RADICAL TRANSFER ON STYRENIC MACROMONOMERS OF POLYOXYETHYLENE .2. STUDIES ON MODEL COMPOUNDS

In a previous study of the copolymerization of butyl acrylate with styrenic macromonomers, it was shown that benzylic hydrogen atoms are involved in a transfer process. In order to investigate these latter reaction, model compounds were synthesized and used as transfer agents in the polymerization of butyl acrylate. For a non-substituted benzylic ether, i. e. having two benzylic hydrogen atoms, the transfer constant was estimated to be around 0. 0021; kinetic studies showed that the efficiency of reinitiation is about 80%. Replacement of a benzylic hydrogen atom by a methyl group led to a transfer process with no reinitiation. The incorporation of the transfer agents in the polymer was followed by GPC, u. v. and NMR spectroscopies.