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
Benzoic Acid as an Efficient Organocatalyst for the Statistical Ring-Opening Copolymerization of ε-Caprolactone and L-Lactide: A Computational Investigation
Coralie Jehanno,Leila Mezzasalma,Leila Mezzasalma,Haritz Sardon,Fernando Ruipérez,Olivier Coulembier,Daniel Taton +6 more
TL;DR: Statistical copolymers of l-lactide (L-LA) and e-caprolactone (CL) are of major interest as a result of the desired combination of properties they exhibit for high-added-value applications as discussed by the authors.
Journal ArticleDOI
Organocatalytic synthesis of astaxanthin-containing poly(lactide)s
TL;DR: In this article, the synthesis of astaxanthin-containing poly(lactide)s is reported by the ring-opening polymerization of lactide initiated from residual alcohol groups on a thiourea/tertiary amine catalyst.
Journal ArticleDOI
Boric acid as biocatalyst for living ring-opening polymerization of ε-caprolactone
TL;DR: In this article, the authors investigated the role of boric acid as metal-free biocatalyst for the bulk ring-opening polymerization (ROP) of e-caprolactone (CL) initiated by benzyl alcohol (BnOH).
Journal ArticleDOI
Synthesis and characterization of high grafting density bottle-brush poly(oxa)norbornene-g-poly(ε-caprolactone)
TL;DR: Thermal analyses show a higher stability of the bottle-brush poly(oxa)norbornene-g-PCLs compared to their PCL-based (oxa), together with a weaker crystallinity resulting from steric hindrance.
Patent
Patterning nano-scale patterns on a film comprising unzipping polymer chains
Urs T. Duerig,Jane Frommer,Bernd Gotsmann,James L. Hedrick,Armin W. Knoll,Robert D. Miller,David Pires,Charles G. Wade +7 more
TL;DR: In this paper, a method for patterning a surface of a polymeric material is proposed. But the method is limited to a single polymeric surface and it is not suitable for the patterning of many polymeric surfaces.
References
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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.
Journal ArticleDOI
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.
Journal ArticleDOI
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.