Correlation between Physicochemical Properties and Film-Forming Performance of Natural Lacquer from Representative Chinese Regions

Abstract Natural lacquer, obtained from Toxicodendron vernicifluum, is an important renewable bio-based material with long-standing traditional use and increasing potential in modern sustainable coating systems. However, its broader industrial application remains limited by variations in raw material quality, chemical composition, and film-forming performance. This study systematically evaluated the physicochemical and film properties of traditional natural lacquers sourced from Hubei Maoba (MB), Sichuan Mianyang (MY), and Shanxi Ankang (AK) to establish a scientific foundation for correlating material attributes with processing and application performance. The key physicochemical parameters, including solid content, viscosity, and urushiol concentration, were measured, along with volatile profiles obtained via gas chromatography−mass spectrometry (GC−MS). The cured lacquer films were further assessed for gloss, surface roughness, and impact resistance. The results indicated that the MB lacquer offered considerable advantages, particularly in solid content and urushiol abundance. The MB lacquer exhibited outstanding gloss and a dense microstructure, whereas the AK lacquer was distinguished by its leveling properties and unique chemical composition. This research provides a comprehensive scientific framework for quality grading and application-oriented material selection.