Preparation of PMMA/SiO2 PCM microcapsules and its thermal regulation performance on denim fabric

Purpose This study aims to evaluate the thermal performance of phase change materials (PCMs) microcapsules (MCs) attached using SiO2 microspheres and investigate the thermal regulation effect on the coated denim fabric. Design/methodology/approach The PCM microcapsule was prepared by in situ polymerization using a mixture of solid paraffin and butyl stearate as core material (CM) and methyl methacrylate as a monomer. The SiO2 microparticles were attached to the outer layer of the membrane to enhance the thermal performance of MCs. The morphology, chemical structure, latent heat storage and thermal resistance of MCs were characterized. PCM MCs were coated on the denim fabric and thermo-gravimetric analysis was conducted; thermal insulation and thermal infrared imaging performance of the coated fabrics were also investigated. Findings The diameters of SiO2 particles and PCMs MCs were 300-500 nm and 1 μm, respectively. SiO2 was wrapped on single-wall PCMs MCs with the mass ratio of 1:5. With the addition of SiO2, the phase transition temperature range of MCs increased from 34°C to 39°C, and the endothermic and exothermic latent heat decreased by 5.35 J/g and 10.07 J/g, respectively. The degradation rate of MCs was significantly slowed down at high temperature. The denim fabric coated with MCs revealed thermal regulation property. After absorbing heat, the MCs slowed down the rate of heat loss and extended the heat release time. Research limitations/implications The phase transition temperature of the composite CM was wide, and the latent heat storage was reduced. The addition of SiO2 particles can significantly slow down the rate of heat loss, but it further reduces the latent heat storage performance. Practical implications The method developed provided a simple and practical solution to improve the thermal regulation performance of fabrics. Originality/value The method of adjusting the phase transition temperature range of the composite CM is novel and many applications could be found in preparation of PCMs and thermal management.