MICROSTRUCTURE OF COPOLYPEROXIDES OF ALPHA-METHYLSTYRENE WITH STYRENEAND METHYL-METHACRYLATE

This paper reports a study on the microstructure of two series of copo lyperoxides of alpha-methylstyrene, with styrene and with methylmethac rylate. The copolyperoxides were synthesized by the free radical-initi ated oxidative copolymerization of the vinyl monomer pairs. The copoly peroxide compositions obtained from the H-1 and C-13 NMR spectra led t o the determination of the reactivity ratios. The product of the react ivity ratios indicates that alpha-methylstyrene forms a block copolype roxide with styrene and a random copolyperoxide with methylmethacrylat e. Microstructural parameters like average sequence length, run number , etc. have been determined for the latter copolyperoxide from analysi s of its C-13 NMR spectrum. The aromatic quaternary and carbonyl carbo ns were found to be sensitive to triad sequences. The end groups of th e copolyperoxides have been identified by H-1 NMR as well as FTIR spec troscopic techniques. The thermal degradation of the copolyperoxides h as been studied by differential scanning calorimetry, which confirms t he alternating peroxide units in the copolyperoxide chain.