KINETIC-STUDY OF THE REACTIONS BETWEEN HYDROXYLATED POLYBUTADIENE AND ISOCYANATES IN CHLOROBENZENE .4. REACTIONS WITH TOLYLENE DIISOCYANATE, 3-ISOCYANATOMETHYL-3,5,5-TRIMETHYLCYCLOHEXYL ISOCYANATE AND HEXAMETHYLENE DIISOCYANATE

A comparative kinetic study of the reactions of three diisocyanates [tolylene diisocyanate (TDI), 3-isocyanatomethyl-3, 5, 5,-trimethylcyclohexyl isocyanate (IPDI) and hexamethylene diisocyanate (HDI)] with a hydroxyl-terminated polybutadiene (R-45M) was carried out in chlorobenzene solution. The kinetic data were compared with those obtained previously using toluene as solvent and with the data for the reaction between the prepolymer and the dimer diacid diisocyanate (DDI) reported in preceding papers. It was observed that TDI reacted more quickly than the three other diisocyanates. DDI and HDI showed similar reactivities at lower temperatures; with increasing temperature, DDI reacted more quickly than HDI. IPDI showed slightly lower reactivity than HDI. The kinetic data indicated that the effect of the solvent depends on the diisocyanate structure.