PREPARATION AND CHARACTERIZATION OF LACTITOL-BASED POLY(ETHER POLYOL)S FOR RIGID POLYURETHANE FOAM

Propoxylation of lactitol [4-O-beta-D-galactopyranosyl-D-glucitol] und er alkaline conditions afforded poly(ether polyol)s (PEP) which have b een characterized by their unsaturation content, alpha color, hydroxyl number, viscosity, hygroscopicity, and molecular weight distribution. The analogous sucrose-based PEP were prepared for comparison. Lactito l was found to require shorter reaction times and produced lighter-col ored polyols than did sucrose. Polyols produced from lactitol displaye d similar physical properties to sucrose-based PEP. Molecular weight a nalysis by GPC using the universal calibration method showed lactitol PEP to have polydispersities between 1.04 and 1.07. Negligible decompo sition of lactitol during propoxylation was confirmed by C-13-NMR and GPC. H-1-NMR of trifluoroacetyl derivatives of lactitol PEP afforded s econdary determination of M(n). In addition, rigid polyurethane foams (PURF) formulated with lactitol-, sucrose-, or commercial sucrose-glyc erin-based polyols and PAPI 27 were prepared and characterized. Lactit ol-based PURF were found to compare favorably with sucrose-based foams , displaying a density and compressive strength of 28.9 kg/m(3) and 1. 213 X 10(5) N/M(2), respectively. (C) 1996 John Wiley & Sons, Inc.