CRYSTALLINE STRUCTURES AND alpha AND beta POLYMORPHS TRANSFORMATION INDUCED BY NANOCLAY IN PVDF-BASED NANOCOMPOSITE

چکیده مقاله

Poly(vinylidene °uoride) (PVDF) nanocomposites were prepared by melt-mixing. The dispersion of clay platelets and rheology of nanocomposites were analyzed using X-ray di®raction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and rheometric mechanical spectrometer (RMS). The transformation of to and phase in PVDF was induced by the addition of nanoclay and subsequently the isothermal crystallization kinetics of neat PVDF and its nanocomposite have been investigated. The interaction between clay nano¯llers and PVDF macromolecular chains induced the change of conformation from trans-gauche to alltrans crystal structure in PVDF segment. The isothermal crystallization of PVDF/clay nanocomposites was carried out by Di®erential Scanning Calorimetry (DSC) technique. The in°uence of clay platelets on nucleation crystallization rate and Avrami exponent were studied. PVDF/ clay nanocomposite showed higher crystallization rate indicating that nanoclay has acted as an e®ective nucleation agent. This nucleation e®ect of nanoclay increased the Avrami exponent and decreased the degree of crystallinity.