation tests were performed. SEM images and EDS mapping allowed to conclude the phenomena that occurred in the treatments. The untreated fibers obtained a tensile strength of 37.23 MPa, in contrast to 104.26 MPa obtained by the fibers treated with 5 % NaOH solution. It was concluded that the partial elimination of impurities and waxes improved the mechanical behavior of the fibers by 180 %. Regarding elongation, the fibers treated with 4 % NaOH solution obtained the best result with 3.7 %. It was determined that the partial elimination of lignin favors elongation by 48 %. Excessive hemicellulose removal was found to cause fibril separation and detachment. Considerable contraction of vascular bundles occurred. Roughness in the fibers surface topography were improved.
Presently, novel materials based on natural fibers are emerging daily to replace synthetic fibers in various engineering disciplines, as they minimize environmental pollution, allow for easy processing, provide superior strength, and promote industrial sustainability. The global demand for novel eco-friendly fibers for composites has paved the way for this work. This work uses epoxy as a matrix material, and polymer composites with reinforcement from untreated and alkali-treated Zanthoxylum acanthopodium bark fibers (5–25 wt.%). Hand lay-up was used in the development of the epoxy composites. The mechanical characteristics and water absorption rates of the produced epoxy composites were evaluated following ASTM standards. Epoxy composites containing 20 wt.% of alkali-treated Zanthoxylum acanthopodium bark fibers had excellent mechanical qualities, including an ultimate tensile strength of 47.3 MPa, according to the test findings. However, there was a positive correlation between fiber loading and water absorption. The fiber bonding and void properties of the investigated composites were viewed with a scanning electron microscope.
The prime objective of this research study was the investigation the new natural cellulosic fiber extracted from the stem of Abutilon Indicum plants as an alternative reinforcement in greener composite materials for structural applications. Abutilon Indicum a flowering plant with unique medicinal values are abundantly found in India and other south Asian countries. The fibers extracted from the stem of the Abutilon Indicum plant are proven to be sustainable, ecofriendly, and novel and hence this fiber is chosen for characterization study. In this experimental investigation the physical, chemical, thermal, morphological, crystallinity, chemical constituents, and surface characteristics of raw Abutilon Indicum fibers (AIF) were analyzed. Chemical analysis results convey the presence of higher cellulose content of (56.12 wt.%) in AIF. The diameter (175 μm) and density (1.170 g/cm3) of AIFs are determined by physical analysis of the raw fibers. Such lower density values observed in AIF make it as a perfect material for lightweight applications. Crystalline properties of AIFs are determined from X‐ray diffraction tests with a crystalline index of 77.35%, and crystalline size of 2.20 nm, which attributes to the presence of cellulose‐1β and the crystallites are ordered in nature. Thermal stability of 175°C, maximum degradation temperature upto 302.6°C and kinetic activation energy of 86.95 kJ/mol of AIF are established based on thermo gravimetric analysis. Morphological and surface characteristics of AIF through a scanning electron microscope (SEM) and atomic force microscope (AFM) analysis revealed that the raw fibers display a relatively finer surface. Research findings of the AIF mentioned above conclude that the AIFs prove to be an ideal, alternative reinforcement in greener composite materials for sustainable and cleaner production of components in structural applications.
The aim of the present work was to extract novel natural cellulosic fibers from the leaves of purple bauhinia trees. To the best of our knowledge, this is the first time that, the morphological, physical, chemical, structural, mechanical, and thermal properties of purple bauhinia fibers (PBFs) have been investigated and characterized. The lateral surface of PBFs exhibited impurities, and cellulosic and non-cellulosic constituents, while, the transverse section appeared porous. The high cellulose (60.54%) and low hemicellulose (9.17%) contents of PBFs indicated the potential to exploit the fibers as a reinforcement material in polymer composites. Analysis of the functional groups present in the PBFs confirmed the cellulose and hemicellulose contents. The crystallinity index of the PBFs was found to be 54.98%, and the crystallites were ordered in nature. The optimal mechanical properties were found to be a tensile strength of 373.3 MPa, a tensile modulus of 5.31 GPa and an elongation at break of 6.9%. The maximum degradation temperature of the PBFs was 341 °C, and the thermal activation energy of the fibers was determined using three different approaches. The results showed that, these fibers have the potential to be used as a reinforcement material for the fabrication of polymer composites with better mechanical and thermal properties.
First time, this study reports the effect of benzoyl chloride (BC), potassium permanganate (PP), and stearic acid (SA) treatments on the surface morphology, physical, chemical, structural, mechanical, and thermal properties of cellulosic fiber obtained from date palm plant petioles. Morphology analysis displayed the existence of protrusions on treated fiber surface, which stimulates the mechanical interlocking between the fiber and polymer matrix. Highest cellulose (67.22%) and lowest hemicellulose (9.25%), lignin (14.02%), ash (3.25%), wax (0.10%), and moisture (8.93%) content were observed in SA‐treated fibers than others. Similarly, highest weight loss (20.80%), reduced diameter (0.3166 mm), and density (0.389 g/cc) were obtained in SA‐treated fibers than the other fibers investigated. Outcomes of FT‐IR spectra evident the presence of cellulose and partial removal of non‐cellulosic constituents in BC‐, PP‐, and SA‐treated fibers. Enhanced crystallinity index (69.5%) and crystallite size (7.43 nm) values of SA‐treated fiber indicated the elimination of amorphous lignin and hemicellulose, and made the structure to be more crystalline which supports to obtain higher tensile properties (tensile strength of 489.07 MPa and tensile modulus of 9.4 GPa) than others. Maximal degradation temperature of SA‐treated fiber was 328.86°C and also having kinetic activation energy of 90.7 kJ/mol.
