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
Efficient Polymerization of Methyl-ε-Caprolactone Mixtures To Access Sustainable Aliphatic Polyesters
TL;DR: Aliphatic polyesters are a versatile class of materials that can be sourced from bioderived feedstocks and can be used to make degradable thermoplas...
Journal ArticleDOI
o-Benzenedisulfonimide as a recyclable cationic organocatalyst for the controlled/living ring-opening polymerization of δ-valerolactone and ε-caprolactone
Yu Jin,Yufeng Ji,He Xiaojiang,Suli Kan,Haidong Xia,Binqi Liang,Jia Chen,Hao Wu,Kai Guo,Zhenjiang Li +9 more
TL;DR: In this paper, a ring-opening polymerization (ROP) using benzyl alcohol as the initiator was demonstrated. And the polymerization proceeded to afford poly(δ-valerolactone)-block-poly(e-caprolactone) with controlled molecular weights and narrow polydispersities.
Journal ArticleDOI
Organocatalytic Ring-Opening Polymerization of Trimethylene Carbonate To Yield a Biodegradable Polycarbonate
Julian M. W. Chan,Xiangyi Zhang,Megan K. Brennan,Haritz Sardon,Haritz Sardon,Amanda C. Engler,Courtney H. Fox,Curtis W. Frank,Robert M. Waymouth,James L. Hedrick +9 more
TL;DR: In this paper, students work in pairs to synthesize a simple aliphatic polycarbonate via ring-opening polymerization of trimethylene carbonate using 1,8-diazabicyclo[5.4.0]undec-7-ene and thiourea as organocatalysts.
Journal ArticleDOI
Multicyclic Polymer Synthesis through Controlled/Living Cyclopolymerization of α,ω-Dinorbornenyl-Functionalized Macromonomers
Takuya Isono,Tetsuya Sasamori,Kohei Honda,Yoshinobu Mato,Takuya Yamamoto,Kenji Tajima,Toshifumi Satoh +6 more
TL;DR: In this article, a novel synthesis of multicyclic polymers that feature ultradense arrays of cyclic polymer units has been developed by exploiting the cyclopolymerization of α,ω-norbornenyl end-functionalized macromonomers mediated by the Grubbs third-generation catalyst (G3).
Journal ArticleDOI
Bulk Organocatalytic Synthetic Access to Statistical Copolyesters from l-Lactide and ε-Caprolactone Using Benzoic Acid.
TL;DR: Benzoic acid (BA), a naturally occurring, cheap, readily recyclable, and thermally stable weak acid, is shown to trigger the organocatalyzed ring-opening copolymerization (OROcP) of l-LA and CL under solvent-free conditions at 155 °C, in presence of various alcohols as initiators, with good control over molar masses and dispersities.
References
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TL;DR: This work focuses on the characterization of the phytochemical components of Lactide ROP and their role in the regulation of cell reprograming.
Journal ArticleDOI
Polymerization of Lactide with Zinc and Magnesium β-Diiminate Complexes: Stereocontrol and Mechanism
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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.