Reprocessable, Photothermal Phase Change Material-Based Hybrid Polymeric Networks for Solar-to-Thermal Energy Storage

Polymeric photothermal phase change material composite (PPCMC) networks with excellent reprocessability, high latent heat, and intrinsic network stability have the great advantages of solar energy storage and conservation and environmental protection resulting from the covalent crosslinking network structure and long-life inorganic photothermal agents. Herein, the reprocessable PPCMCs were successfully prepared by introducing the reactive diisocyanate-terminated poly(ethylene glycol) (PEG) and multiple amino-functionalized carbon black (CB)that serve as the phase change component and the photothermal curing agent, respectively. The phase change properties, mechanical strength, and photothermal efficiency of PPCMCs can be tuned by the chain length of PEG and the loading content of CB and the catalyst. PPCMCs possess the largest latent heat of 126.7 J/g, the highest photothermal conversion efficiency of 89.0%, superior shape stability even at 140 °C, high thermal stability beyond 300 °C, and reprocessing ability by introducing the catalyst of the transcarbamoylation reaction. Also, the PPCMCs exhibit high thermal reliability after accelerated thermal cycling and reprocessing, featuring nearly consistent chemical and crystalline structures, latent heat, phase change temperature, and photothermal properties. This synthetic strategy provides an alternative to obtain multi-functional PPCMCs due to the enhanced interfacial interaction between inorganic particles and the polymer matrix via covalent linkages.