Jannick Duchet

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Papers by Jannick Duchet

Morphology and mechanical and viscoelastic properties of rubbery epoxy/organoclay montmorillonite nanocomposites

Journal of Applied Polymer Science, 2006

The morphology and mechanical and viscoelastic properties of rubbery epoxy/organoclay montmorillo... more The morphology and mechanical and viscoelastic properties of rubbery epoxy/organoclay montmorillonite (MMT) nanocomposites were investigated with wideangle X-ray scattering (WAXS), transmission electron microscopy (TEM), tensile testing, and dynamic mechanical thermal analysis. An ultrasonicator was used to apply external shearing forces to disperse the silicate clay layers in the epoxy matrix. The first step of the nanocomposite preparation consisted of swelling MMT in a curing agent, that is, an aliphatic diamine based on a polyoxypropylene backbone with a low viscosity for better diffusion into the intragalleries. Then, the epoxy prepolymer was added to the mixture. Better dispersion and intercalation of the nanoclay in the matrix were expected. The organic modification of MMT with octadecy

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Chemical and electrochemical synthesis of polypyrrole nanotubules

Synthetic Metals, May 1, 1999

The synthesis of polyaniline/platinum composites (PANI/Pt) has been achieved using both chemical ... more The synthesis of polyaniline/platinum composites (PANI/Pt) has been achieved using both chemical and electrochemical methods. The direct chemical synthesis of PANI/Pt proceeds through the oxidation of aniline by PtCl 6 2− in the absence of a secondary oxidant. SEM images of these samples indicate that the Pt particles are on the order of ∼1 m for the chemically prepared composite. Electrochemical PANI/Pt synthesis is initiated by the uptake and reduction of PtCl 6 2− into an a priori electrochemically deposited PANI film. This method produces a uniform dispersion of Pt particles with smaller particles with diameters ranging between 200 nm and 1 m. The results indicate that electrochemical methods may be more suitable for controlling particle dimension. Both materials show reduced proton doping relative to PANI without Pt, indicating the metal particles directly influence proton doping and the oxidation state of the polymer. The electrochemical data indicate that the conductivity in solution is sufficient such that the normal acid doping is attainable for PANI/Pt produced using either synthetic method.

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Chemical and electrochemical synthesis of polyaniline micro- and nano-tubules

Synthetic Metals, Jun 1, 2000

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Alkylsilanes and silane-functionalized polyethylenes grafted on silica. Consequences on the polyethylene/glass adhesion

Polymer preprints, 1996

New Epoxy Thermosets Organic-Inorganic Hybrid Nanomaterials Derived from Imidazolium Ionic Liquid Monomers and POSS®Ph

Nanomaterials, 2022

New epoxy-amine networks issue from epoxydized imidazolium ionic liquid monomers (ILMs) and isoph... more New epoxy-amine networks issue from epoxydized imidazolium ionic liquid monomers (ILMs) and isophorone diamine (IPD) were modified for the first time by incorporating unmodified trisilanol phenyl POSS® (POSS®Ph-triol) and two ionic liquid-modified POSS®Ph (IL-g-POSS®Ph) having chloride (Cl−) and bis-trifluoromethanesulfonimidate (NTf2−) counter anions. Then, 5 wt.% of unmodified and IL-modified POSS®Ph were introduced in order to develop new solid electrolytes. First, a homogeneous dispersion of the POSS®Ph aggregates (diameters from 80 to 400 nm) into epoxy networks was observed. As a consequence, ILM/IPD networks with glass transition temperatures between 45 and 71 °C combined with an enhancement of the thermal stability (>380 °C) were prepared. Moreover, a significant increase of the hydrophobic character and high oil repellency of the network surfaces were obtained by using IL-g-POSS®Ph (19–20 mJ.m−2), opening up promising prospects for surface coating applications. Finally, ...

