Synthèse de polysiloxanes acyloxyméthylés par réaction des acides acétique,benzoïque et méthacrylique,en présence de triéthylamine,sur des polysiloxanes chlorométhylés, 2. Etude de la réaction sur trisiloxane et tétrasiloxane modèles

The reaction of acetic, benzoic and methacrylic acids with 3-chloromethylheptamethyltrisiloxane and 3,5-bis(chloromethyl)octamethyltetrasiloxane in toluene in the presence of triethylamine was studied. Beside the expected transformation of oxy(chloromethyl)methylsilanediyle ( A ) units into oxy(acyloxymethyl)methylsilanediyle ( C ) units, redistributions of A , C and trimethylsilyl/oxytrimethylsilyl (M) were observed. The conversion versus time curves of distribution of the former oligomers (mole fractions of trisiloxanes: F₁ = m_{M- X -M} = m_{M- A -M} + m_{M- C -M} and tetrasiloxanes: F₂ = m_{M- X - X -M} = m_{M- A - A -M} + m_{M- A - C -M} + m_{M- C - C -M}) were followed. The reaction rates were not only controlled by the acid used but also by the starting oligosiloxane (trisiloxane or tetrasiloxane). The distributions of the homogeneous and heterogeneous oligomers seem to result from controlled combinations of A , C and M according to orientations of cleavages and to relative affinities of RCOOH/NEt₃ towards various siloxanes. For the total conversions the mole fractions F₁ and F₂ fit with those calculated by a law based on a hazard combination of C and M. This result may be explained by the compensation of electronic and steric factors.     

Synthèse de polystyrènes chlorométhylés renfermant des radicaux tétrathiafulvalène carbonyloxyméthyles

In order to solve the problem of polymer swelling, which limits the resolution for negative resists, new resists were developed which show no swelling. The undesirable swelling can be suppressed by converting nonpolar crosslinked polymers into polar ones, which are soluble after irradiation. This aim was attained by mixing a polystyrene bearing tetrathiafulvalenyl (TTF) groups with 1,2-dibromo-1,1,2,2-tetrachloroethane. For our study, we applied resists including poly(4-chloromethylstyrene)s containing tetrathiafulvalenecarbonyloxymethyl groups ( 1 and 2 ). Poly(4-chloromethylstyrene)s ( 4 ) or poly[styrene-co-(4-chloromethyl)styrene]s ( 5 ) with a variety of controlled molecular weights and molecular weight distributions were prepared by radical chain polymerization. The reaction of cesium tetrathiafulvalenecarboxylate ( 3 ) with 4 or 5 was carried out and the resultant substituted polymers 1 and 2 were characterized.     

Synthèse de polystyrènes chlorométhylés renfermant de nouveaux groupements tétrathiafulvalénylcarbonyloxyméthyles

In order to conserve high contrast while improving the sensitivity of microlithographic resins made up of polystyrene bearing tetrathiafulvalene (TTF) units, we prepared new polystyrenes containing tetrathiafulvalenylcarbonyloxymethyl groups which are methylated or non-methylated. The polymers were synthesized by reaction of poly[styrene-co-(p-chloromethyl-styrene)] with the corresponding caesium tetrathiafulvalenecarboxylate. To optimize this grafting reaction, preliminary reactions were carried out with model molecules.     

Synthèse de polystyrènes chlorométhylés renfermant des radicaux tétrathiafulvalénylphénoxyméthyles

In order to study the influence of the nature of the moiety bearing a tetrathiafulvalenyl group in the polymers upon the microlithographic properties of resists, poly(p-chloromethylstyrene)s and poly(styrene-co-p-chloromethylstyrene)s containing the 4-tetrathiafulvalenylphenoxymethyl group with a variety of controlled molecular weights and molecular weight distributions were studied. The copolymers were all prepared by reaction of poly(4-vinylbenzyl chloride) with potassium 4-tetrathiafulvalenylphenolate ( 3 ). Without exception, the resulting poly[p-chloromethylstyrene-co-p-(tetrathiafulvalenylphenoxymethyl)styrene]s are highly insoluble. However, by reaction of potassium 4-tetrathiafulvalenylphenolate with poly(styrene-co-p-chloromethylstyrene) soluble copolymers could be prepared.     