The current work deals with the study extraction and characterization of fibers from Pennisetum orientale grass. The fibers were extracted, treated chemically with hydrochloric acid and sodium hydroxide (alkali) solutions. The chemically modified and unmodified fibers were analyzed for its thermal, chemical, crystalline, physical, morphological and tensile characteristics. The test results showed that chemical treatment using alkali helped to increase the cellulose content by 65.1% with a reduction in amorphous contents and moisture. But the hydrochloric acid treatment reduced the cellulose contents due to its more acidic attack whose values were lower than the untreated one. The crystalline size of alkali treatment based fibers had 42.92 nm, which is lower than untreated one 62.02 nm. Thus the Pennisetum orientale grass can be suggested as a potential reinforcement for light-weight polymeric applications.
This study aims to investigate the natural cellulosic fibers extracted from novel Ziziphus Mauritiana plants. The fibers were treated with alkali solution and epoxy composites were developed for both untreated and chemically modified fibers through hand lay-up process. Physico-chemical and thermomechanical characterization were carried for both untreated and alkali treated Ziziphus Mauritiana fibers through physical analysis, chemical analysis, Thermogravimetric analysis, Fourier transform infrared spectroscopy, X-Ray diffraction test and single fiber tensile test. The alkali treatment facilitates to remove amorphous constituents and improves the crystalline index by 1.31 times, thermal stability by 1.15 times and fiber strength by 1.44 times, which is supported by chemical analysis and Fourier transform infrared spectroscopy analysis. Later, developed Ziziphus Mauritiana composites were analyzed as per ASTM for its mechanical and sound absorption characteristics. The reduction in amorphous constituents after chemical treatment improved the surface roughness in alkali-treated Ziziphus Mauritiana fibers which influenced the bonding behavior. Also it improved the ultimate tensile strength by 2.12 times, flexural strength by 1.38 times and sound absorption coefficient by 1.15 times. Thus, the Ziziphus Mauritiana fibers are potentially suitable for use in lightweight structures.
There has been much effort to provide eco-friendly and biodegradable materials for the next generation of composite products owing to global environmental concerns and increased awareness of renewable green resources. An increase in the use of natural materials in composites has led to a reduction in greenhouse gas emissions and carbon footprint of composites. In addition to the benefits obtained from green materials, there are some challenges in working with them, such as poor compatibility between the reinforcing natural fiber and matrix and the relatively high moisture absorption of natural fibers. Green composites can be a suitable alternative for petroleum-based materials. However, before this can be accomplished, there are a number of issues that need to be addressed, including poor interfacial adhesion between the matrix and natural fibers, moisture absorption, poor fire resistance, low impact strength, and low durability. Several researchers have studied the properties of natural fiber composites. These investigations have resulted in the development of several procedures for modifying natural fibers and resins. To address the increasing demand to use eco-friendly materials in different applications, an up-do-date review on natural fiber and resin types and sources, modification and processing techniques, physical and mechanical behaviors, applications, life-cycle assessment, and other properties of green composites is required to provide a better understanding of the behavior of green composites. This paper presents such a review based on 322 studies published since 1978.
Phoenix pusilla fibres (PPFs) were extracted from the leaves of a plant belonging to thefamily of Arecaceae, which is widely grown in Sri Lanka and Southern parts of India forsome medicinal purposes. Their use as possible reinforcement in hydrophobic polymericmatrix composites is yet to be studied and for this reason, the better understanding oftheir microstructure, chemical composition, and mechanical properties becomes essential.In this view, the present investigation deals with the study on the effect of various chemicaltreatments on the mechanical, chemical structure, thermal and morphological behaviourof PPFs. The chemical treatment of fibres was initially involved with NaOH and then fol-lowed by benzoyl peroxide, potassium permanganate and stearic acid solution at differentconcentrations for the suitable time interval. The results revealed that chemical treatmentshelp in diminishing the amorphous content from the fibres, while the FTIR analysis clearlyindicates the removal of many polar impurities. The increase in crystallinity index andcrystallite size was seen in all the modified fibres when compared with the raw ones. Theimproved thermal stability behaviour in all the chemically treated fibres was demonstratedby thermogravimetric and differential scanning calorimetry analysis. The tensile propertiesof the fibres were analyzed through ASTM standard and finally, the surface morphology wasanalyzed using scanning electron microscopy. All the favourable results indicated that thePPFs could be used in the applications of natural fibre composites.
