The synthesis and characterization of phase change material microcapsules with titanium oxide nanotubes for thermal energy regulation

Abstract

In this work, highly efficient phase change materials have been used to enhance the temperature regulation of epoxy resin composites, with the aim of reducing building energy consumption. To overcome the leakage and poor thermal conductivity of organic phase change materials, we have designed to dope the titanium dioxide nanotubes into the shell of phase change material microcapsules. Firstly, titanium dioxide nanotubes were prepared via an emulsion-templated interfacial polycondensation reaction. Then, the resultant titanium dioxide nanotubes were doped into novel microcapsules based on a cetyl alcohol core and a polymethyl methacrylate shell through in-situ polymerization. The thermogravimetric analysis proved that the phase change material microcapsules with titanium dioxide nanotubes had enhanced thermal stability, manifested as an increase of 6.1 % in residual mass. Differential scanning calorimetry showed that the latent heat and initial melting temperature of the phase change material microcapsules with titanium dioxide nanotubes were 165.8 J/g and 45.7 °C. The results of cone calorimeter tests indicated that the peak heat release rate and total heat release rate of epoxy resin containing microcapsules with titanium dioxide nanotubes were 501.72 KW/m2 and 62.02 MJ/m2, which decreased by 31.65 % and 16.46 % compared to that containing the microcapsules. Using a mini-room model to evaluate the temperature regulation, the results proved that the phase change material microcapsules with titanium dioxide nanotubes made the peak indoor temperature decrease from 30.09 °C to 28.52 °C. This study provides an effective method for improving the temperature regulation and fire safety of epoxy resin composites.