Investigation of an Abnormal α Polymorph Formation in Miscible PVDF Nanocomposite Blend Using Kinetics of Crystallization

چکیده مقاله

Poly(vinylidene fluoride)(PVDF)/Acrylic rubber(ACM)/Nanoclay miscible nanocomposite blends were prepared using melt-mixing method. Fourier transform infrared spectroscopy (FTIR) was employed to investigate the real-time conformational changes of PVDF chain segments during crystallization of corresponding nanocomposite blends under isothermal condition. This analysis demonstrated the formation of α polymorph in nanocomposite blends, which is quite abnormal compared to polymorphism of PVDF nanocomposite. Differential Scanning Calorimetry (DSC) technique was also conducted to study the isothermal crystallization kinetic of the mentioned system. Furthermore, Avrami equation was employed to evaluate the overall crystallization rate. It was shown that addition of nanoclay to PVDF/ACM miscible blends slightly affects Avrami parameters. According to Lauritzen-Hoffman theory, the presence of crystals was observed at regime II of crystallization. Free energy of folding of miscible nanocomposite blends was comparable with that of miscible blends, suggesting the fact that PVDF molecules interact with ACM chains within nanocomposite blends, whereas nanoclay particles are wrapped by ACM molecules. De Gennes' theory was used to explain the emergence of a different polymorph in miscible nanocomposite blends compared to that in PVDF nanocomposites.