Understanding the Thermal and Resistive Properties from the Perspective of Molecular Interaction of Epoxy/POSS Composite

Abstract

Molecular interaction among different functional groups of insulating polymers manipulates the thermal and electrical properties. Two types of polyhedral oligomeric silsesquioxane (POSS) are added to epoxy and the outcome is studied by thermal conductivity, differential scanning calorimetry, and volume resistivity. A molecular dynamic simulation was set out using Material Studio 2017 software to investigate the intermolecular interaction mechanism that influences the thermal and electrical properties. The results show that doping epoxycyclohexyl POSS (ECH-POSS) with epoxy enhances the thermal conductivity, while glass transition temperature (Tg) is lowered compared to octa glycidyl POSS (OG POSS) doped epoxy composite and higher than pristine epoxy. Moreover, blending OG-POSS with epoxy demonstrates a positive impact on thermal conductivity and volume resistivity, which is attributed to the functionality of side groups. From the molecular simulations, the molecular interaction energy of EP/OG-POSS composites synergistically improves the thermal and electrical properties. In the last, the steric hindrance effect of POSS side chains is argued and the modified properties of epoxy/POSS composite are associated to the crosslinking brought by the side groups of POSS.