Blends of polybutyleneterephthalate with ethylene-propylene elastomer containing isocyanate functional group

Ethylene-propylene elastomer (EPM) grafted with an isocyanate-containing monomer (HT) was blended with polybutyleneterephthalate (PBT), and its morphological, rheological, and mechanical properties were studied. The monomer HI was prepared by the reaction of 2-hydroxylethylnlethacrylate and isophorone diisocyanate. The HI was successfully incorporated onto EPM backbone through solution graft reaction with radical initiator. When the PET was blended with HI-grafted EPM (EHI), the morphologies of the dispersed phase displayed differences with respect to particle size and interfacial adhesion, when compared with those of the PBT/EPM blend. The increase in complex viscosity, storage modulus and impact strength of PBT/EHI blends ensured that the compatibility between PET and EPM was improved through functionalization of EPM with the isocyanate moiety. These results are mainly due to in situ graft PBT-EPM copolymer that formed through the chemical reaction between the isocyanate group of EHI and hydroxyl or carboxyl end groups of PET. (C) 2001 Elsevier Science Ltd. All rights reserved.