Search

International audience; Polymeric materials derived from fatty acids (FA)s were synthesized through free radical polymerization and evaluated as viscosity index improvers (VII) in an organic triglyceride lube oil (OTO). For this purpose, various FA-based copolymers were designed to own a reduced solubility at low temperature in OTO which can be gradually improved by increasing temperature. Different fatty amide methacrylates were chosen for their poorly oil-miscible repeating units while fatty ester methacrylates, 2-(methacryloyloxy)ethyl oleate (MAEO) and 2-(methacryloyloxy)ethyl 4-(dodecylthio)oleate (MAEOSC12), were used as oil-miscible comonomers for providing copolymers with a minimum of solubility in the lube oil. All copolymers were synthesized with a 50:50 M feed ratio and were fully characterized through 1H NMR, SEC, DSC, and TGA analyses. Then, rheological study of oil-copolymer blends revealed that copolymers containing –NH function were able to have a higher impact on oil viscosity at high than at low temperatures suggesting the coil copolymer expansion. This improvement of thickening power with temperature in OTO was further optimized by increasing the copolymer molecular weight, dispersity, concentration, pendant aliphatic chain length or by adding an additional aliphatic chain in the copolymer backbone. Moreover, copolymer additions in OTO did not disturb the initial Newtonian behavior of OTO at −30 °C which corresponds to the lube oil pour point.

International audience; Oligomers coming from glycerin carbonate acrylate (GCA) and solketal acrylate (SolA) were synthesized in good yields by free-radical chain transfer polymerization using 2-mercaptoethanol (ME) as chain transfer agent. These oligomers were totally soluble in solvents and did not exhibit branching or gelation. The efficiency of the chain transfer polymerization process on these glycerol-based acrylate monomers was demonstrated and reactive cotelomers bearing both acetal and cyclocarbonate groups were obtained. The structure of these oligomers was well-characterized by NMR, SEC, FTIR and MALDI-Tof spectroscopies. The oligo(GC-stat-Sol)s are particularly interesting, notably in terms of reactivity and solubility in various organic solvents and water that can be modulated by varying different SolA/GCA ratios. These results open the way to a widespread valorization of glycerol.

International audience; Amphiphilic photo-induced triblock copolymers were successfully prepared by photodimerization of a photo-active initiator bearing coumarin moieties (CmTs2) before synthesizing, by cationic ring-opening polymerization (CROP), various lengths of polyoxazoline block. The DLS and TEM studies of the triblock copolymers self-assembly in water revealed that over 99% of the nanoparticles have a DH-value of 10 nm. The total photo-activity of the coumarin units permitted p-stacking interactions in the nanoparticle core and further its crystallization as demonstrated by DSC and X-ray diffractometry. An original nonspherical morphology of the nanoparticles resulted with an elongated shape.

Photopolymerization is the subject of a growing interest both at industrial and academic levels because it provides high reaction kinetics, low emissions of volatile organic solvents and in some cases, low shrinking stress. This polymerization route has been largely developed using radical polymerization of vinyl monomers, but to a lesser extent by ring-opening polymerization (ROP). Beyond epoxides, which were the first monomers polymerized by a cationic ring-opening polymerization (CROP), the photopolymerization of other cyclic monomers has recently spread out thanks to the emergence of novel initiating systems. This review states an overview of the spectrum of cyclic monomers that have been polymerized by light-induced polymerization processes. In a first part, the photosensitive species able to trigger or to induce a change of kinetics of ROP reactions are presented according to their activation mechanism, i.e photouncaging, photoswitching or photoredox. In a subsequent part, the different monomer classes and their photopolymerization mechanisms are described with an emphasis on the properties of resulting materials. The last part covers the use of photoROP for several applications.

