Constructing a novel porous skeleton based on polycarbonate/expandable graphite for phase change materials with improved flame retardancy and shape stability

Abstract

Phase change materials (PCMs) have been utilized in thermal management to stabilize the temperature and improve the fire safety of operating electronics. Paraffin wax (PW) is usually used as PCMs due to its high latent heat, stable performance, environmental friendliness, and low cost. However, PW has inherent weakness of easy leakage and high flammability. In this work, a porous skeleton composed of polycarbonate (PC) and expandable graphite (EG) was innovatively fabricated, and then the skeleton was applied to construct PCMs with enhanced flame retardancy and reduced leakage of PW by absorbing PW and triphenyl phosphate (TPP) into the PC-EG skeleton. The phase change performance, fire safety, and thermal management capacity of the PC-based PCMs were characterized. The results showed that at the loading ratio of PW/TPP = 3/1, the PC-based PCMs had a leakage ratio of only 0.26 % and a latent heat of 94.1 J g−1. The peak heat release rate (pHRR) and total heat release (THR) of the PC-EG/(PW/TPP-3:1) sample were decreased by 58.8 % and 39.1 %, respectively compared with that of the PC-EG/PW sample. The char residue was increased to 10.0 % from 5.0 % by the presence of TPP. The as-prepared PCMs exhibited high thermal management ability in the pouch cell operation. It is suggested that the PC/EG skeleton have never been used in PCMs for the improvement of flame retardancy and shape stability. This work provides a feasible method to fabricate PC-based PCMs with excellent flame retardancy, shape stabilization, and high phase change efficiency, which has great potential to produce ideal thermal management materials.