Effect of the compatibility on dielectric performance and breakdown strength of poly(vinylidene fluoride)/low‐density polyethylene blends

ABSTRACT Immiscible polymer blends with high dielectric constant ( ε ) and improved breakdown strength ( E b ) performance were obtained by composing poly(vinylidene fluoride) (PVDF) with low‐density polyethylene (LDPE) or the LDPE grafted with maleic anhydride (LDPE‐ g ‐MAH) through melt‐blending way. The dielectric properties of these blends were emphasized for considering the compatibility effect on the energy storage application. Interface morphology, co‐continuity behavior, and grafted ratio were simultaneously investigated to detect the compatibility enhancement after introducing MAH. Results showed that the MAH positively improved the dielectric properties. Both the measured E b of PVDF/LDPE and PVDF/LDPE‐ g ‐MAH blends showed a minimum value at v PVDF = 50 vol % because of the worst compatibility; meanwhile, higher E b of PVDF/LDPE‐ g ‐MAH than that of PVDF/LDPE blend was observed owing to the better compatibility. For considering the effect interface morphology on the dielectric performance, layer‐structure films composing with pure PVDF and LDPE layers were further constructed and studied. It was revealed that the layered structure could be treated as a helpful way to improve ε and E b for immiscible polymer blends. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132 , 42507.