Comparison of two encapsulation systems of UV stabilizers on the UV protection efficiency of wood clear coats

Abstract

One of the major issues in the wood industry is the durability of clear coatings. The addition of organic ultraviolet absorbers (UVAs) improves coating resistance by the absorption and conversion of UV radiation into harmless heat. Organic UVAs are, however, easily degraded by free radicals produced by photodegradation inside the polymer matrix and are prone to migration in the coating. In this study, commercial UVAs and hindered amine light stabilizers (HALS) entrapped into poly(methyl methacrylate) (PMMA) microspheres and CaCO3 templates coated with UV-responsive polymers were added into clear acrylic water-based coating formulation. Artificial accelerated weathering experiments were performed on each formulation. Raman spectroscopy mapping was performed to visualize the concentration and distribution of UVAs and HALS. This study also presents a comparison of the mechanical properties of coatings obtained by dynamic mechanical analysis. Results showed that coating mechanical properties were improved when using encapsulated UVAs and HALS inside PMMA microspheres. The color change of the wood and coating system was minimized and the production of photo-oxidation compounds in the binder was also limited.

Boron-Based Mildew Preventive and Ultraviolet Absorbent Modification of Waterborne Polyurethane Coatings on Laminated Bamboo

“…Surface finishing modification involves a coating with added photodegradation resistance additives, and the main types of these additives are ultraviolet absorbents and light stabilizers. Queant et al showed that the clear acrylic water-based coating formulation added with commercial ultraviolet absorbents (UVAs), hindered amine light stabilizers (HALS), or poly (methyl methacrylate) (PMMA) microspheres, saw that the color change of the samples was minimized and the production of photo-oxidation compounds in the binder was also limited [13]. Organic absorbents have been proven to decompose more quickly than inorganic ones during outdoor exposure [14], although organic absorbents have been proven to be more conducive to improving the color stabilization of bamboo, especially for a coating with benzotriazole modifications.…”

Aging of Environmentally Friendly Alkyd Coating Containing Tinuvin 292 under Effect of UV Radiation

“…leads to the blistering, chalking, losing adhesion [1][2][3]. To reduce the aging of coatings exposed to UV radiation, many kinds of UV additives have been added in coatings [3][4][5]. Hu Crescenzo et al [7] studied on photochemical degradation of some binders and pigments in 800 h, results showed that acrylic or styreneacrylic were more stable than vinyl.…”

Effect of Graphene Oxide on UV-Thermo-Humidity Degradation of Environmentally Friendly Alkyd Composite Coating

“…Degradation of polymers in general or paint coating in particular under high temperature, oxygen, sunlight, UV radiations, and humidity leads to losing adhesion, blistering or peeling [1][2][3][4][5]. Jianwen Hu et al [6] showed the degradation of acrylic polyurethane varnish coating under fluorescent UV/condensation and xenon lamp exposure.…”