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International audience; Additive manufacturing is a powerful tool to design materials with original properties. An innovative design of poly (Ethylene Vinyl Acetate) (EVA) containing 30 wt.-% of Aluminum TriHydroxide (ATH) was reported in a previous paper and liquids (water or potassium carbonate aqueous solution) were incorporated in the 3D printed structure. These multi-materials showing interesting properties, but stability, control and processing of these liquid-containing systems were an issue due to porosity of the polymeric matrix. To overcome this issue, the use of hydrogels is considered in this study: being either solid or highly viscous, hydrogels can retain water in the design, despite the high porosity of the EVA/ATH matrix. In this paper, the liquid phase was substituted by flame retardant hydrogels (based on agar, alginate or poly (vinyl alcohol) - PVA), containing in particular vermiculite platelets and for the hydrogel based on alginate, K2CO3 as flame retardant fillers. Excellent behavior under a 50 kW/m2 heat flux during a cone calorimeter test was obtained, with fast extinguishment of the flame and a low peak of Heat Release Rate (pHRR) and Total Heat Release (THR). The physical barrier formed by vermiculite platelets during the test, as well as the condensed phase mechanism of K2CO3 were found to be responsible for these excellent results, as found by confocal microscopy observations, electron probe micro analysis and X-Ray diffraction experiments.

International audience; Soot is one of the degradation products of material burning, having the fingerprints of the conditions in which it is formed. In this work, in-flame soot was probed from flaming combustion of balsa core and its sandwich composite at different heat flux scenarios during mass loss cone calorimeter tests. Soot probing was performed by thermophoresis. Electron microscopy was performed to analyze the size of the particulate media at multiscale. The size of the aggregates and the primary particles were found to be inherent to scenarios, i.e. materials specifications and heat flux rates. Nanoscale structure of in-flame soot was consistent with the results of thermogravimetric analysis of emitted-deposited soot. This semi-quantitative study contributes to soot observations in fire scenarios and constitutes the first application of soot probing by thermophoresis in a bench-scale fire scenario simulated by cone calorimetry. Technique shall be used in future to support emitted soot and smoke data.

International audience; This paper reports the synthesis of novel hybrid poly(lactic acid) by use of a titanium oxo-cluster, acting both as a catalyst and crosslinking agent of the polymer matrix. The already reported oxo-cluster Ti16O16(OEt)32 ([Ti]16) was synthesized and screened at the lab-scale as catalyst for the bulk polymerization of L-lactide (L-LA). [Ti]16 was found to be highly active for this reaction as up to 90% conversion in 30 min was obtained, affording PLLAs with Mn up to 65 000 g·mol−1 and relatively narrow dispersities (1.2–1.6). These polymerization reactions were further transposed to reactive extrusion process in which [Ti]16 oxo-cluster kept its high activity, affording hybrid-PLLA materials with Mn close to 58 000 g·mol−1 (some PLLAs could not be dissolved). Electronic microprobe analysis of the resulting hybrid materials confirmed that the titanium oxo-cluster was well dispersed all over the PLLA matrix. Finally, it was shown that the hybrid PLLA containing [Ti]16 display superior dimensional stability under heat than commercial PLLA of same molar mass.

Lowering fire hazard raised by combustible materials such as plastics may be achieved by the use of suitable flame retardant treatments, like fire protective coatings. However, exposure to long-term environmental conditions can cause loss of their functional properties, thus reducing their effectiveness over time. This is why two or three different layers with specific properties (e.g. adhesive, fire retardant and hydrophobic) are generally needed to provide durable fire retardancy. Effective and economical self-layering coatings can be developed to reduce the number of layers without compromising the advantages of the actual system. In this work, the efficiency of applying a silicone based coating to fire retard polycarbonate and the modification of the behaviors of the system, using a mixture of epoxy/silicone resins, a curing agent and either iron oxide or calcium carbonate as fire retardant filler is investigated. Self-stratification and fillers dispersion were evidenced by microscopic analyses coupled with chemical detection, the flame retardant properties using Limiting Oxygen Index (LOI), UL-94, Mass Loss Calorimetry (MLC), Thermogravimetric analyses (TGA) and a tubular furnace, and aging resistance by accelerated thermal, humidity and UV exposure. It appears that the selected fillers have no negative effect on the layering process when introduced from 2.5 to 10 vol.%: perfect stratification is obtained, with the silicone layer being the top layer. The best improvements in terms of fire retardant properties, adhesion and fillers dispersion were obtained by incorporating 2.5 vol.%: V0 rating at UL-94 and 33 and 35 vol.% at LOI with Fe2O3 and CaCO3 respectively were measured when a 200 μm wet thick coating was applied. The coating containing iron oxide was unaffected by weathering conditions. Finally, the application of those coatings on polycarbonate allows the formation of a protective barrier which limits substrate/flame mass transfers. It therefore results in (i) a delay of the time to ignition, (ii) the inhibition of the flame spread and of dripping when submitted to a flame, and (iii) a reduction of the combustibility of polycarbonate. A modification of the structure of the silica network formed by the particles which enhances the barrier effect of the silicone-based layer would be the most probable assumption to explain these excellent results.