Synthèse de polysiloxanes organofonctionnels, 3. Les poly[(acétoxyméthylméthyl)siloxane]s et leurs modèles

The capability of halogen displacement by metallic acetates in oxyhalomethylmethylsilanediyle units was studied on linear and cyclic model compounds and on homogeneous and heterogeneous polysiloxanes. By displacement of iodine oxyiodomethylmethylsilanediyle units were specifically and quantitatively transformed into acetoxymethylmethylsiloxane units. This displacement was found to be accompanied by rearrangement of siloxane linkages, however, cleavage of substituted methyl and of vinyl groups, as observed in the displacement of chlorine in oxychloromethylmethylsilanediyle units, was not observed.     

Synthèse de polysiloxanes téléchéliques, 2. Synthèse de diamines aromatiques

Telechelic aromatic diamines ( 11 ) containing an oligo- or polysiloxane chain were prepared in a 4-step synthesis. In the first step 1-allyloxy-4-nitrobenzene ( 6 ) was synthesized and subsequently hydrosilylated with chlorodimethylsilane. In the third step the product ( 7 ) was hydrolyzed or condensed with α-hydro-β-hydroxyoligo- or polydimethylsiloxane ( 9a or 9b ). In the last step the nitro groups were reduced into amino groups. The steps were controlled by means of ¹H and ²⁹Si NMR spectroscopy.     

Les concentrés de plaquettes d'aphérèse:méthodes de préparation

Apheresis platelet concentrates are platelet suspension obtainedby apheresis from a blood cell separator. These techniques are now 20 years old. They are best way to collect great quantities of platelets from only one donor. These blood cell separators (discontinuous or continuous flow), realise extracorporeal circuit in which the blood in mixed with an anticoagulant (mainly citrate). All the procedures used arte automatic and adapted with the donor parameters. The platelet donor is between 18 and 60 years old and can give 5 times per year. The platelet concentration in the product is divided into 3 classes (1=2−4×10¹¹−2=4−6×10¹¹−3>6×10¹¹). Each category has a special price. Actually we can store these platelets only 5 days. In the future, we need new studies and new directions (additive solution, new plastic) to propose a better viability and a longer storage.     

Synthèse de polysiloxanes téléchéliques, 1. Synthèse de diols et diépoxydes

Telechelic poly(dimethylsiloxane)s ( 4, 5, 6 ) with acetoxy, hydroxyl or 2,3-epoxypropoxy functions as end groups were synthesized. As starting materials chloro-3-acetoxy-[or 3-(2,3)-epoxypropoxy]-propyldimethylsilanes ( 2 and 3 ) were prepared by hydrosilylation of the corresponding allylic derivatives with chlorodimethylsilane, and subsequently condensed with α-hydro-ω-hydroxyoligo- (or poly-) dimethylsiloxanes ( 1b – d ) in the presence of pyridine. The hydroxyl derivatives 5a – d were obtained by hydrolysis of the acetoxy derivatives, and the 3-(2,3-epoxypropoxy)propyl derivatives 6a, b by reaction of the diols with 1-chloro-2,3-epoxypropane.     

Synthèse et caractérisation de copolymères coordinés par des sels métalliques

The anionic block copolymerisation of isoprene and 2-vinylpyridine (2VP) followed by a coordination with iron (III) chloride, leads to thermoreversibly crosslinked copolymers. These copolymers are character+ed by a low polydispersity (M?_w/M?_w≈1,1) between the coordination nodules of poly(2-vinylpyridine). The study of the swelling ratio at the equilibrium in benzene shows that such a polymeric network does not reach the equilibrium state expected from the thermodynamic analysis of the system. The presence of 2VP in the copolymer induces a screening effect which prevents the solvent diffusion through the polyisoprene network.     

