https://sam.ensam.eu:443 The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material. Mon, 15 Jun 2026 14:42:14 GMT 2026-06-15T14:42:14Z http://hdl.handle.net/10985/13812 Combined compatibilization and plasticization effect of low molecular weight poly(Lactic acid) in poly(lactic acid)/poly(3-hydroxybutyrate-co-3-hydroxyvalerate) blends MIQUELARD-GARNIER, Guillaume; GUINAULT, Alain; SOLLOGOUB, C.; GERVAIS, Matthieu Improving overall properties of poly(lactic acid) (PLA) by blending it with another biobased polymer has been a strong field of research over the last years. In this study we demonstrate the synergetic effect of a small amount (between 0.1 and 1 wt%) of oligomer-like PLA (oLA) on the thermal, mechanical and gas barrier properties of the widely studied PLA-poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) blends (90–10 wt%). Films of PLA/PHBV/oLA blends were prepared via single-screw extrusion. oLA being miscible with both PLA and PHBV, its compatibilizing effect was demon- strated by a decrease of the interfacial tension, a slight shift in the Tgs of both polymers, and an increase in the elongation at break. It was also showed that oLA had a plasticizing effect on the PHBV dispersed phase, increasing its crystallinity rate. This resulted in a decrease in the permeability of the films while improving Young’s modulus. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10985/13812 2018-01-01T00:00:00Z MIQUELARD-GARNIER, Guillaume GUINAULT, Alain SOLLOGOUB, C. GERVAIS, Matthieu Improving overall properties of poly(lactic acid) (PLA) by blending it with another biobased polymer has been a strong field of research over the last years. In this study we demonstrate the synergetic effect of a small amount (between 0.1 and 1 wt%) of oligomer-like PLA (oLA) on the thermal, mechanical and gas barrier properties of the widely studied PLA-poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) blends (90–10 wt%). Films of PLA/PHBV/oLA blends were prepared via single-screw extrusion. oLA being miscible with both PLA and PHBV, its compatibilizing effect was demon- strated by a decrease of the interfacial tension, a slight shift in the Tgs of both polymers, and an increase in the elongation at break. It was also showed that oLA had a plasticizing effect on the PHBV dispersed phase, increasing its crystallinity rate. This resulted in a decrease in the permeability of the films while improving Young’s modulus. http://hdl.handle.net/10985/17950 Laser shock peening: toward the tse of pliable polid polymers for confinement LE BRAS, Corentin; RONDEPIERRE, Alexandre; SEDDIK, Raoudha; SCIUS-BERTRAND, Marine; ROUCHAUSSE, Yann; VIDEAU, Laurent; GERVAIS, Matthieu; MORIN, Leo; VALADON, Stéphane; ECAULT, Romain; FURFARI, Domenico; BERTHE, Laurent; FAYOLLE, Bruno This paper presents the first extensive study of the performances of solid polymers used as confinement materials for laser shock applications such as laser shock peening (LSP) as opposed to the exclusively used water-confined regime up to now. The use of this new confinement approach allows the treatment of metal pieces needing fatigue behavior enhancement but located in areas which are sensitive to water. Accurate pressure determination in the polymer confinement regime was performed by coupling finite element simulation and experimental measurements of rear free-surface velocity using the velocity interferometer system for any reflector (VISAR). Pressure could reach 7.6 and 4.6 GPa for acrylate-based polymer and cross-linked polydimethylsiloxane (PDMS), respectively. At 7 and 4.7 GW/cm2, respectively, detrimental laser breakdown limited pressure for acrylate and PDMS. These results show that the pressures produced were also as high as in water confinement, attaining values allowing the treatment of all types of metals with LSP and laying the groundwork for future determination of the fatigue behavior exhibited by this type of treated materials. Tue, 01 Jan 2019 00:00:00 GMT http://hdl.handle.net/10985/17950 2019-01-01T00:00:00Z LE BRAS, Corentin RONDEPIERRE, Alexandre SEDDIK, Raoudha SCIUS-BERTRAND, Marine ROUCHAUSSE, Yann VIDEAU, Laurent GERVAIS, Matthieu MORIN, Leo VALADON, Stéphane ECAULT, Romain FURFARI, Domenico BERTHE, Laurent FAYOLLE, Bruno This paper presents the first extensive study of the performances of solid polymers used as confinement materials for laser shock applications such as laser shock peening (LSP) as opposed to the exclusively