Chemical treatments on plant-based natural fibre reinforced polymer composites: An overview
TL;DR: In this article, a comprehensive overview of surface treatments applied to natural fibres for advanced composites applications is presented, where the effects of different chemical treatments on cellulosic fibres that are used as reinforcements for thermoset and thermoplastics are studied.
Abstract: This paper provides a comprehensive overview on different surface treatments applied to natural fibres for advanced composites applications. In practice, the major drawbacks of using natural fibres are their high degree of moisture absorption and poor dimensional stability. The primary objective of surface treatments on natural fibres is to maximize the bonding strength so as the stress transferability in the composites. The overall mechanical properties of natural fibre reinforced polymer composites are highly dependent on the morphology, aspect ratio, hydrophilic tendency and dimensional stability of the fibres used. The effects of different chemical treatments on cellulosic fibres that are used as reinforcements for thermoset and thermoplastics are studied. The chemical sources for the treatments include alkali, silane, acetylation, benzoylation, acrylation and acrylonitrile grafting, maleated coupling agents, permanganate, peroxide, isocyanate, stearic acid, sodium chlorite, triazine, fatty acid derivate (oleoyl chloride) and fungal. The significance of chemically-treated natural fibres is seen through the improvement of mechanical strength and dimensional stability of resultant composites as compared with a pristine sample.
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Abstract: 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. 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.
2,182 citations
Cites background from "Chemical treatments on plant-based ..."
...Alkali treatment also modifies cellulose structure; modest treatments have been seen to bring about increased cellulose crystallinity considered to be due to removal of materials that could obstruct cellulose crystallinity, whereas at harsher treatments crystalline cellulose has been converted to amorphous material [61,62]....
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TL;DR: A comprehensive review of the most appropriate and widely used natural fiber reinforced polymer composites (NFPCs) and their applications is presented in this paper. But, the results of the review are limited due to the high water absorption, inferior fire resistance, and lower mechanical properties of NFPCs.
Abstract: Natural fibers are getting attention from researchers and academician to utilize in polymer composites due to their ecofriendly nature and sustainability. The aim of this review article is to provide a comprehensive review of the foremost appropriate as well as widely used natural fiber reinforced polymer composites (NFPCs) and their applications. In addition, it presents summary of various surface treatments applied to natural fibers and their effect on NFPCs properties. The properties of NFPCs vary with fiber type and fiber source as well as fiber structure. The effects of various chemical treatments on the mechanical and thermal properties of natural fibers reinforcements thermosetting and thermoplastics composites were studied. A number of drawbacks of NFPCs like higher water absorption, inferior fire resistance, and lower mechanical properties limited its applications. Impacts of chemical treatment on the water absorption, tribology, viscoelastic behavior, relaxation behavior, energy absorption flames retardancy, and biodegradability properties of NFPCs were also highlighted. The applications of NFPCs in automobile and construction industry and other applications are demonstrated. It concluded that chemical treatment of the natural fiber improved adhesion between the fiber surface and the polymer matrix which ultimately enhanced physicomechanical and thermochemical properties of the NFPCs.
1,022 citations
Cites background from "Chemical treatments on plant-based ..."
...The reagent functional groups in the chemical treatments have ability to react on the fiber structures and alter the fiber composition [9]....
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...At temperatures as high as 240C, natural fibers start degrading whereas constituents of fiber, such as hemicelluloses, cellulose, lignin, and others, start degrading at different levels of temperature; for example, at 200C lignin starts to decompose whereas at temperatures higher than this other constituents will also degrade [9]....
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...The surface of the fibers is cleaned during the chemical treatments to ensure there are no impurities which increases the fiber surface roughness and preventing the moisture absorption via the removal of the coat of OH groups of fiber as seen in equation below [5, 9]:...
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...Development of fibers and materials that provide services are two important aspects which should be considered while degradating natural fibers [9]....
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...In a review of chemical treatments of natural fibers, Kabir and coworkers [9] concurred that treatment is an important factor that has to be considered when processing natural fibers....
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TL;DR: A review of natural fiber reinfocred composites focusing on natural fiber types and sources, processing methods, modification of fibers, matrices (petrochemical and renewable), and their mechanical performance is presented in this paper.
Abstract: This century has witnessed remarkable achievements in green technology in material science through the development of natural fiber reinforced composites. The development of high-performance engineering products made from natural resources is increasing worldwide day by day. There is increasing interest in materials demonstrating efficient use of renewable resources. Nowadays, more than ever, companies are faced with opportunities and choices in material innovations. Due to the challenges of petroleum-based products and the need to find renewable solutions, more and more companies are looking at natural fiber composite materials. The primary driving forces for new bio-composite materials are the cost of natural fibers (currently priced at one-third of the cost of glass fiber or less), weight reduction (these fibers are half the weight of glass fiber), recycling (natural fiber composites are easier to recycle) and the desire for green products. This Review provides an overview of natural fiber reinfocred composites focusing on natural fiber types and sources, processing methods, modification of fibers, matrices (petrochemical and renewable), and their mechanical performance. It also focuses on future research, recent developments and applications and concludes with key issues that need to be resolved. This article critically summarizes the essential findings of the mostly readily utilized reinforced natural fibers in polymeric composite materials and their performance from 2000 to 2013.
691 citations
TL;DR: A detailed review of the different types of retting processes, chemical and surface treatments and characterization techniques for natural fibers, and major findings from the literature are summarized.
534 citations
TL;DR: In this paper, the reinforcement potential of natural fibers and their properties have been described in numerous papers and the chemical composition and properties of each of the fibers changes, which demands the detailed comparison of these fibers.