Natural composites can be fabricated through reinforcing either synthetic or bio-based polymers with hydrophilic natural fibers. Ultimate moisture absorption resistance at the fiber–matrix interface can be achieved when hydrophilic natural fibers are used to reinforce biopolymers due to the high degree of compatibility between them. However, the cost of biopolymers is several times higher than that of their synthetic counterparts, which hinders their dissemination in various industries. In order to produce economically feasible natural composites, synthetic resins are frequently reinforced with hydrophilic fibers, which increases the incompatibility issues such as the creation of voids and delamination at fiber–matrix interfaces. Therefore, applying chemical and/or physical treatments to eliminate the aforementioned drawbacks is of primary importance. However, it is demonstrated through this review study that these treatments do not guarantee a sufficient improvement of the moisture absorption properties of natural composites, and the moisture treatments should be applied under the consideration of the following parameters: (i) type of hosting matrix; (ii) type of natural fiber; (iii) loading of natural fiber; (iv) the hybridization of natural fibers with mineral/synthetic counterparts; (v) implantation of nanofillers. Complete discussion about each of these parameters is developed through this study.
There is significant work published in recent years about natural fibres polymeric composites. Most of the studies are about the characterization of natural fibres and their comparison with conventional composites regarding mechanical behaviour and application performance. There are dozens of types of natural fibres with different properties influencing their use, or not, in specific industrial applications. The natural origin of these materials causes, in general, a wide range of variations in properties depending mainly on the harvesting location and conditions, making it difficult to select the appropriate fibre for a specific application. In this paper, a comprehensive review about the properties of natural fibres used as composite materials reinforcement is presented, aiming to map where each type of fibre is positioned in several properties. Recent published work on emergent types of fibres is also reviewed. A bibliometric study regarding applications of natural fibres composites is presented. A prospective analysis about the future trends of natural fibres applications and the required developments to broaden their applications is also presented and discussed.
Natural swollen finger grass fibers being novel are botanically known as “Chloris barbata fibers (CBFs)” and are selected for this study in order to understand their morphological properties. The CBF has higher cellulose (65.37 wt%) content and lower density (634 kg/m³). Crystallinity Index (CI) of CBF was calculated from X-ray diffraction studies and is valued as 50.29%. The surface of CBF was examined using a Scanning Electron Microscope (SEM) for observing the surface morphology. Structural characterization and Chemical functional group were confirmed by Fourier transform infrared spectroscopy (FT-IR). The thermal behavior of CBFs was determined using TG and DTG curves from Thermo gravimetric (TG) analysis. Findings show that the fiber has a semi-elongated nearly circular cross-sectional shape, the fiber diameter is between 180 and 200 μm. TG analysis revealed that these fibers are thermally stable until 210°C. Thus the characterization results confirm the possibility of using CBF for the manufacture of sustainable fiber reinforced polymer composite.
This investigation summarizes the characteristics of bio fiber extracted from the Perotis
indica (PI) plant. Cellulose content (68.4 wt.%), density (785 kg/m3
),crystallinity index
(48.3%), tensile strength (317–1608 MPa), and Young’s modulus (8.41– 69.61 GPa)
properties were identified in the Perotis indica fibers (PIFs), and thermal stability was
studies using TG and DTG analysis which revealed its cellulose degraded at a
temperature of 339.1°C. Further, the properties of PIFs ensured that it can play an
imperative role as new reinforcement as green composites in the manufacturing
industries
The versatile characteristic of epoxy and its diversity made it suitable for different industrial applications such as laminated circuit board, electronic component encapsulations, surface coatings, potting, fiber reinforcement, and adhesives. However, the pervasive applications in many high-performance field limited the epoxy use because of their delamination, low impact resistance, inherent brittleness, and fracture toughness behavior. The limitations of epoxy can be overcome by incorporation and modification before their industrial applications. Currently, modified epoxy resins are extensively used in fabrication of natural fiber-reinforced composites and in making its different industrial products because of their superior mechanical, thermal, and electrical properties. Present review article designed to be a comprehensive source of recent literature on epoxy structure, synthesis, modified epoxy, bio-epoxy resin, and its applications. This review article also aims to cover the recent advances in natural fiber-based epoxy composites and nanocomposites research study, including manufacturing techniques and their different industrial applications.
Recently, there has been a rapid growth in research and innovation in the natural fibre composite (NFC) area.
Interest is warranted due to the advantages of these materials compared to others, such as synthetic fibre
composites, including low environmental impact and low cost and support their potential across a wide range of
applications. Further benefits include low density, low machine wear and friendly fracture, such that their
fractured edges are softer than for synthetic fibre composites. Much effort has gone into increasing their
mechanical performance to extend the capabilities and applications of this group of materials. This review aims
to provide an overview of the factors that affect the mechanical performance of NFCs and details achievements
made with them.
