New crystal structure and discharge efficiency of poly(vinylidene fluoride-hexafluoropropylene)/poly(methyl methacrylate) blend films

A series of PMMA/poly(vinylidene fluoride-hexafluoropropylene) [P(VDF-HFP)] blend films were prepared with a solution blending process to improve discharge efficiency. The crystal structure and properties of the PMMA/P(VDF-HFP) blend films were carefully studied. The results show that the crystallinity, the dielectric constant and the loss of the polymer blend films decreased, while melting temperature increased with the increase in PMMA content. The XRD results demonstrate the existence of a γ-2b phase. It is believed that the phase transition of the P(VDF-HFP) crystals from α to γ-2b contributes to the increase in melting temperature. The energy loss of P(VDF-HFP) reduced significantly with the addition of PMMA. The blend film with 10% PMMA showed the best discharge efficiency with a value above 80% in 300 MV m−1. This increase in discharge efficiency is thought to result mainly from the formation of γ crystals.

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