| 초록 |
The thermo-regulated composite films containing nanoencapsulated n-octadecane were synthesized by condensation polymerization. There are two processes in this study. In the 1st step, nanoencapsuled n-octadecane as a core material were prepared by miniemulsion polymerization with polystyrene as a shell material. The surfactant system is dissolved in water, the costabilizer is dissolved in the monomers and mixed under stirring. Then, the mixture is subjected to high efficient homogenization. In the 2nd step, polyurethane prepolymers were prepared from IPDI (isophorone diisocyanate), polyol and DMPA (dimethylol propionic acid). This prepolymers were dispersed in the PS PCM latex by neutralization emulsification. The stable of PCM nanocapsules were obtained by miniemulsion polymerization, which could be attributed to the prevention of Ostwald ripening by PCM as co-surfactant. And polyurethane latex stabilized with PCM capsules in the water. The reaction parameters were NCO/OH ratio, TEA/DMPA mole ratio and solid content of nanocapsule. The film properties were measured on UTM. The thermal efficiency of PCM PUD film was measured through DSC and TGA results and efficiency was increased at optimal process. Obtained PCMs capsules were evaluated through DSC, and they showed thermoregulating effect at 27℃. The distribution of particle size and the morphology of PCM-PUD were analyzed by CHDF, SEM, and TEM respectively. |
