CATIONIC COPOLYMERIZATION OF 2-METHYLENE-5,5-DIMETHYL-1,3-DIOXANE WITH 2-METHYLENE-1,3-DIOXOLANE AND 2-METHYLENE-1,3-DIOXANE

Copolymers of the cyclic ketene acetals, 2-methylene-5,5-dimethyl-1,3- dioxane, 3, (M(1)) with 2-methylene-1,3-dioxolane, 4, (M(2)) Or 2-meth ylene-1,3-dioxane, 5, (M(2)), were synthesized by cationic copolymeriz ation. An experimental method was designed to study the reactivity of these very reactive and extremely acid sensitive cyclic ketene acetal monomers. The reactivity ratios, calculated using a computer program b ased on a nonlinear minimization algorithm, were r(1) = 6.36 and r(2) = 1.25 for the copolymerization of 3 with 4, and r(1) = 1.56 and r(2) = 1.42 for the copolymerization of 3 with 5. FTIR and H-1-NMR spectra when combined with the values of r(1) and r(2) showed that these copol ymers were formed by a cationic 1,2-polymerization (ring-retained) rou te. Furthermore the tendency existed to form very short blocks of M(1) or M(2) within the copolymers. Cationic copolymerization of cyclic ke tene acetals have the potential to be used for synthesis of novel poly mers. (C) 1996 John Wiley & Sons, Inc.