bulk polymerization of lactides initiated by aluminium

Formation of Poly(lactide) with Controlled Molecular ...

Poly(lactide) with narrow molecular weight distribution was obtained by the ring-opening polymerization of D-lactide with (5,10,15,20-tetraphenylporphinato)aluminum alkoxide as initiator. The polymerization was demonstrated to proceed via the ring-opening of lactide at the acyl-oxygen bond to give (porphinato)aluminum alkoxide as the growing ...

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Highly Isoselective Ring-Opening Polymerization of rac ...

Nov 16, 2020· The crystal structures of rac3 and rac5 are also identified by single crystal X-ray diffraction. In the presence of i PrOH initiator, these aluminum complexes catalyze the ring-opening polymerization (ROP) of rac-lactide (rac-LA) in a controlled manner and produce polymers with high to excellent isoselectivity (Pm up to 0.93).

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Bulk polymerization of lactides initiated by aluminum ...

Abstract. Commercially available Al isopiopoxide (Al(OiPr)3) has proved to be an efficient initiator for the bulk polymerization of lactide. The ring-opening polymerization proceeds through a "coordination-insertion" mechanism and the selective rupture of the acyl-oxygen bond of the monomer Polyester chains are selectively end-capped with an aluminum alkoxide and an isopropoxy group.

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Synthesis and Characterization of Biodegradable Poly(ester ...

opening polymerization of -caprolactone ( -CL) either in solution or in bulk. However, the rela-tively high crystallinity of PCL reduces its com-patibility with soft tissues, lowers its biodegrad-ability, and limits its applications. Poly(adipic an-hydride) (PAA) is another biodegradable polymer characterized by nontoxicity and biocompatibil-

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Catalytic Systems for the Production of Poly(lactic acid ...

Aug 12, 2017· Degée P, Dubois P, Jérôme R (1997) Bulk polymerization of lactides initiated by aluminium isopropoxide, 3. Thermal stability and viscoelastic properties. Macromol Chem Phys 198(6):1985–1995. doi: 10.1002/macp.1997.021980624 CrossRef Google Scholar

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Ring-Opening Polymerization of Lactides by (Pyrazol-1 ...

The ring-opening polymerization of lactides can be cata- ... bulk of the pyrazolyl ligand in 1 ... active than the aluminium alkoxide catalyst reported by Zhong et al.27 which displays apparent rate constant of 0.902 day–1 in the L-LA polymerization reactions. 4.3. Order of Reaction With Respect to Initiator

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Theoretical studies on aluminum trialkoxide-initiated ...

Dec 01, 2016· Since the calculations will be used to compare with the bulk polymerization ... Effect of monomer, solvent, and initiator on the ring-opening polymerization as initiated with aluminum alkoxides. ... A family of versatile initiators for the ring-opening polymerization of lactones and lactides. Makromol. Chem., Macromol. Symp., 42–43 (1991), pp ...

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coordination-insertion ring-opening polymerization of 1.4-dioxan-2-one (DX) as initiated by aluminium triiso- propoxide (A~(OPX-)~) either in bulk or in solution. First, polymerization of DX has been canied out in bulk at 100 'C and compared to the ring -opening polymerization promoted by tin(I1)octoate. Block copolymers of e-capro-

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Ring-Opening Polymerization of rac-Lactide with Aluminum ...

May 27, 2014· The bulk polymerization was performed by heating rac-lactide (2.84 g, 19.8 mmol) and an Al catalyst (0.050 mmol) in a Schlenk flask under nitrogen with an oil bath preset at 130 °C. The heating was discontinued when the melt became very viscous and stirring stopped, usually within 2 h.

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Initiation of ring-opening polymerization of lactide: The ...

Sep 01, 2012· A comprehensive computational study of the initiation stage of the ring-opening polymerization (ROP) of meso-lactide catalyzed by various metal alkoxides MOR (M = Li, Mg, Zn, OR = O i Pr, O t Bu) is presented. Density functional theory at B3LYP/6-31G(d,p) level is applied in examining the coordination-insertion mechanism and reactivity.

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Stereoselective Ring‐Opening Polymerization of a Racemic ...

