Surface energy matching and montmorillonite barriers enabled acrylonitrile butadiene rubber/palmitic acid phase change composites for high-performance thermal management

The development of flexible phase change composites (PCCs) with high latent heat, low leakage, and reliable performance in harsh environments remains a great challenge. This study presents a novel PCC by employing acrylonitrile butadiene rubber (NBR) as a flexible matrix, palmitic acid (PA) as the phase change material, and polydopamine-modified montmorillonite (DMMT) as a barrier filler. NBR grade with 26% acrylonitrile content exhibited optimal compatibility with PA, driven by a close match in dispersion surface energy components. The DMMT, uniformly dispersed and exfoliated within NBR, constructed a tortuous labyrinth, which worked with the NBR crosslinking network to encapsulate the PA. This endowed the PCC with a high latent heat of 118.6 J g -1 and low leakage rate (1.1% after 8 h at 80 °C). Furthermore, the PCC demonstrated outstanding cyclic stability and remarkable performance retention in transformer oil. This work provides profound insights into the compatibility mechanism and an effective preparation strategy for high-performance PCCs, demonstrating great potential for thermal management applications in harsh conditions. • The NBR/PA compatibility is dominated by dispersion surface energy matching, not simply by polarity. • A synergistic barrier network is constructed by DMMT layers and the NBR crosslinking network to encapsulate PA. • The composite exhibits outstanding cyclic stability and remarkable performance retention in transformer oil. • The superior microstructure enables high latent heat and low leakage simultaneously.