Abstract: Natural fibers today are a popular choice for applications in composite manufacturing. Based on the sustainability benefits, biofibers such as plant fibers are replacing synthetic fibers in composites. These fibers are used to manufacture several biocomposites. The chemical composition and properties of each of the fibers changes, which demands the detailed comparison of these fibers. The reinforcement potential of natural fibers and their properties have been described in numerous papers. Today, high performance biocomposites are produced from several years of research. Plant fibers, particularly bast and leaf, find applications in automotive industries. While most of the other fibers are explored in lab scales they have not yet found large-scale commercial applications. It is necessary to also consider other fibers such as ones made from seed (coir) and animals (chicken feather) as they are secondary or made from waste products. Few plant fibers such as bast fibers are often reviewed briefly but other p...
447 citations
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TL;DR: In this article, a survey about physical and chemical treatment methods which improve the fiber matrix adhesion, their results and effects on the physical properties of composites is presented, and the influence of such treatments by taking into account fibre content on the creep, quasi-static, cyclic dynamic and impact behaviour of natural fibre reinforced plastics are discussed in detail.
4,160 citations
"Chemical treatments on plant-based ..." refers background in this paper
...In accordance with a specific type of fibre, cellulose microfibrils have their own cell geometry which is a factor responsible for the properties of the fibre [2]....
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...[2]....
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...These two components are combined in order to achieve specific characteristics and properties [2]....
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...These parameters determine the characterization factor for fibres [2-4]....
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...This results strong adhesion at the interface and improves composite properties [2]....
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TL;DR: The structural aspects and properties of several biofibers and biodegradable polymers, recent developments of different biofiber and biocomposites are discussed in this paper.
Abstract: Recently the critical discussion about the preservation of natural resources and recycling has led to the renewed interest concerning biomaterials with the focus on renewable raw materials. Because of increasing environmental consciousness and demands of legislative authorities, use and removal of traditional composite structures, usually made of glass, carbon or aramid fibers being reinforced with epoxy, unsaturated polyester, or phenolics, are considered critically. Recent advances in natural fiber development, genetic engineering and composite science offer significant opportunities for improved materials from renewable resources with enhanced support for global sustainability. The important feature of composite materials is that they can be designed and tailored to meet different requirements. Since natural fibers are cheap and biodegradable, the biodegradable composites from biofibers and biodegradable polymers will render a contribution in the 21st century due to serious environmental problem. Biodegradable polymers have offered scientists a possible solution to waste-disposal problems associated with traditional petroleum-derived plastics. For scientists the real challenge lies in finding applications which would consume sufficiently large quantities of these materials to lead price reduction, allowing biodegradable polymers to compete economically in the market. Today's much better performance of traditional plastics are the outcome of continued RD however the existing biodegradable polymers came to public only few years back. Prices of biodegradable polymers can be reduced on mass scale production; and such mass scale production will be feasible through constant R&D efforts of scientists to improve the performance of biodegradable plastics. Manufacture of biodegradable composites from such biodegradable plastics will enhance the demand of such materials. The structural aspects and properties of several biofibers and biodegradable polymers, recent developments of different biodegradable polymers and biocomposites are discussed in this review article. Collaborative R&D efforts among material scientists and engineers as well as intensive co-operation and co-ordination among industries, research institutions and government are essential to find various commercial applications of biocomposites even beyond to our imagination.
2,612 citations
TL;DR: A review of natural fiber reinforced composites is presented in this paper with special reference to the type of fibers, matrix polymers, treatment of fibers and fiber-matrix interface.
Abstract: Natural fiber reinforced composites is an emerging area in polymer science. These natural fibers are low cost fibers with low density and high specific properties. These are biodegradable and non-abrasive. The natural fiber composites offer specific properties comparable to those of conventional fiber composites. However, in development of these composites, the incompatibility of the fibers and poor resistance to moisture often reduce the potential of natural fibers and these draw backs become critical issue. This review presents the reported work on natural fiber reinforced composites with special reference to the type of fibers, matrix polymers, treatment of fibers and fiber-matrix interface. © 1999 John Wiley & Sons, Inc. Adv in Polymer Techn 18: 351–363, 1999
2,210 citations
TL;DR: In this article, the thermal properties, crystallinity index, reactivity, and surface morphology of untreated and chemically modified fibers have been studied using differential scanning calorimetry (DSC), X-ray diffraction (WAXRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), respectively.
Abstract: Plant fibers are rich in cellulose and they are a cheap, easily renewable source of fibers with the potential for polymer reinforcement. The presence of surface impurities and the large amount of hydroxyl groups make plant fibers less attractive for reinforcement of polymeric materials. Hemp, sisal, jute, and kapok fibers were subjected to alkalization by using sodium hydroxide. The thermal characteristics, crystallinity index, reactivity, and surface morphology of untreated and chemically modified fibers have been studied using differential scanning calorimetry (DSC), X-ray diffraction (WAXRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM), respectively. Following alkalization the DSC showed a rapid degradation of the cellulose between 0.8 and 8% NaOH, beyond which degradation was found to be marginal. There was a marginal drop in the crystallinity index of hemp fiber while sisal, jute, and kapok fibers showed a slight increase in crystallinity at caustic soda concentration of 0.8–30%. FTIR showed that kapok fiber was found to be the most reactive followed by jute, sisal, and then hemp fiber. SEM showed a relatively smooth surface for all the untreated fibers; however, after alkalization, all the fibers showed uneven surfaces. These results show that alkalization modifies plant fibers promoting the development of fiber–resin adhesion, which then will result in increased interfacial energy and, hence, improvement in the mechanical and thermal stability of the composites. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 2222–2234, 2002
1,396 citations
TL;DR: In this article, water immersion tests were conducted by immersing specimens in a de-ionised water bath at 25 °C and 100 °C for different time durations.
1,298 citations