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
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
Citations
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Journal ArticleDOI
Ring-Opening Polymerization of Trimethylene Carbonate Catalyzed by Methanesulfonic Acid: Activated Monomer versus Active Chain End Mechanisms
TL;DR: In this article, the authors investigated the ring-opening polymerization (ROP) of trimethylene carbonate (TMC) initiated by water or n-pentanol and catalyzed by trifluoromethanesulfonic acid (HOTf) or methaneulfonic acids (MSA).
Journal ArticleDOI
Organocatalysts for the Controlled “Immortal” Ring-Opening Polymerization of Six-Membered-Ring Cyclic Carbonates: A Metal-Free, Green Process
Marion Helou,Olivier Miserque,Jean-Michel Brusson,Jean-François Carpentier,Sophie M. Guillaume +4 more
TL;DR: These catalyst systems enable among the highest activities and productivities ever reported for the ROP of TMC, and remain highly active in the iROP of technical-grade, unpurified TMC.
Journal ArticleDOI
Organocatalytic synthesis of (poly)hydroxyurethanes from cyclic carbonates and amines
TL;DR: In this article, the reaction rates between cyclic carbonates and amines were investigated in the presence of a variety of organocatalysts, which operate under different mechanisms to promote the reaction.
Journal ArticleDOI
Hybrid Copolymerization of ε-Caprolactone and Methyl Methacrylate
TL;DR: In this article, a hybrid copolymerization of e-caprolactone and methyl methacrylate with (1-tert-butyl-4,4, 4,4-tris(dimethylamino)-2,2-bis[tris (dimethyamino)phophoranylidenamino]-2Λ5, Λ5-κε-5-catenadi(phosphazene) (t-BuP4) was studied.
Journal ArticleDOI
Polymers from sugars: cyclic monomer synthesis, ring-opening polymerisation, material properties and applications
TL;DR: An overview of sugar-based polymers that can be made by Ring-Opening Polymerisation is given, in particular, recent advances in the synthetic routes towards monomers that preserve the original carbohydrate core structure are presented.
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.