Natural fibers

Abstract

The term “natural fibers” covers a broad range of vegetable, animal, and mineral fibers. However, in the composites industry, it usually refers to wood fiber and agrobased bast, leaf, seed, and stem fibers. These fibers often contribute greatly to the structural performance of the plant and, when used in plastic composites, can provide significant reinforcement. Below is a brief introduction to some of the natural fibers used in plastics. More detailed information can be found elsewhere. Although natural fibers have been used in composites for many years, interest in these fibers has waned with the development of synthetic fibers such as glass and carbon fibers. However, recently there has been a resurgence of interest. One of the largest areas of recent growth in natural fiber plastic composites is the automotive industry, particularly in Europe, where natural fibers are advantageously used as a result of their low density and increasing environmental pressures. Most of the composites currently made with natural fibers are press-molded, although a wide range of processes have been investigated. Table 11-1 shows the consumption of natural fibers by the European automotive industry and projections of future total consumption. Flax is the most widely used natural fiber in the European automotive industry, comprising 71% of the natural fibers consumed in 2000. Most of this is short-fiber flax obtained as a by- product of the textile industry. Natural fibers are typically combined with polypropylene, polyester, or polyurethane to produce such components as door and trunk liners, parcel shelves, seat backs, interior sun roof shields, and headrests. Increased technical innovations, identification of new applications, continuing political and environmental pressures, and government investment in new methods for fiber harvesting and processing are leading to projections of continued growth in the use of natural fibers in composites, with expectation of reaching 100,000 tonnes per annum by 2010.

Citation

Clemons, Craig M.; Caulfield, Daniel F. 2005. Natural fibers. Functional fillers for plastics. Weinheim : Wiley-VCH, 2005: pages [195]-206