Improvement of surface photostability of bamboo scrimber by application of organic UV absorber coatings

Abstract

Improving the durability of biological materials is essential for expanding their application areas. In this study, an organic ultraviolet (UV) shielding layer (coating) composed of a UV-curable paint, ethyl acetate, anhydrous alcohol, and an organic UV absorber is constructed on the surface of outdoor bamboo scrimber (OBS). The behaviour of OBS with or without this coating was investigated under accelerated weathering. The physical properties photostability of the samples before and during exposure were evaluated by characterizing the colour and glossiness. Contact angle (CA) measurements and surface free energy (SFE) calculations were performed to investigate the wettability of the coatings. Attenuated total reflectance Fourier transform infrared spectroscopy was used to characterize the changes in the functional groups of the coatings during weathering. The experimental results have shown that the colour, glossiness, CA, SFE, and functional groups photostability of the sample with the UV shielding coating increased significantly compared to those of the control sample. The coating with 5% organic UV absorber was considered as the best UV shielding layer in this study, as it successfully protected the OBS and reduced the surface photodegradation of the substrate and the coating itself.