Coating performance enhancement of moso bamboo (Phyllostachys edulis) via hand sanding: Effects of surface dewaxing and fibrillation

Bamboo, despite its environmental advantages, often suffers from poor coating adhesion because of its natural surface characteristics, thereby limiting its application as an exterior material. This study aimed to improve the performance of coatings applied to moso bamboo (Phyllostachys edulis) by introducing surface sanding as a pretreatment. Sanding was performed using #100 sandpaper with stroke counts of 10, 20, 30, and 40; the resulting changes in the epidermal and fibrous layers and their influence on the coating adhesion were evaluated. The 40-stroke treatment exposed the fibrous layer and enhanced the surface wettability. According to the ISO 2409 (2020) cross-cut test, the sanded specimens exhibited excellent adhesion (Grade 1), in contrast to untreated specimens, for which coating delamination was evident. Furthermore, under accelerated-aging tests, coating adhesion was maintained for the sanded samples, whereas pronounced delamination was observed for the untreated samples. These findings demonstrated the effectiveness of surface sanding. In conclusion, surface pretreatment is essential for improving the durability and coating quality of moso bamboo, and the results of this study can serve as fundamental data for the practical application and broader utilization of bamboo materials.