Synthesis and characterization of novel alternating fluorinated copolymers bearing oligo(ethylene oxide) side chains

The synthesis and characterization of novel poly(CTFE-g-oligoEO) graft copolymers [chlorotrifluoroethylene (CTFE) and ethylene oxide (EO)] are presented. First, vinyl ether monomers bearing oligo(EO) were prepared by transetherification of ω-hydroxyoligo(EO) with ethyl vinyl ether catalyzed by a palladium complex in 70-84% yields. Two vinyl ethers of different molecular weights (three and 10 EO units) were thus obtained. Then, radical copolymerization of the above vinyl ethers with CTFE led to alternating poly(CTFE-alt-VE) copolymers that bore oligo(OE) side chains in satisfactory yields (65%). These original poly(CTFE-g-oligoEO) graft copolymers were characterized by ¹H, ¹⁹F, and ¹³C NMR spectroscopy. Their molecular weights reached 19,000 g mol^-1, and their thermal properties were investigated while their glass transition temperatures ranged between -42 and -36 °C. Their thermogravimetric analyses under air showed decomposition temperatures of 270 °C with 10% weight loss (T_d,10%). These novel copolymers are of potential interest as polymer electrolytes in lithium ion batteries, showing room temperature conductivities ranging from 4.49 × 10^-7 to 1.45 × 10^-6 S cm^-1 for unplasticized material.