Radiation-induced radical polyaddition of bis(α-trifluoromethyl-β,β-difluorovinyl) terephthalate with excess of various ethers

Radiation-induced radical polyaddition of bis(a-trifluoromethyl-P,P-difluorovinyl) terephthalate [CF2=C(CF3)OCOC6H4COOC(CF3)=CF2] (BFP) in the presence of an excess of cyclic and acyclic ethers in feed was examined at 0 degrees C using gamma-ray irradiation. Irradiation of BFP with an 8-fold excess of 1,4-dioxane (DOX) and diethyl ether (EE) gave monomodal polymers consisting of the alternating unit of BFP and DOX moieties (poly(BFP-alt-DOX) (M) over bar (n,as-prepared) 5.1 x 10(3)) and of BFP and EE (poly(BFPalt-EE) (M) over bar (n,as-prepared) = 3.9 x 10(3)), respectively. The irradiation of BFP with an 8-fold excess of tetrahydrofuran or tetrahydropyran provided only 1:2 addition products in high yields. Monofunctional 2-benzoxypentafluoropropene [CF2=C(CF3)OCOC6H5] (BPFP) as a model compound showed preferential formation of the 2:1 adduct to the 1:1 adduct with DOX and EE. The kinetic analysis of the model reactions revealed that the rate constants for the formation of the 2:1 adducts (k(d)) of BPFP with DOX and EE were 2 orders of magnitude higher than those of the 1:1 adducts (k(m)). Poly(BFP-alt-DOX) showed higher radiation resistance than poly(BFP-alt-EE) in solid state as well as in solution. It was concluded that radiation-induced step-growth polymerization under the stoichiometric imbalance of the two compounds requires a high k(d)/k(m) value as well as high radiation resistance for the formation of high molecular weight polymers.