Radical copolymerization reactivity of methacryloyl-terminated poly(ethylene glycol methylether) with vinylbenzyl-terminated polystyrene macromonomers

Free-radical copolymerizations of vinylbenzyl-terminated polystyrene (PS-VM; M-1) and methacryloyl-terminated poly(ethylene glycol methylether) (PEG-MC; M-2) were carried out in various solvents (benzene, 1,1-dioxane and N,N-dimethylformamide). The reactivity ratios obtained for the binary macromonomer systems were different from corresponding model system of styrene and methyl methacrylate (r(1) = 0.52 and r(2) = 0.46) due to phase separation. PEG macromonomers could not interpenetrate sufficiently into propagating copolymer chains that had radical sites due to phase separation. On the other hand, the reactivity ratios (r(1) = 0.25 and r(2) = 0.02) obtained for the binary copolymerizations of PS-VM and PEG-MC/tin tetrachloride macromonomers showed strong alternation. It was suggested that alternation results from the homopolymerization of 1:I complexs formed between the donor and acceptor monomers. (C) 1999 Elsevier Science Ltd. All rights reserved.