Preparation and characterization of high efficiency microencapsulated phase change material based on paraffin wax core and SiO2 shell derived from sodium silicate precursor

Advanced thermal management system based on paraffin wax (PW) is an effective method to alleviate the increasing energy consumption. In this work, a new encapsulated phase change material (EPCM) was prepared by in-situ dehydration and condensation reaction, which consists of silica shell derived from sodium silicate and PW core. The chemical structure, crystal structure and microstructure of EPCMs were characterized by FT-IR, XRD, OM, TEM and SEM, which proved that the PW was successfully encapsulated by silica shell. In addition, the DSC, TGA, and leakage testing demonstrated that EPCMs possessed depressed supercooling, good thermal stability and leak-proof performance. When the mass ratio of PW/SiO2 is 4:1, the encapsulation ratio and encapsulation efficiency can reach 74.51% and 75.58%, respectively, and the corresponding latent heat is 94.4 J/g (melting process) and −93.2 J/g (solidifying process). In addition, the heat storage/release rate, thermal regulation ability and thermal cycling ability indicated that the EPCM has good thermal management performance. Due to the low cost and availability of sodium silicate and PW, the encapsulation technology proposed in this work has great potential practical application feasibility in the field of thermal management, including packaging, clothing and architecture. © 2021