Abstract: The effect of silicone phosphate on the transesterification reaction in the PBT/PET blend was studied using differential scanning calorimetry by observing the crystallization and melting behavior during two cycles of heating and cooling scannings. Upon addition of silicone phosphate, the crystallization temperature of PBT/PET blend increased by 4.5℃, the relative viscosity increased by 0.1 dL/g, and the heat deflection temperature increased by 7.0℃, based on the neat system. In contrast, the counterpart containing TPPi showed a decrease of 1.5C in crystallization temperature. Silicone phosphate was more effective than TPPi in decreasing the content of end hydroxyl groups and thus more effective in depressing the transesterification between PBT and PET. The introduction of inhibitors did not influence much the mechanical properties of the blends.

Key words: poly(ethylene terephthalate), poly(butylene terephthalate), silicone phosphate, transesterification reaction, inhibitor