A novel shape memory-assisted and thermo-induced self-healing boron nitride/epoxy composites based on Diels–Alder reaction

Abstract

Hexagonal boron nitride (hBN), as one of the two-dimensional (2D) materials, possesses many excellent properties like others. Herein, we report a novel self-healing epoxy filled with hBN. High compatibility between hBN and the epoxy matrix was obtained by the modification of hBN with silane coupling agent (Mi-Si). At the meantime, excellent self-healing behavior was achieved by retro Diels–Alder (r-DA) reaction between the maleimide functional group in the modified hBN (m-hBN-OH) and the added furfurylamine. Besides, the inadequate curing of epoxy led to the glass transition temperature (Tg), which is also seemed as the transition temperature for the shape memory of the epoxy, below the r-DA reaction temperature, and endowed the system with the shape memory-assisted self-healing properties. The m-hBN-OH was characterized by Fourier transform infrared spectra, nuclear magnetic resonance (1H-NMR) spectra, X-ray diffraction experiments, X-ray photoelectron spectroscopy measurements and so on. The new m-hBN-OH modifier was prepared with the optimized Mi-Si/hBN-OH weight ratio of 3.0, which could both improve the thermal property and achieve better thermal conductivity. This designed m-hBN-OH/epoxy could actually show ideal self-healing properties due to the shape memory-assisted self-healing effect. The thermal conductivity of the neat epoxy resin and the m-hBN-OH/epoxy was 0.2156 W m−1 K−1 and 0.4358 W m−1 K−1, respectively. As a novel material with efficient thermal conductivity, hBN made great contribution to the thermally induced shape memory and self-healing property. Systematic researches reveal that the composites are promising as long durable thermal interface materials, anti-scratch materials and so on.