Simultaneous phase change energy storage and thermoresponsive shape memory properties of porous poly(vinyl alcohol)/phase change microcapsule composites

Porous poly(vinyl alcohol) (PVA)/phase change microcapsule composites with shape memory properties were prepared by physical foaming, cycles of freezing-thawing and freeze drying. The effects of phase change microcapsules on pore structure, phase change energy storage capacity, thermal stability, crystallinity, mechanical properties, shape memory properties and water absorption and retention of the porous composites were investigated. With an increase of the proportion of phase change microcapsules, the pore density, pore size and water absorption and retention of the porous composite materials were decreased, while the phase change energy storage performance was improved and Delta H-m was up to 31.22 J g(-1). The phase change energy storage of the porous composites was stable even after 50 phase transition cycles. Meanwhile, the thermal stability of the porous composites was also not affected by the addition of phase change microcapsules. The entanglement of PVA molecular chains in the porous composites was affected by the microcapsules embedded in the matrix of PVA during freezing-thawing cycles, resulting in a change of crystallinity and mechanical properties of the porous composites. The porous composites with phase change energy storage capacity also showed good shape memory performance with shape recovery rate of 100% even after multiple deformation, which was expected to expand the multi-field application of dual-functional materials. (c) 2020 Society of Chemical Industry

Automated summary

Porous poly(vinyl alcohol) (PVA)/phase change microcapsule composites with shape memory properties were prepared and studied in this research. It was found that the addition of phase change microcapsules could enhance the phase change energy storage performance and shape memory properties, while reducing pore structure and water absorption capacity of the porous composites.