Lignin-Polyvinyl Polymer Blends
Similar to the case with polyolefins, vinyl lignin polymers have attracted interest primarily as blending lignin can improve the UV and thermal stability properties of vinyl polymers. Several researchers have studied the blending of lignin to polyvinylchloride [80-84], polyvinyl alcohol [85-87], polyvinylacetate [88] and their physical properties. In general, unmodified lignin has poor compatibility with non-polar vinyl polymers; while the modulus of these blends is increased, reductions in tensile strength and elongation at break are observed. Early work found good compatibility between hydrophobic lignin and relatively polar polyvinyl chloride (PVC), but poor compatibility with polystyrene. However, the source of the lignin can have a considerable impact on miscibility and Pucciariello et al. have reported successful blending of straw lignin powder with atactic polystyrene into a readily processible material [89].