Influence of SiO2 nanoparticles on morphological, thermal, and dielectric properties of PVDF

Abstract

The morphology, crystalline structure, and thermal stability in a system of SiO2 nanoparticles dispersed in PVDF matrix are investigated. SEM/TEM indicated that SiO2 nanoparticles present in PVDF matrix have been homogeneously dispersed. The spherulite texture of PVDF was significantly disrupted by the presence of SiO2 nanoparticles as observed by optical micrographs. The XRD pattern shows that the intensity decreases, while full width at half maximum increases with the increasing nanoparticles content, which is ascribed to the significant decline in crystallinity. DSC also shows that the crystallinity is influenced by the SiO2 nanoparticles in the PVDF matrix. The thermal properties of nanocomposites directly reflect the morphological and structural changes induced by SiO2 nanoparticles. TG shows that the nanocomposites have higher decomposition temperatures in comparison with the PVDF. The increase in thermal stability with the addition of SiO2 nanoparticles is mainly attributed to interfacial interactions between the organic polymer and inorganic nanoparticles. The investigation of the dielectric properties at different frequencies and temperature revealed that the relaxation mechanism, which controls the movement of the charge carriers in the nanocomposites, is strongly related to the morphology of the system.