Synthèse de monoalcools et de monoacides chlorofluorés par télomérisation avec des telogènes chlorofluorés

Telomerizations of chlorofluorinated telogens CF₃CCl₃ and \documentclass{article}\pagestyle{empty}\begin{document}$${\rm Cl\rlap{--} (CFCl \hbox{---} CF}_{\rm 2} {\rm \rlap{--} )}_{\rm n} {\rm CCl}_{\rm 3}$$\end{document} (1 ≤ n ≤ 4) with acrylic, allylic, and vinylic monomers were studied. With allyl alcohol and 2-hydroxyethyl acrylate the corresponding fluorinated adducts 1 and 2 were obtained directly. Vinyl and allyl acetates led to the adducts 4a , b and 5a , b , respectively, which could be transformed into the corresponding acetals and alcohols. Telomerizations of methyl acrylate and methacrylate led to the fluorinated adducts 12a and b in the presence of copper chloride as catalyst or also with iron trichloride in the case of methyl methacrylate. By intramolecular elimination the methacrylate adducts were transformed into the lactons 13 and 14 and the acrylate adducts by reduction into the alcohols 1 and 2 . The same reduction of the methacrylate adduct led to the 2,4,4-trichloro-5,5,5-trifluoro-2-methyl-1-pentanol ( 15 ). Independent on the applied catalyst the telomerization of vinylacetic acid led to the monoaddition product, whereas in the case of methacrylic or acrylic acid the formation of monoadducts or higher addition products was found to depend on the catalyst.     

Synthèse et transformations chimiques des télomères de l'undécène-10 oate de méthyle, 2. Synthèse de diols polyhalogénés

Several telomers of methyl 10-undecenoate were prepared with different telogens and identified by IR and NMR spectroscopy or by GPC. Chemical transformations of these telomers led to new polyhalogenated acids of alcohols having high molecular weights.     

Synthèse de polyglutarimides à partir de PMMA,de la cyclohexylamine et de la méthylamine, 3 Etude du mécanisme d'imidification sur des modèles macromoléculaires

In order to check the mechanism of intramolecular cyclization to obtain glutarimide rings, we have prepared various homo and copolymers: homo N‐methyl‐ and homo N‐cyclohexylmethacrylamide and the corresponding copolymers with MMA and MAA. This first study showed that methacrylamides are less reactive than other methacrylic derivatives as shown by the r₁ and r₂ values of MMA and N‐cyclohexylmethacrylamide. The cyclization at 250°C in xylene proves that in the case of N‐cyclohexyl derivatives, the following reactivity is obtained: amide‐acid ≫ amide‐amide ≫ amide‐ester. On the contrary with N‐methyl derivatives, the reactivity of each complex is higher although amide‐acid remains the more reactive. The steric hindrance may account for this phenomenon.     

Synthèse, étude physicochimique et diélectrique de poly(acétoxyméthylstyrène)s

Various poly(acetoxymethylstyrene)s were synthesized. Examination of the physicochemical properties of the polymers as a function of the type of substitution revealed the influence of the position of polar groups on the thermal (glass transition temperature) and electrical (dielectric constant and loss factor) characteristics of the polymers. Because of their good solubility and their electrical properties over a wide range of temperatures and frequencies the polymers proved to be interesting materials for dielectric films.     

Etude par 1H NMR des groupements chlorométhyles du poly(chlorure de vinyle), 1. Synthèse et étude de modèles moléculaires chloro-4 chlorométhyl-3 heptane et trichloro-1,2,4 pentane

4-Chloro-3-chloromethylheptane ( 2 ) and 1,2,4-trichloropentane ( 3 ) were synthesized and analysed by means of ¹H NMR. These compounds — with two asymmetric carbon atoms — are models for two types of structure involving chloromethyl groups present in poly(vinyl chloride): short chloromethyl branches and chain end groups resulting from reinitiation by a chlorine atom. The spectra of these compounds allow a better understanding of the corresponding resonance region observed in standard PVC.     

