Other Natural Fibers

The first fibers used by humans were probably those that occur naturally as tissues or excretions of either vegetables or animals (see Table 87). At much later times, after metals had been discovered, humans also learned to manufacture - from some of the ductile metals, mainly gold, silver, and their alloys - thin filaments (not fibers, however), which have since been used to decorate textile fabrics. It was only during the twentieth century, after synthetic plastics were discovered, that it became possible to make artificial human made fibers. The great majority of the natural fibers, such as cotton and wool, occur as staple fibers, short fibers whose length is measured in centimeters. Silk is different from all other natural fibers in that it occurs as extremely long and continuous filaments several hundred meters long. 

Dust in the air of a mill engaged in the mechanical processing of cotton, flax, hemp, or certain other natural fibers is generally agreed to cause byssinosis (1 -4). No specific causative agent of byssinosis in the dust, however, has yet been unequivocally identified ( ). Certain bacteria dispersed from cotton fiber or bracts into mill air have been suggested to be a probable cause. 

Antioxidant used for wood or other natural fiber filled polyolefins, elastomers and hot melt adhesives when light exposure and maintenance of color is important. 

C.A. Correa, C.A. Razzino, and E. Hage. DMTA analysis of interface adhesion in wood-plastic composites. In Eighth International Conference on Woodflber-Plastic Composites (and Other Natural Fibers), Madison, WI, 2005. 

Customer preferences for recycled products have encouraged a more efficient use of wood and natural fibers. One potential approach to preserve wood and use natural fibers is the development of commodity-engineered composites that blend wood and natural fibers with other materials, such as plastic. The idea of combining wood and plastic is to produce a product with performance characteristics that combine the positive attributes of both materials. Wood and other natural fibers have been used as fillers and/or reinforcement to improve the mechanical properties of a variety of products. The combination of wood and plastic creates the ability to develop diverse products using many different manufacturing processes. 

Wood-plastic and other natural fiber-plastic composite materials are being increasingly used in automotive industries. Woodstock, made with a mix of about 50% wood flour and 50% PP, is still widely used for automotive interiors, but the industry appears to be especially interested in components made form recycled plastics, and the introduction of wood-filled compounds for molding has spurred some of this interest. 

Hemcore does not see the product as meeting every application need of the fiber-RPs industry, but it considers that the fiber could find some price/performance gaps. No yield figures have yet been published, but it is possible that, in common with other natural fibers, a very large area of land will be needed to produce viable quantities. 

These and other natural fibers may be slowly commercialized, depending on market demands for bio-based, renewable, low-carbon-footprint material content in plastics [7-44, 7-45, 7-46, 7-50, 7-56]. 

The demands of staple fiber are different from those of filament yarns. Staple fiber is a continuous filament cut into short lengths in centimeters. Staple fibers are discontinuous and are crimped and chopped to the desired staple fiber length to blend at the carding stage with cotton (short staple), wool (long staple), or other natural fibers. The raw polyester fibers are... 

Synthetic fibers do not contain natural impurities although there are added impurities such as sizing materials and oil stains. Therefore, their pretreatment process is simpler than other natural fibers. However, synthetic fibers such as polyester and acrylic have poor wettability, dyeability, and antistatic behavior. After plasma treatment, the fiber surface gets physically altered, and hydrophilic functional groups are introduced to the fiber surface, which improves the wettability of the fiber significantly. In recent years, many researchers have studied ways to modify polyester textile materials, and good results have been obtained (Morent et al., 2008). 

Further research showed that the same effect can be obtained when using other natural fibers, for instance, hemp or sisal. 

Like other natural fibers, PALF vary in their properties according to species, geographical regions, age, locations in each plant, and weather conditions among others (Bismarck et al. 2005). There are many different species under the genus of A. comosus, while in the works on PALF and PALF-reinforced polymer composites reviewed, specific species of pineapple from which PALF were extracted were barely mentioned. Only in Bhaduri et al. (1983) the chemical compositions... 

Henequen (Agave fourcroydes) fibers are hard, strong, and long similar to sisal fiber family. These fibers are obtained from long leaves of Agave plants, which are mainly used for making twines, ropes, carpets, and cordages. When compared with other natural fibers, these fibers are of relatively lower cost and density for biocomposites. 

Physico-Chemical and Mechanical Properties of Sisal Fiber and Its Comparison with Other Natural Fiber... 

A study on hybrid composites of sisal fiber with other natural fibers or synthetic fiber is needed to achieve optimum benefit for broader applications. Sisal fiber/ matrix interface and relationship between interface and bulk composites need to be studied in detail for a better understanding leading to the development of a unique process for better bonding between fiber and matrix and compatibility with a wider range of other materials/components. Further R D, new initiatives, and innovation are needed to develop a unique mechanism for the manufacture of environmental... 

Polymers reinforced with cellulose fibers have received much attention in recent years because of their low density, nonabrasive, combustible, nontoxic, low cost and biodegradable properties. Several authors have reviewed recent advances in the use of natural fibers in composites like flax [ 1 ], jute [2,3], straw [4], kenaf [5,6], coir [7-9], fique [10], among others. Natural fibers have been used to reinforce thermoplastics and thermosets polymers in automotive and aerospace applications [11]. The influence of surface treatments of natural fibers on interfadal characteristics was also studied [12-17], and Joshi et al. [18] compared the life-cycle environmental performance of natural fiber composites with glass fiber composites. In this study, natural fiber composites were found to be environmentally superior in most applications. 

As mentioned previously, the main bottleneck in the broad use of these fibers in thermoplastics is the poor compatibility between the fibers and the matrix. The inherent high moisture sorption of lignocellulosic fibers certainly has an effect on their dimensional stability [28]. This may lead to the microcracking of the composites and degradation of mechanical properties [28]. Like other natural fibers, kenaf absorbs moisture due to its hydrophilicity. The key issue related to the development and production of natural fiber-reinforced composites is the interfacial adhesion between the fiber and polymer matrix. Because of their inherent dissimilarities, natural fibers/polymer matrix composites are not compatible and interfadal adhesion in these composites tends to be poor. The weak bonding at the interfaces between natural fibers and polymer matrix is surely a critical cause of the reduction of useful properties and performance of the... 

K. Okubo, and T. Fujii, Eco-composites using bamboo and other natural fibers and their mechanical properties. Proceedings of the international workshop on Green composites, pp. 17-21 (2002). 

Flax is the most used natural fiber (excluding wood) in the European automotive industry, most of which is obtained as a by-product of the textile industry [5]. However, other natural fibers such as jute, kenaf sisal, coir, hemp, and abaca are also used. Natural fibers are typically combined with polypropylene, polyester, or polyurethane to produce such components as door and trunk liners, parcel shelves, seat backs, interior sunroof shields, and headrests [6]. 

The environmental benefits of wood and other natural fibers have been an important influence on their use, particularly in Europe. Natural fibers are derived from a renewable resource, do not have a large energy requirement to process, and are biodegradable [21]. 

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