Incompatibility between hydrophilic natural fibers and hydrophobic matrix is known to affect the adhesion of the fiber and matrix. Therefore, it becomes necessary to modify the surface of natural fibers for improved adhesion between the fiber and matrix. Prosopis juliflora fibers (PJFs) are known to possess desirable properties for use as reinforcement in polymer matrices. Using chemical analysis, the optimal condition for alkali treatment of the PJFs was found to be 5% (w/v) of NaOH concentration with 60 min soaking time. Chemical modifications favorably changed the physiochemical properties of PJFs and undoubtedly diminished the amorphous and wax contents.
In this work, natural fibres (sisal, kenaf, hemp, jute and coir) reinforced polypropylene composites were processed by compression moulding using a film stacking method. The mechanical properties of the different natural fibre composites were tested and compared. A further comparison was made with the corresponding properties of glass mat reinforced polypropylene composites from the open literature. Kenaf, hemp and sisal composites showed comparable tensile strength and modulus results but in impact properties hemp appears to out-perform kenaf. The tensile modulus, impact strength and the ultimate tensile stress of kenaf reinforced polypropylene composites were found to increase with increasing fibre weight fraction. Coir fibre composites displayed the lowest mechanical properties, but their impact strength was higher than that of jute and kenaf composites. In most cases the specific properties of the natural fibre composites were found to compare favourably with those of glass.
This study focuses on the development and property enhancement of novel Muntingia Calabura bark micro-fiber reinforced bio-epoxy composite through surface modification techniques using NaOH and silane. The proposed novel plant fiber was extracted from an agro-waste after the tree’s lifespan which was causing landfill. The performance characteristics of the developed composites were evaluated through physico-chemical and thermomechanical analysis. These fibers are subjected to chemical and physical analysis, while the composites are subjected to their mechanical, thermal, thermomechanical, and viscoelastic performance. The results revealed that the silane and NaOH modification of fiber reduced the fiber diameter by 9.17% and 17.43%; improved crystalline index by 41.01% and 14.86%; improved thermal stability by 14.15% and 4.81%; and increased the tensile strength by 37.75% and 28.92%. The complete analysis revealed silane treatment was the best for Muntingia Calabura micro-fiber compared to NaOH treatment and using raw fibers. Finally, based on improved results, this novel plant fiber was identified as a potential resource of environmentally friendly and sustainable raw material for reinforcement in polymer composites, which can be used to develop the green composites for lightweight structural applications.
Grewia damine is a flowering plant found in India and Sri Lanka. The fiber taken out from the stem bark of G. damine is found to be novel and selected for characterization study. The G. damine stem bark fiber (GDSF) has rich in cellulose contents (57.78 ± 3.56%). Its lower density (1.378 ± 0.036 g/cm³) makes it fit for use in lightweight applications. The weight percentage values of the chemical constituents confirm the use of GDSF for structural applications. Crystallinity index of GDSF was noted as 30.35%. The mechanical properties of GDSF were predicted as 375.6 ± 16.58 MPa tensile strength and 126.2 ± 11.93 GPa modulus of elasticity. The morphological and atomic force microscopy study results revealed that the fiber has rough surface even in its raw form. Hence it can be used to prepare composite specimens with better bonding strength between fiber and polymer. The thermal stability of GDSF was noted as 326 °C. Weibull distribution plots were drawn for validating the physical and tensile property values of GDSF.
The foremost intention of this work is to test the suitability of the Ficus religiosa Root Fiber (FRRF) as the better reinforcement for the natural fiber-reinforced composite structures. In the current work, the attempts have been made with the view of improving the physical, thermal, chemical, surface, and crystalline properties of FRRF employing 5 wt% of NaOH solution. Five samples of FRRF have been prepared by soaking the raw fiber in the alkali solution under different soaking times. The thermogravimetric analysis results reveal that the alkali-treated FRRF soaked for 60 min holds a maximum range of thermal stability (improved by 9.54%); in turn, the remaining analyses have been carried out with that fiber samples. The increased quantity of cellulose contents was witnessed over the surface of treated FRRF. The improvement in the CI from 42.92–48.64% was noted as the result of X-Ray Diffraction test. The morphology study results ensured that the surface of the treated FRRF became so rough comparably, which confirms the removal of unwanted wax and impurities on the fiber surface. All the above observations validated that the proposed fiber is suitable to prepare the composite structures after the optimal alkali treatment.
The current global scenario has a great impact on the development of new bio-based materials due to its vital advantages that are helpful in replacing synthetic and hazardous materials. This perspective review presents the advancement in the processing techniques, characterizations, future scope and methods to overcome the limitations in biofibers, biopolymers, biofilms, and bio composites. This provides vital information on advanced bio-based materials and its composites for their potential usage in biomedical, commercial and engineering sectors to the researchers and scientists. The usage of bio-based materials that are renewable in the field of constructions and engineering will improve the sustainability by reducing wastages, landfills and toxic emissions leading to greener and cleaner environment.
