Journal ArticleDOI
Guanidine and Amidine Organocatalysts for Ring-Opening Polymerization of Cyclic Esters
Bas G. G. Lohmeijer,Russell C. Pratt,Frank A. Leibfarth,John W. Logan,David A. Long,Andrew P. Dove,Fredrik Nederberg,Jeongsoo Choi,Charles G. Wade,Robert M. Waymouth,James L. Hedrick +10 more
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TLDR
In this article, the ring-opening polymerization (ROP) of cyclic esters such as lactide (LA), δ-valerolactone (VL), and e-caprolactone(CL) was achieved.Abstract:
1,5,7-Triazabicyclo[4.4.0]dec-5-ene (TBD), N-methyl-TBD (MTBD), and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) are effective organocatalysts for the ring-opening polymerization (ROP) of cyclic esters such as lactide (LA), δ-valerolactone (VL), and e-caprolactone (CL). TBD is shown to polymerize LA, VL, and CL in a fast and controlled manner, whereas MTBD and DBU polymerized LA and addition of a thiourea cocatalyst led to the ROP of VL and CL being achieved. Each of the catalysts produced polymers displaying high end group fidelity, good correlation between theoretical and observed molecular weight, and linear relationships between conversion and molecular weight. The enhanced activity of TBD relative to MTBD and DBU is attributed to its bifunctionality, enabling the simultaneous activation of both the cyclic ester monomer and the alcohol group of the initiator/propagating species. Temperature-dependent NMR studies generated individual association constants for MTBD with benzyl alcohol and thiourea with VL. ...read more
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Journal ArticleDOI
Bismuth halide‐catalyzed polymerizations of ε‐caprolactone
TL;DR: In contrast to BiF3, the other three Bi-halides catalyzed the ring-opening polymerization of e-caprolactone (e-CL) in bulk.
Journal ArticleDOI
Liquid Degradable Poly(trimethylene-carbonate-co-5-hydroxy-trimethylene carbonate): An Injectable Drug Delivery Vehicle for Acid-Sensitive Drugs.
Sara Mohajeri,Sara Mohajeri,Fei Chen,Fei Chen,Fei Chen,Mitchell de Prinse,Mitchell de Prinse,Ta Phung,Ta Phung,Jonah Burke-Kleinman,Donald H. Maurice,Brian G. Amsden,Brian G. Amsden +12 more
TL;DR: A new viscous liquid copolymer is reported on that degrades through intramolecular cyclization in mild alkaline environments, producing glycerol, carbon dioxide, and water-soluble trimethylene carbonate, and represents a promising formulation approach for local and sustained release of acid sensitive drugs.
Journal ArticleDOI
High pressure water-initiated ring opening polymerization for the synthesis of well-defined α-hydroxy-ω-(carboxylic acid) polycaprolactones
Andrzej Dzienia,Paulina Maksym,Magdalena Tarnacka,Iwona Grudzka-Flak,Sylwia Golba,Andrzej Zięba,Kamil Kaminski,Marian Paluch +7 more
TL;DR: In this article, the authors used a combination of high pressure, temperature and water to produce polyesters with a well-defined chemical structure and narrow molecular weight distributions by using NMR experiments supported by further MALDI TOF analysis.
Journal ArticleDOI
Polystyrene Beads Supported Phosphazene Superbase as Recyclable Organocatalyst for Ring-Opening Polymerization of δ-Valerolactone
TL;DR: In this paper, the authors demonstrated that PS-t-BuP2 was an efficient and recyclable catalyst for the ring-opening polymerization (ROP) of δ-valerolactone (δ-VL).
Journal ArticleDOI
Tuning Biocompatible Block Copolymer Micelles by Varying Solvent Composition: Dynamics and Populations of Micelles and Unimers
Bryce E. Kidd,Xiuli Li,Rachele Piemonte,Tyler J. Cooksey,Avantika Singh,Megan L. Robertson,Louis A. Madsen +6 more
TL;DR: In this article, the authors present a study of PEO-PCL block copolymer spherical micelles that self-assemble at 1% wt/vol in D2O-THF-d8 mixtures.
References
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Journal ArticleDOI
Controlled ring-opening polymerization of lactide and glycolide.
TL;DR: This work focuses on the characterization of the phytochemical components of Lactide ROP and their role in the regulation of cell reprograming.
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Polymerization of Lactide with Zinc and Magnesium β-Diiminate Complexes: Stereocontrol and Mechanism
Bradley M. Chamberlain,Ming Cheng,David Roger Moore,Tina M. Ovitt,Emil B. Lobkovsky,Geoffrey W. Coates +5 more
TL;DR: The substituents on the beta-diiminate ligand exert a significant influence upon the course of the polymerizations, affecting both the degree of stereoselectivity and the rate of polymerization.
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A review of biodegradable polymers: uses, current developments in the synthesis and characterization of biodegradable polyesters, blends of biodegradable polymers and recent advances in biodegradation studies
TL;DR: A review of the uses of biodegradable polymers in terms of their relevance within current plastic waste management of packaging materials, biomedical applications and other uses is presented in this paper.
Journal ArticleDOI
Extension of the self-consistent spectrophotometric basicity scale in acetonitrile to a full span of 28 pKa units: unification of different basicity scales.
Ivari Kaljurand,Agnes Kütt,Lilli Sooväli,Toomas Rodima,Vahur Mäemets,and Ivo Leito,Ilmar A. Koppel +6 more
TL;DR: The earlier compiled self-consistent spectrophotometric basicity scale in acetonitrile (AN) was expanded to range from 3.8 to 32.0 pK(a) units, that is 28 orders of magnitude, and 54 new relative basicity measurements were carried out and 37 new compounds were introduced to the scale.
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Stereochemistry of Lactide Polymerization with Chiral Catalysts: New Opportunities for Stereocontrol Using Polymer Exchange Mechanisms
Tina M. Ovitt,Geoffrey W. Coates +1 more
TL;DR: A polymer exchange mechanism is proposed to account for the PLA microstructures resulting from rac-4, which polymerizes meso-lactide to syndiotactic poly(lactic acid) (PLA) and heterotactic and isotactic stereoblock PLA, respectively.