used water-confined regime up to now. The use of this new confinement approach allows the treatment of metal pieces needing fatigue behavior enhancement but located in areas which are sensitive to water. Accurate pressure determination in the polymer confinement regime was performed by coupling finite element simulation and experimental measurements of rear free-surface velocity using the velocity interferometer system for any reflector (VISAR). Pressure could reach 7.6 and 4.6 GPa for acrylate-based polymer and cross-linked polydimethylsiloxane (PDMS), respectively. At 7 and 4.7 GW/cm2, respectively, detrimental laser breakdown limited pressure for acrylate and PDMS. These results show that the pressures produced were also as high as in water confinement, attaining values allowing the treatment of all types of metals with LSP and laying the groundwork for future determination of the fatigue behavior exhibited by this type of treated materials. http://hdl.handle.net/10985/16037 Controlling the order of triblock copolymer via confinement induced by forced self-assembly MIQUELARD-GARNIER, Guillaume; GERVAIS, Matthieu; GUINAULT, Alain; SOLLOGOUB, , Cyrille; ROLAND, Sébastien We report the making of multilayered self-assembled films by coextrusion, composed of alternated layers of confining polycarbonate and confined poly(styrene-. b-butadiene-. b-methyl methacrylate), whose blocks are chemically different from the confining polymer, and presenting a self-assembled morphology directly after extrusion. The triblock copolymer layers thicknesses was varied from few hundreds to few tens of nanometers. As the triblock layer thickness is decreased and the draw ratio is increased, the triblock morphology is constrained into a preferential orientation and higher long-range order is observed by transmission electron microscopy and small angle X-ray scattering. This one-step and industrially scalable method allowing long-range ordering of the nanodomains is of interest for many engineering applications for which producing large quantity of materials is necessary. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10985/16037 2016-01-01T00:00:00Z MIQUELARD-GARNIER, Guillaume GERVAIS, Matthieu GUINAULT, Alain SOLLOGOUB, , Cyrille ROLAND, Sébastien We report the making of multilayered self-assembled films by coextrusion, composed of alternated layers of confining polycarbonate and confined poly(styrene-. b-butadiene-. b-methyl methacrylate), whose blocks are chemically different from the confining polymer, and presenting a self-assembled morphology directly after extrusion. The triblock copolymer layers thicknesses was varied from few hundreds to few tens of nanometers. As the triblock layer thickness is decreased and the draw ratio is increased, the triblock morphology is constrained into a preferential orientation and higher long-range order is observed by transmission electron microscopy and small angle X-ray scattering. This one-step and industrially scalable method allowing long-range ordering of the nanodomains is of interest for many engineering applications for which producing large quantity of materials is necessary. http://hdl.handle.net/10985/18602 An alternative radiolytic route for synthesizing conducting polymers in an organic solvent BAHRY, Teseer; CUI, Zhenpeng; DENISET-BESSEAU, Ariane; GERVAIS, Matthieu; SOLLOGOUB, Cyrille; BUI, Thanh Tuân; RÉMITA, Samy A new and simple promising method for synthesizing conducting polymers in organic solvents was successfully achieved for the first time thanks to the oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) monomers dissolved in dichloromethane by means of gamma-radiolysis. The EDOT polymerization was controlled and optimized thanks to the study of the dose effect under an inert atmosphere. UV-Vis absorption spectroscopy was used to follow the polymerization process and to estimate both the radiolytic yield of EDOT oxidation and the required irradiation dose for quantitative poly(3,4-ethylenedioxythiophene) (PEDOT) preparation. Size exclusion chromatography (SEC) was used to determine the molar mass of the PEDOT polymers and thus their degree of polymerization. Polymers containing up to 20 EDOT units were detected. After deposition, ATR-FTIR spectroscopy and Energy-Dispersive X-ray (EDX) analysis highlighted the in situ doping of PEDOT polymers with chloride ions generated during dichloromethane radiolysis, while XRD analysis demonstrated the amorphous