Abstract:
Nanoencapsulated phase change materials (PCM) with a polystyrene shell and a paraffin core were synthesized by the miniemulsion polymerization using sodium α olefin sulfonate (AOS) as polymerizable emulsifier. Effect of the amount of polymerizable emulsifier, chain transfer agent, and crosslinking agent on the particle morphology was investigated. The critical micelle concentrations of aqueous solution and miniemulsion solution of AOS were 0.59, 6.0 g/L respectively as determined by conductivity.The emulsifying ability test showed that the emulsifying ability of AOS was better than that of sodium dodecyl benzene sulfonate. The morphology, structure and thermal properties of nanoencapsulated PCM were characterized by XRD, FT IR, DLS, TEM, DSC and TG. The results suggested that paraffin was encapsulated by the shell of polystyrene and PCM particle showed a core shell structure when the mass fractions of emulsifier and cross linker were 4.0% and 0.5%—1.0%, respectively. The encapsulation efficiency reached the maximum value the phase change temperature of the nanoencapsulated PCM was very close to that of paraffin when the mass fraction of emulsifier was 7% as observed by DSC.The latent heat of PCM phase transition was 151.8 J/g which was similar to that measured by TG.