Journal of Materials Science, Vol.54, No.4, 2990-3008, 2019
Electroactive phase nucleation and isothermal crystallization kinetics in ionic liquid-functionalized ZnS nanoparticle-ingrained P(VDF-HFP) copolymer nanocomposites
Poly(vinylidene fluoride-co-hexafluoropropylene) (P(VDF-HFP))-based copolymer nanocomposites are prepared by blending with hydrophobic ionic liquid-functionalized ZnS nanoparticles. Different characterization techniques such as X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy and differential scanning calorimetry (DSC) are employed to investigate the effect of the nano-additives to the conformational changes of copolymer chain segments before and after the melt crystallization. Isothermal crystallization kinetics of the nanocomposites are studied using DSC at different crystallization temperatures. Analysis of the experimental data reveals that the functionalized nanoparticles in nanocomposites gradually retard the crystallization rate through strong dipole-dipole interaction, but accelerates the nucleation rate, providing a large number of heterogeneous nucleation sites. However, at higher loading, they substantially restrict the crystal growth rate, leading to the formation of a large number of imperfect crystallites and a consecutive reduction in overall crystallinity. Different nucleation parameters such as initial laminar thickness, fold surface free energy and the work of chain folding during isothermal crystallization were evaluated from the analysis of the crystallization kinetics data using Avrami, Hoffman-Week and Lauritzen-Hoffman theories, also supports the same.