Chemical Treatments of Natural Fiber for Use in Natural Fiber-Reinforced Composites: A Review
04 Jan 2007-Journal of Polymers and The Environment (Kluwer Academic Publishers-Plenum Publishers)-Vol. 15, Iss: 1, pp 25-33
TL;DR: In this article, different chemical modifications on natural fibers for use in natural fiber-reinforced composites are reviewed, including alkali, silane, acetylation, benzoylation, acrylation, maleated coupling agents and permanganate.
Abstract: Studies on the use of natural fibers as replacement to man-made fiber in fiber-reinforced composites have increased and opened up further industrial possibilities. Natural fibers have the advantages of low density, low cost, and biodegradability. However, the main disadvantages of natural fibers in composites are the poor compatibility between fiber and matrix and the relative high moisture sorption. Therefore, chemical treatments are considered in modifying the fiber surface properties. In this paper, the different chemical modifications on natural fibers for use in natural fiber-reinforced composites are reviewed. Chemical treatments including alkali, silane, acetylation, benzoylation, acrylation, maleated coupling agents, isocyanates, permanganate and others are discussed. The chemical treatment of fiber aimed at improving the adhesion between the fiber surface and the polymer matrix may not only modify the fiber surface but also increase fiber strength. Water absorption of composites is reduced and their mechanical properties are improved.
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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
TL;DR: This review aims to provide a summary of the current state of knowledge on the structural features of wood and introduces a new class of solvents, called ionic liquids, which have many attractive properties, including chemical and thermal stability, nonflammability, and immeasurably low vapor pressure.
Abstract: Sustainability, industrial ecology, eco-efficiency, and green chemistry are directing the development of the next generation of materials, products, and processes. Biodegradable plastics and biocompatible composites generated from renewable biomass feedstock are regarded as promising materials that could replace synthetic polymers and reduce global dependence on fossil fuel sources.1 It is estimated that the world is currently consuming petroleum at a rate 100 000 times faster than nature can replace it.2 The growing global environmental awareness and societal concern, high rate of depletion of petroleum resources, concepts of sustainability, and new environmental regulations have triggered the search for new products and processes that are more compatible with the environment. The most abundant natural polymer in our environment is cellulose. It has an estimated annual biosphere production of 90 × 109 metric tons and, consequently, represents the most obvious renewable resource for producing biocomposites.3 Its highly ordered structure is responsible for its desirable mechanical properties but makes it a challenge to find suitable solvents for its dissolution.4 The first attempts to dissolve cellulose date back to the early 1920s.5 Several aqueous and nonaqueous cellulose solvents have been discovered since then, but all of these solvents suffer either from high environmental toxicity or from insufficient solvation power.6 In general, the traditional cellulose dissolution processes require relatively harsh conditions and the use of expensive and uncommon solvents, which usually cannot be recovered after the process.6-10 However, a new class of solvents was opened to the cellulose research community, when in 2002 Swatloski et al. reported the use of an ionic liquid as solvent for cellulose both for the regeneration of cellulose and for the chemical modification of the polysaccharide.7 In 1934, Graenacher had discovered a solvent system with the ability to dissolve cellulose, but this was thought to be of little practical value at the time.11,12 Ionic liquids are a group of salts that exist as liquids at relatively low temperatures (<100 °C). They have many attractive properties, including chemical and thermal stability, nonflammability, and immeasurably low vapor pressure.12 First discovered in 1914 by Walden, their huge potential in industry and research was only realized within the last few decades.13,14 This review aims to provide a summary of our current state of knowledge on the structural features of wood * To whom correspondence should be addressed. E-mail: ken.marsh@ canterbury.ac.nz. Tel.: +64 3364 2140. Fax: +64 3364 2063. † Department of Chemical and Process Engineering. ‡ Department of Mechanical Engineering. Andre Pinkert was born in Schwabach, Germany, in 1981. He studied Chemistry at the University of Erlangen-Nurnberg, Germany, and received his prediploma and diploma degrees in 2004 and 2008, respectively. During 2005, he joined the Marine Natural Products Group, lead by Murray H. Munro and John W. Blunt, at the University of Canterbury (UoC), New Zealand, working on the isolation and characterization of bioactive metabolites. In early 2006, he returned to Germany and resumed his studies at the University of Erlangen-Nurnberg, finishing his degree under the supervision of Rudi van Eldik. Associated with his studies, during 2007, he worked for AREVA NP on radio-nuclear chemistry and computer modeling. Since 2008, he is studying towards a Ph.D. degree at UoC under the supervision of Shusheng Pang, Ken Marsh, and Mark Staiger. His research focuses on biocomposites from natural fibers, processed via ionic liquids. Chem. Rev. 2009, 109, 6712–6728 6712
1,252 citations
TL;DR: In this article, the use of pretreated natural fibers in polymer matrix-based composites has been reviewed and the effect of surface modification of natural fibers on the properties of fibers and fiber reinforced polymer composites is also discussed.
