Reprocessable, biodegradable polyester-based solid-solid phase change materials networks from dynamic ionic crosslinking with high latent heat capability

Abstract

Thermosetting polyethylene (PEG)-based solid-solid phase change materials networks (PCMNs) have high latent leat and form stability from the covalent crosslinking, yet they remain a great challenge in reprocessing and recycling of PCMNs without compromising a high latent heat above 100 J/g. Herein, the polyester-based solid-solid PCMNs with PEG as phase change component were synthesized via ionic crosslinking between the linear multiple carboxyl-functionalized phase change materials (CPCMs) polyester and zinc cations. The CPCMs were synthesized via polyesterification reaction between pyromellitic dianhydride (PMDA) and diol containing PEG and ethylene glycol, meanwhile forming multiple carboxyl along molecular chains. The dynamic ionic bonds and hydrolysable ester bonds endowed PCMNs with the reprocessability and biodegradability, respectively. PCMNs had the ΔH = 120 J/g with PEG weight fraction of ∼0.91 and concentration of carboxyl of ∼0.26 mmol/g. Also, PCMNs had good phase change ability, thermal stability and thermal reliability before and after thermal cycling and reprocessing. The robust approach enabled the combination of the reprocessing ability and high latent heat of PCMNs by ionic crosslinking.