International audience; Because of its widespread use in furniture upholstery, buildings, and transportation, the flame retardancy of flexible polyurethane foam is a matter of great concern. In an effort to impart fire resistance in an environmentally benign manner, hexagonal boron nitride (h-BN) nanosheets were dispersed by an aqueous route and deposited as a single bilayer with polyethylenimine (PEI) on flexible polyurethane foam by using layer-by-layer assembly. Butane torch exposure and cone calorimetry show that the nanocoating performs similarly to vermiculite clay (VMT), while in situ quantitative gas phase analysis reveals that carbon monoxide emissions are lower with h-BN. The PEI/h-BN system also maintains foam flexibility and protects against weathering, preventing yellowing. These combined properties make the use of h-BN nanoplatelets an interesting alternative for the protection of polyurethane foam (and perhaps other flammable substrates).

Epoxy-based intumescent coatings are effective solutions for protecting steel against fire. To design a successful product, it is, however, of primary importance to investigate its long-term durability. Some of these coatings do not resist accelerated aging conditions such as contact with salted water. One solution to overcome this drawback consists of applying a specific topcoat. In this work, various topcoats were applied on a model intumescent coating. Topcoats were shown to impact, under heating, the char expansion, char morphology, and char strength. The general trend is that the topcoats, before any aging exposure, improve the fire resistance behavior of the intumescent coatings. Most topcoats, however, do not limit penetration of salted water into the coating, thus affecting the intumescent properties. Only a silane-based topcoat was reported to trap or limit the diffusion of sodium and chlorine ions, thus protecting the underlying intumescent coating.

Lignin is an abundant polyphenol biopolymeric material. Due to its aromatic structure it develops a char under fire conditions. Lignin was used as flame retardant in acrylonitrile-butadiene-styrene (ABS). Enhancement of flame retardancy was observed, and the lignin was then phosphorylated to achieve highest performance. For the first time, characterization of FR phosphorylated lignin (P-LIG) was undertaken in detail. Grafting phosphorus onto lignin significantly increases the amount of residue from the polymer blend at high temperature. At 30 wt.%, P-LIG is well dispersed in ABS and leads to a significant reduction of the peak of heat release rate. It is shown that P-LIG promotes char formation by reacting with ABS during thermal decomposition. The char is therefore more cohesive and acts as a protective layer, such that less fuel from ABS degradation is released to the flame. Thus phosphorylated lignin is as a promising bio-based flame retardant for ABS.

Effect of accelerated ageing on neat and flame retarded (FR) polylactide (PLA) has been investigated. The influence of temperature and relative humidity on (i) the visual aspect, (ii) the fire performances, (iii) the molecular mass and (iv) the thermal properties of the formulations has been evaluated. The flame retardant (FR) properties of samples before and after ageing were compared using Limiting Oxygen Index (LOI) and Mass Loss Calorimetry (MLC). It was reported that degradation of PLA, mainly driven by hydrolysis phenomenon, is accelerated in presence of FR fillers (melamine and ammonium polyphosphate). This is even more pronounced when an organomodified montmorillonite is added. However the FR properties are enhanced after ageing due to the physicochemical of the flame retarded materials (e.g. migration of the flame retardants, decrease of the molecular mass…).

The aim of this work was to study the photocatalytic degradation of Methylene Blue and phenol by nano-particles coated on diatomite as a new nano-composite catalyst. Titanium dioxide (Degussa P25) was immobilized on diatomite powder at different compositions by a very simple and low cost technique. Diatomite powder (also called Kieselguhr) is an Algerian substance with a snow-white color and porosity greater than 72%. High porosity allowed the diatomite powder to float on the surface of water providing a means for the treatment process that enabled separation from water without any need for pumping as well as the exposure to solar radiation when supported beneath titanium dioxide (TiO2) during photocatalysis. The morphology characterization of the prepared catalysts was carried out by X-ray diffraction analysis, scanning electron microscopy and infrared spectroscopy (IR). Photocatalytic activity was initially tested in a single reactor followed by pH, conductivity and absorbance analyses. Photocat...

