SYNTHESIS OF POLYURETHANE ACRYLATE OLIGOMERS BASED ON POLYBUTADIENE POLYOL

Polyurethane acrylate oligomers (PUA) were prepared by a competitive r eaction of 4,4'-dicyclohexyl methane diisocyanate (H(12)MDI) with hydr oxy terminated polybutadiene (HTPB) and hydroxyethylacrylate (HEA). Ki netic models were established for noncatalytic and catalytic systems, and the reaction constants were calculated using a numerical method. T he evolution of the noncatalyzed and catalyzed reactions were analyzed , respectively, by SEC and FTIR. Comparing the reactivities of HTPB an d HEA, as well as other small molar mass model alcohols, the HTPB show ed the higher reactivity. HTPB is 700 times more reactive than HEA at 80 degrees C. This high reactivity was analyzed as a result of lower c oncentration of hydrogen bonds in bulk HTPB. The activation energy of the noncatalyzed and catalyzed reactions were found to be, respectivel y, 56.98 and 45.16 KJ/mol. The structures of the PUA synthetized in on e-step or two-step process were analyzed and discussed using a gelatio n model and the kinetic data obtained. (C) 1996 John Wiley & Sons, Inc .