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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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
Dormant Polymers and Their Role in Living and Controlled Polymerizations; Influence on Polymer Chemistry, Particularly on the Ring Opening Polymerization.
TL;DR: This mini review is devoted to living polymerizations, mostly polymerizations by the Ring-Opening Polymerization mechanisms (ROP) compared with some selected close to living vinyl polymerizations involving dormancy, as well as controlled radical and cationic polymerizations of vinyl monomers.
Journal ArticleDOI
Synthesis and properties of poly(L-lactide-co-glycolide)-b-Poly(|[epsiv]|-caprolactone) multiblock copolymers formed by self-polycondensation of diblock macromonomers
TL;DR: In this article, a ring-opening copolymerization of lactide and glycolide initiated by benzyl-protected PCL in the presence of tin 2-ethylhexanoate (Sn(Oct)2) or organic catalysts (N-cyclohexyl-N’-[3,5-(trifluoromethyl)phenyl]thiourea (TU) and Tris[2-(dimethylamino)ethyl]amine (Me6TREN)).
Journal ArticleDOI
Toward Sustainable Elastomers from the Grafting-Through Polymerization of Lactone-Containing Polyester Macromonomers
TL;DR: In this article , a grafting-through approach was developed for the synthesis of telechelic poly(l-lactide) (PLLA) with a polymerizable lactone group at one chain-end.
Journal ArticleDOI
Dithiolane-Crosslinked Poly(ε-caprolactone)-Based Micelles: Impact of Monomer Sequence, Nature of Monomer, and Reducing Agent on the Dynamic Crosslinking Properties
Yanna Liu,Mies J. van Steenbergen,Zhiyuan Zhong,Sabrina Oliveira,Wim E. Hennink,Cornelus F. van Nostrum +5 more
TL;DR: These dithiolane-crosslinked micelles showed reduction-responsive dissociation in the presence of 10 mM glutathione, making them promising drug delivery systems for the intracellularly triggered cargo release.
Journal ArticleDOI
Reactivity and Structural Diversity in the Reaction of Guanidine 1,5,7-Triazabicyclo[4.4.0]dec-5-ene with CO2, CS2, and Other Heterocumulenes
Niklas von Wolff,Claude Villiers,Pierre Thuéry,Guillaume Lefèvre,Michel Ephritikhine,Thibault Cantat +5 more
TL;DR: In this paper, the guanidine 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) reacted with the heterocumulenes CO2, CS2, iPr2NCNiPr2, p-tolylNCO, and p-Tolyl NCS to give three types of products: TBD-CO2 (1) and TBD-p-tolNCS (5), resulting from the addition of the cumulene to TBD, TBD(H)({
References
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Journal ArticleDOI
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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
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