Abstract: Polyphenylmethyl and polybenzylmethyl siloxanes were prepared individually by the condensation of phenylmethyldiethoxysilane or benzylmethyldiethoxysilane,and their reactions with fluorinated acyl peroxide(FAP),carried out under mild conditions,were investigated by the titration,IR,¹H NMRand ¹⁹F NMRspectrometry.It was found that no detectable fluorinated carboxylic acid was formed during the reactions,and the predominantly formed product was the polysiloxane fluoroalkylated in benzene ring.The utilization ratio of fluoroalkyl group in FAPwas obviously dependent upon the molar ratios of the reactants and the solvent used,and it was observed that over one fluoroalkyl group in FAPcould be introduced into the benzene ring of polyphenylsiloxane.In addition,the surface tension of the polyphenylsiloxanes was markedly reduced by the introduction of fluoroalkyl group at low fluoroalkylation ratios.Based on the experimental observations,we can consider that the FAPwas valuable reagents for introducing fluoroalkyl group into polyphenylsilioxanes conveniently,and the reactions,initiated by the thermal decomposition of FAP,possibly underwent via the fluoroalkyl radical attack on the benzene ring.

Key words: Fluoroalkylation, Phenylsiloxane, Fluorinated acyl peroxide, Surfactant property