Compatibilization of polycarbonate and poly(vinylidene fluoride) blends studied by time-of-flight secondary ion mass spectrometry and scanning electron microscopy

The compatibilization of polycarbonate (PC) and poly(vinylidene fluoride) (PVDF) by poly(methyl methacrylate) (PMMA) was elucidated in detail using time-of-flight secondary ion mass spectrometry (ToF-SIMS) and scanning electron microscopy (SEM). Special PC/(PMMA/PVDF) sandwich-like samples were prepared for ToF-SIMS analysis. The ToF-SIMS results revealed that during the lamination of the PC and PMMA/PVDF sheets at high temperature, PMMA diffused from the PMMA/PVDF blend to the PC side. However, PC did not diffuse from the PC side to the PMMA/PVDF side. These results provided direct evidence to support that the improved interfacial adhesion of the PC/PVDF blend was due to PMMA and also indicated that PMMA may act as a compatibilizer for the PC/PVDF blends. A comparison of ToF-SIMS chemical images obtained from PC/PVDF (70/30) and PC/PMMA/PVDF (70/5/25) blends shows that the addition of PMMA greatly decreases the domain size of the PVDF phase and causes a homogeneous distribution of the PVDF phase. These results further confirmed the compatibilizing effect of PMMA on PC/PVDF blends. The effects of PMMA content and molecular weight on the morphology of PC/PMMA/PVDF blends were also studied and discussed.