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ABSTRACT An organocatalytic approach to controlled/living ring-opening polymerizations (ROPs) of O-carboxyanhydrides (OCAs) using N-heterocyclic carbenes (NHCs) as nucleophilic catalysts has been investigated. NHCs with different structures were used in order to compare the catalytic performances in the ROP of OCA of l-lactic acid. 1H NMR, SEC, and MALDI-TOF MS measurements of the products clearly indicated a controlled/living manner of the polymerization. The controlled/living nature was further confirmed by kinetic and chain extension experiments. Additionally, polylol initiators were used to produce α,ω-dihydroxy telechelic, 3-, and 4-armed star-shaped polymers. Moreover, star-shaped diblock copolymer, bearing methyl and phenyl side groups, has been successfully synthesized with OCA/NHC system. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014. 52, 2306-2315 [ABSTRACT FROM AUTHOR]

Abstract: The ring-opening polymerization (ROP) of trimethylene carbonate (TMC) catalyzed by phosphoramidic acid (PAA) and initiated with benzyl alcohol (BnOH) has been investigated. The polymerization conditions were optimized to afford well-defined polytrimethylene carbonates (PTMCs). The molecular weight of the obtained PTMC with the [TMC]0/[BnOH]0/[PAA]0 ratio of 40:1:1 was analyzed by 1H NMR, M n = 4180 g mol−1, showed good agreement with that estimated from the initial ratio, M n = 3830 g mol−1. The kinetics and chain extension experiments have been carried out to further justify the controlled/living nature of this polymerization. The 1H NMR, SEC, and MALDI-TOF MS measurements were applied to analyze the obtained PTMCs. [Copyright &y& Elsevier]

ABSTRACT The ring-opening polymerization (ROP) of trimethylene carbonate (TMC) using imidodiphosphoric acid (IDPA) as the organocatalyst and benzyl alcohol (BnOH) as the initiator has been investigated. The polymerization proceeded without decarboxylation to afford poly(trimethylene carbonate) (PTMiC) with controlled molecular weight and narrow polydispersity. 1H NMR, SEC, and MALDI-TOF MS measurements of the obtained PTMC clearly indicated the quantitative incorporation of the initiator at the chain end. The controlled/living nature for the IDPA-catalyzed ROP of TMC was confirmed by the kinetic and chain extension experiments. A bifunctional activation mechanism was proposed for IDPA catalysis based on NMR and FTIR studies. Additionally, 1,3-propanediol, 1,1,1-trimethylolpropane, and pentaerythritol were used as di-ol, tri-, and tetra-ol initiators, producing the telechelic or star-shaped polycarbonates with narrow polydispersity indices. The well-defined diblock copolymers, poly(trimethylene carbonate)- block-poly(δ-valerolactone) and poly(trimethylene carbonate)- block-poly(ε-caprolactone), have been successfully synthesized by using the IDPA catalysis system. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014, 52, 1009-1019 [ABSTRACT FROM AUTHOR]