May 15, 2007· Dongni Li, Bo Gao and Qian Duan, Synthesis of biodegradable and biorenewable polylactides initiated by aluminum complexes bearing m -xylylenediamine derivatives via the ring-opening polymerization of lactides, New Journal of Chemistry, 10.1039/C9NJ01268K, (2019).

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Research Article Enzyme-Mediated Ring-Opening ...

ization (ROP) of lactides or lactones of corresponding HAs [ ]. Generally, such type of polymerization is initiated and ... bulk in vacuum-sealed ampoule. ...,namely,L-lactide, resulted in a product with [] = 0.7 dL/g at C. us, it is obvious that reactivity of PDL in polymerization initiated by stannous octoate seems to be relatively low, this ...

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Recent developments in main group metal complexes ...

This review describes recent development of ring-opening polymerization of lactides and related cyclic esters using main group metal complexes as catalysts/initiators. The complexes described here are classified according to metal groups. Most attention is devoted to the well-defined metal complexes

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New catalysis for fast bulk ring-opening polymerization of ...

[en] The ring-opening polymerization of lactides has been studied in bulk using either 2-ethylhexanoic acid tin(II) salt, Sn(Oct)2, or aluminum triisopropoxide, Al(OiPr)3, as the initiator over a wide range of temperature and monomer-to-initiator molar ratio, A high increase in the bulk polymerization rate has been observed when the initiator ...

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Mechanism of the Living Lactide Polymerization Mediated by ...

Jan 12, 2011· Dhanadech Chandanabodhi, Tanin Nanok, A DFT study of the ring-opening polymerization mechanism of l -lactide and ε -caprolactone using aluminium salen-type initiators: Towards an understanding of their reactivities in homo- and copolymerization, Molecular Catalysis, 10.1016/j.mcat.2017.04.005, 436, (145-156), (2017).

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Ring-Opening Polymerization of L-lactide Initiated by ...

Background: The synthesis of the aliphatic polyesters obtained by the ring opening polymerization has been achieved using as initiators a large am...

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Controlled synthesis of biodegradable lactide polymers and ...

Jan 01, 2004· Syntheses of biodegradable and biorenewable polylactides initiated by aluminum complexes bearing porphyrin derivatives by the ring-opening polymerization of lactides. Li D, Gao B, Duan Q. J Biomater Sci Polym Ed, 30(10):846-860, 08 May 2019 Cited by: 0 articles | PMID: 30961446

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(PDF) Ring-Opening Polymerization of Lactide by Aluminium ...

Lactide polymerization has been analyzed by NMR and GPC methods. The present paper emphasizes on the polymerization kinetics and the control exhibited by the different types of aluminium ...

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Stereo block copolymers of L- and D-lactides — University ...

T1 - Stereo block copolymers of L- and D-lactides. AU - Yui, Nobuhiko. AU - Dijkstra, Pieter J. AU - Feijen, Jan. PY - 1990. Y1 - 1990. N2 - Sequential diblock copolymers composed of L- and D-lactic acid residues were synthesized through a living ring-opening polymerization of L- and D-lactide initiated by aluminium tris(2-propanolate).

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Bulk polymerization of ε-caprolactone: Rheological ...

Apr 19, 2000· 17. Cryometric and viscosimetric analysis of the species active in the ring-opening polymerization of lactones, lactides, and cyclic anhydrides as initiated by aluminium triisopropoxide," Macromolecules 27, 5950– 5956 (1994). Google Scholar Crossref; 27. Schindler, A., Y. M. Hibionada, and C. G. Pitt, " Aliphatic polyesters.

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Chinese J. Polym. Sci

Isoselective Ring-opening Polymerization of Racemic Lactide Catalyzed by N-heterocyclic Olefin/(Thio)urea Organocatalysts. Chinese J. Polym. Sci, 2020, 39(): 1-7. doi: 10.1007/s10118-021-2535-x [15] Chong He, Xiang Zhu, Xiao-Hong Li, Xiao-Ming Yang, Ying-Feng Tu. Thermodynamics of Aromatic Cyclic Ester Polymerization in Bulk.

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Ring-opening polymerization of cyclic esters initiated by ...

Solvent-free bulk polymerization of L-lactide initiated by dinuclear zirconium complex 2 with a conversion >90% can be achieved within 10 min, yielding high molecular weight polylactide with low polydispersity index. Kinetic studies reveal the ROP of L-lactide initiated by dinuclear zirconium complex 3 has a first-order dependency on [LA].

