Polymerization of trimethylene carbonates using organic phosphoric acids

The homopolymerization of trimethylene carbonates (TMC) and their diblock copolymerization to PTMC- b -PVL and PTMC- b -PCL were carried out using benzyl alcohol (BnOH) as the initiator and 1,1-binaphthyl-2,2-diyl hydrogen phosphate (BNPH) as the catalyst in toluene at room temperature. The measured 1 H NMR molecular weight (PTMC, M n, NMR = 5300 g mol 1 ) and the theoretical one (PTMC, M n, theo = 5100 g mol 1 ) calculated from the initial ratio of [TMC] 0 /[BnOH] 0 and the monomer conversion matched ideally. The 1 H NMR, SEC and MALDI-ToF MS measurements clarified that the obtained polymers were exactly as expected. Kinetics and chain extension experiments demonstrated the controlled/living nature for the ROP of TMC using BNPH. NMR titration experiments confirmed that the polymerization proceeded via a bifunctional activation mechanism. Extension of the initiators by using multifunctional 1,3-propanediol, pentaerythritol, propargyl alcohol, 5-hexen-1-ol, and N -(2-hydroxyethyl)maleimide installed ,-dihydroxy telechelic, star-shaped, and clickable end-functionalized polycarbonates. Block copolymers poly(trimethylene carbonate)- block -poly(-valerolactone), poly(trimethylene carbonate)- block -poly(-caprolactone), and poly(trimethylene carbonate)- block -poly( l -lactide) had been successfully obtained, which suggests that the BNPH catalysis is broadly applicable. 1,1-Binaphthyl-2,2-diyl hydrogen phosphate (BNPH) catalyzed a controlled/living ROP of TMC through a bifunctional activation mechanism, leading to end-functionalized PTMC and block polymers.