Controlled Synthesis of Polylactides Using Biogenic Creatinine Carboxylate Initiators

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• 作者：Hong Li ; Saihui Zhang ; Jieping Jiao ; Zhifeng Jiao ; Lijun Kong ; Jie Xu ; Jinling Li ; Jiaqing Zuo ; Xiaona Zhao
• 刊名：Biomacromolecules
• 出版年：2009
• 出版时间：May 11, 2009
• 年：2009
• 卷：10
• 期：5
• 页码：1311-1314
• 全文大小：157K
• 年卷期：v.10,no.5(May 11, 2009)
• ISSN：1526-4602

文摘

Two biogenetic guanidine carboxylates, i.e., creatinine acetate (CRA) and creatinine glycolate (CRG) based on creatinine (CR) were synthesized and structurally characterized by ¹H NMR, ¹³C NMR and X-ray diffraction (XRD) analysis of the single crystals. The characterization demonstrated that CRA and CRG are CR−guanidinium carboxylates in nature, and the carboxylates are associated with the guanidinium via hydrogen bonds. CRA and CRG were successfully used as single-component initiators for ring-opening polymerizations (ROPs) of l-lactide (LLA), dl-lactide (DLLA) producing polymers with controlled molecular weights and narrow polydispersities (PDI = 1.16−1.26). The investigation on the kinetics of the ROPs indicated the typical characteristics of living polymerization as evidenced by the linear relationship of ln [M]₀/[M]_t versus time and M_n (number-average molecular weight of formed polymer) versus monomer conversion. A study of the terminator-adding effect on the growing polymers revealed that the polymerization follows the coordination propagation mode. The structures of the living oligomers and product polymers were characterized with ¹H NMR spectroscopy. The mechanism of the polymerization was proposed on the basis of the experimental investigation.