structure of the polymers. The morphology of the radiosynthesized PEDOT polymers was characterized in solution by Cryo-TEM microscopy and after deposition by SEM microscopy as well as by high-resolution AFM-IR microscopy coupled with infrared nanospectroscopy. In all cases, aggregated and packed spheroidal PEDOT particles with diameters comprising between 100 nm and 1.5 μm were observed. Besides, cyclic voltammetry (CV), four-point probe measurements and thermogravimetric analysis (TGA) showed that the PEDOT polymers radiosynthesized in dichloromethane are characterized by interesting electrical properties and good thermal stability. The present study bears witness to the tremendous potential of our radiation-based methodology and gives us a glimpse of future promising syntheses of different kinds of conducting polymers in organic solvents and even in complex matrices. Mon, 01 Jan 2018 00:00:00 GMT http://hdl.handle.net/10985/18602 2018-01-01T00:00:00Z BAHRY, Teseer CUI, Zhenpeng DENISET-BESSEAU, Ariane GERVAIS, Matthieu SOLLOGOUB, Cyrille BUI, Thanh Tuân RÉMITA, Samy A new and simple promising method for synthesizing conducting polymers in organic solvents was successfully achieved for the first time thanks to the oxidative polymerization of 3,4-ethylenedioxythiophene (EDOT) monomers dissolved in dichloromethane by means of gamma-radiolysis. The EDOT polymerization was controlled and optimized thanks to the study of the dose effect under an inert atmosphere. UV-Vis absorption spectroscopy was used to follow the polymerization process and to estimate both the radiolytic yield of EDOT oxidation and the required irradiation dose for quantitative poly(3,4-ethylenedioxythiophene) (PEDOT) preparation. Size exclusion chromatography (SEC) was used to determine the molar mass of the PEDOT polymers and thus their degree of polymerization. Polymers containing up to 20 EDOT units were detected. After deposition, ATR-FTIR spectroscopy and Energy-Dispersive X-ray (EDX) analysis highlighted the in situ doping of PEDOT polymers with chloride ions generated during dichloromethane radiolysis, while XRD analysis demonstrated the amorphous structure of the polymers. The morphology of the radiosynthesized PEDOT polymers was characterized in solution by Cryo-TEM microscopy and after deposition by SEM microscopy as well as by high-resolution AFM-IR microscopy coupled with infrared nanospectroscopy. In all cases, aggregated and packed spheroidal PEDOT particles with diameters comprising between 100 nm and 1.5 μm were observed. Besides, cyclic voltammetry (CV), four-point probe measurements and thermogravimetric analysis (TGA) showed that the PEDOT polymers radiosynthesized in dichloromethane are characterized by interesting electrical properties and good thermal stability. The present study bears witness to the tremendous potential of our radiation-based methodology and gives us a glimpse of future promising syntheses of different kinds of conducting polymers in organic solvents and even in complex matrices. http://hdl.handle.net/10985/19482 Optimal strategy based on radiation chemistry for facile and direct synthesis of poly(3-thiophene acetic acid) polymers in water and dichloromethane BAHRY, Teseer; CUI, Zhenpeng; DENISET-BESSEAU, Ariane; GERVAIS, Matthieu; MBOMEKALLE, Israël; SOLLOGOUB, Cyrille; AUBERT, Pierre-Henri; BUI, Thanh-Tuân; REMITA, Samy In this work, synthesis of nanostructured conducting poly(3-thiophene acetic acid) (PTAA) polymers was developed by means of γ-induced oxidative polymerization of TAA monomers dissolved either in water or in dichloromethane. This synthesis was shown to be facile and directly feasible without any prior esterification of TAA and in the absence of oxidizing agents. Radiolytic yields of TAA oxidation as well as irradiation doses required for quantitative PTAA preparation were determined for each solvent. UV-Vis and ATR-FTIR spectroscopies demonstrated the successful formation of two PTAA polymers, so-called "PTAAH2O"and "PTAACH2Cl2". Size exclusion chromatography (SEC) highlighted convergent molecular weight values corresponding to approximately 13 monomer units. A similar behavior for both radio-synthesized PTAAs was monitored by thermogravimetric analysis (TGA). The morphological structures of PTAAH2O and PTAACH2Cl2 were analyzed in solution by Cryo-TEM and after deposition by SEM and AFM. Microscopic observations revealed the presence of two distinguishable nanostructures: nano-spherules of several hundreds of nanometers made of PTAAH2O and nano-granules of several tens of nanometers made of PTAACH2Cl2. Cyclic voltammetry analysis and the Tauc plot method were employed to calculate the electrical and optical band gaps. Both polymers possess similar electrical band gaps. However, PTAACH2Cl2 affords a lower optical band gap than PTAAH2O. Four-point probe measurements showed that the radio-synthesized PTAA polymers are characterized by interesting electrical properties: a higher electrical conductivity was nevertheless recorded for PTAACH2Cl2. This study highlights the powerful ability of the radiation chemistry-based methodology to lead, as a simple, versatile and reliable method, to nanostructured PTAA conducting polymers either in aqueous or organic solutions. Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10985/19482 2020-01-01T00:00:00Z BAHRY, Teseer CUI, Zhenpeng DENISET-BESSEAU, Ariane GERVAIS, Matthieu MBOMEKALLE, Israël SOLLOGOUB, Cyrille AUBERT, Pierre-Henri BUI, Thanh-Tuân REMITA, Samy In this work, synthesis of nanostructured conducting poly(3-thiophene acetic acid) (PTAA) polymers was developed by means of γ-induced oxidative polymerization of TAA monomers dissolved either in water or in dichloromethane. This synthesis was shown to be facile and directly feasible without any prior esterification of TAA and in the absence of oxidizing agents. Radiolytic yields of TAA oxidation as well as irradiation doses required for quantitative PTAA preparation were determined for each solvent. UV-Vis and ATR-FTIR spectroscopies demonstrated the successful formation of two PTAA polymers, so-called "PTAAH2O"and "PTAACH2Cl2". Size exclusion chromatography (SEC) highlighted convergent molecular weight values corresponding to approximately 13 monomer units. A similar behavior for both radio-synthesized PTAAs was monitored by thermogravimetric analysis (TGA). The morphological structures of PTAAH2O and PTAACH2Cl2 were analyzed in solution by Cryo-TEM and after deposition by SEM and AFM. Microscopic observations revealed the presence of two distinguishable nanostructures: nano-spherules of several hundreds of nanometers made of PTAAH2O and nano-granules of several tens of nanometers made of PTAACH2Cl2. Cyclic voltammetry analysis and the Tauc plot method were employed to calculate the electrical and optical band gaps. Both polymers possess similar electrical band gaps. However, PTAACH2Cl2 affords a lower optical band gap than PTAAH2O. Four-point probe measurements showed that the radio-synthesized PTAA polymers are characterized by interesting electrical properties: a higher electrical conductivity was nevertheless recorded for PTAACH2Cl2. This study highlights the powerful ability of the radiation chemistry-based methodology to lead, as a simple, versatile and reliable method, to nanostructured PTAA conducting polymers either in aqueous or organic solutions. http://hdl.handle.net/10985/19935 Radiation-induced polymerization of 3-hexylthiophene in oxygen-free and oxygen-saturated dichloromethane solvent BAHRY, Teseer; CUI, Zhenpeng; DAZZI, Alexandre; GERVAIS, Matthieu; SOLLOGOUB, Cyrille; GOUBARD, Fabrice; BUI, Thanh-Tuân; REMITA, Samy As alternative radiolytic approach, the synthesis of P3HT was made possible thanks to the oxidation of 3HT monomers by chloromethyl and dichloromethyl radicals or by their corresponding peroxyl radicals in situ produced by dichloromethane solvent radiolysis. Under two different experimental conditions, in oxygen-free solution and in oxygen-saturated solution, two different polymers, “P3HTN2” and “P3HTO2” respectively, were successfully synthesized. Both produced materials were discerned by several analytical and spectroscopic techniques. UV–Vis absorption spectroscopy results showed that the radiolytic yield of 3HT oxidation in dichloromethane solvent is higher under O2 atmosphere. Indeed, a dose of 75 kGy was needed to polymerize 10 mM in 3HT under N2 atmosphere, meanwhile a dose of 35 kGy was sufficient to polymerize the same amount of 3HT under O2. The average molecular weight of P3HTO2was found higher than that of P3HTN2 as revealed by SEC chromatography analysis. Also, P3HTO2exhibits better thermal stability than P3HTN2. ATR-FTIR spectroscopy revealed the specific presence into P3HTO2 polymers of some functional groups such as carbonyl, hydroxyl and carboxyl moieties, which clearly explains the difference between the morphological structures of P3HTN2 and P3HTO2 as highlighted by cryo-TEM, SEM and AFM microscopies. Finally, both radio-synthesized P3HTN2 and P3HTO2 polymers were found characterized by remarkably significant conductive, electronic and optical properties. We thank Jean-Michel Guigner (IMPMC, Université Pierre et Marie Curie, France) for Cryo-TEM experiments. Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10985/19935 2021-01-01T00:00:00Z BAHRY, Teseer CUI, Zhenpeng DAZZI, Alexandre GERVAIS, Matthieu SOLLOGOUB, Cyrille GOUBARD, Fabrice BUI, Thanh-Tuân REMITA, Samy As alternative radiolytic approach, the synthesis of P3HT was made possible thanks to the oxidation of 3HT monomers by chloromethyl and dichloromethyl radicals or by their corresponding peroxyl radicals in situ produced by dichloromethane solvent radiolysis. Under two different experimental conditions, in oxygen-free solution and in oxygen-saturated solution, two different polymers, “P3HTN2” and “P3HTO2” respectively, were successfully synthesized. Both produced materials were discerned by several analytical and spectroscopic techniques. UV–Vis absorption spectroscopy results showed that the radiolytic yield of 3HT oxidation in dichloromethane solvent is higher under O2 atmosphere. Indeed, a dose of 75 kGy was needed to polymerize 10 mM in 3HT under N2 atmosphere, meanwhile a dose of 35 kGy was sufficient to polymerize the same amount of 3HT under O2. The average molecular weight of P3HTO2was found higher than that of P3HTN2 as revealed by SEC chromatography analysis. Also, P3HTO2exhibits better thermal stability than P3HTN2. ATR-FTIR spectroscopy revealed the specific presence into P3HTO2 polymers of some functional groups such as carbonyl, hydroxyl and carboxyl moieties, which clearly explains the difference between the morphological structures of P3HTN2 and P3HTO2 as highlighted by cryo-TEM, SEM and AFM microscopies. Finally, both radio-synthesized P3HTN2 and P3HTO2 polymers were found characterized by remarkably significant conductive, electronic and optical properties. http://hdl.handle.net/10985/25143 Radiation induced reduction of graphene oxide: a dose effect study ABOU ZEID, Souad; BENCHERIF, Selma; GHASEMI, Rasta; GOGOI, Rituporn; CHOULI, Yamina; GERVAIS, Matthieu; DRAGOE, Diana; GHILANE, Jalal; SIRIL, Prem Felix; REMITA, Samy In this paper, we present a novel approach for the preparation of reduced graphene oxide (rGO) through the radiolytical reduction of commercial graphene oxide (GO). The method is highly efficient and environmentally friendly compared to other synthetic routes. We conducted a detailed study on the influence of absorbed doses during the synthesis process. The reduction process for the production of rGO is induced by the radiolysis of water at ambient temperature and pressure, confirmed using several sophisticated techniques. Our results demonstrate the efficiency of the radiolytical process compared to conventional methods of GO reduction. The C/O ratio increased from 3.3 (GO) to 11.2 (rGO), surpassing those of other reduction methods. Additionally, the intensity ratio of D and G bands (ID/IG) increased for rGO due to an increase in order by reduction, implying the restoration of π-conjugation. Furthermore, the thermal stability of GO improved upon irradiation. Electrochemical measurements finally showed that our rGO exhibited a specific capacitance of 229.3 F g−1, indicating its high potential as a candidate for energy storage applications. © 2024 The Royal Society of Chemistry. Thu, 01 Feb 2024 00:00:00 GMT http://hdl.handle.net/10985/25143 2024-02-01T00:00:00Z ABOU ZEID, Souad BENCHERIF, Selma GHASEMI, Rasta GOGOI, Rituporn CHOULI, Yamina GERVAIS, Matthieu DRAGOE, Diana GHILANE, Jalal SIRIL, Prem Felix REMITA, Samy In this paper, we present a novel approach for the preparation of reduced graphene oxide (rGO) through the radiolytical reduction of commercial graphene oxide (GO). The method is highly efficient and environmentally friendly compared to other synthetic routes. We conducted a detailed study on the influence of absorbed doses during the synthesis process. The reduction process for the production of rGO is induced by the radiolysis of water at ambient temperature and pressure, confirmed using several sophisticated techniques. Our results demonstrate the efficiency of the radiolytical process compared to conventional methods of GO reduction. The C/O ratio increased from 3.3 (GO) to 11.2 (rGO), surpassing those of other