Morphology, structure and thermal stability of microencapsulated phase change material with copolymer shell

A series of microencapsulated phase change materials (MicroPCMs) with n-octadecane as core were successfully fabricated by suspension-like polymerization. The influence of initiator type and polymerization temperature on MicroPCMs were investigated systemically. The morphology of these microcapsules with different copolymer shells and various phase changing material (PCM) contents were observed by scanning electron microscopy (SEM). In addition, the core-shell structure and the shell thickness of microcapsules were also characterized by SEM. Thermal gravimetric analysis (TGA) curves indicate that the effects of different copolymer shell and various PCM contents on thermal stability of MicroPCMs were insignificant. Besides, SEM micrographs show that all of the MicroPCMs with various PCM contents remained intact after heat treatment at 200 °C for 30 min, however, all of the heat-treated MicroPCMs had no enthalpy as demonstrated by differential scanning calorimetry (DSC) curves. From above results, the weight loss of MicroPCMs may be caused by the penetration of decomposed gas of n-octadecane through the intact shells.

Research highlights
► A series of MicroPCMs with styrene-based copolymer shells were fabricated.
► Influence of initiator and polymerization temperature on MicroPCMs was investigated.
► Effects of different shells and PCM contents on thermal stability were insignificant.
► The weight loss mechanism of styrene-based copolymer MicroPCMs was investigated.