Phase behavior and mechanical properties of injection molded poly(ethylene terephthalate)/polyarylate blends

Abstract
Directly injection molded blends, composed of poly(ethylene terephthalate) and a polyarylate of bisphenol A, and isophthalic/terephthalic acids have been studied. Both their phase behavior and their mechanical properties after this blending method have been determined. After injection molding, the poly(ethylene terephthalate)/polyarylate blends show a single glass transition by differential scanning calorimetry, although the transition peaks of the blends widen when observed by dynamic mechanical analysis. The calorimetric results show a hindered crystallization of poly(ethylene terephthalate), due to the presence of polyarylate and the occurrence of interchange reactions. The mechanical behavior observed shows an improvement in the small‐strain properties of the blends with respect to those of the pure components. The break and impact properties of the blends show negative deviations with respect to linearity. These deviations are less important when high polyarylate content exists in the blends.