Abstract
The synthesis of original cotelomers based on 3,3,3-trifluoropropene (TFP) and vinylidene fluoride (VDF) with a general formula: RF-[CH2ACF2]nA [CH2ACH(CF3)]mAI (where n ¼ 1–63, m ¼ 2–640, and RF ¼ (CF3)2CF) was achieved by sequential and random cotelomerizations in the presence of RFI. The radical cotelomerizations were initiated by thermal decomposition of different peroxide and persulfate initiators either in bulk, in solution (in the presence of acetonitrile or 1,1,1,3,3-pentafluorobutane as the solvents), and in aqueous process (emulsion). Different adducts were obtained in good yield (50–70 wt %) with a relative proportion of each adduct depending on (i) the R0 ¼ [RFI]0/([TFP]0þ[VDF]0) initial molar ratio, (ii) the reaction temperature, and (iii) C0 ¼ [In]0/([TFP]0þ[VDF]0). Random cotelomerization gave higher yields than those obtained from the sequential cotelomerization. When the concentration of the chain transfer agent increased, the molecular weights of the resulting poly(VDF-co-TFP) cotelomers decreased and showed that the R0 ratio targeted the molecular weights (~700–66,000 g mol-1). Some of the obtained molecular weights were exceptionally high for a (co)telomerization. The kinetics of the radical cotelomerization of VDF and TFP led to the determination of the reactivity ratios of both comonomers (rVDF = 0.28 +/-0.07 and rTFP= 2.35+/- 0.26 at 75°C).