Fabrication and Characteristics of Microencapsulated Phase Change Materials Modified by Graphene Quantum Dots and Aluminum Nanopowders
ZHOU Yufei1, YUAN Yiming2, QIU Zhongzhu1, LE Ping3, LI Peng4, JIANG Weiting1, ZHENG Puyan1, ZHANG Tao1, LI Chunying5
1 College of Energy and Mechanical Engineering, Shanghai University of Electric Power, Shanghai 200090 2 College of Mechanical Engineering, Tianjin University of Technology, Tianjin 300384 3 Shanghai Hongqiao Business District Energy Service Co., Ltd, Shanghai 201107 4 College of Mechanical Engineering, Tongji University, Shanghai 200092 5 College of Real Estate, Beijing Normal University, Zhuhai 519085
Abstract: This work aimed to explore the modification effects of graphene quantum dots (GQDs) and aluminum nanopowders on thermal properties and physical stability of microencapsulated phase change materials (MPCM). We used paraffin as core and urea-melamine-formaldehyde polymer as shell to synthesize three samples of MPCM, i.e. blank sample with no GQDs & aluminum nanopowders, MPCM incorporated with 1.5wt% GQDs, MPCM incorporated with 1.5wt% GQDs and 7wt% nano-aluminum, via an in-situ polymerization. The fabricated MPCM samples were characterized by means of SEM, particle size analyzer, hot disk sensor, DSC, etc. with respect to morphology, particle size distribution, thermal conductivity, thermophysical properties and suspension stability. The results showed that the modified MPCMs all exhibited satisfactory spherical shape, and the introduction of GQDs was conducive to a better particle size distribution. The MPCM sample incorporated with both GQDs and aluminum nanopowders was determined to have a superior thermal conductivity (0.78 W/(m·K)) in excess of 254.55% compared to the ordinary MPCM sample, and a higher encapsulation rate (92.65%). Meanwhile, the corresponding suspension can remain unstratified for 48 h.
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