Abstract: In recent years, natural fibers reinforced composites have received much attention because of their lightweight, nonabrasive, combustible, nontoxic, low cost and biodegradable properties. Among the various natural fibers; flax, bamboo, sisal, hemp, ramie, jute, and wood fibers are of particular interest. A lot of research work has been performed all over the world on the use of natural fibers as a reinforcing material for the preparation of various types of composites. However, lack of good interfacial adhesion, low melting point, and poor resistance towards moisture make the use of natural fiber reinforced composites less attractive. Pretreatments of the natural fiber can clean the fiber surface, chemically modify the surface, stop the moisture absorption process, and increase the surface roughness. Among the various pretreatment techniques, graft copolymerization and plasma treatment are the best methods for surface modification of natural fibers. Graft copolymers of natural fibers with vinyl monomers provide better adhesion between matrix and fiber. In the present article, the use of pretreated natural fibers in polymer matrix-based composites has been reviewed. Effect of surface modification of natural fibers on the properties of fibers and fiber reinforced polymer composites has also been discussed. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers
1,201 citations
TL;DR: This review focuses on recent developments in pretreatments, nanofibrillated cellulose production and its application in nanopaper applications, coating additives, security papers, food packaging, and surface modifications and also for first time its drying.
994 citations
TL;DR: In this article, an overview of the developments made in the area of kenaf fiber reinforced composites, in terms of their market, manufacturing methods, and overall properties is presented.
993 citations
Cites background from "Chemical Treatments of Natural Fibe..."
...Silane treatment also enhanced the tensile strength of the composites, minimized the effect of moisture on the composite’s properties, increased adhesion, and thereby, the composites strength [43,45,46]....
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...Alkaline treatment (or mercerization) is one of the most widely used chemical treatments for natural fibers, especially the kenaf fiber when reinforcing thermoplastics and thermosets [34,37,44,45]....
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...Consequently, alkaline treatment has a lasting effect on the mechanical behavior of natural fibers, especially on their strength and stiffness [43,45,46]....
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...It has been shown that etherification improves the dispersion of fibers in a polymer matrix, as well as the dimensional stability and interface of the final composites [45,46]....
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References
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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
TL;DR: In this paper, a twin-screw extruder with flax fiber content of 30 and 40 wt.% was used to produce a composite material with high impact strength.
1,370 citations
TL;DR: A review of biocomposites highlighting recent studies and developments in natural fibers, bio-polymers, and various surface modifications of natural fibers to improve fiber-matrix adhesion is presented in this paper.
Abstract: A review of biocomposites highlighting recent studies and developments in natural fibers, bio-polymers, and various surface modifications of natural fibers to improve fiber-matrix adhesion is presented. One of the most important factors which determine the final performance of the composite materials is the quality of the fiber-matrix interface. A sufficient degree of adhesion between the surface of hydrophilic ligno-cellulosic natural fibers and the polymer matrix resin is usually desired to achieve optimum performance of the biocomposite. Dewaxing, alkali treatment, isocyanate treatment, peroxide treatment, vinyl grafting, bleaching, acetylation, and treatment with coupling agents are useful ways to improve fiber-matrix adhesion in natural fiber composites. Two major areas of biocomposites will be discussed in this article. One is the most predominant biocomposite currently being commercialized for semi-structural use in the durable goods industries, e.g. auto-industries, i.e. natural fiber-polypropylen...
911 citations
TL;DR: In this paper, the Young's modulus of a flax fiber is estimated by taking into account the composition of the fibre and the evolution of the orientation of the fibrils during a tensile test.
Abstract: The knowledge of the behaviour of flax fibres is of crucial importance for their use as a reinforcement for composites materials. Flax fibres were tested under tensile loading and in repeated loading–unloading experiments. We have shown that fibre stiffness increases with the strain. This phenomenon is attributed to the orientation of the fibrils with the axis of the fibre when a strain occurs. By using micro-mechanical equations, the Young's modulus of a flax fibre is estimated by taking into account the composition of the fibre and the evolution of the orientation of the fibrils during a tensile test. A good agreement is found between experimental and calculated results. The origin of the large spread observed in the mechanical characteristics is analysed here.
890 citations
TL;DR: In this article, the effect of fiber treatment on the mechanical properties of unidirectional sisal-reinforced epoxy composites was investigated, and the relationship between optimized fiber treatment and performance improvement of sisal composites is proposed.
860 citations