Synthèse et modélisation moléculaire de polyamides biosourcés

Dans le contexte actuel de raréfaction des ressources fossiles, le développement des polymères biosourcés est d'une grande importance. Le travail de cette thèse consiste donc en la synthèse et le développement d'un polyphtalamide amorphe à base d'acide furan-2,5-oique. Dans un premier temps, un protocole de modélisation moléculaire permettant de calculer la Tg de polyphthalamides a été développé. Pour cela, des PPA modèles (basés sur un mélange d'acides isophtaliques et téréphtaliques ainsi que l'hexaméthylène diamine) ont été synthétisés et caractérisés. En comparant les Tg obtenues par modélisation et par mesure en DSC, le protocole de modélisation a été validé. Dans un deuxième temps, ce protocole a été appliqué à des PPA à base de FDCA. Ces polymères ont également été synthétisés et caractérisés. Il en ressort que le PA 6-F subit une importante décarboxylation durant sa synthèse, l empêchant d'atteindre une masse molaire importante. Il a aussi été montré que l'ajout de FDCA dans des copolyphthalamides diminuait leurs propriétés thermiques et mécaniques.In the current context of oil resources rarefaction, the development of biobased polymers is of major importance. The present work focused on the development of a biobased amorphous polyphthalamide, based on furan-2,5-dicarboxylic acid. The first part of the study was devoted to the development of a molecular modelling protocol that could calculate the glass transition temperature of polyphthalamides with accuracy. In order to do this, model polyphthalamides based on isophthalic, terephthalic acid and hexamethylene diamine were synthesized and characterized as well as simulated. By comparison between simulated and measured Tg, the protocol was validated. In a second part of the study, this protocol was applied to FDCA based polyphthalamides. These PPA were also synthesized. It was found that the PA 6-F undertakes a decarboxylation, preventing it from reaching high a molar mass. It was also found that the mechanical and thermal properties decrease as the amount of FDCA in the copolymers increases.VILLEURBANNE-DOC'INSA-Bib. elec. (692669901) / SudocSudocFranceF

Synthesis and properties of polyamides from 2,5-furandicarboxylic acid

International audienc

Synthesis and properties of polyamides from 2,5-furandicarboxylic acid

International audienc

Extracorporeal membrane oxygenation network organisation and clinical outcomes during the COVID-19 pandemic in Greater Paris, France: a multicentre cohort study

Erratum inCorrection to Lancet Respir Med 2021; published online April 19. https://doi.org/10.1016/S2213-2600(21)00096-5.International audienceBackground: In the Île-de-France region (henceforth termed Greater Paris), extracorporeal membrane oxygenation (ECMO) for severe acute respiratory distress syndrome (ARDS) was considered early in the COVID-19 pandemic. We report ECMO network organisation and outcomes during the first wave of the pandemic.Methods: In this multicentre cohort study, we present an analysis of all adult patients with laboratory-confirmed SARS-CoV-2 infection and severe ARDS requiring ECMO who were admitted to 17 Greater Paris intensive care units between March 8 and June 3, 2020. Central regulation for ECMO indications and pooling of resources were organised for the Greater Paris intensive care units, with six mobile ECMO teams available for the region. Details of complications (including ECMO-related complications, renal replacement therapy, and pulmonary embolism), clinical outcomes, survival status at 90 days after ECMO initiation, and causes of death are reported. Multivariable analysis was used to identify pre-ECMO variables independently associated with 90-day survival after ECMO.Findings: The 302 patients included who underwent ECMO had a median age of 52 years (IQR 45-58) and Simplified Acute Physiology Score-II of 40 (31-56), and 235 (78%) of whom were men. 165 (55%) were transferred after cannulation by a mobile ECMO team. Before ECMO, 285 (94%) patients were prone positioned, median driving pressure was 18 cm H2O (14-21), and median ratio of the partial pressure of arterial oxygen to the fraction of inspired oxygen was 61 mm Hg (IQR 54-70). During ECMO, 115 (43%) of 270 patients had a major bleeding event, 27 of whom had intracranial haemorrhage; 130 (43%) of 301 patients received renal replacement therapy; and 53 (18%) of 294 had a pulmonary embolism. 138 (46%) patients were alive 90 days after ECMO. The most common causes of death were multiorgan failure (53 [18%] patients) and septic shock (47 [16%] patients). Shorter time between intubation and ECMO (odds ratio 0·91 [95% CI 0·84-0·99] per day decrease), younger age (2·89 [1·41-5·93] for ≤48 years and 2·01 [1·01-3·99] for 49-56 years vs ≥57 years), lower pre-ECMO renal component of the Sequential Organ Failure Assessment score (0·67, 0·55-0·83 per point increase), and treatment in centres managing at least 30 venovenous ECMO cases annually (2·98 [1·46-6·04]) were independently associated with improved 90-day survival. There was no significant difference in survival between patients who had mobile and on-site ECMO initiation.Interpretation: Beyond associations with similar factors to those reported on ECMO for non-COVID-19 ARDS, 90-day survival among ECMO-assisted patients with COVID-19 was strongly associated with a centre's experience in venovenous ECMO during the previous year. Early ECMO management in centres with a high venovenous ECMO case volume should be advocated, by applying centralisation and regulation of ECMO indications, which should also help to prevent a shortage of resources