Copolymers of the ST and the TBPCA compounds, P(ST-co-TBPCA) were prepared in 25-mL glass screw cap vials at ST/TBPCA = 3 (mol) the monomer feed using 0.12 mol/L of ABCN at an overall monomer concentration 2.44 mol/L in 10 mL of toluene. The copolymerization was conducted at 70ºC. After a predetermined time, the mixture was cooled to room temperature, and precipitated dropwise in methanol. The composition of the copolymers was determined based on the nitrogen content (cyano group in TBPCA). The novel synthesized TBPCA compounds copolymerized readily with ST under free-radical 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 11.1 and 29.8 mol% of TBPCA is present in the copolymers prepared at ST/TBPCA = 3 (mol), which is indicative of relatively high reactivity of the TBPCA monomers towards ST radical which is typical of alkyl ring-substituted TBPCA . Since TBPCA monomers do not homopolymerize, the most likely structure of the copolymers would be isolated TBPCA monomer units alternating with short ST sequences (Scheme 2).