Evolution of metamodels can be represented at the finest grain by the trace of atomic changes such as add, delete, and update of elements. For many applications, like automatic correction of models when the metamodel evolves, a higher grained trace must be inferred, composed of complex changes, each one aggregating several atomic changes. Complex change detection is a challenging task since multiple sequences of atomic changes may define a single user intention and complex changes may overlap over the atomic change trace.In this paper, we propose a detection engine of complex changes that simultaneously addresses these two challenges of variability and overlap. We introduce three ranking heuristics to help users to decide which overlapping complex changes are likely to be correct. In our approach, we record the trace of atomic changes rather than computing them with the difference between the original and evolved metamodel. Thus, we have a complete and an ordered sequence of atomic changes without hidden changes. Furthermore, we consider the issue of undo operations (i.e. change canceling actions) while recording the sequence of atomic changes, and we illustrate how we cope with it. We validate our approach on 8 real case studies demonstrating its feasibility and its applicability. We observe that a full recall is always reached in all case studies and an average precision of 70.75%. The precision is improved by the heuristics up to 91% and 100% in some cases. HighlightsRecording the trace of atomic changes ensure the chronological order and the absence of hidden changes.Both issues of hidden changes and overlapping complex changes reduce the recall of the detection, if not considered.Our detection algorithm reaches 100% recall for the eight case studies.In the eight case studies, our heuristics never rank the correct overlapping complex changes with a lower priority than the incorrect ones.

International audience; The effects of polylactide-graft-cellulose nanocrystals on the thermal and mechanical properties of poly(l-lactide) matrices were investigated. Cellulose nanocrystals (CNCs) were grafted with polylactide chains via a solvent-free process by ring-opening polymerization of l-lactide using magnesium hydride as a catalyst. The efficiency of grafting was determined by infra-red, X-ray photoelectron spectroscopy and nuclear magnetic resonance analyses. X-ray diffraction analyses showed that the crystalline nature of the CNCs was preserved. Nanocomposites based on poly(l-lactide) matrix containing ungrafted nanocrystals (PLLA/CNCs) and grafted nanocrystals (PLLA/PLLA-g-CNCs) were investigated. DSC revealed that the grafted nanocrystals exhibited a strong influence on the crystallinity of the nanocomposites, inducing a significant enhancement of the mechanical properties of PLLA/PLLA-g-CNCs compared with PLLA/CNCs material. The role played by the polylactide grafted layer on the interaction between the CNCs and PLLA matrix was revealed by mechanical analyses in the solid and molten states.

The use of functional polymers for the sorption of metallic species in water was widely practiced in treatment processes. Such sorbents offered the possibility to remove a large range of metals because of the variety of possible functional groups on polymeric backbones. In particular, acidic groups (carboxylic, phosphonic or sulfonic groups) proved to be of great interest for the sorption of different cations. Sorption efficiency and selectivity through complexation or ion exchange interactions were directly linked to the nature of both the functional groups and the cationic metallic ions. In addition, the physical nature of materials was another important parameter that had to be considered. Depending on the polymer solubility, the cross-linking density, and the polymeric architecture, significant differences regarding sorption properties were observed in the sorption kinetics. Thus, it was challenging to select the appropriate polymeric sorbent with the most relevant physical nature and functionality in the area of wastewater treatment. This review aims at reporting organic polymeric materials bearing acidic groups able to interact (selectively or not) with metallic cations. Both synthetic and bio-based materials were reviewed and main parameters that had to be considered when choosing functional organic sorbents for the removal of metallic pollution were highlighted. Finally, recyclability of the polymeric sorbents was also considered.

An iodine modified polypropylene surface was synthesized by iodine plasma activation. The obtained polypropylene surface was found to be a useful platform for secondary reactions. For instance, an azide-functionalized PP was prepared by nucleophilic exchange reaction. The surface was proven to be reactive toward R group of an alkyne modified RAFT agent via the copper-catalyzed azide–alkyne cycloaddition. RAFT mediated graft polymerization of methacrylic acid was carried out and lead to a controlled polymerization from the surface. Characterizations of the modified surface and the grafted polymers were performed through FTIR-GATR, XPS, AFM and colorimetric assays.

