Thermal, structural, optical and electrical properties of PVA/MAA:EA polymer blend filled with different concentrations of Lithium Perchlorate

Abstract

Structural, optical, thermal and morphological studies were performed on pure Polyvinyl alcohol/Methacrylic Acid – Ethyl Acrylate (PVA/MAA:EA (50:50)) blend and PVA/MAA:EA blend filled with different concentrations (5, 10 and 15 wt%) of Lithium Perchlorate (PVA/MAA:EA: LiClO4) prepared by a solution casting method. XRD patterns demonstrated that the peak intensity at 2θ = 19.5° decreased and the bandwidth increased with increasing the concentration of LiClO4, which implied a decrease in the degree of crystallinity and hence caused an increase in the amorphous nature. UV – Visible analysis revealed that the values of both direct and indirect band gaps were decreased with increasing LiClO4 content in the polymer host. This indicated the formation of charge transfer complexes between the polymer blend and the filler. The dTGA curves show three different steps of weight loss. This is due to the loss of water adsorbed, the elimination of the side chains, and the decomposition of the main chain. For LiClO4 filled PVA/MAA:EA, FTIR spectra showed disappearance of some bands with the change in their intensities as compared to pure PVA/MAA:EA film. This indicated considerable interaction between the polymer blend and LiClO4 filler. SEM images of the polymer blend films complexed with LiClO4 suggested the presence of a structural rearrangement of the polymer chains. The electrical conductivity of the prepared films was measured using the impedance analyzer in the frequency range from 1 Hz to 5 MHz at room temperature. It was observed that the conductivity increased with increase of the Li+ion concentration. Keywords: Polymer, Lithium Perchlorate, PVA/MAA:EA blend, FTIR, TGA, X – ray, SEM and optical energy