CATIONIC COPOLYMERIZATION OF CYCLIC KETENE ACETALS - THE EFFECT OF SUBSTITUENTS ON REACTIVITY

Cationic copolymerizations of 4-methyl-2-methylene-1,3-dioxane, 2 (M-1 ), with 2-methylene-1,3-dioxane, 1 (M-2); of 4,4,6-trimethyl-2-methyle ne-1,3-dioxane, 3 (M-1), with 2-methylene-1,3-dioxane, 1 (M-2); of 4-m ethyl-2-methylene-1,3-dioxolane, 5 (M-1), with 2-methylene-1,3-dioxola ne, 4 (M-2); and of 4,5-dimethyl-2-methylene-1,3-dioxolane, a (M-1), w ith 2-methylene-1,3-dioxolane, 4(M-2) were conducted. The reactivity r atios for these four types of copolymerizations were r(1) = 1.73 and r (2) = 0.846; r(1) = 2.26 and r(2) = 0.310; r(1) = 1.28 and r(2) = 0.82 5; r(1) = 2.23 and r(2) = 0.515, respectively. The relative reactiviti es of these monomers towards cationic polymerization are: 3 > 2 > 1; a nd 6 > 5 > 4. With both five-and six-membered ring cyclic ketene aceta ls, the reactivity increased with increasing methyl substitution on th e ring. (C) 1998 John Wiley & Sons, Inc.