Abstract:
In this research, the preparation of polymethyl methacrylate microcapsules encapsulated RT 27 (PMMA/RT 27) by iodine transfer microsuspension polymerization (microsuspension ITP) was studied.
The polymer microcapsules encapsulated RT 27 were prepared by the conventional radical microsuspension polymerization with various polymer shells, PMMA, polydivinylbenzene (PDVB) and polystyrene (PS). It was found that the latent heats of the encapsulated RT 27 with PMMA shell were similar to those of pure RT 27 and higher than those of PDVB and PS shells due to the complete phase separation of the encapsulated RT 27 core and PMMA shell. However, approximately 45 wt% of free PMMA particles were formed in aqueous medium resulting in the reduction of shell thickness and strength. As a result, the nonspherical PMMA microcapsules were formed. Therefore, to solve this problem, the preparation of PMMA encapsulated RT 27 by microsuspension ITP was carried out. From the result, the prepared PMMA/RT27 microcapsules have spherical shape with a small dimple at the surface. The latent heats also closed to those of pure RT 27. Moreover, the free PMMA particles in aqueous medium were not observed.
Therefore, it can be concluded that high performance PMMA/RT 27 microcapsules were successfully prepared by microsuspension ITP. The latent heats of the encapsulated RT 27 were high similar to those of pure RT 27. Moreover, the formation of free PMMA particles in aqueous medium was drastically reduced.