Biomass-derived guar gum/polyvinyl alcohol aerogels with polyurea-encapsulated n-eicosane microcapsules for thermal management

To address the global energy crisis and achieve carbon neutrality goals, the development of efficient building thermal management technologies is imperative. Phase change materials (PCMs) have gained significant attention due to their high latent heat capacity. However, their practical application is constrained by limitations in packaging stability and mechanical properties. In this study, we developed a novel composite aerogel by constructing a three-dimensional porous matrix from biomass-derived guar gum (GG) and polyvinyl alcohol (PVA), which was then integrated with polyurea-encapsulated n-eicosane phase change microcapsules (MC) via freeze-drying. The synergistic combination of this tailored GG/PVA scaffold and the MC filler was systematically investigated. The results reveal that an optimized GG:PVA ratio of 1:1 confers exceptional morphological stability (volume shrinkage of 18.75 %) and mechanical strength (compression modulus of 857 kPa for GP@MC-5). The composite's enthalpy efficiency directly correlates with MC content, achieving a high relative enthalpy efficiency exceeding 96.26 %, a latent heat of 160.56 J/g, and a low thermal conductivity of 0.06452 W/(m·K). The material exhibits remarkable reliability, maintaining stable phase change enthalpy and microstructure after 100 thermal cycles, with a thermal decomposition temperature above 150 °C and a leakage rate below 1 %. Owing to its optimized structure and multifunctionality, the composite aerogel demonstrates outstanding thermal management performance. This work highlights its potential for application in energy-efficient buildings. Furthermore, its lightweight and flexible nature suggests promising utility in smart textiles for personal thermal management.