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
Imidodiphosphorimidate (IDPi) as an efficient organocatalyst for controlled/living ring-opening polymerization of lactones
TL;DR: Imidodiphosphorimidate (IDPi) is demonsatreted as a novel acid/base bifunctional organocatalyst for controlled/living ring-opening polymerization of lactones, which delivered the metal-free poly(δ-valerolactone) and poly(e-caprolactone), with excellent control over the molecular weight and narrow dispersity at a low catalyst loading under mild conditions as discussed by the authors.
Journal ArticleDOI
Organocatalyzed ring opening polymerization of lactide from the surface of cellulose nanofibrils
Michael Lalanne-Tisné,Michael Lalanne-Tisné,Maarten Mees,Samuel Eyley,Philippe Zinck,Wim Thielemans +5 more
TL;DR: DMAP was readily removed from the products whereas metal catalysts can be hard to remove from the final material, potentially shortening the material lifespan and making it unfit for some applications, so the use of an easily removable and more efficient organocatalyst can be considered a good alternative toMetal catalysts.
Journal ArticleDOI
Modulating bioactivities of primary ammonium-tagged antimicrobial aliphatic polycarbonates by varying length, sequence and hydrophobic side chain structure.
TL;DR: The benefits of blood compatibility of the cationic aliphatic polycarbonates with the use of the primary ammonium side chains have been reported for the first time and could be an advantage over previously reported QAS-tagged antimicrobialpolycarbonates.
Journal ArticleDOI
Reinvestigation of the mechanism of polymerization of β-butyrolactone from 1,5,7-triazabicyclo[4.4.0]dec-5-ene
Sébastien Moins,Céline Henoumont,J. De Winter,Ali Khalil,Ali Khalil,Sophie Laurent,Sandrine Cammas-Marion,Olivier Coulembier +7 more
TL;DR: In this article, a trisubstituted β-lactone, β-butyrolactone (BL), was used to ring-open 1,5,7-triazabicyclo[4.4.0]dec-5-ene.
Patent
Methods of ring opening polymerization and catalysts therefor
TL;DR: A salt catalyst as discussed by the authors is an ionic complex of a nitrogen base comprising one or more guanidine and/or amidine functional groups, and an oxoacid comprising a carbonyl group (C═O), sulfoxide group (S═O) and a phosphonyl groups (P═O).
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.