Coating Performance of Water-Based Polyurethane-Acrylate Coating on Bamboo/Bamboo Scrimber Substrates

In this paper, a kind of high solid content water-based polyurethane-acrylate (PUA) coating was synthesized in laboratory. Bamboo, bamboo scrimber, and heat-treated bamboo scrimber were selected as substrates and coated with the PUA coating. The coating properties of those materials were investigated. The results showed that PUA coating could well cover the surface of the three kinds of materials. However, the coating performances varied among these substrates due to their different chemical and morphological surfaces. Due to the densified structures, small pores, and improved hydrophobicity of bamboo scrimber, it was difficult for PUA coating to wet and penetrate into the substrate, where the smaller contact angle and penetration depth were obtained compared with bamboo. In contrast, heat-treated one had better hydrophilicity and smaller contact angle with PUA coating than pure bamboo scrimber. Therefore, the coating performance of heat-treated bamboo scrimber was better with lower average roughness value. However, the adhesion classification between the coating and all substrates was 2 (with 5-15% cross-cut area of flaking along the edges).