To encapsulate and deliver poorly water-soluble drugs, castor oil/silica hybrid microparticles (HMP)s were synthesized. Green chemistries were used to silylate the oil and further cross-link it into solid microparticles by sol-gel reaction. Silylated castor oils (ICO)s at various silylation ratios were prepared and allowed the solubilization of ibuprofen at several concentrations up to 16 wt%. The HMPs were formulated by ThermoStabilized Emulsion (TSE) process which permits to “freeze” the oil-in-water emulsion while the sol-gel reaction occurs. The hybrid mineral/organic composition and the morphology (spherical shape and micrometric size) of these HMPs were determined by complementary technics (SEM, TGA, EDX, 29Si NMR and FTIR spectroscopies). The HMPs reached a good ibuprofen loading efficiency regardless to the formulation used while the release kinetics in simulated oral administration exhibited a tunable release during 3 h according to the silylation ratio. The ibuprofen rate also influenced its own amorphous or crystalline character within the HMPs. For subcutaneous conditions, ibuprofen release took place over 15 days. Finally, biodegradability assays in simulated digestion medium suggested a surface-limited hydrolysis of the particles and cytocompatibility studies on NIH-3T3 and Caco-2 cells demonstrated an excellent cellular viability.

Experimental conditions for the synthesis of poly(e-caprolatone)-graft-poly(vinyl alcohol) (PCL-g-PVA) and poly( l -lactide)-graft-poly(vinyl alcohol) (PLLA-g-PVA) via a PVA/MgH2 macroinitiator were optimized. Heat stability of PVA (99% hydrolyzed) in l -lactide (L-LA) melt was studied by DSC, TGA to lower the reaction temperature and time in order to avoid degradation. Thus, no degradation of copolymers occurred and 13C NMR study showed that l -lactide was incorporated in graft chains as isotactic poly( l -lactide) without racemisation for 140–160 °C, up to 25 h, L-LA/PVA ratio in the range 3–12. Such synthesis using non-toxic catalyst and reactants in a solvent-free medium can be described as environment-friendly. Amphiphilic behavior of copolymers was studied in aqueous solution according to their chemical structures: critical micelle concentration CMC (0.03–0.5 g L−1), average diameter of micelles (80–150 nm), surface tension γCMC (46–63 mN m−1), hydrophilic to lipophilic balance HLB (Griffin definition 4–7), and also from cast films: surface energy γs (36–50 mJ m−2). This environment-friendly process is suitable for the use of graft PVA copolymers in biomedical area for investigations under micelle applications.

International audience; The synthesis of amphiphilic lipid-polyoxazoline based on copolymers (CO-POxn) with narrow distribution has been achieved via cationic ring-opening polymerization of 2-methyl-2-oxazoline (MOx). Lipid-macroinitiator (COTs) was obtained from commercial castor oil (CO), widely renewable agricultural resource. CO-POxn with various length segments were synthesized from a macroinitiator COTs in order to investigate the effect of the length of the hydrophilic segment on the solution behavior of the nonionic polymer surfactants CO-POxn. The results showed that the critical micelle concentration rised with the increase of POx content and inversely surface tension decreased. The average size of aggregates of these structures suggested the formation of vesicles or nonspherical micelles. Star-shaped morphology of CO-POxn in solid state has also been observed using environmental scanning electron microscopy (ESEM). Addionally energy dispersive X-ray (EDX) analysis demonstrated the presence of POx block in the concentric stripes of the texture.

International audience; Novel organic/inorganic hybrid material was synthesized from poly(acrylazapropyl-trimethoxysilane)-b-poly( Ne-trifluoroacetyl-L-lysine) (P(AAPTMS)-b-P(TLL)) block copolymer using the sol–gel process. The treatment with ammonia solution permitted the hydrolysis of both trifluoro acetyl and trimethoxysilyl groups of the hydride copolymer followed by the condensation of the silanol groups, leading to crosslinked copolymers. The resulting cross-linked hybrid material was characterized using FT-IR, 29Si NMR, DSC, TGA, and environmental scanning electron microscopy. These techniques evidenced that a siloxane network was obtained. Amphiphilic polypeptide/inorganic hybrid copolymers were achieved and selforganized as particles in water.

