Basic structure-property behavior of UV curable polyurethane acrylates

Effects of hard segment type, soft segment type, soft segment length, and crystallization at various levels of reactive diluent have been studied in polyurethane acrylates. PTMG-IPDI-based PU acrylates gave better soft segment-hard segment phase separation as compared with PTMG-TDI-based ones. Among PTMG-, PCL-, and PTAd-IPDI-based materials, only PTMG-based one gave clean phase separation, and PTAd-based gave the poorest phase separation. With greater phase separation, higher modulus was obtained. Crystallization of soft segment in PTAd-IPDI-based material gave a significant increase in tensile modulus and elongation at break, with a notable difference in dynamic mechanical properties. (C) 1996 John Wiley & Sons, Inc.