polyurethanes from alcell lignin fractions obtained by sequential solvent extraction

摘要

Lignin-derived polyurethane films were synthesized by solution casting using three fractions of distinct molecular weight and chemical functionality form Alcell lignin. A three-component system of lignin fraction, polyethylene glycol (PEG) of MW=400 g mol~-1 and polymeric methyl-diisocyanate (MDI) was used. For each lignin fraction, the effects of varying the NCO/OH ratio and lignin content on the crosslink density, ultimate tensile properties and dielectric strength of the polyurethanes were studied. The crosslink density was found to increase with molecular weight of lignin.