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Recent advances in the synthesis of aliphatic polyesters ...

Polymerization is then initiated by any nucleophile, e.g., water or alcohol, present in the polymerization medium as impurities or as compound added on purpose. In the second mechanism, the organometallic plays the role of initiator and the polymerization proceeds through an 'insertion-coordination' mechanism (Scheme 5). Metal

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Biodegradation of Poly-ε-caprolactones and Poly- l ...

Sep 17, 2018· This work assessed biodegradation, by Aspergillus, Fusarium, Penicillium and Parengyodontium fungi, of four samples of poly-ε-caprolactone (PCL), three samples of poly-l-lactide (PLA) and one sample of poly-d,l-lactide (DL-PLA) produced by ring-opening polymerization initiated by aluminium complexes of corresponding lactones. Mesophilic .

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Bulk Ring-Opening Polymerization of Lactides Initiated by ...

adshelp[at]cfa.harvard.edu The ADS is operated by the Smithsonian Astrophysical Observatory under NASA Cooperative Agreement NNX16AC86A

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Chinese J. Polym. Sci

Isoselective Ring-opening Polymerization of Racemic Lactide Catalyzed by N-heterocyclic Olefin/(Thio)urea Organocatalysts. Chinese J. Polym. Sci, 2020, 39(): 1-7. doi: 10.1007/s10118-021-2535-x [15] Chong He, Xiang Zhu, Xiao-Hong Li, Xiao-Ming Yang, Ying-Feng Tu. Thermodynamics of Aromatic Cyclic Ester Polymerization in Bulk.

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Polymerization of l-lactide with SnCl2: A Low Toxic and ...

Polymerizations of l-lactide catalyzed either by neat SnCl2 or by SnCl2 + difunctional cocatalysts were conducted in bulk at 180, 160 and 140 °C with variation of the Lac/ ratio and time. With neat SnCl2 poly(L-lactide) having weight average molecular weights (uncorrected Mw's) up to 190 000 g mol−1 were obtained mainly consisting of linear chains. Addition of salicylic acid or 1,1 ...

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Mechanism of the Living Lactide Polymerization Mediated by ...

Jan 12, 2011· Dhanadech Chandanabodhi, Tanin Nanok, A DFT study of the ring-opening polymerization mechanism of l -lactide and ε -caprolactone using aluminium salen-type initiators: Towards an understanding of their reactivities in homo- and copolymerization, Molecular Catalysis, 10.1016/j.mcat.2017.04.005, 436, (145-156), (2017).

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Polymerization of lactides and lactones: VII. Ring-opening ...

Ring-opening polymerization of D,L-lactide has been initiated with rare earth phenyl compound in bulk and solution. These rare earth phenyl initiators .

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[PDF] The mechanism of the ring-opening polymerization of ...

To obtain more insight in the ring-opening polymerization of lactones, complex formation of the initiators tetraphenyltin, stannous octoate, tin tetrachloride, aluminium bromide and triisobutylaluminium (TIBA), and the monomers L(−)-lactide, D,L-lactide and glycolide was studied by i.r.-spectroscopy. When equimolar benzene or toluene solutions of initiators and monomers were combined, only ...

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Stereo block copolymers of L- and D-lactides

D-lactides with a narrow molecular weight distribution and well defined block-lengths. This paper reports on the synthesis and characterization of sequential diblock copolymers of poly(L-lactide) and poly(D-lactide), obtained by a living ring-opening polymerization of L- and D-lactides, initiated by aluminium tris(2-propanolate) (1).

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Ring-opening polymerization of cyclic esters initiated by ...

Solvent-free bulk polymerization of L-lactide initiated by dinuclear zirconium complex 2 with a conversion >90% can be achieved within 10 min, yielding high molecular weight polylactide with low polydispersity index. Kinetic studies reveal the ROP of L-lactide initiated by dinuclear zirconium complex 3 has a first-order dependency on [LA].

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Ring‐Opening Polymerization of Lactide with Group 3 Metal ...

Abstract A series of new alkoxy‐amino‐bis(phenols) (H2L 1–6) has been synthesized by Mannich condensations of substituted phenols, formaldehyde, and amino ethers or .

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