International audience; Self-stratification is an innovative one-step process used to design multi-functional coatings gathering simultaneously in a one-pot formulation the primer, the intermediate layer and the top coat properties. Many selfstratifying coatings contain oil-based epoxy resins but the literature is scarce in the development of “greener” solutions. In this work, silicone resins and bio-based epoxy resins were dissolved in various solvent blends, applied on a composite substrate and cured under different conditions to obtain stratified coatings. To reach aperfect stratification, the influence of various parameters including (i) the surface tension and the polarity of the resins, (ii) the solvents volatility, (iii) the curing temperature and (iv) the reactivity of the epoxy/amine reaction was studied by a systematic approach. In accordance with the literature, it was demonstrated that a large difference in surface energy and polarity favors resins separation. The volatility of the solvent blend was also shown to be a key factor in the stratification process. However, the predominant parameter, rarely taken into account, isthe curing temperature, which impacts the cross-linking reaction of the epoxy resin. The increase in molecular weight (MW) of epoxy resins due to the cross-linking reaction favors the incompatibility between resins by increasing the difference in MW between epoxy and silicone resins. Thus, optimization of process conditions allowed the design of perfectly stratified bio-based epoxy/silicone coatings. The mechanism of film stratification was also elucidated thanks to in-situ analyses.

International audience; This work aims at studying the impact of silane-based coatings, generated by atmospheric pressure plasma spraying (APPS) of a liquid precursor (hexamethydisiloxane – HMDSO), on dairy antifouling and antibacterial properties of food-grade 316L stainless steel. The influence of the manufacturing parameters (precursor flow rate, nozzle-to-substrate distance and scanning speed) on the coatings properties was investigated using a wide range of characterization techniques (drop shape analysis, X-Ray Mappings, Scanning Electron Microscopy, Fourier-Transformed Infrared Spectroscopy, Atomic Force Microscopy). Coating’s roughness in particular was shown to strongly increase when precursor flow rate increases. A pilot pasteurizer, fed with a model foulant solution (whey protein and calcium), allowed performing two consecutive industrial-like isothermal dairy fouling tests, revealing the promising anti-fouling properties of the HMDSO-coated steel. A fouling reduction of up to 90% compared to bare stainless steel was achieved after first cycle for all samples. The second fouling run allowed to select the best-performing sample, which kept the same antifouling properties as in the first test. Its mechanism of action was investigated, which revealed that a nanostructured, Si-O-Si rich surface was efficient to prevent isothermal dairy fouling. The adhesion of the pathogenic bacterium Staphylococcus aureus also proved to be impacted by this plasma coating, with a significant decrease of adhered cells (−30% compared to native stainless steel).

This paper aims at developing an innovative approach to characterize the char residue of an intumescent coating obtained after a UL1709 furnace test. The intumescent formulation is based on an epoxy resin and contains numerous additives including zinc borate, ammonium polyphosphate and silicate fibers. The purpose is to characterize the numerous reactions that can occur upon burning using crossed methods including Electron Probe Micro-Analysis (EPMA), X-ray diffraction (XRD) and 1D/2D solid state Nuclear Magnetic Resonance (NMR). In particular, it emphasizes the potential of the advanced NMR technique namely two-dimensional Dipolar Heteronuclear Multiple Quantum Correlation (2D D-HMQC) NMR. As a result, EPMA evidenced that B/P and B/Si are located in the same domain suggesting the formation of boron-phosphorus and/or boron-silicone containing compounds on the sample surface. H3BO3 was identified by XRD as a main crystalline specie, additional species (e.g. SiO2, Zn4O(BO2)6) were also identified. The borate, silicate and phosphate chemical species were then characterized using 1D NMR but no definitive assignments could be given. To specify those assignments, 2D D-HMQC NMR was performed and the formation of amorphous borophosphates and borosilicates was evidenced emphasizing the chemical reactivity between the ingredients of the formulation. It was suggested that these species allow reinforcing the char and improving the fire protective properties of the coatings. This work highlights the particular interest of advanced NMR technique, which provides unique information on the characterization of intumescent char.

Flexible polyurethane foam is one of the most versatile materials used in upholstered products; however, untreated polyurethane flexible foams are prone to rapid fire growth. In order to overcome issues encountered by the addition of flame retardant additives during the manufacturing process, the sol–gel process was evaluated to make flexible polyurethane foams flame retardant. Various formulations using different catalysts and monomers were prepared and deposited on flexible polyurethane foams by an impregnation process. Coating morphology was assessed by scanning electron microscopy analyses to optimize the formulation and to obtain a homogenous crack-free coating. Flame retardant properties were measured by mass loss calorimeter and UL 94, and thermal degradation was evaluated by thermogravimetric analysis. Chemical and structural analyses were carried out using attenuated total reflectance Fourier transformed infra-red spectroscopy and electron probe microanalysis. It appears that when a mixture of an appropriate ratio of 3-amino propyl triethoxysilane and diethyl phosphate is prepared in association with tetraethoxysilicate and methyltriethoxysilicate and deposited on flexible polyurethane foam, the coating shows an intumescent behavior when exposed to a flame. The foam also self-extinguishes after 30 seconds of flame application during UL94 test and a 60% reduction of the peak of heat release rate is obtained under mass loss calorimeter conditions.

