Preparation and characterization of phase change material microcapsules with carbon nanotubes loaded with Mg Al layered double hydroxides for controlling temperature in the building

Tubular structure embedding technique has promising applications in improving the thermal conductivity of phase change material microcapsules (PCMM). In this paper, the carbon nanotubes (CNT) were pretreated with flame retardant using magnesium‑aluminum layered double hydroxide (LDH) by co-precipitation method and then embedded in the shell of microcapsules. Thus, a phase change material microcapsule with both temperature control capability and flame retardancy was prepared. The microcapsules used capric acid (CA) as the core and polymethyl methacrylate (PMMA) as the shell, and the particle size was 100 nm-1 μm. The successful composition of the samples was verified by TEM and FT-IR. DSC test proves that CNT and LDH-modified CNT have very positive performance in improving the thermal conductivity of microcapsules. The outcome of TGA analysis and cone calorimeter test showed that the incorporation of modified PCMM into the rigid polyurethane foam (RPUF) matrix had a significant effect on improving its thermal stability and flame retardancy. The infrared thermal image analysis and self-created mini-chamber model were set up to characterize the temperature control performance of the sample. The results showed that the modified phase change material microcapsules have broad prospects in the field of building material temperature control.