Publication

Abstract : The role of two solvents, namely N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMAc), on the dispersion of CNF in PVDF matrix has been studied when the composites are synthesized by non-solvent precipitation route followed by melt crystallization at 200 °C and quenching in water. The electrical conductivities of melt-crystallized PVDF–CNF, PVDF-7 wt% graphite-CNF nanocomposites synthesized using DMAc solvent are higher than that of composites synthesized using DMF solvent. Thermogravimetric analysis of PVDF-7 wt% graphite, PVDF-3 wt% CNF suggests that the onset temperature of thermal degradation of the composite synthesized using DMAc is 20 °C higher than that of the same composite synthesized by using DMF. The SEM analysis of cross section of melt-crystallized, water-quenched PVDF-3 wt% CNF clearly proves better dispersion of CNF when DMAc solvent is used. Structure development in the polymer when CNF is incorporated has been understood in terms of lattice mismatch theory. DSC analysis proves the nucleating ability of CNF when incorporated in the polymer matrix as crystallization temperature (Tc) is enhanced by 5 °C. At low frequency (40 Hz), the intergranular capacitance is more than two times higher for PVDF-3 wt% CNF composites synthesized by using DMAc solvent when compared to that of DMF employed composites. The enhancement of storage modulus at − 90 °C for PVDF-7 wt% CNF composites synthesized by using DMAc solvent when compared to that of DMF employed same composite supports better dispersion of CNF in PVDF matrix in the former case as revealed by DMA.