Synthesis and characterisation of polyester from dimethylketene and carbonyled compounds

L’objectif de cette étude est de synthétiser et de caractériser des polyesters entre le diméthylcétène et des composés carbonylés choisis (acétone, méthyléthylcétone et acéthaldéhyde) par deux voies distinctes : une copolymérisation directe, et une voie passant d’abord par la synthèse de la beta-lactone puis sa polymérisation par ouverture de cycle. La caractérisation a mis en évidence la structure parfaitement alternée du polyester entre le diméthylcétène et l’acétone, et des structures plus complexes avec la méthyléthylcétone et l’acétaldéhyde. Les analyses ont également montré le caractère polymorphe complexe de ces copolymères. Les trois beta-lactones correspondantes ont également été synthétisées. Seule la polymérisation de la beta-lactone avec l’acétaldéhyde a été menée à bien, du fait de son faible encombrement stérique. Enfin, une étude cinétique par infrarouge a également été effectuée et a permis de mieux connaître les cinétiques de polymérisation par ouverture de cycle.The aim of this study is to synthesise and to characterise polyesters between dimethylketene and chosen carbonyled compounds (acetone, methylethylketone and acetaldehyde) by two distinct pathways: a direct copolymerisation, and another path proceeding in the synthesis of the beta-lactone then its ring opening polymerisation. The characterisation has highlighted the perfectly alternated structure of the polyester between dimethylketene and acetone, and more complex structures with dimethylketone and acetaldehyde. The analyses have also shown the complex polymorphism of these copolymers. The three corresponding beta-lactones have been synthesised. Only the polymerisation of the acetaldehyde beta-lactone has been accomplished because of its weak steric hindrance. At last, an infrared kinetic study has also been carried out and has permitted a better comprehension of the kinetic of the ring opening polymerisation

Synthèse et caractérisation de polyesters à partir du diméthylcétène et de composés carbonylés

The aim of this study is to synthesise and to characterise polyesters between dimethylketene and chosen carbonyled compounds (acetone, methylethylketone and acetaldehyde) by two distinct pathways: a direct copolymerisation, and another path proceeding in the synthesis of the beta-lactone then its ring opening polymerisation. The characterisation has highlighted the perfectly alternated structure of the polyester between dimethylketene and acetone, and more complex structures with dimethylketone and acetaldehyde. The analyses have also shown the complex polymorphism of these copolymers. The three corresponding beta-lactones have been synthesised. Only the polymerisation of the acetaldehyde beta-lactone has been accomplished because of its weak steric hindrance. At last, an infrared kinetic study has also been carried out and has permitted a better comprehension of the kinetic of the ring opening polymerisation.L’objectif de cette étude est de synthétiser et de caractériser des polyesters entre le diméthylcétène et des composés carbonylés choisis (acétone, méthyléthylcétone et acéthaldéhyde) par deux voies distinctes : une copolymérisation directe, et une voie passant d’abord par la synthèse de la beta-lactone puis sa polymérisation par ouverture de cycle. La caractérisation a mis en évidence la structure parfaitement alternée du polyester entre le diméthylcétène et l’acétone, et des structures plus complexes avec la méthyléthylcétone et l’acétaldéhyde. Les analyses ont également montré le caractère polymorphe complexe de ces copolymères. Les trois beta-lactones correspondantes ont également été synthétisées. Seule la polymérisation de la beta-lactone avec l’acétaldéhyde a été menée à bien, du fait de son faible encombrement stérique. Enfin, une étude cinétique par infrarouge a également été effectuée et a permis de mieux connaître les cinétiques de polymérisation par ouverture de cycle

Synthèse et caractérisation de polyesters à partir du diméthylcétène et de composés carbonylés