10 pages; International audience; The telomerization of 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) in the presence of 2-mercaptoethanol was investigated at 80 C in acetonitrile. In our case, the efficiency of 2-mercaptoethanol as telogen agent, with TMSPMA, was demonstrated and the transfer constant (CT) was determined. Moreover, cotelomerization of TMSPMA with perfluorodecylacrylate (PFDA) using various PFDA contents was investigated in order to obtain a-hydroxy oligomers with statistical copolymer-type main chains bearing trimethoxysilyl and perfluoro pendant chains. Until 10 mol% PFDA, no phase separation occured. In this composition, rTMSPMA and rPFDA reactivity ratios were calculated, thus showing a tendency for a statistical distribution of the monomer units in the copolymer.

International audience; A new method to prepare ionomers bearing terminal ionic groups has been developed by modification of different hydroxyl terminated oligomers and using vinyl phosphonic acid as reagent. The different oligomers have been characterized by NMR, MALDI-TOF, SAXS, SEM-EDX, thermal analysis and their ionic crosslinking was achieved using different cations. Characterization of the network was performed and proved that an efficacious crosslinking was reached depending on the nature of the cations.

International audience; Glycolysates coming from the chemical recycling of PET scraps are most often very crystalline compounds making them difficult to perform in further reactions like step growth polyaddition with diisocyanates to obtain polyurethanes. The glycolysis of PET was investigated using unusual reagents: polyesters based oligomers, bisphenol A, cycloaliphatic alcohol and aliphatic diols. The thermal properties of the glycolysates obtained were compared in terms of crystallinity with that of coming from the glycolysis with DEG. The crystallinity extents were calculated using X-ray diffraction. Surprisingly, the crystalline or non-crystalline nature of the reactants do not predict the morphology of the final glycolysates.

The telomerization of dimethylaminoethyl methacrylate (DMAEMA) with mercaptoethanol initiated by 2,2′-azobisisobutyronitrile was first investigated at 70 °C and the influence of the type of solvent was studied. The results showed that well-defined telomers of DMAEMA could not be synthetized via telomerization of DMAEMA in water or water/acetonitrile mixture since the telomerization reaction is in competition with the nucleophilic addition of thiol onto the monomer. Transfer constants for mercaptoethanol in benzene and acetonitrile were determined by Mayo's and O'Brien's methods. The transfer constant obtained in acetonitrile (0,6) was higher than that obtained in benzene. This difference can be explained by the fact that the thiol was consumed by two reactions: nucleophilic addition and telomerization. The influence of solvents on the polymerization kinetics was enlightened. These results were applied to the synthesis of macromonomers of DMAEMA with isocyanatoethyl methacrylate (IEM). These macromonomers were copolymerized with styrene.

We propose Concurrent Transaction Frame Logic (CTFL) as a language to provide formal semantics to UML activity and class diagrams. CTFL extends first-order Horn logic with object-oriented class hierarchy and object definition terms, and with five new logical connectives that declaratively capture temporal and concurrency constraints on updates and transactions. CTFL has coinciding, sound and refutation complete proof and model theories. CTFL allows using a single language to (1) formally describe the semantics of both activity and class diagrams, (2) verify UML models based on these two diagrams using theorem proving and (3) implement the model as an executable, object-oriented logic program.

Polyethylene terephthalate (PET) was alcoholised with ethylene glycol to synthesize hydroxytelechelic oligomers of PET. On the other hand, commercial hydroxytelechelic polyϵ-caprolactone was modified in order to synthesize carboxytelechelic polyϵ-caprolactone. The chemical structure of the products was investigated by 1H NMR. Multiblock copolyesters were then synthesized by polyesterification of hydroxytelechelic PET and carboxytelechelic polyϵ-caprolactone oligomers, using several catalysts and different reaction conditions, which have been linked with the average molecular weight of the obtained block copolyesters. It appeared that residual distannoxane species coming from glycolysis step are best catalyst for polyesterification reaction. The chemical structure of the synthesized copolyesters was investigated by size exclusion chromatography and 1H NMR. The thermal and thermomechanical behavior of the synthesized copolyesters was investigated by differential scanning calorimetry and by dynamic mechanical analyses. The ester–ester interchange reaction between the two types of oligopolyesters has been enlightened and estimated taking in account the different reaction parameters. This side reaction led to the miscibility of the two phases of the oligomers, that can be explained by a random structure of the copolyester, and prevented to obtain multiblock copolymer.

