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Cyclopropenimine Superbases: Competitive Initiation Processes in Lactide Polymerization.

ABSTRACT: Cyclopropenimine superbases were employed to catalyze the ring-opening polymerization of lactide. Polymerization occurred readily in the presence and absence of alcohol initiators. Polymerizations in the absence of alcohol initiators revealed a competitive initiation mechanism involving deprotonation of lactide by the cyclopropenimine to generate an enolate. NMR and MALDI-TOF analysis of the poly(lactides) generated from cyclopropenimines in the absence of alcohol initiators showed acylated lactide and hydroxyl endgroups. Model studies and comparative experiments with guanidine and phosphazene catalysts revealed the subtle influence of the nature of the superbase on competitive initiation processes.

SUBMITTER: Stukenbroeker TS

PROVIDER: S-EPMC4762272 | biostudies-literature | 2015 Aug

REPOSITORIES: biostudies-literature

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Cyclopropenimine Superbases: Competitive Initiation Processes in Lactide Polymerization.

Stukenbroeker Tyler S TS Bandar Jeff S JS Zhang Xiangyi X Lambert Tristan H TH Waymouth Robert M RM

ACS macro letters 20150730 8

Cyclopropenimine superbases were employed to catalyze the ring-opening polymerization of lactide. Polymerization occurred readily in the presence and absence of alcohol initiators. Polymerizations in the absence of alcohol initiators revealed a competitive initiation mechanism involving deprotonation of lactide by the cyclopropenimine to generate an enolate. NMR and MALDI-TOF analysis of the poly(lactides) generated from cyclopropenimines in the absence of alcohol initiators showed acylated lact ...[more]

PMID: 26913218

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