부산대학교 도서관

Cellulose esters have long been used as a rheology modifier of coatings to improve the flow-and-leveling, the drying rate, and the final appearance of dry film. In this work, we demonstrate a quantitative measure of some of the performance attributes that cellulose esters can provide to automotive coatings in the presence of cellulose esters. A series of pigmented basecoat formulations, which contained cellulose acetate butyrates (CAB) of varying molecular weights at different levels based on the total of the coating formulation, were prepared. The nonvolatile content of the formulations was also varied and the weight loss was monitored by high resolution thermo-gravimetric analysis (TGA). The viscoelastic behavior of a typical automotive basecoat formulation during the film drying process was then investigated using a novel rheological technique. The final appearance of the coating was investigated by several microscopic techniques, such as laser scanning confocal microscopy, scanning electron microscopy and atomic force microscopy, and attempts were made to correlate bulk measurements like "flop index" with the microstructure of the coating.