This research is focused to fundamentally understand the benefits of using Agave Americana C. plant as potential reinforcement in polymeric composites. The fibers were extracted from the external part of the bark of the plant, which grows worldwide in pastures, grasslands, open woodlands, coastal and riparian zones. In order to use the natural fiber as reinforcement it is paramount important to probe their chemical composition, microstructural behavior and mechanical properties. Hence, firstly the extracted fibers were chemically treated with NaOH, stearic acid, benzoyl peroxide and potassium permanganate. The chemical composition in terms of cellulose, hemicellulose, lignin and other waxy substances were determined using a standard TAPPI method. FT-IR technique was used to understand the character of molecular bonds, crystallinity and their correlations with various bonds in fiber structure. The thermal stability was investigated through thermogravimetric and differential scanning calorimetric analysis, and the mechanical characterization was performed by applying standard tensile test. The surface morphology of fibers was examined through scanning electron microscopy (SEM) and finally reliability scrutiny of all the analysis was carried out. The results of chemical modification techniques applied on the surfaces of natural fibers allows to produce superior fibers used to form the novel composite materials for light-weight application.
Kigelia africana also known as sausage plant, yields highly fibrous fruit with a hard shell. Many medicinal uses are reported for the extracts from the fruits, seeds and leaves of sausage trees. In this research, natural cellulose fibers were extracted from the fruit using NaOH and later bleached and characterized for their properties. Results revealed that significant amount of hemicellulose and lignin was lost after the alkali treatment and bleaching leading to a highly cellulosic fiber (up to 71 %). Morphologically, surface of the fibers varied from rough to smooth depending on the extent of treatment. The thermal stability, crystallinity and hydrophobicity increased after the treatment. Sausage fibers also possessed anti-microbial activity against common gram negative and gram positive bacteria. Overall, sausage fibers have properties similar to that of cotton and better than fibers obtained from many unconventional sources. With improved hydrophobicity and anti-bacterial properties, sausage fibers could be potentially applied in functional polymer composites.
In the present scenario, the searching for novel plant fibers able to be used as reinforcement of polymer composites is highly appreciable. This study deals with extraction and characterization of Eleusine indica grass fibers extracted from its stem by manual retting process. From this study, it was found that the Eleusine indica has higher cellulose of 61.3 wt% content, density of 1143 kg/m³, average tensile strength and Young’s modulus equal to 22 MPa and 10.75 GPa, respectively. From the XRD studies, it was noted that the Crystallinity Index (CI) of Eleusine indica was 45%. The surface morphology of Eleusine indica grass was examined using a Scanning Electron Microscope (SEM) and Chemical functional group were confirmed by Fourier transform infrared spectroscopy (FT-IR). The thermal stability of EIF was evaluated using TG and DTG curves from Thermogravimetric (TG) analysis. The characterization results confirmed that Eleusine indica grass could be used for the production of sustainable fiber-reinforced polymer composites.
The objective of this investigation is to check the suitability novel cellulosic fibre extracted from the aerial roots of Banyan tree (ARBFs) as reinforcement in fibre reinforced plastics. The Fundamental properties of ARBFs such as density, tensile strength, chemical composition, crystallinity index, crystalline size, thermal stability, maximum degradation temperature and surface roughness were studied. The chemical analysis results revealed that after the alkalization cellulose content was improved while hemi-cellulose, lignin and wax content were demised. The enhancement in the crystallinity index (76.35% from 72.47%) and crystalline size (7.74 nm from 6.28 nm) of alkali treated ARBFs were evidenced by the X-ray diffraction analysis. Thermal analysis results confirmed that maximum degradation temperature (368 °C) and kinetic activation energy (75.45 kJ/mol) of alkali treated ARBFs had increased from 358 °C and 72.65 kJ/mol respectively. The results of scanning electron microscopic and atomic force microscopic analysis exhibited that impurities and wax on the outer surface of the ARBFs were removed after the alkali treatment. All the above finding concluded that ARBFs is the appropriate material to use as a reinforcement in fibre reinforced plastics.
The current study deals with the investigation on the properties of lignocellulose fiber from the stem of Cardiospermum Halicababum. The Cardiospermum Halicababum fibers (CHF) were extracted from its stem by manual retting process. The retted fibers were analyzed for various physical, chemical, crystalline, thermal stability, tensile and morphological properties as per standard procedure. From the chemical investigation, it was found that the CHF has cellulose (59.82%), hemicellulose (16.75%), lignin (9.3%) and wax (1.3%). The CHF possessed a crystallinity index of 32.21%, with thermal stability up to 336°C. The average ultimate tensile strength of CHF was 20.7 ± 1.0 MPa. Morphological characteristics showed lesser lacuna space in between the cell walls thereby preventing the reduction in strength properties.
In the current study, deals with the characterization of Parthenium hysterophorus fibers (PHF) extracted from its stem by manual retting process. Then, extracted fibers were alkali-treated, and its characteristics were compared with untreated one. The various behaviors of the alkali-treated and untreated PHF was studied using physical-chemical analysis, Fourier-transform infrared spectroscopy, X-ray diffraction, Thermogravimetric analysis, Tensile test, and Scanning Electron Microscopy. Results showed that alkali-treated PHF showed an increase in cellulose content by 8.9% than untreated PHF while the char residue was 38.5%. It also showed a better crystalline index, surface characteristics, and good tensile strength.
