Reed-based phase change microcapsules/polyurethane foam composites with enhanced thermal storage, mechanical properties, and interfacial compatibility

The incorporation of phase change microcapsules (microPCMs) into polyurethane foams (PUFs) for phase change thermal insulation composites (MePCMs-PUFs) is significant for promoting low-carbon building development and mitigating global climate change. However, the interfacial incompatibility between conventional microPCMs and PUFs continues to be a critical factor limiting both the mechanical performance and thermal energy storage capacity of MePCMs-PUFs. In this study, microPCMs with polyurethane shells (RP-MePCMs) and PUFs containing liquefied residue (RP-PUFs) were synthesized from reed-based polyols and subsequently combined to fabricate MePCMs-PUFs. The effects of the core-shell ratio, stirring speed, and shell material ratio on the structure and thermal storage performance of RP-MePCMs were investigated. Additionally, the interfacial compatibility mechanism between RP-MePCMs and RP-PUFs was elucidated. The results demonstrate that RP-MePCMs with a core-shell ratio of 3:1, a stirring speed of 300 rpm, and 25 % reed-based polyol content exhibit superior thermal storage performance (∆Hm = 194.1 J/g, ∆Hc = 193.1 J/g), high energy storage efficiency (E = 88.3 %), and excellent cycling durability. Phytolith in the reed (Phragmites australis) enhances the thermal storage performance of RP-MePCMs by improving the thermal conductivity of the shell material and facilitating the crystallization of the core material. Chemical bonding (-OH/-NCO) interactions between RP-MePCMs and RP-PUFs effectively enhance the interfacial compatibility, significantly improving both the foaming ability and thermal storage performance of MePCMs-PUFs (∆Hm = 36.12 J/g, ∆Hc = 36.09 J/g). The novel reed-based MePCMs-PUFs contribute to sustainable resource utilization and energy peak shaving and valley filling, showing promising application potential in building and industrial energy conservation.