Silicone rubber/paraffin@silicon dioxide form-stable phase change materials with thermal energy storage and enhanced mechanical property

A kind of silicone rubber (SR)/paraffin (Pa)@silicon dioxide (SiO2) composite form-stable phase change material (PCM) was developed in this paper. Pa@SiO2 was obtained by choosing Pa as PCM core microencapsulated in SiO2 shell based on tetraethoxysilane (TEOS) and gamma-aminopropyl triethoxysilane (APTES) as precursors, then Pa@SiO2 microencapsules were embedded in SR matrix to fabricate SR/Pa@SiO2 composites. The SiO2 shell can provide a barrier for the melted Pa and meanwhile have reinforcing effect on SR as inorganic filler. The in-situ modification of SiO2 shell using APTES owing to the amino groups can not only prevent agglomeration, but also increase interfacial bonding between Pa@SiO2 with SR. The thermal and mechanical properties of the form stable PCMs were characterized by differential scanning calorimetry (DSC) and mechanical tests. The results showed that the thermal and mechanical properties of SR/Pa@SiO2 composites were better than those of SR/Pa and SR/Pa/SiO2. Leakage test was conducted by heating the prepared composites over the melting temperature of Pa. The SR/Pa@SiO2 composites were found as form-stable PCM with low leakage rate. The phase change latent heat of the SR/Pa@SiO2 composites was up to 92.39 J g(-1) and the composites can be used for thermal energy storage.