Detection of compatibilizer efficiency in conductive polymer blends by impedance spectroscopy: Microstructure evaluation approach

Abstract

A novel approach of electrical impedance spectroscopy (EIS) is proposed to investigate the role of a compatibilizer on nanoparticle distribution in polymer blends with a co‐continuous morphology. Polypropylene/poly(ethylene‐co‐vinyl acetate) PP/EVA blends containing 3 vol% carbon nanotubes (CNT) with varying contents of polypropylene‐grafted‐ maleic anhydride (PP‐g‐MA) as compatibilizer were directly melt mixed. Microscopy, rheology, and thermodynamic analyses confirmed the distribution of CNTs in PP, EVA, and their interface. The EIS behavior of the blend nanocomposites was remarkably changed due to the formation of interphase by PP‐g‐MA/CNT. It was found that as the efficiency of compatibilizer increases the frequency dependency of the impedance diminishes showing a significant shift in the frequency cutoff from 104 Hz to 5 × 105 Hz. The EIS results also showed that compatibilizer can affect the loss factor. Incorporating 5 vol% or 10 vol% of the compatibilizer slightly reduced the loss factor, but a considerable reduction was observed at 20 vol% at which a conductive continuous interphase of compatibilizer formed at the interface. Moreover, the presence of compatibilizer led to a remarkable increase in dielectric constant by four orders of magnitude. EIS can effectively and comfortably trace the performance of a compatibilizer in a conductive polymer blend nanocomposite.Highlights EIS measurements describe microstructure of conductive polymer blend. EIS detects morphology development of a compatibilizer at varying contents. Migration of compatibilizer intensifies the Nyquist diameter decrement. Compatibilizer decreases dielectric relaxation time.