Recycling of mixed plastic wastes composed of low-density polyethylene (LDPE) matrix and polypropylene (PP) was carried out by compounding using single-screw or twin-screw extruders. Blends of virgin polymers have been prepared to compare mechanical properties of both virgin and regenerated materials. First, a model composition of virgin LDPE/PP blend was prepared to study the effect of process parameters and that of different types of compatibilizers. Second, the results were applied to plastic wastes coming from industrial post-consumer plastic wastes. By adding compatibilizing agents such as ethylene–propylene–diene monomer, ethylene–propylene monomer, or PE-g-(2-methyl-1,3-butadiene) graft copolymer, elongation at break and impact strength were improved for all blends. The effect of these various copolymers is quite different and is in relation with their chemical structure. The recycled blends exhibit suitable properties leading to applications that require good mechanical properties.

Background . Long-term results after composite graft aortic root replacement may depend on the insertion technique. The aim of this study is to assess the influence of the technique of coronary artery implantation on long-term results in composite aortic root replacement. Methods . One hundred fifty consecutive patients (mean age, 55 years; 119 men) with different disorders of the ascending aorta who underwent aortic root replacement with a composite graft prosthesis between January 1985 and December 1999 were retrospectively studied. Thirteen patients had previously undergone cardiovascular surgery. The open button technique was performed in 65 patients (43.3%, group 1) and the inclusion technique in 85 patients (56.7%, group 2). Mean follow-up was 70.5 months. Surgery was elective in 110 procedures (73%). Results . Global actuarial survival was 76.1% ± 4.3% for group 1 and 73.7% ± 3.9% for group 2 at 10 years ( p = 0.22). Freedom from reoperation excluding early deaths was 81% ± 3% for group 1 and 86% ± 2.2% for group 2 at 10 years ( p = 0.62). Group 2 demonstrated a statistically significantly higher occurrence of pseudoaneurysm formation versus group 1 ( p = 0.04). Conclusions . Composite graft aortic root replacement is a safe and effective therapy for proximal aortic aneurysm and dissection, resulting in good early and long-term results irrespective of the anastomotic technique. However, the open button technique seems to avoid late false aneurysm formation at the anastomotic sites.

Study objectives To compare cardiac troponin I (cTnI), cardiac troponin T (cTnT), and creatine kinase MB (CKMB mass) in patients with and without new Q wave on the ECG following coronary artery bypass graft (CABG) surgery. Patients After ethic committee's approval and informed consent, 82 patients, mean age 63±10 years, scheduled for CABG were included. Interventions Arterial blood samples were drawn during cardiopulmonary bypass, before, and 6, 12, 24, and 48 h after aortic cross-clamp release. cTnI, cTnT, and CKMB mass were measured. The appearance of new Q wave on the ECG performed preoperatively and 24 h postoperatively was used to assess myocardial lesion independently of biological markers. Results There were 69 patients without new Q wave on the ECG (group 1) and 13 with (group 2). In group 1, cTnI reached a peak of 2.1 μg/L (median, interquartile range [IQ]=2.4) at 12 h, cTnT increased progressively with a peak of 0.22 μg/L (IQ=0.2) at 48 h, and CKMB presented an earlier peak of 10 μg/L (IQ=6.2) at 6 h. Starting with the same median value, group 2 patients presented significantly higher peaks: cTnI: 17 μg/L (IQ =16) at 12 h; cTnT: 1.4 μg/L (IQ=2.3) at 12 h; and CKMB mass: 74 μg/L (IQ=61) at 6 h. Receiver operating characteristic (ROC) curves were constructed. The area under the curve was 0.90 for cTnI, 0.84 for CKMB, and 0.81 for cTnT (not significant). The best cutoff values to discriminate between group 1 and group 2 patients were determined with the ROC curves: cTnI=5 μg/L; CKMB mass=20 μg/L; cTnT=0.3 μg/L. Sensitivity, specificity, and positive and negative values for cTnI (5 μg/L) were 91%, 82%, 53%, and 98%, respectively. Conclusions There was little differences among cTnI, cTnT, and CKMB after CABG to diagnose myocardial damage as assessed by new Q wave on the ECG. There was a trend of cTnI to be a better discriminator than cTnT, but it did not reach statistical significance.

