Preparation of serpentine fiber/poly (vinyl alcohol) aerogel with high compressive strength to stabilize phase change materials for thermal energy storage

Abstract

The applications of paraffin used as phase change materials (PCMs) in energy saving buildings have been greatly limited due to its inherent leakage problem. Herein, a novel serpentine/poly(vinyl alcohol) (SER/PVA) composite aerogel was fabricated by incorporation of SER fibers treated with ball milling into PVA via self-assembly and freeze-drying, which has high compressive strength and can be used as a supporting material to encapsulate paraffin and prevent its leakage. The results show that the aerogel has excellent mechanical properties, the shrinkage of aerogels prepared with SER after ball milling was reduced from 42.8% to 5.0%, and its compressive strength can reach 6.30 MPa at 80% strain. With the increase of the ball milling time, the compressive strength of the composite aerogel increase. Then, the SER/PVA@P composite PCMs were prepared by vacuum impregnation with paraffin (P) into SER/PVA. The loading mass of paraffin in the SER/PVA@P composite PCMs is up to 89.14%, resulting in a superior latent heat storage capacity of 184.8 J/g in the melting process. The leakage-proof test shows that the SER/PVA@P appears no melting paraffin trace evenly heating at 60 °C for 10 min. The composite PCMs have excellent thermal reliability over 400 thermal cycles. The thermal conductivity of SER/PVA@P reached 0.237 W/(m∙K), which was lower than that of pure paraffin. Therefore, the prepared SER/PVA@P composite PCMs with high latent heat storage capacity, lower thermal conductivity, excellent thermal reliability, and good leakage-proof demonstrate a potential application in energy saving buildings.