This paper investigates the flame retardant (FR) mechanism of action of a flexible PU foam, flame retarded with a sol-gel coating made of a mixture of tetraethoxysilane (TEOS), methyl triethoxysilane (MTES), 3-amino propyl triethoxysilane (APTES) and diethyl phosphite (DEP) in an ethanol/water solution. To build a mechanism of action, the coating as well as the residues obtained after fire testing were analyzed using solid state nuclear magnetic resonance (NMR), rheology, thermogravimetric analyses coupled with infrared detection (TGA-FTIR), microcalorimetry of combustion (MCC), smoke box and Pyrolysis Gas chromatography coupled with mass spectrometry (Py-GCMS). The coating shows an intumescent behavior upon burning exhibiting significant expansion and bubbling. The expansion occurs in two steps: a first step around 190 °C, related to the release of ethanol, and a second one around 380 °C, related to the release of non-degraded DEP, ammonia and propylene during degradation of the PU matrix. The flame retardant effect occurs (i) in the condensed phase by intumescence, which yields a thermal insulating layer made of a SiO2 and Si-O-P network mixed with orthophosphate at the surface of the PU foam, but also (ii) in the gas phase by the release of non-degraded DEP, which acts as free radical scavenger. The coating allows the protection of the underlying PU foam during burning as well as the reduction of the amount of smoke released.

International audience; Heat-induced fouling is a financial and environmental burden for food and dairy industries and its control is therefore desperately needed. A better understanding of the fouling mechanisms and their relation to stainless steel surface properties is thus of considerable interest. This work aims at studying the impact of stainless steel's surface morphology and surface free energy on fouling by a model dairy solution by a close examination of the deposit's growth and adhesion at the substrate-fluid interface. Pristine model surfaces of controlled roughness and surface energy, i.e. native, mirror polished and biomimetic femtosecond laser textured stainless steel surfaces, fluorosilanized or not, were tested under isothermal conditions in a pilot pasteurization facility fed with a model dairy fluid (whey protein and calcium solution). Multi-scale characterizations of those surfaces before and after fouling, using a wide range of analytical tools (goniometry, SEM, ToF-SIMS, EPMA X-Ray mappings) allowed for a better comprehension of the impact of surface energy and morphology modifications on the fouling behavior while highlighting their complex interactions in fouling governance. Lower surface energy was shown to be an asset against deposit growth, as fluorosilanization of native stainless steel allowed to reduce fouling by 72% (wt.%). The relative sizes of surface relief versus fouling agents has been found crucial, as it impacts interlocking phenomena. Textured surfaces have shown a tremendous increase in fouling (+391% for textured, +86% for fluorosilanized textured). However, interesting fouling performances were obtained on smooth, hydrophobic surfaces, as a reduction by 83% of fouling weight was achieved with fluorosilanized polished samples. Crown Copyright (C) 2018 Published by Elsevier Ltd. All rights reserved.

International audience; In this report, indium-tin-oxide (ITO)-layer extraction from end-of-life (EOL) Liquid Crystal Displays (LCDs) was discussed by sulfuric acid leaching with simultaneous application of ultrasonication on the ITO-side of glass/ITO panels, exhibiting various dimensions. Applying this technique presents several advantages compared to the traditional leaching process such as fast and controllable kinetics, high extraction yield of indium and tin, selective recovery of these two metals possible, and the opportunity to recycle the neat glass separately avoiding additional separation processes. ITO-dissolution kinetics from EOL LCD panels were investigated as function of leaching time and acidity of sulfuric acid. At a temperature of 60°C, a nearly quantitative indium yield was obtained using an acid concentration of 18 mol/L by simultaneous application of ultrasonication, whereas only 70 % were recovered in the absence of ultrasound. Results from ICP-AES agreed well with SEM/BSE observations demonstrating the high efficiency of the ultrasound assisted process since only 3-4 min were required to obtain maximum ITO recovery.

Pasteurization of dairy products is plagued by fouling, which induces significant economic, environmental and microbiological safety concerns. Herein, an amphiphilic silicone coating was evaluated for its efficacy against fouling by a model dairy fluid in a pilot pasteurizer and against foodborne bacterial adhesion. The coating was formed by modifying an RTV silicone with a PEO-silane amphiphile comprised of a PEO segment and flexible siloxane tether ([(EtO)3Si-(CH2)2-oligodimethylsiloxanem-block-(OCH2CH2)n-OCH3]). Contact angle analysis of the coating revealed that the PEO segments were able to migrate to the aqueous interface. The PEO-modified silicone coating applied to pretreated stainless steel was exceptionally resistant to fouling. After five cycles of pasteurization, these coated substrata were subjected to a standard clean-in-place process and exhibited a minor reduction in fouling resistance in subsequent tests. However, the lack of fouling prior to cleaning indicates that harsh cleaning is not necessary. PEO-modified silicone coatings also showed exceptional resistance to adhesion by foodborne pathogenic bacteria.