Objective: This study was initiated to test the hypothesis that fetal hemodynamic changes observed under pulsatile flow bypass might be related to the release of endothelium-derived relaxing factor through oscillating shear stress. Methods: Normothermic bypass was instituted in utero in 21 preterm fetal lambs for a 1-hour period through the right atrium and main pulmonary artery. Ultrasonic flowmeters were positioned around the descending aorta and the umbilical artery. The circuit consisted of an oxygenator and a pump set to either continuous flow ( n = 7) or pulsatile flow ( n = 7) and adjusted to maintain a fetal main arterial pressure of 50 mm Hg. In seven other animals, endothelium-derived relaxing factor was blocked by a continuous infusion of N ω -nitro-l-arginine after 30 minutes of pulsatile flow. Results: During the first 30 minutes of bypass, pump flows were significantly lower in the continuous-flow group than in the pulsatile-flow or blocked-flow groups (respectively, 612 ± 144, 907 ± 153 and 987 ± 228 ml/min), with similar changes in aortic and umbilical flows. Systemic vascular resistances were significantly lower in the pulsatile-flow and blocked-flow groups than in the continuous-flow group (550 ± 106 vs 821 ± 212 dynes/sec/cm −5 ). However, after blockade of endothelium-derived relaxing factor, resistances increased gradually in the blocked-flow group to reach the level of that of the continuous-flow group at the end of bypass (943 ± 77 vs 556 ± 143 dynes/sec/cm −5 in the pulsatile-flow group). Conclusions: Blockade of endothelium-derived relaxing factor after 30 minutes of pulsatile flow returns fetal hemodynamics to continuous flow conditions. The specific inhibitor of endothelium-derived relaxing factor used in this experiment suggests that nitric oxide may be released by fetal endothelium during pulsatile bypass.(J Thorac Cardiovasc Surg 1997;114:738-45)

Resume Deux agents tensioactifs methacryliques polymerisables ont ete synthetises et leurs caracteristiques ( C T , k p 2 k Te ) ont ete determinees. Lorsque l'on realise la polymerisation de ces deux agents tensioactifs en milieu aqueux nous obtenons des polymeres avec des degres de polymerisation voisins de 40 et ceci, que l'amorcage soit realise par irradiation ou avec un amorceur radicalaire. La polymerisation en milieu homogene dans un solvant organique conduit a de plus grandes longueurs de chaines. Ces differents comportements a la polymerisation proviennent de la stabilisation thermodynamique des micelles qui limite la polymerisation et la longueur des chaines. Par ailleurs, le temps de vie des radicaux pour ces monomeres est plus court que le temps de vie des micelles. De ce fait, la polymerisation s'effectue bien au sein des micelles.

Summaries typically convey maximal information in minimal space. In this paper, we describe an approach to summary generation that opportunistically folds information from multiple facts into a single sentence using concise linguistic constructions. Unlike previous work in generation, how information gets added into a summary depends in part on constraints from how the text is worded so far. This approach allows the construction of concise summaries, containing complex sentences that pack in information. The resulting summary sentences are, in fact, longer than sentences generated by previous systems. We describe two applications we have developed using this approach, one of which produces summaries of basketball games (STREAK) while the other (PLANDOC) produces summaries of telephone network planning activity; both systems summarize input data as opposed to full text. The applications implement opportunistic summary generation using complementary approaches. STREAK uses revision, creating a draft of essential facts and then using revision rules constrained by the draft wording to add in additional facts as the text allows. PLANDOC uses discourse planning, looking ahead in its text plan to group together facts which can be expressed concisely using conjunction and deleting repetitions. In this paper, we describe the problems for summary generation, the two domains, the linguistic constructions that the systems use to convey information concisely and the textual constraints that determine what information gets included.

