SURFACE-PROPERTIES OF FLUOROSILICONE COPOLYMERS AND THEIR SURFACE MODIFICATION EFFECTS ON PVC FILM

The fluorosilicone copolymers were synthesized using a fluorine-contai ning monomer and silicone-containing monomers by free-radical random c opolymerization, and their surface properties and surface modification ability were investigated. The fluorine-containing monomer used was p erfluoroalkyl ethyl acrylate (FA), and the silicone-containing monomer s used were 3-[tris(trimethylsilyloxy)silyl]propyl methacrylate (SiMA) , vinyltrimethoxy silane (VTMS), and vinyltriethoxy silane (VTES). The surface free energies of the fluorosilicone copolymers prepared were estimated from the contact angle data measured by sessile-drop method. And, the surface free energies of poly(vinyl chloride) (PVC) films mo dified by the fluorosilicone copolymers were also analyzed using the c ontact angle data. The fluorosilicone copolymers exhibit the surface f ree energies of about 8-23 dyn/cm dependent on the molecular weight of the fluorosilicone copolymers. The surface free energies of the fluor osilicone copolymers decrease with increasing molecular weight in the range of 2,000-10,000 (M-w). Among the fluorosilicone copolymers prepa red in this study, PFAr-PSiMA was found to be the most effective as a surface modification agent for PVC film. The inherent surface free ene rgy of PFA-r-PSiMA was estimated to be about 9.0 dyn/cm. The desirable molecular weight of PFA-r-PSiMA seems to be more than 4,000 (M-w). Ho wever, it is expected that the fluorosilicone copolymers having the mo lecular weight of much higher than 10,000 (M-w) may not be suitable as surface modification additives because their compatibility with other polymers will decrease with the molecular weight. The optimum concent ration of PFA-r-PSiMA added to PVC film is about 1.0 wt.%. PFA-r-PSiMA is expected to be an effective additive for surface modification of P VC films. (C) 1998 Academic Press