Influence of siloxanes viscosity and concentration on low‐temperature impact modification and melt flow behavior of polycarbonate

Abstract Reactive blending of polycarbonate (PC) with hydroxyl terminated polydimethylsiloxane (PDMSOH) enhances the impact strength at sub‐zero temperature and also influences the melt flow property of the modified PC. Both viscosity and concentration of the siloxane play role differently on modification of the properties. PDMSOH was incorporated in the polymer chains of PC by transesterification reaction in presence of alkali catalyst. Higher concentrations of siloxane though increased low‐temperature ductility but often at the expense of undue enhancement of melt flow property. Selection of PDMSOH of an appropriate viscosity however could overcome this problem. Different grades of siloxane modified PC could be developed having good impact strength at −30°C while simultaneously maintaining its desired melt flow property. Izod impact tester, melt flow index meter, viscometer, UV–Vis spectrometer and scanning electron microscope were used to characterize the material. This work will pave the way for developing desired grades of PC for low‐temperature applications.