Preparation of high performance copolymer microcapsule encapsulated heat storage material without supercooling

ABSTRACT

The methyl methacrylate (MMA)-based copolymer microcapsules encapsulating Rubitherm®27 (RT27) used as a phase change material were successfully prepared by microsuspension polymerization. The influence of three types of crosslinked comonomers such as ethylene glycol dimethacrylate), trimethylolpropane trimethacrylate, and divinylbenzene (DVB) on the microcapsule formation was studied at various ratios of MMA:crosslinked comonomer. It was found that using MMA:DVB at 70:30 wt% was the optimum ratio. The obtained microcapsules were nonspherical in shape with a dent and high shell strength. In addition, the latent heats of melting and crystallization of the encapsulated RT27 were about 140 J/g-RT27 which were close to those of the original RT27. However, the crystallization temperatures (T_c) of the encapsulated RT27 (14°C) were lower than that of the original RT27 (25°C) which was called supercooling. To prevent supercooling, the effect of nucleating agents (emulgen 150, 1-octadecanol, and RT58) on decreasing supercooling of the encapsulated RT27 was investigated. The results clearly presented that the addition of at least 5 wt% of RT58 significantly increased T_c (25°C) of the encapsulated RT27, whereas the observed latent heats were pretty close to original RT27.

Graphical Abstract

KEYWORDS:

• Microsuspension polymeriation
• copolymer microcapsule
• phase change material
• supercooling
• nucleating agent

Additional information

Funding

This work was partially supported by Thailand Institute of Scientific and Technological Research “Partnership Program in Production of Graduates in Master’s degree and Doctoral Degree Between Thailand Institute of Scientific and Technological Research (TISTR) and Educational institutions” (code 5912070100 given to P.P, P.C and P. N.) and RMUTT annual government statement of expenditure in 2016 (NRMS No. 2559A16502036 given to P.C.).

Notes on contributors

Priyagorn Pholsrimuang

Priyagorn Pholsrimuanga received the B.Sc. and M.Sc. degree in the field of Chemistry, Chemistry Department from Rajamangala University of Technology Thanyaburi, Pathumthani, Thailand, in 2014 and 2017, respectively. She worked as a Research Assistant in Department of Chemistry, Faculty of Science and Technology, Rajamangala University of Technology Thanyaburi, Thailand. Currently, her research interests in the field of microsuspension polymerization and microencapsulation for various applications.

Piyalak Ngernchuklin

Piyalak Ngernchuklin was born in Bangkok, Thailand. She received the B.Sc. and M.Sc. degree in the field of Ceramic Technology, Material Science Department from Chulalongkorn University, Bangkok, Thailand, in 1998 and 2000, respectively. She worked as a senior researcher in the Expert Centre of Innovative Materials (InnoMat) of Thailand Institute of Scientific and Technological Research (TISTR) under Ministry of Science and Technology, Thailand. Currently, Piyalak’s research interests include structure-processing-property relations in advanced ceramic materials (piezoelectric electrostricitive materials and their applications in actuator and sensor technology), and in advanced polymer materials.

Preeyaporn Chaiyasat

Preeyaporn Chaiyasat received the B.Sc. and M.Sc. degree in the field of Chemistry, Chemistry Department from Chiang Mai University, Chiang Mai, Thailand, in 1997 and 2001, respectively. She worked as an Assistant Professor in Department of Chemistry, Faculty of Science and Technology, Rajamangala University of Technology Thanyaburi, Thailand. Currently, Preeyaporn’s research interests include polymerization in aqueous dispersed system, micro- and nano-encapsulation and also the preparation of biopolymer for various applications.