Fabrication and Performance of Composite Microencapsulated Phase Change Materials with Palmitic Acid Ethyl Ester as Core

Abstract

Microencapsulation of phase change materials (PCMs) could prevent the leakage of PCMs during solid–liquid phase change process. However, their applications are mainly limited by the compactness and thermal stability of the traditional polyurea shell microcapsules. To increase the thermal compactness and thermal stability of PCM microcapsules, tetraethylorthosilicate (TEOS) was employed to form polymer/SiO 2 composite shells to enhance the mechanical performance of polyurea and polyurethane microcapsule via interfacial polymerization and in situ polymerization. The morphology and chemical components of the microcapsules were characterized by field-emission scanning electron microscope (FE-SEM) and Fourier transform infrared (FT-IR) spectroscopy, respectively. The thermal properties of the microcapsules were investigated by differential scanning calorimetry (DSC) and thermal gravity analysis (TGA). The results showed the smoothness and compactness of both polyurea–SiO 2 and polyurethane–SiO 2 microcapsules enhanced slightly, when compared with that without TEOS addition. Moreover, the SiO 2 composite shell had good effect on thermal compactness, as the weight loss rate of polyurea–SiO 2 microcapsules and polyurethane–SiO 2 microcapsules decreased 3.5% and 4.1%, respectively.

Preparation of High Thermo-Stability and Compactness Microencapsulated Phase Change Materials with Polyurea/Polyurethane/Polyamine Three-Composition Shells through Interfacial Polymerization

“…The reason is that the stability of the emulsion system was improved at a higher stirring speed, and so the formation of the shell was more uniform and the compactness was improved. When the stirring speed was 6000 rpm, the mass loss rate of the composite shell microcapsules treated at 120 °C for 1 h was only 5.6%, while the mass loss rate of polyurea microcapsules reinforced with tetraethyl orthosilicate under the same test conditions was as high as 8% [ 25 ]. This fully shows that the three-component composite shell can effectively improve the compactness of microcapsules.…”

“…This is because the existing literature mainly focuses on single component polyurea or polyurethane shells [ 23 , 24 ]. Yin et al selected tetraethyl orthosilicate (TEOS) as functional shell-forming monomers to enhance the thermal stability and compactness of traditional polyurea MicroPCMs [ 25 ], and the result indicated that the smoothness and compactness of both polyuria-SiO 2 and polyurethane-SiO 2 microcapsules was enhanced slightly when compared with that without TEOS. Hong et al [ 26 ] prepared polyurethane-TiO 2 microcapsules through interfacial polymerization, and the result indicated that the addition of TiO 2 enhances the thermal stability and mechanical strength of the prepared composite microcapsules.…”

A Comprehensive Review of Microencapsulated Phase Change Materials Synthesis for Low-Temperature Energy Storage Applications

“…Furthermore, using aliphatic isocyanate allows controlling the polycondensation rate, obtaining a uniform and compact microcapsule shell. Yin et al used ethyl palmitate to solubilize IPDI and tetraethylorthosilicate (TEOS), at 30 • C, as monomer or precursor for the shell formation through interfacial polycondensation [131]. The presence of TEOS led to the formation of a polyurea-polyurethane-SiO 2 shell, allowing to enhance the thermal stability of the mPCMs.…”

Methods for Determining the Thermal Transfer in Phase-Changing Materials (PCMs)

“…The use of these materials offers a maximum benefit when applied to buildings insulated with lightweight material as they have small intrinsic storage capacity. Thus, in order to achieve isolation with light energy efficiency, the following conditions must be met: reduced external energy exchange ensured by thermal insulation; the use of renewable energy sources; the reduction of energy requirements by using phase-changing materials [1][2][3][4][5].…”