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Effect of alfa fiber loading on the mechanical, physical and dielectric properties of epoxy-amine composite

Journal of Composite Materials

In this work, a varied content of alfa fiber was used as reinforcement and epoxy resin as matrix ... more In this work, a varied content of alfa fiber was used as reinforcement and epoxy resin as matrix material. In order to eliminate the amorphous part of the alfa fiber, the fibers are treated with 5% of sodium hydroxide solution and their weight fraction is varied between 10% and 30%. Dielectric and water characteristics of different content of untreated and alkali treated alfa reinforced epoxy matrix is carried out in order to determine the role of cellulosic fibers in electrical field. Then, the Fourier transform infrared (FTIR) is employed to analyze the chemical structure of epoxy resin before and after curing with amine hardener. FTIR and Differential Scanning Calorimetry analysis confirm that epoxy resin is completely cured with amine hardener at room temperature. For composites loaded with 30% treated and untreated alfa fiber, a decrease in tensile and dielectric properties has been obtained, this may be related to the random distribution of alfa fiber in the epoxy matrix. Scan...

Effect of epoxy matrix architecture on the self-healing ability of thermo-reversible interfaces based on Diels–Alder reactions: demonstration on a carbon fiber/epoxy microcomposite

RSC Advances, 2016

Thermally reversible Diels–Alder adducts formed between furan and maleimide groups have been intr... more

Ionic PMMA/nanosilica interfaces from grafting ionic liquids under supercritical CO2 conditions

European Polymer Journal, 2018

Supercritical carbon dioxide (scCO 2) was considered as an environmental friendly medium for graf... more Supercritical carbon dioxide (scCO 2) was considered as an environmental friendly medium for grafting the surface of silica nanoparticles with a series of reactive imidazolium-based ionic liquids (IL), denoted as IL-silanes. The effects of the reaction conditions on the resulting IL-grafted layers on the silica surface were characterized from thermogravimetric (TGA) and transmission electronic microscopy (TEM) analyses. The IL-grafted nanoparticles were introduced into poly(methyl methacrylate) (PMMA) via melt mixing in order to design nanocomposites and to demonstrate the ability of IL-grafted nanoparticles to be dispersed into a polymer medium. The role of the IL-grafted surfaces on the morphology of PMMA-based nanocomposites was evidenced by TEM and small angle neutron scattering (SANS). It was demonstrated that longer the alkyl chain length of the IL-silane, better the state of dispersion of nanoparticles within PMMA. In addition, better thermal stabilities and mechanical performances, as well as new surface properties were observed for the designed PMMA-based nanocomposites.

format_quoteIncreasing operating pressure from 16 to 20 MPa raised silane grafting on silica nanoparticles by 7%, indicating pressure's crucial role in grafting yield.format_quote

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Nanocomposites à nanocharges lamellaires

Plastiques et composites, 2015

常時監視データから見た福井県の水環境の推移（第３報）― 嶺南地域の河川水質―

Gelled Electrolyte Containing Phosphonium Ionic Liquids for Lithium-Ion Batteries

Nanomaterials (Basel, Switzerland), Jan 14, 2018

In this work, new gelled electrolytes were prepared based on a mixture containing phosphonium ion... more In this work, new gelled electrolytes were prepared based on a mixture containing phosphonium ionic liquid (IL) composed of trihexyl(tetradecyl)phosphonium cation combined with bis(trifluoromethane)sulfonimide [TFSI] counter anions and lithium salt, confined in a host network made from an epoxy prepolymer and amine hardener. We have demonstrated that the addition of electrolyte plays a key role on the kinetics of polymerization but also on the final properties of epoxy networks, especially thermal, thermo-mechanical, transport, and electrochemical properties. Thus, polymer electrolytes with excellent thermal stability (>300 °C) combined with good thermo-mechanical properties have been prepared. In addition, an ionic conductivity of 0.13 Ms·cm at 100 °C was reached. Its electrochemical stability was 3.95 V vs. Li⁰/Li⁺ and the assembled cell consisting in Li|LiFePO₄ exhibited stable cycle properties even after 30 cycles. These results highlight a promising gelled ele...