The grafting reaction of fluorinated maleamic acid and maleimide oligomers on to high-density polyethylene (HDPE) in the molten state is described. Temperature and roller speed play an important role since the greater these are, the greater the grafting rate. The same compounds have also been grafted using an initiator under the same conditions. It has been shown that the maleimide forms are more reactive than maleamic acid. This can be explained by steric hindrance which decreases the grafting rate. The use of an initiator favours grafting.

Resume La present travail vise la preparation de resines epoxydes tetrafonctionnelles a partir de diamines aromatiques et d'epichlorhydrine. La vitesse de cette reaction etant liee a la basicite de l'amine, une etude modele a ete realisee en partant de monoamines presentant divers substituants en position para. La condensation de l'epichlorhydrine sur ces amines montre que les substituants electrodonneurs (OCH 3 ) ou faiblement electrodonneurs (CH 3 ) conferent une plus grande reactivite comparativement aux substituants electroattracteurs (NO 2 ). Dans un deuxieme temps, nous avons prepare des resines epoxydes tetrafonctionnelles a partir de diamines de basicite variable: la diamino 4 4′ diphenyl methane, la diamino 4 4′ diphenyl sulfone, la 4 amino phenyl ether et enfin, une diamine aromatique a pont ether et pont perfluore. Les resines obtenues ont ete caracterisees principalement par RMN 1 H. On observe normalement que la diamino 4 4′ diphenyl sulfone est moins reactive que son homologue la diamino 4 4′ diphenyl methane. Aucune conclusion n'a pu etre tiree de la reactivite de la 4 amino phenyl ether dont la solubilite est tres reduite et dont les produits obtenus, apres epoxydation, sont tres instables. Enfin, en ce qui concerne l'amine fluoree, sa basicite, qui devrait etre augmentee par la presence du groupement ether en position para, est en fait attenuee par les groupements perfluores en α des ponts ethers.

The condensation reaction of perfluorinated amines on to (succinic anhydride)-HDPE (high-density polyethylene) graft copolymer have been studied. Four different amine structures have been synthesized which have been analyzed by 1 H NMR spectroscopy GC-MS methods. Model structures of succinimide and succinamic acid have been synthesized with each amine and analyzed by FT-IR spectroscopy in order to determine the structure of the copolymer obtained. A scale of reactivity has been deduced as a function of the amine structure. Grafting levels of copolymer have been determined by elemental analysis of fluorine.

Diblock copolymers are obtained by addition of monofunctional telomers to aromatic diisocyanates [telomers of butyl acrylate or methyl methacrylate with mercaptoethanol]. These copolymers were synthesized in two steps: preparation of a prepolymer from a monofunctional telomer and a diisocyanate, then, condensation of the prepolymer isocyanate function with a second telomer. Acrylic diblock copolymers with different chain lengths have been prepared according to this procedure.

Resume Faisant suite a des travaux realises dans ce sens sur d'autres polymeres, le present memoire envisage le cas de l'ozonisation du polyfluorure de vinylidene (PVDF). L'etude a permis de determiner le taux d'activation de ce polymere comparativement a des produits tels que le polyethylene (PE) et le polychlorure de vinyle (PVC) traites dans les memes conditions, et montre que ce polymere s'active beaucoup plus difficilement. Par la suite, la reactivite du PVDF ozonise a eteevaluee par la determination de la constante de vitesse de dissociation kd des peroxydes et hydroperoxydes generes et par le calcul de l'energie d'activation Ea de cette reaction. Les valeurs trouvees pour kd (5,9– 10−4 sec−1 a 80°C) et pour Ea (37,4 kJ/mol) sont du meme ordre de grandeur que celles obtenues dans le cas du PE et du PVC.

Resume Cette etude resume les principales methodes permettant d'obtenir une bonne adhesion sur les polyolefines et propose une solution. La synthese de copolymeres greffes par activation de polymeres par l'ozone est decrite. Le greffage s'effectue par reaction en masse avec divers monomeres acryliques. La purification et l'analyse de tous les copolymeres sont detaillees et leur application dans le domaine des adhesifs pour composites et des colles “Hot-melt” est decrite.

