Structure change and energy storage property of poly(vinylidene fluoride-hexafluoropropylene)/poly (methyl methacrylate) blends

In this work, in order to reduce the energy loss induced by the ferroelectric P(VDF-HFP) and improve energy storage property, a series of P(VDF-HFP)/PMMA blend films were prepared via biaxiallyoriented technology. The results showed that the ratio of alpha crystal continuously decreased with the addition of PMMA, the ratio of beta crystal firstly increased, followed by a reduction with further rising the PMMA percentage. Though gamma ratio was small, it enhances steadily. With the addition of PMMA, it could be found out the disorder in crystal structure, the reduction in crystal size, and the drop in crystallinity of P(VDF-HFP). The structure change improved the discharge efficiency and temperature stability. With the addition of PMMA, tan delta is enhanced more than 10A degrees C, and the discharge energy efficiency improved from 45% of pure PVDF to 75% under 400 MV/m after modifying with PMMA. This improvement in the discharge energy efficiency is thought due to the formation of new crystal gamma-2b.