Cotton fiber reinforcements

Molding Powders. Urea-formaldehyde resins are compounded with alpha-cellulose cotton fiber reinforcement to produce molding powders (4 percent) for compression, transfer, and injection molding. Typical molding conditions are 127 to 182°C and 2000 to 8000 psi. They are superior to phenolics in white color, electrical resistance, and low cost, but are limited by moisture sensitivity (Table 3.13). They are used primarily in electrical wiring devices such as wall outlets, receptacles, electric blanket controls, circuit breakers, and knob handles. Smaller amounts are used in bottle caps, housewares, buttons, and sanitary ware. 

Hashmi, S. A. R., Dwivedi, U. K., and Chand, N. (2007). Graphite modified cotton fiber reinforced polyester composites under sliding wear conditions. Wear262 ll-l2), 1426-1432. 

Seventy years ago, nearly all resources for the production of commodities and many technical products were materials derived from natural textiles. Textiles, ropes, canvas, and paper were made of local natural fibers, such as flax and hemp. Some of them are still used today. In 1908, the first composite materials were applied for the fabrication of big quantities of sheets, tubes, and pipes in electrotechnical usage (paper or cotton as reinforcement in sheets made of phenol- or melamine-formaldehyde resins). In 1896, for example, airplane seats and fuel tanks were made of natural fibers with a small content of polymeric binders [1]. 

In one of the first reports on fiber reinforcement of rubber, natural rubber (NR) was used by Collier [9] as the rubber matrix, which was reinforced using short cotton fibers. Some of the most commonly used rubber matrices for fiber reinforcement are NR, ethylene-propylene-diene monomer (EPDM) rubber, styrene-butadiene rubber (SBR), polychloroprene rubber, and nitrile rubber [10-13]. These rubbers were reinforced using short and long fibers including jute, silk, and rayon [14—16]. 

One can classify fibers in a variety of ways. For example, one may divide the whole field of fibers into apparel and nonapparel fibers, i.e. based upon the final use of fibrous material. The apparel fibers include synthetic fibers such as nylon, polyester, spandex, and natural fibers such as cotton, jute, sisal, ramie, silk, etc. Nonapparel fibers include aramid, polyethylene, steel, copper, carbon, glass, silicon carbide, and alumina. These nonapparel fibers are used for making cords and ropes, geotextiles, and structural applications such as fiber reinforcements... 

Moldings. Melamine-formaldehyde resin (M/F = 1/2) is reinforced with alpha-cellulose cotton fiber, catalyzed with phthahc anhydride, and molded at 145 to 165°C and 4000 to 8000 psi (Table 3.14). Moldings have the highest hardness and scratch resis-... 

J. Prachayawarakorn, P. Sangnitidej, and P. Boonpasith, Properties ofthermoplastic rice starch composites reinforced by cotton fiber or low-density polyethylene. Carbohydr. Polym. 81, 425-433 (2010). 

Reinforcements. Both the resole and novolac compounds use a broad array of reinforcements to meet the demands of the market place wood flour, cotton flock, minerals, chopped fabric. Teflon, glass fibers (long and short), nylon, rubber, and kevlar. Asbestos, which had been a widely used filler in many thermosetting compotmds, has been replaced over the past 20 years with glass fiber-reinforced phenolic compounds in many applications. 

Glass/Mineral- filled Cellulose- filled Glass Fiber-reinforced Glass PAN Carbon Woodflour- tilled Woodflour-and Mineral-tilled High-Strength Glass Fiber-reinforced Cotton- tilled Cellulose-tilled... 

Silva C G, Beneducci D and Frollini E (2012), Lyocell and cotton fibers as reinforcements for a thermoset polymer , BioResources, 1, 78-98. 

Cellulose is the most abundant polysaccharide in nature with approximately 180 billion tons produced and broken down every year (Engelhard 1995). Cellulose, which occurs as microfibrils, is the component responsible for the excellent load bearing properties of plant cell walls (for a summary for the cellulose content of the different cell wall layers, see Table 6-1). The cellulose microfibrils in wood fibers are important raw material for the pulp and paper industries, and those in cotton and hemp for the textile industries. Moreover, the renewable plant fibers have substantial potential to replace man-made fibers in fiber-reinforced thermosets and thermoplastics to produce environmentally friendly materials (Mohanty et al. 

Natural fiber-reinforced PLA composites are attractive because both the reinforcement (natural fiber) and matrix (PLA) are obtained from renewable resources. Natural fibers are considered as environment friendly alternatives to conventional reinforcing fibers such as glass, carbon, aramid, and so on. Natural fibers can be subdivided into three categories plant (cotton, jute, flax, hemp, etc.), animal (wool, silk, etc.), and mineral fibers (asbestos, inorganic whiskers, etc.). Generally, plant fibers are more popularly used as natural fiber reinforcements. Of these fibers, the most used are flax, jute, sisal, ramie, hemp, kenaf, and cotton. Plant fibers can generally be classified as nonwood (vegetable fibers) and wood fibers [20]. 

Fibers are widely used in polymeric materials to improve mechanical properties. Vegetable fibers (e.g., cotton, flax, hemp, jute) can generally be classified as bast, leaf or seed-hair fibers. Cellulose is the major substance obtained from vegetable fibers, and applications for cellulose fiber-reinforced polymers have again come to the forefront with the focus on renewable raw materials [198 - 200]. Hydrophilic cellulose fibers are very compatible with most natural polymers. 

C5 ras VP, Manfredi LB, Ton-That M-T, Vazquez A (2008) Physical and mechanical properties of thermoplastic starch/montmorillonite nanocomposite films. Carbohydr Polym 73 55-63 de Morals Teixeira E, Correa A, Manzoli A, de Lima Leite F, de Oliveira C, Mattoso L (2010) Cellulose nanofibers from white and naturally colored cotton fibers. Cellulose 17 595-606 de Moura MR, Aouada FA, Avena-Bustillos RJ, McHugh TH, Krochta JM, Mattoso LHC (2009) Improved barrier and mechanical properties of novel hydrox5q)ropyl methylcellulose edible films with chitosan/tripolyphosphate nanoparticles. J Food Eng 92 448—453 Dean K, Yu L, Wu DY (2007) Preparation and characterization of melt-extruded thermoplastic starch/clay nanocomposites. Compos Sci Technol 67 413 21 Duanmu J, Gamstedt EK, Rosling A (2007) Hygromechanical properties of composites of crosslinked allylglycidyl-ether modified starch reinforced by wood fibres. Compos Sci Technol 67 3090-3097... 

Cellulose fibers in the form of papers and cotton had been used in combination with phenol-formaldehyde polymer as one of the earUest fiber-polymer composites [12]. Glass fibers later came on the scene and contributed to the commerciahzation of fiber-reinforced plastics [13]. The technical appHcations of fiber-reinforced plastic composites are shown in Figure 13.2. At least 50% of the fiber-reinforced plastics is used for automotive and construction applications. 

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