Boosting flowability and curing reaction of ultra-fine powder coatings using facile-fabrication Al₂O₃/C₄H₆N₂ nanocomposite

In recent years, the utilization of fiber-reinforced plastic (FRP) parts has become increasingly widespread in various industries, including aerospace, marine, and automobile industries, as a consequence of their potential to enhance energy efficiency and reduce weight. However, the challenge of meeting the demand for eco-friendly and high-quality coatings on FRPs persists. Ultra-fine powder coatings have emerged as a promising solution, offering a cost-effective and high-quality alternative to traditional solvent paints and emitting zero volatile organic compounds (VOCs). Despite their potential benefits, two main obstacles to applying ultra-fine powder coatings on FRPs exist: low powder flowability and high curing temperature. To address these obstacles, we fabricated a nanocomposite comprising Al₂O₃ and C₄H₆N₂ (2-methylimidazole) and evaluated its functional properties in ultra-fine powder coatings. Our findings demonstrate that the addition of 0.3–0.5 wt% of the nanocomposite significantly improved static and dynamic powder flowability to qualified grades and effectively boosted curing reactions, consequently reducing the curing temperature by 20 °C. Furthermore, the film thickness decreased by approximately 50 %, and final appearance, roughness and water resistance were enhanced significantly. Overall, our results suggest that the nanocomposite boosted the flowability and curing reaction of the ultrafine powders effectively and successfully obtained thin and qualified films on FRP substrates, which holds great promise for expanding the application of ultra-fine powder coatings in the coating industry.