Autocatalytic Equation Describing the Change in Molecular Weight during Hydrolytic Degradation of Aliphatic Polyesters

2010 ◽  
Vol 11 (4) ◽  
pp. 1118-1124 ◽  
Author(s):  
Harro Antheunis ◽  
Jan-Cees van der Meer ◽  
Matthijs de Geus ◽  
Andreas Heise ◽  
Cor E. Koning
Keyword(s):  
Molecular Weight ◽  
Hydrolytic Degradation ◽  
Aliphatic Polyesters

scholarly journals 1,3-Dioxolan-4-Ones as Promising Monomers for Aliphatic Polyesters: Metal-Free, in Bulk Preparation of PLA

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2396
Author(s):  
Stefano Gazzotti ◽  
Marco Aldo Ortenzi ◽  
Hermes Farina ◽  
Alessandra Silvani
Keyword(s):  
Molecular Weight ◽  
Thermal Properties ◽  
Acid Catalyst ◽  
Monomer Conversion ◽  
Reaction Conditions ◽  
Aliphatic Polyesters ◽  
Metal Free ◽  
Weight Growth ◽  
Double Activation

The first example of solvent-free, organocatalyzed, polymerization of 1,3-dioxolan-4-ones, used as easily accessible monomers for the synthesis of polylactic acid (PLA), is described here. An optimization of reaction conditions was carried out, with p-toluensulfonic acid emerging as the most efficient Brønsted acid catalyst. The reactivity of the monomers in the tested conditions was studied following the monomer conversion by 1H NMR and the molecular weight growth by SEC analysis. A double activation polymerization mechanism was proposed, pointing out the key role of the acid catalyst. The formation of acetal bridges was demonstrated, to different extents depending on the nature of the aldehyde or ketone employed for lactic acid protection. The polymer shows complete retention of stereochemistry, as well as good thermal properties and good polydispersity, albeit modest molecular weight.

scholarly journals Thermal characterization of novel aliphatic polyesters with ether and thioether linkages

e-Polymers ◽  
2010 ◽  
Vol 10 (1) ◽  
Author(s):  
M. Soccio ◽  
N. Lotti ◽  
L. Finelli ◽  
A. Munari
Keyword(s):  
Thermal Stability ◽  
Molecular Weight ◽  
Chemical Structure ◽  
Room Temperature ◽  
Crystallization Rate ◽  
Thermal Characterization ◽  
Scanning Calorimetry ◽  
Aliphatic Polyesters ◽  
Good Thermal Stability

AbstractSeveral novel ether or thioether linkage containing aliphatic polyesters and poly(alkylene dicarboxylate)s were synthesized for comparison and characterized in terms of chemical structure and molecular weight. The thermal behavior was examined by thermogravimetric analysis and differential scanning calorimetry. All the polymers showed a good thermal stability, even though lower for the ether or thioether linkage-containing polyesters. The decrement of the thermal stability appears to be more relevant in the case of the presence of sulphur atoms. At room temperature the samples appeared semicrystalline, except PTTDG and PDEDG, which were viscous oils; the effect of the introduction of ether or thioether group was an increment of the Tgvalue, a decrement of the melting temperature and a significant decrease of the crystallization rate. The entity of the variations was found to be affected by the kind of group introduced, and the trend observed can be explained on the basis of atom electronegativity and dimensions

scholarly journals New 1,2,3-Triazole Containing PolyestersviaClick Step-Growth Polymerization and Nanoparticles Made of Them

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Tengiz Kantaria ◽  
Temur Kantaria ◽  
Giorgi Titvinidze ◽  
Giuli Otinashvili ◽  
Nino Kupatadze ◽  
...  
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Sodium Azide ◽  
Dicarboxylic Acids ◽  
Solution Concentration ◽  
One Pot ◽  
Bromoacetic Acid ◽  
Aliphatic Polyesters ◽  
Step Growth ◽  
Step Growth Polymerization