Self-stratifying coatings are promising coating systems based on incompatible polymer blends which can produce polymer/polymer laminate. A complex multi-layer or gradient coating structure is formed from one single coat, providing an undercoat and finishing coating. The preferential distribution of concentration through the film thickness greatly eliminates the interfacial adhesion failure without compromising the advantages of a multi-layer system, and thus favors an industrial eco-efficient process. Powder, waterborne and solventborne coating systems are able to stratify: the most well-known and effective systems are described in this review. Finally, this concept constitutes a great possible versatile process for a broad range of applications and could thus favor the development of new products, taking into account the reduction of solvent and labor cost

The self-stratification is an eco-efficient process since it reduces solvent emission, time of implementation and labor cost. Moreover it could lead to the development of a large range of new products for extensive application fields. For self-stratification to occur, liquid coatings must contain at least two incompatible resins, giving rise in “one pot” to a two-phases mixture after the formation of the solid film. In this work, an innovative self-stratifying coating, based on an epoxy/silicone blend, has been developed and applied on a plastic substrate (Polycarbonate). The perfect self-stratification of this system was evidenced by microscopic analysis coupled with X-ray mappings. The influence of solvents and a curing agent on the stratification process has been investigated. It is shown that the system diluted in butylacetate:xylene (at a 1:1 ratio) leads to the best stratification pattern, with the silicone phase located on the top of the coating. Three pigments (red iron oxide, calcium carbonate and zinc phosphate) were also incorporated in this epoxy/silicone system. They do not affect stratification, whereas visual appearance and adhesion are strongly dependent on the phase in which pigments are dispersed, as well as on the solvent used.

The self-stratifying approach is a one step process allowing the formation of a complex laminated coating structure at the surface of plastics or other substrates, combining optimized surface and adhesion properties. These coatings have already been developed for various application fields but have never been considered for fire retardant purposes, whatever the substrate involved. In this work, the self-layering concept has been used to make polycarbonate fire retardant, using a mixture of epoxy and fluoropolymer resins, and iron oxide as flame retardant additive (10 wt%). Self-stratification was evidenced by microscopic analyses. The flame retardant properties were evaluated according to Limiting Oxygen Index (LOI), UL-94 and Mass Loss Calorimetry (MLC). Weathering resistance by accelerated UV, thermal and humidity exposure was also considered. In the first part, the effect of solvent on the self-layering process was investigated. It was shown that the system diluted in a blend of butylacetate : xylene (1 : 1 ratio) exhibits a perfect stratification and excellent adhesion onto polycarbonate. In such a system, an outstanding improvement of the fire retardant properties (V0 rating at UL-94 and 32 vol% at LOI), unaffected by weathering (both UV and temperature/humidity exposure), was observed when a 200 μm wet thick coating was applied. The coating allows the formation of a protective barrier and the presence of metal particles avoids dripping and promotes a charring effect.

International audience; Three different accelerated ageing scenarios were applied on flame retarded polylactic acid (FR-PLA). The influence of (i) Temperature and UV-light exposure (T/UV), (ii) Temperature and relative humidity exposure (T/RH) and (iii) combined Temperature, UV-light and relative humidity (T/UV/RH) exposure on (i) the morphology, (ii) the physico-chemical properties and (iii) the fire performances of FR-PLA were evaluated. The influence of FR fillers (melamine, ammonium polyphosphate and organomodified montmorillonite) as well as the associated mechanisms of degradation (i.e. photo-degradation under T/UV, hydrolysis under T/RH and a combination of both phenomena under T/UV/RH) were explained. The flame retardant properties of FR-PLA before and after ageing were compared using Limiting Oxygen Index (LOI) and Mass Loss Calorimetry (MLC). It was reported that FR-PLA aged under T/UV/RH conditions is more degraded compared to FR-PLA exposed to T/RH or T/UV. Surprisingly, the FR properties are enhanced after ageing, even if the degradation of the samples is observed.

International audience; Fouling is a widespread and costly issue, faced by all food-processing industries. Particularly, in the dairy sector, where thermal treatments are mandatory to ensure product safety, heat-induced fouling represents up to 80% of the total production costs. Significant environmental impacts, due the massive consumption of water and energy, are also to deplore. Fouling control solutions are thus desperately needed, as they would lead to substantial financial gains as well as tremendous progress toward eco-responsible processes. This work aims at presenting a novel and very promising dairy fouling-mitigation strategy, inspired by nature, and to test its antifouling performances in real industrial conditions. Slippery liquid-infused surfaces were successfully designed directly on food grade stainless steel, via femtosecond laser ablation, followed by fluorosilanization and impregnation with an inert perfluorinated oil. Resulting hydrophobic surfaces (water contact angle of 112 degrees) exhibited an extremely slippery nature (contact angle hysteresis of 0.6 degrees). Outstanding fouling-release performances were obtained for these liquid-infused surfaces as absolutely no trace of dairy deposit was found after 90 min of pasteurization test in pilot-scale equipment followed by a short water rinse.

