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

Ethylene–propylene elastomer (EPM) grafted with an isocyanate-containing monomer (HI) was blended with polybutyleneterephthalate (PBT), and its morphological, rheological, and mechanical properties were studied. The monomer HI was prepared by the reaction of 2-hydroxylethylmethacrylate and isophorone diisocyanate. The HI was successfully incorporated onto EPM backbone through solution graft reaction with radical initiator. When the PBT 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 PBT 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 PBT.