Monomer design strategy has become a powerful tool to access polymers with desired and diverse functionalities. Here, we designed a novel monomer 2-((benzyloxy)methyl)-1,4-oxathiepan-7-one (BTO) via installing a benzy...Monomer design strategy has become a powerful tool to access polymers with desired and diverse functionalities. Here, we designed a novel monomer 2-((benzyloxy)methyl)-1,4-oxathiepan-7-one (BTO) via installing a benzyl ether side chain to the structure of 1,4-oxathiepan-7-one (OTO). The ring-opening polymerization of BTO with Zn1 as the catalyst demonstrated the characteristics of living polymerization with turnover frequency (TOF) up to 2520 h^(−1). With a [BTO]_(0)/[Zn1]_(0)/[I]_(0) feed ratio of 2000/2/1, polymer with high number-average molecular weight (Mn = 536 kDa) and narrow dispersity (Ð = 1.06) was obtained. The produced polymer with a glass transition temperature of -17℃ behaved as an elastomer at room temperature. Consequently, the monomer BTO was copolymerized with _(L)-LA to modulate the mechanical properties of P(L-LA). When the BTO content is 10%, the copolymer exhibits excellent strength (24 MPa) and elongation at break (270%), affording a crystalline, hard, and tough plastic material that combines the high ductility of P(BTO) and the high modulus of P(_(L)-LA). In addition, the oxidation of P(BTO) to P(BTO)-SO_(2) led to an improvement of T_(g) from -17℃ to 38℃. Debenzylation of P(BTO)-SO_(2) afforded P(BTO)-SO_(2)-OH containing free hydroxyl groups. Ultimately, P(BTO) could be hydrolyzed under a base condition to recover the corresponding hydroxyl acid intermediate, which could be used to prepare the monomer again and complete the closed-loop from monomer to polymer to monomer.展开更多
基金the National Natural Science Foundation of China(51903177 and 22071163)the“1000-Youth Talents Pro-gram",and the Fundamental Research Funds for the Central Uni-versities(YJ201924 and YJ202209).
文摘Monomer design strategy has become a powerful tool to access polymers with desired and diverse functionalities. Here, we designed a novel monomer 2-((benzyloxy)methyl)-1,4-oxathiepan-7-one (BTO) via installing a benzyl ether side chain to the structure of 1,4-oxathiepan-7-one (OTO). The ring-opening polymerization of BTO with Zn1 as the catalyst demonstrated the characteristics of living polymerization with turnover frequency (TOF) up to 2520 h^(−1). With a [BTO]_(0)/[Zn1]_(0)/[I]_(0) feed ratio of 2000/2/1, polymer with high number-average molecular weight (Mn = 536 kDa) and narrow dispersity (Ð = 1.06) was obtained. The produced polymer with a glass transition temperature of -17℃ behaved as an elastomer at room temperature. Consequently, the monomer BTO was copolymerized with _(L)-LA to modulate the mechanical properties of P(L-LA). When the BTO content is 10%, the copolymer exhibits excellent strength (24 MPa) and elongation at break (270%), affording a crystalline, hard, and tough plastic material that combines the high ductility of P(BTO) and the high modulus of P(_(L)-LA). In addition, the oxidation of P(BTO) to P(BTO)-SO_(2) led to an improvement of T_(g) from -17℃ to 38℃. Debenzylation of P(BTO)-SO_(2) afforded P(BTO)-SO_(2)-OH containing free hydroxyl groups. Ultimately, P(BTO) could be hydrolyzed under a base condition to recover the corresponding hydroxyl acid intermediate, which could be used to prepare the monomer again and complete the closed-loop from monomer to polymer to monomer.
