Novel Fluoro-Terpolymers for Coatings Applications

Abstract

A series of thermally stable, elastomeric and hydrophobic fluoro-terpolymers of tetrafluoroethylene (TFE), vinyl acetate (VAc), and poly(dimethylsiloxane) methyl acrylate-terminated (PDMSMA), P(TFE-ter-VAc-ter-PDMSMA), were synthesized in supercritical carbon dioxide. Because the differences in reactivity ratios of TFE and PDMSMA precluded copolymerization, VAc was introduced into the feed resulting in terpolymers with yields as high as 64%, weight-average molar masses between 29 and 173 kg mol-1, and polydispersity between 1.8 and 3.7. DSC examination of the fluoro-terpolymers indicated a microphase separation consisting of P(TFE−VAc) and P(PDMSMA) domains for all terpolymer compositions. However, P(TFE-ter-VAc-ter-PDMSMA) terpolymers having TFE content greater than or equal to 55.2 mol % had additional semicrystalline domains, providing a Tg of −120 °C [P(PDMSMA) domains], a Tg of 28 °C [P(TFE−VAc) domains], and a Tm of 235 °C [PTFE domains]. Cross-linked terpolymers having 55.2 mol % of TFE lose only 5...