High-molecular-weight AA-BB-type aliphatic polyesters were synthesizedviaCu(I)-catalyzed click step-growth polymerization (SGP) following a new synthetic strategy. The synthesis was performed between diyne and diazide monomers in an organic solvent as one pot process using three components and two stages. The dipropargyl esters of dicarboxylic acids (component 1) were used as diyne monomers, di-(bromoacetic acid)-alkylene diesters (component 2) were used as precursors of diazide monomers, and sodium azide (component 3) was used for generating diazide monomers. The SGP was carried out in two steps: at Step  1 dibromoacetates interacted with two moles of sodium azide resulting in diazide monomers which interacted in situ with diyne monomers at Step  2 in the presence of Cu(I) catalyst. A systematic study was done for optimizing the multiparameter click SGP in terms of the solvent, duration of both Step  1 and Step  2, solution concentration, catalyst concentration, catalyst and catalyst activator (ligand) nature, catalyst/ligand mole ratio, and temperature of both steps of the click SGP. As a result, high-molecular-weight (MWup to 74 kDa) elastic film-forming click polyesters were obtained. The new polymers were found suitable for fabricating biodegradable nanoparticles, which are promising as drug delivery containers in nanotherapy.

An Atomistic Modeling and Quantum Mechanical Approach to the Hydrolytic Degradation of Aliphatic Polyesters

2008 ◽  
Vol 269 (1) ◽  
pp. 47-64 ◽  
Author(s):  
María Entrialgo-Castaño ◽  
Anthony E. Salvucci ◽  
Andreas Lendlein ◽  
Dieter Hofmann
Keyword(s):  
Hydrolytic Degradation ◽  
Quantum Mechanical ◽  
Atomistic Modeling ◽  
Aliphatic Polyesters ◽  
Mechanical Approach ◽  
Quantum Mechanical Approach

Improved Mathematical Model for the Hydrolytic Degradation of Aliphatic Polyesters

2009 ◽  
Vol 42 (7) ◽  
pp. 2462-2471 ◽  
Author(s):  
Harro Antheunis ◽  
Jan-Cees van der Meer ◽  
Matthijs de Geus ◽  
Wieb Kingma ◽  
Cor E. Koning
Keyword(s):  
Mathematical Model ◽  
Hydrolytic Degradation ◽  
Aliphatic Polyesters

Novel unsaturated ε-caprolactone polymerizable by ringopening and ring-opening metathesis mechanisms

e-Polymers ◽  
2002 ◽  
Vol 2 (1) ◽  
Author(s):  
Xudong Lou ◽  
Christophe Detrembleur ◽  
Philippe Lecomte ◽  
Robert Jérôme
Keyword(s):  
Molecular Weight ◽  
Ring Opening ◽  
Unsaturated Polyester ◽  
Side Reaction ◽  
Monomer Conversion ◽  
Ring Opening Metathesis Polymerization ◽  
Aliphatic Polyesters ◽  
Metathesis Polymerization ◽  
Insertion Mechanism ◽  
Alternative Routes

AbstractRing-opening polymerization (ROP) and ring-opening metathesis polymerization (ROMP) of an unsaturated ε-caprolactone, 6,7-dihydro-2(3H)-oxepinone (DHO2), are alternative routes to produce unsaturated aliphatic polyesters with the same molecular structure. Polymerization of DHO2 initiated by Al isopropoxide in toluene at room temperature or at 0°C proceeds by a coordination-insertion mechanism, although intramolecular transesterification takes place beyond complete monomer conversion. The molecular weight distribution is narrow as long as monomer conversion does not exceed 90%. Ring-opening metathesis polymerization of DHO2 initiated by Schrock’s Mo-based catalyst, 1, at 60°C allows higher molecular weight unsaturated polyester to be prepared, even though an intramolecular side reaction also operates. The structure of poly(DHO2) synthesized by ROP and ROMP is the same, as confirmed by 1H, 13C NMR, and FT-IR spectra. Copolymers of DHO2 with norbornene, cis-cyclooctene, and 1,5-cyclooctadiene have been successfully prepared.

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