Lignin is an abundant polyphenol biopolymeric material. Lignin was phosphorylated thanks to the presence of reactive hydroxyl groups in its structure. A detailed characterization allowed us to prove that phosphate groups are covalently bonded to the lignin's structure. The thermal stability of lignin was improved with the presence of phosphorus and was evaluated at 3% w/w. The thermal decomposition of lignin was deeply investigated through gas and condensed phases analyzes. The phosphorus was found to promote dehydration and decarboxylation reactions, thus increasing the amount of carbonaceous residue which was more stable at high temperature. The combustibility of lignin was also lowered when phosphorylated. Finally, even if half of the initial amount was released in the gas phase, the phosphorus mainly acts in the condensed phase by forming different species, which prevents the residue from oxidation.

Layer-by-layer (LbL) assembly of nanocoatings on fabric substrates has been very successful in terms of reduction of flammability. In particular, an LbL system comprised ammonium polyphosphate as the polyanion and chitosan as the polycation, applied to cotton fabric, dramatically reduced cotton flammability. At this point, the fire-retardant (FR) mechanism of action of this system has never been fully elucidated. Sonicated and nonsonicated coated cotton fabrics were evaluated using a vertical flame test and mass loss calorimeter. Coating morphology was investigated before and after burning. Thermal analyses and chemical analyses in the condensed phase (and in the gas phase) were conducted to reveal the FR mechanism of action. At the cotton surface, a combination of both condensed (formation of aromatic char) and gas phase (release of water and highly flammable gases) mechanisms impart the FR behavior, promoting a kind of “microintumescence” phenomenon. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43783.

International audience; Particular coating compositions based on incompatible polymer blends can produce coatings having complex layered structures after film formation. The most traditional approaches to their structural modification are the introduction of additives (extenders, inorganic pigments, surface active agents, etc.). As minor additives, some are capable of substantially accelerating the phase separation process with a moderate or negligible influence on the composition equilibrium of solutions. In contrast, in order to be effective, some have to be introduced in significant amounts, thereby substantially changing the resulting distribution of components through the film. Up to now, most of the liquid additives that have been tested destabilized the solutions while impacting the layering process. In this work, two phosphorus based liquid fillers have been introduced (at 2.5 and 5 wt.%) in a partially incompatible polymer blend based on a silicone resin and a curable epoxy resin to fire retard a polycarbonate matrix. Self-stratification was evidenced by microscopic and chemical analyses, flammability by Limiting Oxygen Index (LOI) and UL-94 tests, fire performances by Mass Loss Calorimetry and thermal stability by using a tubular furnace and ThermoGravimetric Analysis. The ternary compositions including 5 wt.% of additives exhibit the best stratification and excellent adhesion onto polycarbonate. Improvements of the fire resistant properties were observed (+7% for the LOI compared to the virgin matrix) when a 200 µm wet thick coating was applied, due to reduced flame propagation and dripping.

International audience; Using XRD, impedance spectroscopy, and XPS, it was shown that both Bi2Ru2O7 and Pb2Ru2O6.5, generally announced as attractive electrode materials for IT-SOFCs, chemically react with CGO. In addition, a never-mentioned time-instability under electrochemical measurements with YZS as electrolyte mediates the polarization tests. For Pb2Ru2O6.5, long time experiments (stabilization time > 900 h, previously to complementary electrochemical tests), yields strong increasing of the resistance polarization. Concerning Bi2Ru2O7, a partial transformation into Bi3Ru3O11 is observed after impedance measurements. The investigation of the Bi2−xMxRu2O7−δ (M = Sr, Pb) solid solutions was performed with the aim to improve the catalytic/electric properties. For low x values, it shows a time and chemical stabilization of the electrode/electrolyte cells, able to preserve high electrode performances of these materials. For higher substitution, the chemical/electrochemical instability reappears. According to our polarization measurements versus oxygen pressure and temperature in the so-called “stabilized” samples, the electrode performance appears limited by the diffusion of adsorbed oxygen on the triple point boundary. It is fully compatible with the metallic behavior checked in all the series.

