Polyurethanes from renewable resources

Abstract

Liquid polyols and diisocyanates specially synthesized from renewable resource materials have been used in separate studies to form various polyurethanes. The polyols studied were hydroxy-functionalized polytetrahydrofuran monoglucoside and bisglucoside, and polymyrcene prepolymers. The polyols, characterized by end-group analysis, GPC, VPO and NMR, were reacted with 4,4′-methylene diphenylene diisocyanate (MDI) to form materials ranging from segmented copolyurethane elastomers to rubber-toughened, glassy polyurethane resins. In addition, different furan-based diisocyanates (FDI) with structures analogous to MDI were synthesized and characterized by elemental analysis, IR and NMR. Comparative kinetics studies indicated that FDI reactivities were intermediate between those of MDI and alkyl diisocyanates. FDI-based segmented copolyurethanes were formed using mixtures of polytetrahydrofuran and 1,4-butanediols. Polyurethane materials were evaluated by DSC, dynamic mechanical, tensile stress-strain, and fracture measurements. The feasibility of deriving liquid polyols and diisocyanates for polyurethane formation from agricultural and wood wastes is discussed.