The exploration of novel natural fibers can contribute to expand their use in possible eco-friendly applications. In the current work, the physicochemical, thermal, tensile and morphological characteristics were tested for the fibers extracted from the stem of Saccharum Bengalense grass (SB). The results showed that fiber possesses good chemical constituents, namely, α- cellulose (53.45%), hemicellulose (31.45%) with lower lignin (11.7%) as confirmed from chemical analysis, its presence confirmed from Fourier Transform Infrared Spectroscopy (FTIR). Due to the presence of considerable chemical constituents, SB fibers showed good crystallinity index and tensile strength as confirmed from X-Ray diffraction analysis (XRD) and tensile test. Thermal stability was found using Thermogravimetric analysis (TGA), it revealed the SB fibers showed maximum degradation at 336°C and the char residue was 16.4%. Scanning Electron Microscopy (SEM) was used to study the morphological characteristics. Thus, SB fibers could be used as reinforcement in natural fiber-based polymer composites. This fiber utilization in composites may be suggested in potential applications like roofing sheets, bricks, door panels, furniture panels, interior paneling, storage tanks, pipelines, etc.
In this work, the effects of alkali treatment on the chemical composition and thermal decomposition of Acacia planifrons fibers were investigated. The fibers originating from the bark of an Acacia planifrons tree were alkali treated with various concentrations (2% and 5% w/v) for 30 min. The treatment was found to diminish the amorphous contents, improve the crystallinity index and thermal stability of the fiber. The crystallinity index of the untreated, 2% alkali-treated and 5% alkali-treated fibers was estimated to be 65.38%, 69.94% and 74.76%, respectively. The thermal stability of the alkali-treated fiber was quite higher than that of the untreated fiber. The results revealed that 5% alkali-treated Acacia planifrons fibers are suitable to be used as reinforcement in polymer composites.
The aim of this study is to investigate natural cellulosic fibers extracted from Tridax procumbens plants. The obtained fibers were alkali treated for their effective usage as reinforcement in composites. The physical, chemical, crystallinity, thermal, wettability and surface characteristics were analyzed for raw, and alkali treated Tridax procumbens fibers (TPFs). The test results conclude that there was an increase in cellulose content with a reduction in hemicellulose, lignin, and wax upon alkali treatment. This enhanced the thermal stability, tensile strength, crystallinity, and surface roughness characteristics. The contact angle was also lesser for treated TPFs which prove its better wettability with the liquid phase. The Weibull distribution analysis was adopted for the analysis of the fiber diameter and tensile properties. Thus the considerable improvement in the properties of alkali treated TPFs would be worth for developing high-performance polymer composites.
This study aims to examine the effect of sodium hydroxide (NaOH) treatment on the physico-chemical properties, structure, thermal, tensile and surface topography of Carica papaya fibers (CPFs). The surface of raw CPFs was modified by soaking with 5% NaOH solution for 15, 30, 45, 60, 75 and 90 min. The results of thermo-gravimetric analysis revealed that the optimum treatment time for alkali treatment was 60 min. It was found that the alkali treatment improved the properties of the CPFs. The results of TGA, FT-IR, XRD and AFM suggest that the treated CPF is a suitable alternative as reinforcement in polymer composites.
The physical, chemical, tensile, crystalline, thermal, and surface morphological properties of raw and alkali treated Coccinia Grandis.L Fibers (CGFs) were characterized for the first time in this work. The results of the chemical analysis indicate that, after alkali treatment, the cellulose content of CGFs increased whereas hemicelluloses, lignin and wax contents decreased. This directly influenced the tensile strength, crystallinity index, thermal stability and the roughness of alkali-treated CGFs. The thermal stability and activation energy of the CGFs improved from 213.4 °C to 220.6 °C and 67.02 kJ/mol to 73.43 kJ/mol, respectively, due to alkali treatment. The statistical approach, Weibull distribution was adopted to analyze the tensile properties. The improved properties of the alkali treated CGF indicate that it could be an appropriate material for reinforcement in polymer composites.
Increasing environmental concerns, along with the potential declination of the crude worldwide reserves, have made the human beings to utilize more regenerable resources to substitute for the design and development of more new products. This has made us to use the synthetic and natural fibers to develop innovative products. However, more eco-friendly properties of natural fibers have made them to be preferable over the synthetic fibers. To make efficient use of these fibers, it is essential to know the behavioral characteristics of these fibers. So, in this review II paper, an effort has been made to discuss the various characterization analysis studies, like Fourier transform-infrared spectra spectral analysis, X-ray and thermogravimetric methods carried out by various researchers.
The world is in need of more eco-friendly material, therefore researchers around the globe focus on developing new materials that would improve the environmental quality of products. This need for new green materials has led to the utilization of composites made from raw natural fibers and polymer matrices, and this has become one of the most widely investigated research topics in recent times. Natural fiber composites are an alternative for replacing environmentally harmful synthetic materials and help control pollution problems. In addition, they are low cost, have better mechanical properties and require low production energy consumption. Also, using such materials in construction works, it is possible to improve the sustainability by eliminating construction wastes. Keeping in view all the benefits of natural fiber reinforced polymer composites, this paper first discusses various fabrication techniques employed for the production of these composites and then presents a detailed review of the research devoted to the analysis of their structure and properties by a variety of characterization techniques.
