Surface photograft polymerization of vinyl acetate on low density polyethylene film. Effects of solvent

To photograft vinyl acetate (VAc) onto low density polyethylene (LDPE) film , suitable solvents should be determined in advance. Different reagents wer e used as solvents of VAc (acetone, benzene, carbon tetrachloride, cyclohex ane, cyclohexanone, ethyl acetate, methanol, tetrahydrofuran(THF) and N, N- dimethylformamide(DMF). All graft polymerizations mere completed by two-ste ps, i.e., benzophenone (BP) pre-coated dim samples were prepared onto which VAc was grafted. To prepare film samples containing BP, BP should be disso lved in a suitable solvent. The effects of various solvents of BP on grafti ng were examined, including acetone, benzene, chloroform, 2,4-dioxane, DMF, ethyl acetate, n-hexane, methanol and THF. Percent conversion (CP), grafti ng efficiency (GE) and grafting percent (GP) determined by gravimetry and c ontact angles of grafted films against water showed that reagents have diff erent effects on the graft polymerizations. Acetone is the most suitable as solvent of BP or VAc. The behavior of solvents seems closely related to th e affinity with the substrate.