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Advanced characterization of the structuration of ionic liquids in a copolyester

European Polymer Journal, 2019

The influence of the addition in small amounts (2wt%) of two phosphonium-based ionic liquids (ILs... more The influence of the addition in small amounts (2wt%) of two phosphonium-based ionic liquids (ILs) on the nanostructuration and mechanical properties of a poly(butylene-adipate-coterephtalate) (PBAT) matrix was investigated using complementary approaches. Dielectric spectroscopy and nanomechanical characterizations using atomic force microscopy (Peak-Force QNM mode, Bruker) were used along X-ray diffraction, differential scanning calorimetry and dynamic mechanical analysis to explain the mechanical (tensile) properties of each system. The semicrystalline matrix was found to have a spherulitic structure, with crystalline lamellae composed of butylene terephtalate units. In one case, the addition of an immiscible phosphonium-phosphinate ionic liquid (il-TMP) to the matrix, inducing a 33% increase of the strain at break, was found via AFM to induce a nodular microstructure with dissipative effects and smooth nodule-matrix interphases. In the other case, a phosphonium-chloride ionic liquid (il-Cl), being miscible in the amorphous phases, increases the chain mobility of the mobile amorphous fraction (MAF) consisting of free polymer chains, while it hinders the relaxation, thus chain movements, of the confined rigid amorphous fraction (RAF). This double effect induced a moderate macroscopic Young's modulus drop (less than-20%) with a +60% increase of the strain at break, and no significant influence on thermal properties. AFM in situ mechanical measurements, along with dielectric spectroscopy, allowed to propose complete mechanisms for the ILs-matrix interactions, highlighting the potential of such additives for the tuning of the properties of polymers.

format_quoteExcept for il-TMP nodules, the organization of PBAT matrix properties remained unchanged by 2wt% ionic liquids, indicating subtle interactions.format_quote

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Rôle des chaînes connectrices gréffées sur l'adhésion interfaciale entre verre et polyéthylène

Des chaines connectrices miscibles, de meme nature chimique que la matrice, ameliorent significat... more Des chaines connectrices miscibles, de meme nature chimique que la matrice, ameliorent significativement l'adhesion verre/polyethylene. Des polyethylenes fonctionnalises chlorosilane avec differentes masses moleculaires ont ete synthetises en vue d'obtenir : i) des polymeres semi-cristallins capable de cristalliser avec les chaines de la matrice de polyethylene (PEHD ou PEBD); ii) des polymeres reactifs vis-a-vis des groupes silanol du verre. Le renforcement de l'interface verre/PE par des connecteurs polymere a ete etudie, grâce au test de clivage en coin (ADCB) adopte par Brown et Kramer, en fonction de la longueur de diffusion des chaines connectrices greffees et de la structure cristalline des connecteurs (lineaires ou branches) d'une part et de la matrice (PEHD ou PEBD) d'autre part. L'aptitude des connecteurs a diffuser et a former des enchevetrements avec les chaines de la matrice demeure la cause principale a l'origine du renforcement de l'int...

Molecular-Level Investigation of Cycloaliphatic Epoxidised Ionic Liquids as a New Generation of Monomers for Versatile Poly(Ionic Liquids)

Polymers

Recently, a new generation of polymerised ionic liquids with high thermal stability and good mech... more Recently, a new generation of polymerised ionic liquids with high thermal stability and good mechanical performances has been designed through novel and versatile cycloaliphatic epoxy-functionalised ionic liquids (CEILs). From these first promising results and unexplored chemical structures in terms of final properties of the PILs, a computational approach based on molecular dynamics simulations has been developed to generate polymer models and predict the thermo–mechanical properties (e.g., glass transition temperature and Young’s modulus) of experimentally investigated CEILs for producing multi-functional polymer materials. Here, a completely reproducible and reliable computational protocol is provided to design, test and tune poly(ionic liquids) based on epoxidised ionic liquid monomers for future multi-functional thermoset polymers.

