ABSTRACT

In this study, the effects of two transparent UV curing coatings (i.e. epoxy acrylate and urethane acrylate) modified by zero, 0.2, and 0.5 loading percent of zinc oxide nanoparticles (ZN) on the weathering resistance of thermally modified timber were investigated. Both coatings improved the weathering resistance of the modified wood; however, epoxy acrylate showed much better performance compared to urethane acrylate. ATR-FTIR results showed no considerable oxidation or chain scission in the epoxy acrylate-coated specimens after six months of weathering, while significant chemical changes occurred in the urethane acrylate-coated specimens. The addition of the nanoparticles reduced the discoloration of both coatings; however, the contact angle and roughness were not significantly affected. Results also showed that the adhesion strength was reduced for both coatings as a result of weathering with the urethane acrylate coating having a lower adhesion strength than the epoxy acrylate. The addition of the ZN, particularly at the higher content, reduced the adhesion strength of the urethane acrylate coating. Generally, the method of fast and simple UV-cured coating of epoxy acrylate alone or coupled with zinc oxide nanoparticles was found to be effective for the protection of thermally modified timber against weathering in outdoor applications.

摘要

在这项研究中，研究了两种透明 UV 固化涂料（即环氧丙烯酸酯和聚氨酯丙烯酸酯）由零、0.2 和 0.5 负载百分比的氧化锌纳米颗粒 (ZN) 改性对热改性木材耐候性的影响。两种涂料都提高了改性木材的耐候性；然而，与聚氨酯丙烯酸酯相比，环氧丙烯酸酯表现出更好的性能。ATR-FTIR 结果表明，经过 6 个月的风化处理后，环氧丙烯酸酯涂层样品没有明显的氧化或断链，而聚氨酯丙烯酸酯涂层样品发生了显着的化学变化。添加纳米颗粒减少了两种涂层的变色；然而，接触角和粗糙度没有受到显着影响。结果还表明，由于聚氨酯丙烯酸酯涂层的粘附强度低于环氧丙烯酸酯，两种涂层的粘附强度均因风化而降低。ZN 的添加，尤其是较高含量的 ZN，降低了聚氨酯丙烯酸酯涂层的粘合强度。一般而言，环氧丙烯酸酯单独或与氧化锌纳米粒子偶联的快速简单的紫外线固化涂层方法被发现可有效保护热改性木材在户外应用中免受风化。