Effect of processing on the thermal stability of blends based on polyurethane. Part I

The thermal stability of blends of polyurethane with three different elasto mers having reactive functional groups has been studied. The blends have be en prepared by three different blending techniques, keeping the blending ra tio constant. It was found that the thermal stability of the blends was dic tated by the blending technique. Blends prepared by the masterbatch techniq ue degraded at a lower temperature. The degradation temperatures were incre ased when preblending and preheating/preblending techniques were adopted. T his may be due to the formation of interchain crosslink bonds between the t wo elastomer phases, the extent of which was more in the preheated/preblend ed technique. (C) 2000 Published by Elsevier Science Ltd.