Nghiên cứu khoa học Quốc t�?- Đại học Thành Đô

In this study, the kinetic of photopolymerization reaction, mechanical properties and the morphology of UV curable acrylate urethane coating were investigated. Coatings consisting of 2 wt.% of tinuvin 384, R-TiO2, A-TiO2 and ZnO were fabricated. Loading of 2 wt.% of Tinuvin 384 organic UV absorbent was found to decrease the conversion of acrylate double bonds, gel fraction, relative hardness and abrasion resistance of the coating. R-TiO2 nanoparticles showed insignificant impact on the conversion of acrylate double bonds but improved mechanical properties of the coating. A-TiO2 and ZnO enhanced both the conversion of acrylate double bonds and mechanical properties of the coatings. A mechanism of photopolymerization reaction of UV-curable acrylate urethane coating in the presence of inorganic UV absorbents has proposed. Nanoparticles were dispersed well in a polymer matrix, with a size of about 50�?00 nm.

The post The Role of Organic and Inorganic UV-absorbents on Photopolymerization and Mechanical Properties of Acrylate-urethane Coating appeared first on Đại học Thành Đô.

Nghiên cứu khoa học Quốc t�?- Đại học Thành Đô

khanh.dev.htecom — Mon, 05 Apr 2021 00:00:00 +0000

Thi Thuy Trang Nguyen

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Abstract

This work aims to clarify the photocatalytic degradation mechanism and heat reflectance recovery performance of waterborne acrylic polymer/ZnO nanocomposite coating. To fabricate the nanocomposite coating, ZnO nanoparticles (nano‐ZnO) were dispersed into acrylic polymer matrix at the various concentrations from 1 to 6% (by total weight of resin solids). The photocatalytic degradation of nanocomposite coating under ultraviolet (UV) light irradiation has been investigated by monitoring its weight loss and chemical/microstructural/morphological changes. As the topcoat layer, its heat reflectance recovery has been evaluated under UV/condensation exposure by using an artificial dirty mixture of 85 wt% nanoclay, 10 wt% silica particles (1�? μm), 1 wt% carbon black, and 2 wt% engine oil. After 108‐cycle UV/condensation exposure, infrared spectra and weight loss analysis indicated that the maximal degradation for nanocomposite coating is observed at 1 wt% nano‐ZnO. On the other hand, after 96 hr of UV light exposure, the nanocomposite coating with1 wt% nano‐ZnO could restore effectively the reflective index of solar‐heat reflectance coating (from 58.45 to 80.78%). Finally, the photodegradation mechanism of this waterborne acrylic polymer coating has been proposed as the UV‐induced formation of CCCO conjugated double bonds. As a result, its self‐cleaning phenomenon can be achieved as the recovery of heat reflectance.

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