The novel synthesized APCA 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 10.6 and 31.2 mol% of APCA is present in the copolymers prepared at ST/ APCA = 3 (mol), which is indicative of relatively high reactivity of the APCA monomers towards ST radical which is typical of alkoxy ring-substituted APCA . Since APCA monomers do not homopolymerize, the most likely structure of the copolymers would be isolated APCA monomer units alternating with short ST sequences (Scheme 2).