Synthèse et propriété d'échange anionique de quelques résines de type N-(dialkylaminométhyl)-acrylamide

Copolymerisation of N-(dialkylaminomethylacrylamides) ( 7a–e ) with divinylbenzene led to anion exchange resins. The monomers 7a–e were prepared by reaction of acrylamide with mixtures of paraformaldehyde/dialkylamine ( 2 ). The anion exchange properties of the resins were studied and it was found that the rate of H⁺ fixation is slow, whereas the exchange between two anions is fast. The affinity scale of the anions used was found to be: Cl^?<Br^?<I^?<NO^?<SCN^?<ClO^?, which is quite similar to that observed with quaternary ammonium polystyrene resins. The selectivity constants increase with the number of C atoms of the amines. The selectivity, which is low for methyl or ethyl substituents, becomes similar or higher than of commercial analytical resins for the polymer derived from dihexylamine. The hydrophobic character of the dialkylamine groups results in a high stability of anion-cation association for anions of low hydration energy. These features allow an interpretation of the observed properties.     

Synthèse et caractérisation de copolymères séquencés poly(méthacrylate d'alkyle)/poly(oxyéthylène)

Poly(alkyl methacrylate)/poly(oxyethylene) block copolymers were synthesized by anionic polymerization in tetrahydrofurane in vacuum with diphenylmethylpotassium as initiator. In the case of poly(ethyl methacrylate)/poly(oxyethylene) copolymers, samples were fractionated from benzene solution by progressive addition of 2,2,4-trimethylpentane. Nuclear magnetic resonance and lightscattering were used to characterize the fractions. It was shown that copolymers thus prepared are free from homopolymers, and that the polydispersity in weight and composition is small.     

Synthèse et propriétés d'oligomères dièniques partiellement et totalement hydrogénés

Hydrogenations of several hydroxy-terminated low molecular weight polybutadienes (PB) or non functional PB and one polyisoprene by homogeneous catalysis were studied. Hydrogenation of 1,4-polybutadienes gave solid crystalline polymers. In the case of hydrogenated 1,2-polymers a decrease of the glass transition temperature was noted, the hydrogenation leading to amorphous polymers. The rheological behaviour of oligomers was found to be Newtonian at low shear rates (≤ 100 s^?1). The viscosity at T_g+100°C increased in every case with the hydrogenation rate. It was found that hydrogen bonding induced by hydroxyl groups has a great effect on the glass transition temperature but does not change the viscosity at T_g + 100°C.     

Synthèse par voie radicalaire de polymères à extrémités hydroxylées, 3. Synthèse de poly(acétate de vinyle)

On heating, hydrogen peroxide is cleaved into hydroxyl radicals, which can be used as initiators of polymerization in order to give hydroxylated polymers of low molecular weight. The conversion and the number average molecular weights are influenced by the presence of an alcohol in the reaction medium, and the results depend on the solubility of the polymer in the applied alcohol. The following characteristics of the polymerisation of vinyl acetate in methanol are studied: distribution of molecular weights, microstructures, proportion of hydroxyl groups in the macromolecule. The influence of several parameters as reaction time, temperature, proportion of hydrogen peroxyde and solvent, is also investigated.     

Synthèse et caractérisation de copolymères triséquencés de différents méthacrylates d'alkyle

Triblock copolymers of different alkyl methacrylates with side chains containing 1 to 12 carbon atoms were synthesized by anionic polymerization in tetrahydrofuran with diphenylmethyl sodium or naphthalene sodium (sodium dihydronaphthylide) as initiators. The polymer samples were fractionated by means of solvent/non-solvent systems. Gel permeation chromatography (GPC), light scattering, osmometry, and elemental analysis were used to characterize the fractions. The copolymers were found to be free of homopolymers and the polydispersity of molecular weight of the fractions to be very low.