STUDIES ON THE REACTIONS OF POLYPHENYLMET HYL-SILOXANE AND POLYBENZYLMETHYL-SILOXANE WITH FLUORINATED ACYL PEROXIDE

Polyphenylmethyl and polybenzylmethyl siloxanes were prepared individu ally by the condensation of phenylmethyldiethoxysilane or benzylmethyl diethoxysilane, and their reactions with fluorinated acyl peroxide(FAP ), carried out under mild conditions, were investigated by the titrati on, IR, H-1 NMR and F-19 NMR spectrometry. It was found that no detect able 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 FAP was obviously dependent upon the molar ratios of the reactants and the so lvent used, and it was observed that over one fluoroalkyl group in FAP could be introduced into the benzene ring of polyphenylsiloxane. In a ddition, the surface tension of the polyphenylsiloxanes was markedly r educed by the introduction of fluoroalkyl group at low fluoroalkylatio n ratios. Based on the experimental observations, we can consider that the FAP was 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.