The microstructures of two dairy fouling deposits obtained at a stainless steel surface after different processing times in a pilot plate heat exchanger were investigated at different scales. Electron-Probe Micro Analysis, Time-of-Flight Secondary Ion Mass Spectrometry, Atomic Force Microscopy, and X-Ray Photoelectron Spectroscopy techniques were used for this purpose. The two model fouling solutions were made by rehydrating whey protein in water containing calcium or not. Results on samples collected after 2 h processing show that the microstructure of the fouling layers is completely different depending on calcium content: the layer is thin, smooth, and homogeneous in absence of calcium and on the contrary very thick and rough in presence of calcium. Analyses on substrates submitted to 1 min fouling reveal that fouling mechanisms are initiated by the deposit of unfolded proteins on the substrate and start immediately till the first seconds of exposure with no lag time. In presence of calcium, amorphous calcium carbonate nuclei are detected in addition to unfolded proteins at the interface, and it is shown that the protein precedes the deposit of calcium on the substrate. Moreover, it is evidenced that amorphous calcium carbonate particles are stabilized by the unfolded protein. They are thus more easily trapped in the steel roughnesses and contribute to accelerate the deposit buildup, offering due to their larger characteristic dimension more roughness and favorable conditions for the subsequent unfolded protein to depose. (C) 2013 Elsevier Inc. All rights reserved.

International audience; Biomedical MaterialsPaperAnticoagulant and antimicrobial finishing of non-woven polypropylene textilesS Degoutin1,2, M Jimenez1,2, M Casetta1,2, S Bellayer1,3, F Chai1,4, N Blanchemain1,4, C Neut1,5, I Kacem1,2, M Traisnel1,2 and B Martel1,2Published 23 February 2012 • © 2012 IOP Publishing LtdBiomedical Materials, Volume 7, Number 3 Citation S Degoutin et al 2012 Biomed. Mater. 7 0350011281 Total downloads2828 total citations on Dimensions.Turn on MathJaxGet permission to re-use this articleShare this article Share this content via email Share on Facebook (opens new window) Share on Twitter (opens new window) Share on Mendeley (opens new window)Article informationAbstractThe aim of this work is to prepare non-woven polypropylene (PP) textile functionalized with bioactive molecules in order to improve its anticoagulation and antibacterial properties. This paper describes the optimization of the grafting process of acrylic acid (AA) on low-pressure cold-plasma pre-activated PP, the characterization of the modified substrates and the effect of these modifications on the in vitro biological response towards cells. Then, the immobilization of gentamicin (aminoglycoside antibiotic) and heparin (anticoagulation agent) has been carried out on the grafted samples by either ionic interactions or covalent linkages. Their bioactivity has been investigated and related to the nature of their interactions with the substrate. For gentamicin-immobilized AA-grafted samples, an inhibition radius and a reduction of 99% of the adhesion of Escherichia coli have been observed when gentamicin was linked by ionic interactions, allowing the release of the antibiotic. By contrast, for heparin-immobilized AA-grafted PP samples, a strong increase of the anticoagulant effect up to 35 min has been highlighted when heparin was covalently bonded on the substrate, by contact with the blood drop.

International audience; This study investigates the effects of the incorporation of nanoparticles on the reaction to fire of an epoxy resin containing a conventional intumescent flame retardant. Two types of nanoparticles are considered: OctaMethylOligomericSilsesquioxanes (OMPOSS) and Carbon NanoTubes (CNTs). The combination of an intumescent phosphorus-based flame-retardant (APP) and CNTs provides no enhancement of the reaction to fire of this system. In contrast, using OMPOSS in combination with APP provides a large synergistic effect via an intumescence phenomenon. The study of the thermal degradation of these systems shows that the interactions between these fillers modify the viscosity of the degraded matrix. The trapping of degradation gases is enhanced in the case of APP/OMPOSS, which results in the creation of anintumescent protective layer earlier than with the reference system containing APP alone. Furthermore,the presence of OMPOSS permits the creation of silicophosphates which reinforce the residue. In contrast, the residue of the formulation containing carbon nanotubes is excessively stiff and it cracks during combustion, hindering the proper formation of the protective layer.

Fine, home-synthesized, hydroxyapatite powder was formulated with water and alcohol to obtain a suspension used to plasma spray coatings onto a titanium substrate. The deposition process was optimized using statistical design of 2 n experiments with two variables: spray distance and electric power input to plasma. X-ray diffraction (XRD) was used to determine quantitatively the phase composition of obtained deposits. Raman microscopy and electron probe microanalysis (EPMA) enabled localization of the phases in different positions of the coating cross sections. Transmission electron microscopic (TEM) study associated with energy-dispersive x-ray spectroscopy (EDS) enabled visualization and analysis of a two-zone microstructure. One zone contained crystals of hydroxyapatite, tetracalcium phosphate, and a phase rich in calcium oxide. This zone included lamellas, usually observed in thermally sprayed coatings. The other zone contained fine hydroxyapatite grains that correspond to nanometric and submicrometric solids from the suspension that were agglomerated and sintered in the cold regions of plasma jet and on the substrate.