reduction methods. Additionally, the intensity ratio of D and G bands (ID/IG) increased for rGO due to an increase in order by reduction, implying the restoration of π-conjugation. Furthermore, the thermal stability of GO improved upon irradiation. Electrochemical measurements finally showed that our rGO exhibited a specific capacitance of 229.3 F g−1, indicating its high potential as a candidate for energy storage applications. © 2024 The Royal Society of Chemistry. http://hdl.handle.net/10985/20935 Novel Confinement Possibility for Laser Shock: Use of Flexible Polymer Confinement at 1064 nm Wavelength LE BRAS, Corentin; RONDEPIERRE, Alexandre; AYAD, Mohammad; GERVAIS, Matthieu; VALADON, Stéphane; BERTHE, Laurent Through the years, laser shock peening became a treatment of choice in the aerospace industry to prolong the life of certain critical pieces. Water flow is commonly used as a confinement to improve the process capability but some applications cannot allow for water presence in the area of interest. In a previous article, an alternative to the water confinement was presented, a flexible polymer confinement was used and demonstrated the production of pressures equivalent to the water configuration treatment. However, laser parameters have been restricted to a wavelength in the visible range at 532 nm. In this paper, the study is extended to 1064 nm which is commonly used in LSP applications and with two different pulse durations. A 1064 nm near infra-red laser is used to do pressure characterization of shots with polymer confinement through Velocity Interferometer System for Any Reflector (VISAR) measurements coupled with Finite Element Modelling on Abaqus software. The results show that the pressures produced by the confinement is slightly lower with the 1064 nm wavelength, similar to what is observed with the classic water confined regime when switching from 532 nm to a near infra-red wavelength. Nevertheless, the high level of pressure produced by laser shock under the polymer confinement configuration allows for the treatment of common types of metal alloys used in the aerospace industry. Although the use of such a confinement has yet to be applicable to peening setups, it has already uses in some single shot configurations such as LasAT where it allows the avoidance of the water flow optimization. Fri, 01 Jan 2021 00:00:00 GMT http://hdl.handle.net/10985/20935 2021-01-01T00:00:00Z LE BRAS, Corentin RONDEPIERRE, Alexandre AYAD, Mohammad GERVAIS, Matthieu VALADON, Stéphane BERTHE, Laurent Through the years, laser shock peening became a treatment of choice in the aerospace industry to prolong the life of certain critical pieces. Water flow is commonly used as a confinement to improve the process capability but some applications cannot allow for water presence in the area of interest. In a previous article, an alternative to the water confinement was presented, a flexible polymer confinement was used and demonstrated the production of pressures equivalent to the water configuration treatment. However, laser parameters have been restricted to a wavelength in the visible range at 532 nm. In this paper, the study is extended to 1064 nm which is commonly used in LSP applications and with two different pulse durations. A 1064 nm near infra-red laser is used to do pressure characterization of shots with polymer confinement through Velocity Interferometer System for Any Reflector (VISAR) measurements coupled with Finite Element Modelling on Abaqus software. The results show that the pressures produced by the confinement is slightly lower with the 1064 nm wavelength, similar to what is observed with the classic water confined regime when switching from 532 nm to a near infra-red wavelength. Nevertheless, the high level of pressure produced by laser shock under the polymer confinement configuration allows for the treatment of common types of metal alloys used in the aerospace industry. Although the use of such a confinement has yet to be applicable to peening setups, it has already uses in some single shot configurations such as LasAT where it allows the avoidance of the water flow optimization. http://hdl.handle.net/10985/22275 Thermal aging of acrylic-urethane network: Kinetic modeling and end-of-life criteria combined with mechanical properties ISHIDA, Takato; GERVAIS, Matthieu; GAUDY, Alain; KITAGAKI, Ryoma; HAGIHARA, Hideaki; ELAKNESWARAN, Yogarajah; RICHAUD, Emmanuel This study addresses the multiscale