Method for Control of Particle Size and Morphology of Paraffin/Polystyrene-Divinylbenzene Microcapsules
摘要
Microencapsulation of phase change materials (MicroPCMs) has been paid special attention because of their extensive applications in saving and releasing energy. MicroPCMs containing paraffin with a melting point of 55 ℃ in polystyrene-divinylbenzene (P(St-DVB)) were prepared by suspension-like polymerization. The characterization of micro- capsules by FTIR, DSC and TG proved that paraffin had been successfully encapsulated and the proportion of encapsulated paraffin was 49.8%—58.5%. The effects of polyvinylpyrrolidone (PVP) with different molecular weights serving as the suspension stabilizer were investigated in detail. The results illustrated that the type of PVP had a significant influence on the particle size of MicroPCMs. The average diameter of MicroPCMs decreased with an increasing molecular weight of PVP. Moreover, the crosslinker-postaddition method was adopted in this study to improve the morphology of P(St-DVB) MicroPCMs. SEM images showed that when the DVB was added at the 2nd hour of polymerization the morphology of ob- tained P(St-DVB) MicroPCMs exhibited good sphericity since it could avoid the influence of cross-linker agent during the nucleation period.