Free radical copolymerization of 2,2,2‐trifluoroethyl α‐fluoroacrylate and tert ‐butyl α‐trifluoromethylacrylate: Thermal and optical properties of the copolymers

The radical copolymerization of 2,2,2‐trifluoroethyl α‐fluoroacrylate (FATRIFE) with tert ‐butyl α‐trifluoromethylacrylate (MAF‐TBE) initiated by tert ‐butyl 2,2‐dimethylperoxypropanoate was investigated in acetonitrile solution. A series of poly(FATRIFE‐ co ‐MAF‐TBE) copolymers were synthesized with MAF‐TBE compositions, determined by 19 F NMR, ranging from 12 to 44 mol %. MAF‐TBE incorporation was less than 50 mol % as this monomer underwent no radical homopolymerization. The obtained copolymers exhibited number‐average molecular weights and polydispersity indexes ranging from 1.5 × 10 4 to 9.6 × 10 4 g/mol and from 1.5 to 3.1, respectively. The reactivity ratios were determined by the Kelen‐Tüdos method ( r FATRIFE = 1.71 ± 0.01 and r MAF‐TBE = 0 at 74 °C) leading to random copolymers and alternating copolymers when the MAF‐TBE molar ratio in copolymer is close to 50 mol %. Thermal and optical properties of the resulting polymers were examined. Glass transition temperatures of copolymers were varying from 89 to 108 °C. Modifying the compositions of these copolymers allowed a precise control over the refractive index measured at 633, 1320, and 1550 nm. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 4383–4391, 2008