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
Poly(thioester) by Organocatalytic Ring-Opening Polymerization.
TL;DR: The thioester monomer, tCL, is shown to be thermodynamically similar to ε-caprolactam but kinetically similar toε-Caprolactone, and the increased nucleophilicity of thiols (versus alcohols) is implicated in the increased Mw/Mn of the poly(thiocaprolact one) versus poly(caprolACTone), but deleterious transesterification is suppressed in the presence of
Journal ArticleDOI
General route to design polymer molecular weight distributions through flow chemistry
TL;DR: A precise design to synthesis protocol for producing a targeted MWD design with a simple to use, and chemistry agnostic computer-controlled tubular flow reactor is reported.
Journal ArticleDOI
Lewis Pair Polymerization: Perspective on a Ten-Year Journey
TL;DR: Ateniese et al. as mentioned in this paper introduced the concept of Lewis Pair Polymerization (LPP) which employs Lewis acid and base in pairs to activate monomers and effect chain initialization.
Journal ArticleDOI
High Tg aliphatic polyesters by the polymerization of spirolactide derivatives
TL;DR: A series of bicyclic and tricyclic lactide derivatives were prepared using L-lactide as the starting material as discussed by the authors, and these derivatives were subjected to ring-opening polymerization using 1,5,7-triazabicyclo[4.0]dec-5-ene (TBD) as the catalyst.
Journal ArticleDOI
A Simple and Facile Approach to Aliphatic N-Substituted Functional Eight-Membered Cyclic Carbonates and Their Organocatalytic Polymerization
Shrinivas Venkataraman,Victor Wee Lin Ng,Daniel J. Coady,Hans W. Horn,Gavin O. Jones,Tak Shun Fung,Haritz Sardon,Robert M. Waymouth,James L. Hedrick,Yi Yan Yang +9 more
TL;DR: Organocatalytic ring opening polymerization of eight-membered cyclic carbonates was explored as a route to access narrowly dispersed polymers of predictable molecular weights and found to be N-substituent dependent.
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.