The natural fiber Epipremnum aureum was extracted from its plant. E. aureum fibers (EAFs) were investigated by chemical analysis, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and single fiber tensile test. Chemical analysis, FTIR, and X-ray analysis evidenced that these fibers has 66.34% cellulose content with crystallinity index of 49.33%. The thermogravimetric analysis reveals that EAFs can thermally withstand temperatures until 328.9°C. The morphology of the EAFs was observed by scanning electron microscope. It was established that the fiber can be utilized as reinforcement in polymer composites.
The aim of this study is to examine the use of new natural fibers, which are extracted from the Saharan aloe vera cactus plant leaves as reinforcement in polymer composites. The physicochemical, mechanical and thermal properties of the Saharan Aloe Vera Cactus Leaves (SACL) fibers are investigated, through the effect of alkali treatment. The contents of α-cellulose, hemicellulose, wax and moisture present in SACL fibers were characterized by standard test methods The mechanical properties of SACL fibers were measured through single fiber tensile test. The interfacial strength between the fiber and matrix was estimated by the fiber pull-out test. These results ensure that the chemical and mechanical properties of the fibers are improved after the alkali treatment. FT-IR spectroscopic analysis confirms that the alkali treatment process has removed certain amount of amorphous materials from the fibers. XRD analysis results show that the alkali treatment has enhanced the Crystallinity Index and Crystalline Size of the fibers. Thermal behavior of the fibers was analyzed by using TGA. The thermal stability and the thermal degradation temperature increases after the alkali treatment of fibers. The morphologies of fibers were analyzed by SEM and prove that the fiber surfaces become rough after alkali treatment.
This research study was aimed at examining newly identified natural fiber from the bark of Azadirachta indica (AI). The various properties were analyzed and compared with other available bark fibers. The chemical composition of Azadirachta indica fibers (AIFs), high cellulose (68.42 wt.%) content, and low
lignin (13.58 wt.%) were discovered. The lower density of 740 kg/m3, and crystallinity index of 65.04% properties were identified. The maximum peak temperature obtained was 321.2 °C in Differential thermogravimetry (DTG) curve. Taken together, all the properties of AIFs indicated that they could be
suitable to make green composites for various types of applications.
The aim of this paper is to investigate the effect of an alkali treatment on physical, chemical, mechanical, and morphological properties of Phoenix Sp. fibers. The use of natural fibers as reinforcement in polymer composites requires a deep investigation to understand their behavior and which treatment is more appropriate to improve the quality of the untreated material. For this reason, fibers were extracted from the petioles of the Phoenix Sp. plant and they were treated with NaOH solution in different weight concentrations (5%, 10%, and 15%). The mechanical behavior was investigated through tensile test on single fiber at different gauge length (20 mm, 30 mm, 40 mm, 50 mm, and 60 mm). Chemical and physical analysis were performed to define the material properties. In particular, density analysis of untreated and treated fibers, optical analysis to measure the diameter of the fibers, moisture content evaluation, and a chemical composition analysis were carried out through standard methods. The modification of the surface morphology due to the alkali treatment was analyzed through scanning electron microscope analysis.
With growing inclination towards the eco-friendly technology, natural fiber based polymer composite materials have been gaining a lot of momentum nowadays. The present review discusses the much research that has been carried out in the area of the epoxy-based composites reinforced with natural fibers. Influence of the various factors like the fiber content, fiber geometry, fiber size, surface treatment technique, and coupling agent on different properties like mechanical, thermal, behavior towards water absorption and others have been presented. It can be inferred that there is a need and scope for improvement of the surface properties of natural fiber using various methods like physical and chemical treatments, addition of coupling agents, etc. for the manufacturing of the composites having desired properties. These techniques not only modify surface morphology, but also improve other processing parameters like the hydrophilic character of fiber (which is desirable to be low), and hence improve several characteristics such as mechanical properties, thermal stability, water absorption and other considerations of the composites.
Characterization of new natural fiber is rising due to its excellent properties and drives the investigators to create high performance composites. This present investigation was designed to study the physico-chemical properties of fibers obtained from the leaf of theArtistida hystrix(AH). The Artistida hystrix fibers (AHFs) had crystallinity index (44.85%), cellulose (59.54 wt.%), hemicellulose (11.35 wt.%), lignin (8.42 wt.%) and density (540 kg/m3). The tensile strength of AHFs was 440 ± 13.4 MPa with an average strain rate of 1.57 ± 0.04%. Further calculated microfibril angle of AHFs was 12.64° ± 0.45° which influenced the mechanical properties.
