The novel synthesized TPCA compounds copolymerized readily with ST under freeradical conditions (Scheme 2) forming white flaky precipitates when their solutions were poured into methanol. The conversion of the copolymers was kept between 10 and 20% to minimize compositional drift (Table ). Nitrogen elemental analysis showed that between 6.2 and 29.9 mol% of TPCA is present in the copolymers prepared at ST/ TPCA = 3 (mol), which is indicative of relatively high reactivity of the TPCA monomers towards ST radical which is typical of ring-substituted TPCA. Since TPCA monomers do not homopolymerize, the most likely structure of the copolymers would be isolated TPCA monomer units alternating with short ST sequences (Scheme 2).