Spherulitic morphology and crystallization kinetics of poly(vinylidene fluoride)/Poly(vinyl acetate) blends

Spherulitic morphology and crystallization kinetics of the blends of poly(vinylidene fluoride) (PVDF) and poly(vinyl acetate) (PVAc) prepared by solution casting films have been investigated by differential scanning calorimetry (DSC) and polarized optical microscopy (POM). The results suggested that PVAc was mainly segregated into the interlamellar and/or interfibrillar regions due to the volume-filling spherulitic morphology observed. As for the results of crystallization kinetics, it was found that both the PVDF spherulitic growth rate (G(PVDF)) and the overall crystallization rate constant (k(n)) were depressed with either the addition of PVAc component or the increase of crystallization temperature (T-c). The kinetics retardation was attributed to the decrease in PVDF molecular mobility and dilution of PVDF concentration due to the addition of PVAc, which has a higher glass transition temperature (T-g).