Lignin-Based Polymer Blends and Biocomposite Materials

Lignin is a widely available natural polymer well suited for composite fiber applications. Depending on the wood species, and process conditions utilized, technical lignins can have a variety of thermal and chemical properties. Three technical lignins, a softwood kraft lignin (SKL), a hardwood kraft lignin (HKL), and a hardwood organosolv lignin (Alcell) were studied, and the suitability as precursor materials for composite fibers was determined. The hardwood lignins were easily extruded into fiber form, whereas the softwood kraft lignin displayed poor thermal processability. This observation was not unexpected, as the thermal moldability of lignins is very much dependent on its molecular structure. Chemical analysis, GPC, FT-IR, 1741_C21.qxd 2/17/2005 2:52 PM Page 671