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Key Role of the Dispersion of Carbon Nanotubes (CNTs) within Epoxy Networks on their Ability to Release

Polymers

Carbon nanotube (CNT)-reinforced nanocomposites represent a unique opportunity in terms of design... more Carbon nanotube (CNT)-reinforced nanocomposites represent a unique opportunity in terms of designing advanced materials with mechanical reinforcement and improvements in the electrical and thermal conductivities. However, the toxic effects of these composites on human health have been studied, and very soon, some regulations on CNTs and on composites based on CNTs will be enacted. That is why the release of CNTs during the nanocomposite lifecycle must be controlled. As the releasing depends on the interfacial strength that is stronger between CNTs and polymers compared to CNTs in a CNT agglomerate, two dispersion states—one poorly dispersed versus another well dispersed—are generated and finely described. So, the main aim of this study is to check if the CNT dispersion state has an influence on the CNT releasing potential in the nanocomposite. To well tailor and characterize the CNT dispersion state in the polymer matrix, electronic microscopies (SEM and TEM) and also rheological an...

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Mechanical Properties of FeCr‐based Composites Materials Elaborated by Liquid Metal Dealloying towards Bioapplication

Advanced Engineering Materials

Ionic Liquids-Containing Silica Microcapsules: A Potential Tunable Platform for Shaping-Up Epoxy-Based Composite Materials?

Nanomaterials

In this work, silica microcapsules containing phosphonium ionic liquid (IL), denoted SiO2@IL, wer... more In this work, silica microcapsules containing phosphonium ionic liquid (IL), denoted SiO2@IL, were successfully synthesized for the first time using the one step sol-gel method in IL/H20 emulsion. The morphologies of the obtained micron-size microcapsules, including their diameter distribution, were characterized using dynamic light scattering (DLS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The thermal behavior of these microcapsules and the mass fraction of the encapsulated IL in the silica microcapsules were determined using thermogravimetric analysis, showing an excellent thermal stability (up to 220 °C) and highlighting that an amount of 20 wt.% of IL is contained in the silica microcapsules. In a second step, SiO2@IL microcapsules (1 wt.%) were dispersed into epoxy-amine networks to provide proof of concept of the ability of such microcapsules to act as healing agents as microcracks propagate into the epoxy networks.

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The Role of Fluorinated IL as an Interfacial Agent in P(VDF-CTFE)/Graphene Composite Films

Nanomaterials

The incorporation of graphene into a polymer matrix can endow composites with extended functions.... more The incorporation of graphene into a polymer matrix can endow composites with extended functions. However, it is difficult to well disperse pristine graphene into a polymer matrix in order to obtain polymer nanocomposites due to the lack of functional groups on the surface for bonding with a polymer matrix. Herein, we investigated the role of fluorinated ionic liquid (IL) as a new interfacial agent in poly(vinylidene fluoride-co-chlorotrifluoroethylene) (P(VDF-CTFE))/graphene composite films. First, a task-specific IL, perfluorooctyltriphenylphosphonium iodide (IL-C8F13), was synthesized and adsorbed on the surface of graphene oxide (GO) and reduced graphene oxide (rGO) for making functional nanofillers which were capable of being incorporated into the P(VDF-CTFE) matrix. The cation structure of IL combined three phenyls (potential π–π interactions with graphene) and a short fluorinated chain (enhanced miscibility with fluorinated matrix via dipolar interactions) to make a compatibl...

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Probing nanomechanical properties with AFM to understand the structure and behavior of polymer blends compatibilized with ionic liquids

RSC Adv.

The PeakForce QNM AFM mode was used to investigate the nanoscale mechanical properties of poly(bu... more

Grafting characterization of thin organosilane films on silica substrate

AIP Conference Proceedings, 1996

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Jannick Duchet

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