C5 and C6 Polymerizations by Anion Migrated Ring-Opening of 1-Cyclopropylvinylbenzene and 1-Cyclobutylvinylbenzene

Abstract

As an emerging method, anion migrated ring-opening polymerization (AMROP) can effectively regulate the carbon skeletons of polymer backbones with specific vinyl monomers. As reported here, polymers with C5 and C6 skeletons were synthesized by AMROP of 1-cyclopropylvinylbenzene (CPVB) and 1-cyclobutylvinylbenzene (CBVB). Moreover, C4 polymerization of 1-phenyl-1,3-butadiene (1-PB) was also conducted (in a general anionic polymerization process) for comparison with C5 and C6 polymerizations. Among the three base polymers prepared with the C4, C5, and C6 polymerizations, PCBVB exhibited the most flexible carbon skeleton structure and the lowest glass transition temperature (Tg = −18.8 °C). Then, the resultant base polymers with different carbon skeletons were hydrogenated and cyclized. The hydrogenation of P(1-PB), PCPVB, and PCBVB resulted in the formation of products with unique alternating styrene/ethylene (alt-SE), periodic styrene/ethylene/methylene (pd-SEM), and periodic styrene/ethylene/ethylene (pd-SEE) structures. Moreover, pd-SEM and pd-SEE can be considered as sequence-defined template polymers, and these structures cannot be synthesized through general copolymerization of styrene and ethylene. Owing to the specific carbon skeletons exhibited in alt-SE, pd-SEM, and pd-SEE, their Tg values showed significant differences (24.6, 10.9, and −6.0 °C, respectively). Additionally, the specific carbon skeletons of the base polymers resulted in the formation of cyclized polymers with different annular substituents. Moreover, diverse annular substitutes endowed the cyclized polymers with prominent thermal resistance and luminescence properties. Through the above investigations, it is clearly demonstrated that small changes in carbon skeleton structure can remarkably affect the polymer properties. Moreover, AMROP provides a new strategy to design novel polymers with C5 and C6 skeleton structures.