Modification of polycaprolactone-styrene-vinyl trimethoxysilane terpolymer with sunflower oil for coating purposes

Polycaprolactone-styrene-vinyl trimethoxysilane terpolymer was prepared and then modified with sunflower oil partial glyceride (SFOPG) via a sol-gel method for use as a binder in coating applications. Therefore, a vinyl-functionalized polyester-based macromonomer (HPCL) was prepared via ring-opening polymerization of ɛ-caprolactone (CL) using 2-hydroxyethyl methacrylate (HEMA) followed by copolymerization with styrene (St) and vinyl trimethoxysilane (VTMS) to yield a terpolymer (HPCL-St-VTMS). The terpolymer was characterized by FTIR, GPC and 1H NMR. To overcome the fact that the cured film of HPCL-St-VTMS was slightly soft, SFOPG was used as a modifier and was inserted to the structure via a sol-gel reaction between the hydroxyl groups and methoxy silane moieties of the terpolymer. After this modification, the softness disappeared. Nanosize inorganic domains were observed in the SEM image. Thermal analyses of the resulting cross-linked film of SFOM-HPCL-St-VTMS were performed with DSC and TGA. SFOM-HPCL-St-VTMS, which does not melt, resulted in a higher char yield and decomposition temperature at 5% weight loss compared to the unmodified HPCL-St-VTMS film. An evaluation of the film properties indicated that SFOM-HPCL-St-VTMS can be used as a coating material.