Effects of amorphous silica nanoparticles and polymer blend compositions on the structural, thermal and dielectric properties of PEO–PMMA blend based polymer nanocomposites

Abstract

The polymer nanocomposite (PNC) films consisted of poly(ethylene oxide) (PEO) and poly(methyl methacrylate) (PMMA) blend matrices dispersed with nanoparticles of amorphous silica (SiO2) have been prepared by solution-cast method followed by melt-press technique. Effects of SiO2 concentration (x = 0, 1, 3 and 5 wt%) and PEO–PMMA blend compositional ratios (PEO:PMMA = 75:25, 50:50, and 25:75 wt%) on the surface morphology, crystalline phase, polymer-polymer and polymer-nanoparticle interactions, melting phase transition temperature, dielectric permittivity, electrical conductivity, electric modulus and the impedance properties of the PNC films have been investigated. The crystalline phase of the PNC films decreases with the increase of PMMA contents which also vary anomalously with the increase of SiO2 concentration in the films. The melting phase transition temperature and polymer-nanoparticle interactions significantly change with the variation in the compositional ratio of the blend polymers in the PNC films. It is observed that the effect of SiO2 on the dielectric and electrical properties of these PNCs vary greatly with change in the compositional ratio of PEO and PMMA in the blends. The dielectric relaxation process of these films confirm that the polymers cooperative chain segmental dynamics becomes significantly slow when merely 1 wt% SiO2 nanoparticles are dispersed in the polymer blend matrix.