High thermal conductivity insulating AlN/poly(m-phenylenedicarbonyl-m-phenylenediamine) paper realized by enhanced compatibility: a selection of appropriate coupling agent

Abstract

Encouraged by the goal of achieving net-zero carbon emission by 2050, the exploration of insulating material becomes one of the core projects to the electrical equipment innovations. The rise of composites enables the insulating material to be endowed with more functions. By this concern, adopting the coupling agents is one of the effective methods to improve the compatibility of composites, which highly strengthens the desired properties. The functional groups of coupling agents, nevertheless, could not always show a positive impact to access enhanced properties. In this work, four types of silane coupling agents including amino-propyl, glycidyletheroxy-propyl (GP), vinyl, and methacryloxy-propyl functional groups are employed to modify the aluminum nitride (AlN) fillers, and the modification effects on the insulating and thermal conductivity of the AlN/poly(m-phenylenedicarbonyl-m-phenylenediamine) (PMIA) composite paper are systematically investigated and compared. The results show that a proper coupling agent is beneficial to the uniform dispersion of the inorganic filler in the organic matrix and highly contributes to their interface quality, where the heat transfer path is established that boosts the heat dissipation. By tailoring the trap depth and density toward deeper and higher, the carrier transport is highly confined which enhances the breakdown strength to a large extent. Therefore, high breakdown strength and thermal conductivity of 182.9 kV mm−1 and 0.302 W (m·K)−1, respectively, are achieved in the GP modified AlN/PMIA paper, which are 16.7% and 167.4% higher than that of pure PMIA paper.