International audience; An investigation has been conducted in order to study the fatigue behavior of a SAE 1045 steel substrate coated with a Ni-base alloy known commercially as Colmonoy 88, deposited by HVOF spray technique. Fatigue tests were conducted under axial conditions (R = 0.1), employing samples of the substrate material in the as-polished condition, after grit blasting with alumina particles and after grit blasting and coating with a deposit of about 250 μm thick. The fatigue tests were conducted at maximum stresses in the range of 380–533 MPa, depending on the condition of the material. A detailed fractographic analysis of some selected samples tested at different stresses was carried out, aimed mainly at determining the crack nucleation and propagation sequence. The results indicate that the deposition of such a coating leads to a fatigue strength debit of the substrate in the range of 10–20% and a similar debit in fatigue limit of not, vert, similar 11–13%. It has been found that grit blasting is the process responsible for the fatigue strength debit observed in the coated samples. Fatigue cracks have been observed to initiate at the substrate–coating interface and at the free surface of the coating, mainly close to alumina particles embedded on the substrate and sharp notches produced during the process. The fractographic analysis of the fracture surface of the coated specimens points out the characteristic heterogeneous nature of the coating, particularly regarding some of its mechanical properties, such as fracture toughness.

International audience; SnO2 translucent monolith ionogels were obtained by a sol-gel processing using bis(2-methylbutan-2-oxy)di(pentan-2,4-dionato)tin as a precursor in the presence of various ionic liquids: [BMI][Br], [BMI][TFSI], [BMI][BF4]. The confinement of ionic liquids within the gels was evidenced by Differential Scanning Calorimetry, FTIR and FT-Raman spectroscopy. The ionic liquids could be efficiently washed off, which resulted in supermicroporous solids. Calcination in air at 550 degrees C of the dried monoliths resulted in nanoporous nanocrystalline cassiterite tin dioxide particles with crystallite sizes of about 8-12 nm and mean pore sizes around 5 nm.

International audience; Ionogels are solid oxide host networks con. ning at a meso-scale ionic liquids, and retaining their liquid nature. Ionogels were obtained by dissolving lanthanide(III) complexes in the ionic liquid 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide, [C(6)mim][Tf2N], followed by confinement of the lanthanide-doped ionic liquid mixtures in the pores of a nano-porous silica network. [C(6)mim][Ln(tta)(4)], where tta is 2-thenoyltrifluoroacetonate and Ln = Nd, Sm, Eu, Ho, Er, Yb, and [choline](3)[Tb(dpa)(3)], where dpa = pyridine-2,6-dicarboxylate (dipicolinate), were chosen as the lanthanide complexes. The ionogels are luminescent, ion-conductive inorganic-organic hybrid materials. Depending on the lanthanide(III) ion, emission in the visible or the near-infrared regions of the electromagnetic spectrum was observed. The work presented herein highlights that the confinement did not disturb the first coordination sphere of the lanthanide ions and also showed the excellent luminescence performance of the lanthanide tetrakis beta-diketonate complexes. The crystal structures of the complexes [C(6)mim][Yb(tta)(4)] and [choline](3)[Tb(dpa)(3)] are reported.

The objective of the present work is to determine the influence of the heat treatment on the corrosion resistance of a Cr3C2–NiCr coating of 450 μm thickness, deposited by a vacuum plasma spray process (VPS) on a steel substrate. The post-heat treatment of the as-deposited coating was carried out in Ar at 400 °C and 800 °C, respectively. The coatings were characterized by means of an electron probe micro analyzer (EPMA) with wavelength dispersive X-ray spectrometers (WDS). It was found that no significant changes were produced as a consequence of the heat treatment carried out at 400 °C. Therefore, the corrosion experiments were conducted for the substrate, the as-deposited coating and the post-heat treated coating at 800 °C. Potentiodynamic polarization showed that the annealed coating at 800 °C has a better corrosion resistance than the as-deposited coating. The corrosion current density (Icorr) of this coating was approximately 3 and 4 times smaller than that corresponding to the as-deposited coating and steel substrate, respectively. This significant improvement of the corrosion behavior of the post-heat treated coating is mainly due to both the microstructural changes that take place in the coating and the diffusion of Ni into Fe at the coating–substrate interface, which ensures the presence of a metallurgical bond.

International audience; 1H MAS NMR and temperature-dependent relaxation time measurements were carried out for the first time on ionic liquids confined in monolithic silica matrices and enabled us to show that the ionic liquids' dynamics experienced only a very small slowing-down. The confinement preserved the ionic liquids properties and, moreover, allowed liquid-like behaviour at temperatures below the crystallisation temperature of genuine ionic liquids. This study highlights the interest of the ionogel approach to all-solid state devices with genuine IL properties.