ABSTRACT
The demand for environmentally friendly products based on renewable raw materials has increased in the last years. Examples of biodegradable materials include natural fiber reinforced biopolymers (Anonymous, 2007; Avella et al., 2009; Bhardwaj and Mohanty, 2007; Bledzki et al., 2009; Bodros et al., 2007; Cheung et al., 2009; Nampoothiri et al., 2010). As an alternative to natural fibers, man-made fibers based on renewable resources can be used as reinforcement. The advantage of the man-made over the natural fibers is their reproducible quality; a disadvantage is the higher price in comparison to for example bast fibers. An example of a man-made cellulose fiber is lyocell which is regenerated from 100% wood cellulose in the NMMO process using an organic solvent N-methyl-morpholine-N-oxyde. The NMMO process is based on the ability of amino oxide to dissolve cellulose under specific conditions. The cellulose can be regenerated out of these solutions and the fibers are produced by a wet fiber formation process (Albrecht et al., 1997). Lyocell fibers display special force elongation characteristics. They combine a high tensile strength and a high elongation at break in one fiber which is an advantage for the production of composites which must display high tensile and impact strength at the same time. A typical force-elongation curve of lyocell fibers in comparison to kenaf (bast fiber) and cotton (seed hair fiber) is shown in Figure 1.
