Influence of temperature on the confinement effects of micro and nano level graphite filled poly(isoprene-co-isobutylene) composites

Abstract

Electrically conducting elastomer composites using nanocarbon fillers have utmost significance in the current scenario of flexible electronics. Though a large number of reports have come out in this topic, the influence of temperature on the nano reinforcement is little addressed. Here we aim at deducing the confinement effects occurring in the micro and nano composites of poly(isobutylene-co-isoprene) rubber (IIR) under different temperatures. For this various composite samples of IIR were prepared with expanded graphite (micro-sized) and reduced graphene oxide (nano-sized) fillers and the structure and morphology were characterized by Raman spectroscopy, X-ray diffraction studies and scanning electron microscopy. We could observe greater influence of temperature on the properties of rubber nanocomposites compared to the micro and anticipate the applicability of such materials in temperature sensors. With 25–45 °C rise in temperature, the current increases and the sample shows deviations from the non-linear behavior. However at 45 °C, non-linear property is seen as the conducting particles gap increases with temperature. The temperature variation influences the modulus (stiffness) of the polymeric material as well. Finally a correlation is drawn between their electrical and dielectric characteristics and the molecular level interactions from Payne effect at different temperatures.