Mechanical and Thermal Properties of PET/PBT Blends

Poly(ethylene terephthalate)(PET)/poly(butylene terephthalate)(PBT)blends were prepared in ways: by injection molding only and by mixing on extrusion machine and than injection molding. The mechanical properties, thermal behavior and crystallization of PET/PBT blends were investigated. It has been observed that the ways of preparation of the blends have the biggest influence on their mechanical properties, especially on impact strength. The DSC study shows generally double melting endotherms and one crystallization exotherm. The study presents that mixing of PET and PBT only during the injection molding is not sufficient for expected, essential improvement of impact resistant of PET/PBT blends. To warranty the enhanced properties of the injected PET/PBT blends it is necessary to mixed them first on the extrusion machine.