Natural bast fibers

Table 2.7 Properties of selected natural bast fibers...

Loading nose, 226, 232, 233, 236, 238, 239, 241, 242, 245, 253, 256, 265, 274 Long alkyl chain alkoxysilanes, 172 Long cellulose fiber, 79, 92, 98 Long natural fiber, 110 Abaca, 110 Bast fibers, 110 Cost of, no Cotton, 110 Flax, no Fruit fibers, 110 Hemp, no Henequen, 110 Jute, no Kenaf, 110 Leaf fibers, 110 Mesta, no Nettle, no Pineapple, 110 Ramie, 110 Seed fibers, 110 Sisal, no Stalk fibers, 110... 

Natural fibers can be classified as seed fibers (such as cotton), bast fibers (like flax, hemp, jute, kenaf, ramie), hard fibers (like sisal), fi-uit fibers (like coir), and wood fibers. The chemical composition and dimensions of some common agro-fibers are presented in Table 5.21. The origin of wood fibers can be sawmill chips, sawdust, wood flour or powder, cutter shavings, pulp or wood residues. As binders for these fibers, both thermosetting (like phenolic, epoxy, polyester) resins and thermosetting matrices [such as polyethylene (LDPE, HDPE), polypropylene (PP), poly(vinyl chloride) (PVC), polystyrene (PS)j can be used. Thermoplastic composites are, however, less expensive to process than thermosetting composites, in addition to their ability to be manufactured into complex shapes. 

Jute is produced from plants of the genus Corchorus, which includes about 100 species. It is one of the cheapest natural fibers and is currently the bast fiber with the highest production volume. The fibers are extracted from the ribbon of the stem. Among all natural fibers, jute fibers are easily available in fabric and fiber... 

Munder, F. Furll, Ch. Flempel, FI. Advanced decortication technology for unretted bast fibers. Journal of Natural Fibers, 2004, 1,1, 49-66. 

Munder F., FtirU C., Hempel H., Processing of bast fiber plants for industrial application, in Natural Fibers, Biopolymers and Biocomposites, Eds. Mohanty A.K., Misra M. and Drzal L.T., CRC Press Taylor Francis Group, Boca Raton, 2005, pp. 109-140, Chapter 3. 

Abstract A wide variety of natural fibers can be applied as reinforcement or fillers in composites. Bast fibers, such as fiax and hemp, have a long history of cultivation and use. They are characterized by low weight and excellent range of mechanical properties. The properties of bast fibers are influenced by conditions of cultivation, retting, and processing. Pretreatment and surface modification of bast fibers is conducted for optimization of the interfacial characteristics between fiber and matrix as well as improvement of their mechanical properties. Application of bast fibers as reinforcement to replace the glass fibers to composite manufacture brings positive environmental benefits. 

There are many reports in scientific literature that present data determining physical-mechanical properties of bast fibers. The properties of the fiber are related to varieties of fibrous plants, condition of cultivation and retting, as well as the condition of measurement. Natural fibers are also characterized by the variability of individuals and from these reasons it is possible to find some differences between the fiber properties given by different authors in literature. 

Another strong aspect of vegetable fiber application in the industry is their ecological character with possibility of carbon dioxide reduction from the atmosphere during the fibrous plants cultivation processes. Use of bast fibers ensures biodegradability of the end product, if natural polymer, e.g., PLA is applied as a matrix. 

Mukhopadhyay S, Srikanta R (2008) Effect of ageing of sisal fibres on properties of sisal polypropylene composites. Polym Degrad Stab 93 2048-2051 Munder F, Furll C, Hempel H (2005) Processing of bast fiber plants for industrial application. In Mohanty AK, Misra M, Drzal LT (eds) Natural fibers, biopolymers and biocomposites. Taylor Francis, FL, Boca Raton... 

Keywords Agro-residues, banana bunch fibers, biocomposites, biodegradable, corn husk fibers, natural fibers, okra bast fibers, renewable... 

Not all cellulose is crystalline. Less-ordered cellulose is more chemically reactive and has different physical properties. Therefore, it is necessary to understand both the crystalline and noncrystalline phases. Various treatments can be applied to destroy the crystallinity, but less-ordered cellulose also occurs naturally. For example, a given cellulose molecule will often pass through several crystallites, as in ramie (a bast fiber). In ramie, crystallites are long enough to accommodate approximately 300 glucose units (Nishiyama et al. 2003b), but the cellulose molecules in ramie are much longer than that. 

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