Copolymerization (Sch. 1) of VAC and the ring-substituted EOCP resulted in formation of copolymers (Table ) with weight-average molecular masses 1.1 to 6.8 kD. According to the nitrogen elemental analysis, between 42.2 and 49.9 mol% of TSE monomer is present in the copolymers prepared at VAC/EOCP = 3 (mol), which is indicative of relatively high reactivity of the monomers towards VAC. According to the nitrogen elemental analysis, between 42.2 and 49.6 mol% of TSE monomer is present in the copolymers prepared at VAC/EOCP = 3 (mol), which is indicative of relatively high reactivity of the monomers towards VAC.