Background A simplified alternative to the Cox maze procedure to treat atrial fibrillation with epicardial high-intensity focused ultrasound was evaluated clinically, and the initial clinical results were assessed at the 6-month follow-up visit. Methods From September 2002 through February 2004, 103 patients were prospectively enrolled in a multicenter study. Atrial fibrillation duration ranged from 6 to 240 months (mean, 44 months) and was permanent in 76 (74%) patients, paroxysmal in 22 (21%) patients, and persistent in 5 (5%) patients. All patients had concomitant operations, and ablation was performed epicardially on the beating heart before the concomitant procedure. The device automatically created a circumferential left atrial ablation around the pulmonary veins in an average of 10 minutes, and an additional mitral line was created epicardially in 35 (34%) patients with a handheld device by using the same technology. Results No complications or deaths were device or procedure related. There were 4 (3.8%) early deaths and 2 late extracardiac deaths. The 6-month follow-up was complete in all survivors. At the 6-month visit, freedom from atrial fibrillation was 85% in the entire study group (80% in patients with permanent atrial fibrillation, 88% in the 35 patients who had the additional mitral line, and 100% in patients with paroxysmal atrial fibrillation). A pacemaker was implanted in 8 patients. Only the duration and type of atrial fibrillation significantly increased the risk of recurrence. Conclusion Epicardial, off-pump, beating-heart ablation with acoustic energy is safe and cures 80% of patients with permanent atrial fibrillation associated with long-standing structural heart disease.

An inductively coupled argon plasma was evaluated as a source for the determination of oscillator strength values of several lines of Ta I and Ta II. Although there is a departure from LTE, a partial LTE between excited states of injected elements was assumed. This allowed the authors to consider an excitation temperature of 4800 K in the determination of ƒ-values of tantalum.

Resume Un nouveau generateur haute frequence de plasma fonctionnant a 40 MHz a ete concu comme source d'excitation en spectroscopie d'emission atomique et source d'atomisation en absorption atomique. De bonnes performances analytiques ont ete obtenues en emission et en absorption atomique. On peut neanmoins preferer l'emission pour sa simplicite de mise en oeuvre.

Resume Une etude des interferences chimiques et d'ionisation a ete realisee dans un plasma induit par haute frequence utilise comme source d'excitation en spectroscopie atomique. Du fait de la temperature elevee (6000 K), les interferences chimiques sont negligeables. Les interactions produites par la prese signal du phosphore et plus faiblement du chrome, non influences sur d'autres elements) ne peuvent s'expliquer par un changement de l'equilibre des particules dans le plasma (loi de Saha), la densite electronique et la temperature mesurees en fonction de la concentration en sodium ne variant pas de faccon appreciable.

This paper describes software for automatic qualitative and semi-quantitative analysis using inductively coupled plasma (ICP) atomic emission spectrometry with a high-resolution scanning monochromator. This software can be also used for automatic collection of wavelengths and intensities of spectral lines emitted from an ICP.

In an HF plasma at 40 MHz, physical parameters such as the excitation temperature of different elements (Ar, Ti, Fe, V), the electron number density on the basis of profiles of argon (549.5 nm) and hydrogen (Hβ) lines and the ionization temperatures of Mg and V were determined. A study of the smoothing of experimental curves was made in order to apply Abel transformation. Consistent values were obtained by smoothing the curves by means of C hebyshev's orthogonal polynomial method and by the method of least squares. The experimental results showed agreement between the excitation temperatures of the elements indicated (4800 K). The electron number density obtained from the profile of lines broadened by the Stark effect is about 5.5 × 1014 cm−3. The ionization temperature of Ar derived from the Saha equation under assumption of complete LTE (7400 K) differs substantially from the excitation temperature and indicates that complete LTE does not exist. However ionization temperatures calculated by the method of the ratio of ion and atom line intensities, associated with Texc and ne values, are 7300 K for Mg and 6700 K for V but are not significantly different from each other.