analysis of acrylic urethane networks (AUN). To establish the kinetic model for predicting AUN oxidation, this study considered the pure thermal oxidation of AUN at 160, 180, and 200 °C. Chemical changes were monitored using infrared spectroscopy. These indicated the presence of an imide, presumably generated from the oxidation of CH2 at the α-position of nitrogen. On the macromolecular and macroscopic scales, oxidation was shown to induce predominant crosslinking, leading to a drop in toughness (i.e., embrittlement). The novel kinetic model of AUN thermal aging was developed from a mechanistic scheme previously established for polyamide 11, by adding some extra paths of thermolytic alkyl radical formation, oxidative Nsingle bondH bonds decomposition and coupling of aminyl radicals. Sat, 01 Jan 2022 00:00:00 GMT http://hdl.handle.net/10985/22275 2022-01-01T00:00:00Z ISHIDA, Takato GERVAIS, Matthieu GAUDY, Alain KITAGAKI, Ryoma HAGIHARA, Hideaki ELAKNESWARAN, Yogarajah RICHAUD, Emmanuel This study addresses the multiscale analysis of acrylic urethane networks (AUN). To establish the kinetic model for predicting AUN oxidation, this study considered the pure thermal oxidation of AUN at 160, 180, and 200 °C. Chemical changes were monitored using infrared spectroscopy. These indicated the presence of an imide, presumably generated from the oxidation of CH2 at the α-position of nitrogen. On the macromolecular and macroscopic scales, oxidation was shown to induce predominant crosslinking, leading to a drop in toughness (i.e., embrittlement). The novel kinetic model of AUN thermal aging was developed from a mechanistic scheme previously established for polyamide 11, by adding some extra paths of thermolytic alkyl radical formation, oxidative Nsingle bondH bonds decomposition and coupling of aminyl radicals. http://hdl.handle.net/10985/22301 Crystallization behavior and morphological features of ethylene-vinyl alcohol 44 copolymer FREYMOND, Clément; GUINAULT, Alain; GERVAIS, Matthieu; PLUTA, Miroslaw; MAKOWSKI, Tomasz; PIORKOWSKA, Ewa; SOLLOGOUB, Cyrille This work is a first attempt to study the crystallization behavior of ethylene-vinyl alcohol copolymer with 44 mol% of ethylene units (EVOH44) and to observe the supermolecular structures developed during its crystallization. Thermal analysis has evidenced a very fast crystallization and the formation of different crystal populations during isothermal crys-tallization. In-situ wide-angle X-ray scattering experiments using a synchrotron radiation source have shown a unique or-thorhombic morphology, independently of the crystallization conditions. Small spherulites (with an average radius of about 1 µm) were observed using polarized optical microscopy and confirmed by typical four-leaf patterns obtained by small-angle light scattering. In-situ atomic force microscopy has revealed stacked lamellae growing from common centers to form small spherulitic entities. Finally, studies of isothermal crystallization have evidenced the existence of partial crystallization (especially at high crystallization temperatures) and the need for higher undercooling to complete crystallization. © BME-PT. Fri, 01 Apr 2022 00:00:00 GMT http://hdl.handle.net/10985/22301 2022-04-01T00:00:00Z FREYMOND, Clément GUINAULT, Alain GERVAIS, Matthieu PLUTA, Miroslaw MAKOWSKI, Tomasz PIORKOWSKA, Ewa SOLLOGOUB, Cyrille This work is a first attempt to study the crystallization behavior of ethylene-vinyl alcohol copolymer with 44 mol% of ethylene units (EVOH44) and to observe the supermolecular structures developed during its crystallization. Thermal analysis has evidenced a very fast crystallization and the formation of different crystal populations during isothermal crys-tallization. In-situ wide-angle X-ray scattering experiments using a synchrotron radiation source have shown a unique or-thorhombic morphology, independently of the crystallization conditions. Small spherulites (with an average radius of about 1 µm) were observed using polarized optical microscopy and confirmed by typical four-leaf patterns obtained by small-angle light scattering. In-situ atomic force microscopy has revealed stacked lamellae growing from common centers to form small spherulitic entities. Finally, studies of isothermal crystallization have evidenced the existence of partial crystallization (especially at high crystallization temperatures) and the need for higher undercooling to complete crystallization. © BME-PT.