Novel fluorinated hybrid polymer preparation from silsesquioxanes by radical polyaddition

Radical polyaddition of bis(α-trifluoromethyl-β,β-difluorovinyl) terephthalate [CF2C(CF3)OCOC6H4COOC(CF3)CF2] (BFP) with silsesquioxanes was investigated in order to produce a polymer possessing silsesquioxane moiety in polymer main chain. 1,3,5,7,9,11,13,15-octakis(dimethylsilyloxy)pentacyclo[9.5.1.13,9.15,15.17,13]octasiloxane (T8S) with BFP successfully afforded a polymer bearing a molecular weight of about 2.5×105. The polymer obtained were soluble in usual organic solvent such as methanol, tetrahydrofuran and chloroform. In order to get some information on the polyaddition reaction mechanism, model reactions of 2-benzoxypentafluoropropene [CF2C(CF3)OCOC6H5] (BPFP) with dimethylphenylsilane, [(CH3)2SiHC6H5], BPFP with 1,1,3,3-tetramethyldisiloxane {[(CH3)2SiH]2O}, and BFP with dimethylphenylsilane were carried out. The mechanism that the radical abstracts a hydrogen from silane compounds followed by the addition of perfluoroisopropenyl groups was proposed.