Cellulose samples are routinely analyzed by X-ray diffraction to determine their crystal type (polymorph) and crystallinity. However, the connection is seldom made between those efforts and the crystal structures of cellulose that have been proposed with synchrotron X-radiation and neutron diffraction over the past decade or so. In part, this desirable connection is thwarted by the use of different conventions for description of the unit cells of the crystal structures. In the present work, powder diffraction patterns from cellulose Iα, Iβ, II, IIII, and IIIII were calculated based on the published atomic coordinates and unit cell dimensions contained in modified “crystal information files” (.cif) that are supplied in the Supplementary Information. The calculations used peak widths at half maximum height of both 0.1 and 1.5° 2, providing both highly resolved indications of the contributions of each contributing reflection to the observable diffraction peaks as well as intensity profiles that more closely resemble those from practical cellulose samples. Miller indices are shown for each contributing peak that conform to the convention with c as the fiber axis, a right-handed relationship among the axes and the length of a b. Adoption of this convention, already used for crystal structure determinations, is also urged for routine studies of polymorph and crystallinity. The calculated patterns are shown with and without preferred orientation along the fiber axis. Diffraction intensities, output by the Mercury program from the Cambridge Crystallographic Data Centre, have several uses including comparisons with experimental data. Calculated intensities from different polymorphs can be added in varying proportions using a spreadsheet program to simulate patterns such as those from partially mercerized cellulose or various composites.
The X-ray diffraction-based Segal Crystallinity Index (CI) was calculated for simulated different sizes of crystallites for cellulose Iβ and II. The Mercury software was used, and different crystallite sizes were based on different input peak widths at half of the maximum peak intensity (pwhm). The two cellulose polymorphs, Iβ and II, gave different CIs despite having the same pwhm values and perfect periodicity. The higher CIs for cellulose II were attributed to a greater distance between the major peaks that are closest to the recommended 2-θ value for assessing the amorphous content. That results in less peak overlap at the recommended 2-θ value. Patterns calculated with simulated preferred orientation had somewhat higher CIs for cellulose Iβ, whereas there was very little effect on the CIs for cellulose II.
The crystal and molecular structure together with the hydrogen-bonding system in cellulose Ibeta has been determined using synchrotron and neutron diffraction data recorded from oriented fibrous samples prepared by aligning cellulose microcrystals from tunicin. These samples diffracted both synchrotron X-rays and neutrons to better than 1 Angstrom resolution (>300 unique reflections; P2(1)). The X-ray data were used to determine the C and 0 atom positions, The resulting structure consisted of two parallel chains having slightly different conformations and organized in sheets packed in a "parallel-up" fashion, with all hydroxymethyl groups adopting the tg conformation. The positions of hydrogen atoms involved in hydrogen-bonding were determined from a Fourier-difference analysis using neutron diffraction data collected from hydrogenated and deuterated samples. The hydrogen atoms involved in the intramolecular O3...O5 hydrogen bonds have well-defined positions, whereas those corresponding to 02 and 06 covered a wider volume, indicative of multiple geometry with partial occupation. The observation of this disorder substantiates a recent infrared analysis and indicates that, despite their high crystallinity, crystals of cellulose Ibeta have an inherent disorganization of the intermolecular H-bond network that maintains the cellulose chains in sheets.
Quantitative x‐ray diffraction methods have been used to study the orientation of the cellulose chains and lateral ordering around the long chain axes in various commercial and experimental rayons. Lateral order can vary independently of orientation in cellulose, as is the case with other linear polymers such as the polyamides. The degree of lateral order obtainable by aqueous annealing of regenerated cellulose appears to be restricted by the structure originally set up. As noted by Sisson, the well‐known relations between yarn tenacity and orientation and elongation to break and orientation are not unique. At a given orientation, a range of tenacities and elongations are possible, depending upon the influence of other variables. Study of a series of yarns prepared under constant mechanical conditions showed that elongation to break increased with lateral disordering of the cellulose chains at constant orientation. The data support Baker's proposal that local chain disordering in any linear polymer favors higher extensibility. Some yarns of essentially the same orientation and lateral order have shown different properties indicating that other as yet undefined structural variables also have an important effect on physical properties.
The crystal and molecular structure, together with the hydrogen-bonding system in cellulose I(alpha), has been determined using atomic-resolution synchrotron and neutron diffraction data recorded from oriented fibrous samples prepared by aligning cellulose microcrystals from the cell wall of the freshwater alga Glaucocystis nostochinearum. The X-ray data were used to determine the C and O atom positions. The resulting structure is a one-chain triclinic unit cell with all glucosyl linkages and hydroxymethyl groups (tg) identical. However, adjacent sugar rings alternate in conformation giving the chain a cellobiosyl repeat. The chains organize in sheets packed in a "parallel-up" fashion. The positions of hydrogen atoms involved in hydrogen-bonding were determined from a Fourier-difference analysis using neutron diffraction data collected from hydrogenated and deuterated samples. The differences between the structure and hydrogen-bonding reported here for cellulose I(alpha) and previously for cellulose I(beta) provide potential explanations for the solid-state conversion of I(alpha) --> I(beta) and for the occurrence of two crystal phases in naturally occurring cellulose.
opportunity for new developments in all phases of textile manufacturing
- Segal