Free radical copolymerization of α‐fluoroacrylates for optical materials: Synthesis and characterization

Abstract

Abstract Copolymers based on 2,2,2‐trifluoroethyl α‐fluoroacrylate (FATRIFE) and 2,2,2‐trichlororoethyl α‐fluoroacrylate (FATRICE) were synthesized in good yields by radical process initiated by tert ‐butyl 2,2‐dimethylperoxypropanoate. Molar composition of the obtained poly(FATRIFE‐ co ‐FATRICE) copolymers were assessed by means of 19 F nuclear magnetic resonance spectroscopy. The reactivity ratios, r i , of both comonomers have been measured to be r FATRIFE = 0.56 ± 0.01 and r FATRICE = 0.11 ± 0.01 at 74 °C using the Kelen‐Tüdos method. Thermal and optical properties of the resulting polymers were examined. Thermogravimetric analyses showed good thermal stability, thermal decomposition occurring from 300 °C to 310 °C for all copolymers. Moreover, the glass transition temperature of copolymers varied from 113 °C to 127 °C, increasing with the molar ratio of FATRICE in the copolymers. The refractive indices were measured at 633, 1320, and 1550 nm, ranging from 1.3750 to 1.4812 at 1550 nm and were found to increase linearly with the chlorine content of the copolymer, allowing a precise control of the refractive index. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1403–1411, 2009