Thermochromic and temperature regulation properties of phase change materials derived from polymer composites loaded with VO2 particles

Journal article

Authors/Editors

Strategic Research Themes

Innovative Materials, Manufacturing and Construction (Strategic Research Themes)

Publication Details

Author list: Onruthai Srirodpai, Jatuphorn Wootthikanokkhan, Saiwan Nawalertpanya

Publisher: Wiley

Publication year: 2023

Journal: Polymers for Advanced Technologies (1042-7147)

Volume number: 34

Issue number: 6

Start page: 1

End page: 15

Number of pages: 15

ISSN: 1042-7147

eISSN: 1099-1581

URL: https://onlinelibrary.wiley.com/doi/10.1002/pat.6021

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Abstract

This research work concerns the development of phase change materials based on poly(ethylene terephthalate) [PET] mixed with vanadium dioxide particles (VO₂). Monoclinic VO₂ particles were synthesized via a hydrothermal process followed by modification of the particle surface with a silane coupling agent, namely 3-aminopropyl) triethoxysilane (APTES). After that, the metal oxide particles were mixed with PET flakes, derived from used PET bottles, in an internal mixer. In this study, the effects of surface modification and concentrations of VO₂ particles on thermo-mechanical and optical properties of the composites were investigated. From the DSC results, it was found that the percentage crystallinity of PET increased after loading with VO₂. This indicates that VO₂ can act as a nucleating agent inducing the crystallization of the PET chains. From the SEM-EDX images, better dispersion of VO₂ particles in the PET matrix was noticed when the surface modified VO₂ particles were used as a replacement for the normal VO₂ particles. This contributed to the greater percentage of visible light transmittance through the composite sheets. TGA profiles of both PET and PET/VO₂ specimens are similar, indicating that the VO₂ did not accelerate the thermal decomposition of the PET. When the specimens were exposed to an IR lamp, it was found that the temperature behind the PET/VO₂ sheets dropped when compared to that of the neat PET sheets. Some shrinkage and deformation of the PET/VO₂ specimens were also noticed. The higher the VO₂ loading, the greater the deformation. The effect was ascribed to the fact that the actual temperature was above the critical transition temperature of VO₂. Consequently, the NIR transmittance was suppressed at the expense of the greater NIR absorbance by the VO₂ phase in the composites. Finally, when the specimens were exposed to solar irradiation at ambient temperature, the temperature underneath the PET/VO₂ specimens became greater than that of the control specimen (the neat PET). The result was discussed in the light of the emissivity of VO₂ at ambient temperature, which is considerably low. Overall, this study demonstrates that PET/VO₂ can exhibit both cooling and warming effects, depending on the ambient temperature in relation to the critical transition temperature (T_c) of VO₂.

Keywords

polymer composites, Recycled Polyethylene Terephthalate, Surface modification