scholarly journals Reactive Extrusion and Magnesium (II) N-Heterocyclic Carbene Catalyst in Continuous PLA Production

Polymers ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1987
Author(s):  
Rosica Mincheva ◽  
Satya Narayana Murthy Chilla ◽  
Richard Todd ◽  
Brieuc Guillerm ◽  
Julien De Winter ◽  
...  

Reactive extrusion and magnesium (II) N-heterocyclic carbene catalyst are successfully employed in continuous polylactide synthesis. The possibility of using six-membered N-heterocyclic carbene adducts to act as efficient catalysts towards the sustainable synthesis of poly(l-lactide) through ring-opening polymerization of l-lactide (LA) is first investigated in bulk batch reactions. Under optimized solvent-free conditions, polylactide (PLA) of moderate to high molecular weights and excellent optical activities are successfully achieved. These promising results are further applied in the continuous production of PLA in an extruder.

2013 ◽  
Vol 9 ◽  
pp. 647-654 ◽  
Author(s):  
Astrid Hoppe ◽  
Faten Sadaka ◽  
Claire-Hélène Brachais ◽  
Gilles Boni ◽  
Jean-Pierre Couvercelle ◽  
...  

The ring-opening polymerization of ε-caprolactone (ε-CL) and rac-lactide (rac-LA) under solvent-free conditions and using 1-n-butyl-3-methylimidazolium-2-carboxylate (BMIM-2-CO2) as precatalyst is described. Linear and star-branched polyesters were synthesized by successive use of benzyl alcohol, ethylene glycol, glycerol and pentaerythritol as initiator alcohols, and the products were fully characterized by 1H and 13C{1H} NMR spectroscopy, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC). BMIM-2-CO2 acts as an N-heterocyclic carbene precursor, resulting from in situ decarboxylation, either by heating under vacuo (method A) or by addition of NaBPh4 (method B). Possible catalytic and deactivation mechanisms are proposed.


2008 ◽  
Vol 29 (18) ◽  
pp. 1554-1560 ◽  
Author(s):  
Marco Frediani ◽  
David Sémeril ◽  
Alfredo Mariotti ◽  
Luca Rosi ◽  
Piero Frediani ◽  
...  

Polymers ◽  
2018 ◽  
Vol 10 (11) ◽  
pp. 1239 ◽  
Author(s):  
Andrés Posada ◽  
Mario Macías ◽  
Santiago Movilla ◽  
Gian Miscione ◽  
León Pérez ◽  
...  

Five of six new Zn(II) and Cu(II) complexes were active in the ring-opening polymerization (ROP) of ε-caprolactone (CL) under solvent-free conditions, producing polycaprolactones (PCLs) of high crystallinity with molecular weights between 22,900 and 38,700 g mol−1 and decomposition temperatures above 260 °C. 1H NMR analysis demonstrated that the PCLs obtained were mainly linear, having hydroxymethylene groups at the chain ends. The results obtained indicated a significant improvement in terms of the ratio of monomer:initiator compared to related Cu(II) and Zn(II) complexes. In addition, the structures of the complexes 1 and 4 were determined by single-crystal X-ray diffraction. The synthesis and full characterization of all complexes are described in this paper.


RSC Advances ◽  
2021 ◽  
Vol 11 (22) ◽  
pp. 13475-13485
Author(s):  
Divambal Appavoo ◽  
Lara C. Spencer ◽  
Ilia A. Guzei ◽  
Carlos J. Gómez-García ◽  
Juanita L. van Wyk ◽  
...  

We report the synthesis, structure and complete characterization of four new pyrazolyl carboxylate-based copper(ii) complexes that catalyze the ring opening polymerization of ε-caprolactone under solvent-free conditions and of d,l-lactide in toluene.


2020 ◽  
Vol 10 (22) ◽  
pp. 7555-7565
Author(s):  
Chenlin Ji ◽  
Suyun Jie ◽  
Pierre Braunstein ◽  
Bo-Geng Li

New benzoheterocyclic urea/MTBD catalysts are highly efficient and controllable in the ring-opening polymerization of δ-valerolactone under solvent-free conditions or in solution.


Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 13 ◽  
Author(s):  
Rosica Mincheva ◽  
Hazar Guemiza ◽  
Chaimaa Hidan ◽  
Sébastien Moins ◽  
Olivier Coulembier ◽  
...  

In this study, a highly efficient flame-retardant bioplastic poly(lactide) was developed by covalently incorporating flame-retardant DOPO, that is, 9,10-dihydro-oxa-10-phosphaphenanthrene-10-oxide. To that end, a three-step strategy that combines the catalyzed ring-opening polymerization (ROP) of L,L-lactide (L,L-LA) in bulk from a pre-synthesized DOPO-diamine initiator, followed by bulk chain-coupling reaction by reactive extrusion of the so-obtained phosphorylated polylactide (PLA) oligomers (DOPO-PLA) with hexamethylene diisocyanate (HDI), is described. The flame retardancy of the phosphorylated PLA (DOPO-PLA-PU) was investigated by mass loss cone calorimetry and UL-94 tests. As compared with a commercially available PLA matrix, phosphorylated PLA shows superior flame-retardant properties, that is, (i) significant reduction of both the peak of heat release rate (pHRR) and total heat release (THR) by 35% and 36%, respectively, and (ii) V0 classification at UL-94 test. Comparisons between simple physical DOPO-diamine/PLA blends and a DOPO-PLA-PU material were also performed. The results evidenced the superior flame-retardant behavior of phosphorylated PLA obtained by a reactive pathway.


2005 ◽  
Vol 83 (5) ◽  
pp. 505-507 ◽  
Author(s):  
Najmodin Azizi ◽  
Mohammad R Saidi

Lithium perchlorate catalyzed the ring opening of epoxides with amines to provide the corresponding β-aminoalcohols in excellent yields with high regioselectivity. The reaction proceeds rapidly under mild and neutral conditions and worked well with primary, secondary, aliphatic, aromatic, and hindered amines in short times at room temperature, in the absence of solvent.Key words: epoxide, lithium perchlorate, β-aminoalcohols, solvent-free.


2007 ◽  
Vol 264 (1-2) ◽  
pp. 162-169 ◽  
Author(s):  
Rukhsana Ilyas Kureshy ◽  
Surendra Singh ◽  
Noor-ul Hasan Khan ◽  
Sayed Hasan Razi Abdi ◽  
Eringathodi Suresh ◽  
...  

2013 ◽  
Vol 46 (21) ◽  
pp. 8458-8466 ◽  
Author(s):  
Florian Paulus ◽  
Maximilian E. R. Weiss ◽  
Dirk Steinhilber ◽  
Anatoly N. Nikitin ◽  
Christof Schütte ◽  
...  

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