L objectif de cette étude est de synthétiser et de caractériser des polyesters entre le diméthylcétène et des composés carbonylés choisis (acétone, méthyléthylcétone et acéthaldéhyde) par deux voies distinctes : une copolymérisation directe, et une voie passant d abord par la synthèse de la beta-lactone puis sa polymérisation par ouverture de cycle. La caractérisation a mis en évidence la structure parfaitement alternée du polyester entre le diméthylcétène et l acétone, et des structures plus complexes avec la méthyléthylcétone et l acétaldéhyde. Les analyses ont également montré le caractère polymorphe complexe de ces copolymères. Les trois beta-lactones correspondantes ont également été synthétisées. Seule la polymérisation de la beta-lactone avec l acétaldéhyde a été menée à bien, du fait de son faible encombrement stérique. Enfin, une étude cinétique par infrarouge a également été effectuée et a permis de mieux connaître les cinétiques de polymérisation par ouverture de cycle.The aim of this study is to synthesise and to characterise polyesters between dimethylketene and chosen carbonyled compounds (acetone, methylethylketone and acetaldehyde) by two distinct pathways: a direct copolymerisation, and another path proceeding in the synthesis of the beta-lactone then its ring opening polymerisation. The characterisation has highlighted the perfectly alternated structure of the polyester between dimethylketene and acetone, and more complex structures with dimethylketone and acetaldehyde. The analyses have also shown the complex polymorphism of these copolymers. The three corresponding beta-lactones have been synthesised. Only the polymerisation of the acetaldehyde beta-lactone has been accomplished because of its weak steric hindrance. At last, an infrared kinetic study has also been carried out and has permitted a better comprehension of the kinetic of the ring opening polymerisation.ROUEN-INSA Madrillet (765752301) / SudocSudocFranceF

Polyester obtained from dimethylketene and acetone: synthesis and characterization

International audienc

Impact of polymer Microstructure on theSelf-Assembly of Amphiphilic Polymers in Aqueous Solutions

International audienc

Dynamic modeling of in vitro lipid digestion: Individual fatty acid release and bioaccessibility kinetics

The aim of this study was to gain knowledge about the role of triacylglycerol (TAG) composition in fatty acids (FA) of o/w emulsions on both the pancreatic lipolysis kinetics and the bioaccessibility of released products (i.e. contained within the bile salt micellar phase). A mathematical model was developed and its predictions were compared to a set of experimental data obtained during an in vitro digestion of a whey protein stabilized emulsion. Modeling results show that FA residues of TAG were hydrolyzed at specific rates, inducing different bioaccessibility kinetics. The estimated lipolysis rate constants of the studied FA (C8:0, C10:0 >> C18:1 n-9 >> C12:0 > C14:0 > C16:0 approximate to C16:1 n-7 > C22:6 n-3) were in close agreement with the available literature on the substrate specificity of pancreatic lipase. Results also suggest that lipolysis products are very rapidly solubilized in the bile salt mixed micelles with no fractionation according to the FA carbon chain

In vitro digestion of a whey protein stabilized emulsion: Mechanistic modeling reveals the major influence of droplet coalescence on the kinetics of pancreatic lipolysis (poster)

International audienceno abstrac

Modeling the effects of emulsion coalescence and oil composition on in vitro digestion kinetics and fatty acid bioaccessibility (poster)

International audienceno abstrac

Dynamic modeling highlights the major impact of droplet coalescence on the in vitro digestion kinetics of a whey protein stabilized submicron emulsion

Submicron oil-in-water emulsions stabilized with whey proteins have been reported to be relatively resistant and highly sensitive to coalescence during the gastric and intestinal phases of in vitro digestion experiments, respectively. The aim of this study was to assess the impact of droplet coalescence on the intestinal lipolysis kinetics of such emulsion, and to develop a mathematical model able to predict the experimental observations. A submicron whey protein stabilized emulsion made of a mixture of medium-chain (MCT) and long-chain triacylglycerols (LCT) was prepared and submitted to gastrointestinal in vitro digestion. Triacylglycerol concentrations and droplet size distributions were measured before and after the gastric phase and during the intestinal phase using HPLC and laser granulometry, respectively. MCT were fully digested within 15 min of intestinal digestion, whereas LCT were still detected after 5 h. Moreover, the intestinal lipolysis of LCT showed a two-stage behavior with an initial fast rate that markedly slowed down after about 30 min, a time at which a sudden rise in the droplet sizes, attributed to coalescence, was also observed. A mathematical model based on the experimentally measured droplet sizes and assuming a rate of lipolysis proportional to the interfacial area was developed and successfully used to reproduce the observed kinetics. Our results support the idea that droplet coalescence during the intestinal phase was the main reason for the marked slowdown of the kinetics of lipid digestion, hence suggesting that other possible mechanisms, such as an inhibition of the lipolysis reaction, could only explain secondary order effects

Modeling in vitro digestion of emulsions: effects of droplet size and oil composition on lipolysis kinetics and fatty acid bioaccessible profiles (poster)

International audienceno abstrac