Synthèse de l'acide 2-acrylamido 2-méthylpropanoïque et copolymérisation avec l'acrylamide

The synthesis of 2-acrylamido-2-methylpropanoic acid (2A2MPA) was carried out starting from 2-methylpropanoic acid. Copolymerizations of the 2A2MPA salt (2A2MPANa, monomer A) with acrylamide (AM, monomer B) were investigated using K₂S₂O₈ as initiator. They were terminated before reaching 15% conversion. A range of feed compositions was selected (2A2MPANa increasing from 10 to 100 mol-%) and the compositions of the copolymers obtained were assessed through ¹³C NMR. The reactivity ratios for the couple A, B were determined as r_A = 0,76 and r_B = 1,06. One additional copolymerization was allowed to reach 100% conversion, and the final copolymer showed interesting drag reduction properties.     

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 et étude de copolymères sequencés photochromiques

New photochromic polymers were prepared by deactivating living homo or block copolymers with various 2H-chromene-2-spiro-2′-indolines ( 3a–3d ). Classical anionic polymerization was used throughout this work. By varying the chemical nature of the blocks as well as that of the photochromic units, a series of novel materials was obtained and their structure and behaviour were characterized.     

Synthèse et copolymérisation d'acrylamides comportant le groupement dihydroxyphosphoryloxyalkyle

ω-Aminoalkyl dihydrogen phosphates 5a–c , 7 and 9 were obtained in a simple and reproducible fashion by O-phosphorylation of the corresponding aminoalcohols with ClPO₃H₂ generated in situ by controlled hydrolysis of POCl₃. Reaction of these phosphates with acrylic or methacrylic anhydride in water/THF mixture afforded a series of new acrylic monomers ( 11a–h ) bearing a phosphoryl group. Inverted emulsion copolymerization of the latter with the hydrophilic comonomers N-[1,1-bis(hydroxymethyl)-2-hydroxyethyl]acryl- or methacrylamide ( 12a or 12b ) and with the cross-linker N,N′-methylenediacrylamide ( 13 ) afforded various gels in the form of spherical beads. Preliminary experiments showed that some of these copolymers could be efficiently used as stationary phases for the separation of proteins by ion-exchange chromatography.     

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.     

Synthèse et réactions photochimiques d'homopolymères et de copolymères de la p-vinylbenzophénone et du vinylferrocène

Poly(p-vinylbenzophenone), (poly[1-(4-benzoylphenyl)ethylene]), (PVB) has been synthesized for the first time directly from its monomer p-vinylbenzophenone (VB) the preparation of which was improved. In a second step, copolymers containing blocks of photosensitive VB units separated by isolated quenching vinylferrocene (VF) units have been prepared. PVB and the VB-VF copolymers were irradiated in the presence of isopropyl alcohol in benzene solutions. The benzophenone groups inserted in these macromolecular chains obey the same reaction scheme as the photoreduction of the small molecule of benzophenone. However, recombination of the radicals located along the polymeric chain leads to intra- and intermolecular reactions changing drastically the macromolecular morphology by the formation of cycles and networks and by chain scissions. The quantum yields of the photochemical transformations were measured, but they could not be related quantitatively to morphological parameters. In all cases the ferrocene group inhibits strongly the photochemical reaction.     

Synthèse par voie radicalaire de polymères à extrémités hydroxylées 4. Polymérisation et copolymérisation de butènes

The homopolymerization of 1-butene, 2-butene, and isobutene in methanol initiated by hydrogen peroxide affords low molecular weight hydroxylated oligomers in low polymerization yields. The copolymerization of these monomers with a diene monomer such as butadiene can easily be carried out. The reactivity ratios were found to depend on the structure of the monomers; the polymerization and copolymerization rate of 2-butene being higher than those of isobutene, but lower than those of 1-butene.     

Oligomères amphiphiles obtenus par voie radicalaire, 1. Synthèse et caractérisation d'oligomères de l'acide acrylique à extrémité dodécylthio

Oligomeric emulsifiers were prepared by the technique described by Roe, with special care of composition and molecular weight. Acrylic acid was polymerized in 2-propanol with lauroyl peroxide as initiator in the presence (at various ratios) of 1-dodecanethiol ( 8 ) as transfer agent to control the chain length. A good agreement was found between the various methods used for kinetic determination and oligomer characterization (¹H NMR, sulfur analysis, vapor pressure osmometry, acidimetry, GPC). Values of k_pk_t^-1/2, transfer constants for thiol 8 and solvent, nature of chain ends, polydispersity, and molecular weight were determined. Polymer fractionation was successfully performed using different solvents for recovery.     

Polymères thiocarboxyliques, 1. Synthèse et étude de la polymérisation radicalaire de monomères dithiocarboxyliques

The syntheses and free-radical polymerizations of methyl and carboxymethyl 4-vinyldithiobenzoates are described as well as various copolymers. Copolymerisation parameters were determined for the copolymerizations of the methyl dithioester with styrene and with methyl methacrylate.     

Synthèse,polymérisation et copolymérisation d'un dérivé 2h-benzotriazolylphényl de l'acétate de vinyle

1-(4-Acetoxy)-3-(2H-benzotriazolylphenyl)vinyl acetate (4) was synthesized. The polymerization of 4 afforded polymer 5 with a relatively low molecular weight (= 2000). Copolymerizations of 4 (3,7 wt.-%) were carried out with styrene and methyl methacrylate to copolymers 6 and 7, respectively. Polymer 5 and copolymers 6 and 7 were characterized by ¹ H and ¹³ C NMR and by IR and UV spectroscopy. Their UV spectra show a strong absorption in the near UV spectrum. 4 may thus be considered as a potential comonomer for UV protection.     

Synthèse et caractérisation de copolymères séquencés polystyrène/polydiméthylsiloxane et polyisoprène/polydiméthylsiloxane

Polystyrene/polydimethylsiloxane and polyisoprene/polydimethylsiloxane block copolymers were synthesized by anionic polymerization in cyclohexane (styrene and isoprene) and in a cyclohexane-diglyme mixture (hexamethylcyclotrisiloxane) with the use of sec-butyllithium as initiator. Polymers have been fractionated from benzene solution by progressive addition of methanol. Gel permeation chromatography (GPC), light scattering, osmometry, and elementary analysis were used to characterize the fractions. Copolymers, thus prepared, are free of homopolymers and the polydispersity of molecular weight and composition of the fractions is very low.     

Copolymérisation de la N-acryloyl-L-valine et de la N-acryloyl-L-phénylalanine avec l'acrylamide

The synthesis of N-acryloyl-L -valine (NAVAL) and N-acryloyl-L -phenylalanine (NAPHE) have been carried out from L-valine and L-phenylalanine. The chiral compounds have been characterized by ¹H and ¹³C nuclear magnetic resonance (NMR) spectroscopy, infrared (IR) spectroscopy and polarimetry. The copolymerization of NAVAL salt, (NAVAL Na, monomer A) or NAPHE salt (NAPHENa, monomer A′) with acrylamide (AM, monomer B) has been investigated using K₂S₂O₈ as initiator, over a range of the feed compositions for NAVALNa (or NAPHENa) from 10 to 100 mol-%. The compositions of copolymers have been systematically assessed through ¹³C NMR. The reactivity ratios for the couple A, B were determined as r_A = 0,67, r_B = 0,91 and for the couple A′, B they have been evaluated to be: r_A′ = 0,40, r_B = 0,91. The azeotropic composition is located at 21 mol-% for the couple A, B and at 13 mol-% for the couple A′, B. Drag reduction effects are obtained with these polymers.     

Synthèse et caractérisation de polystyrènes siliciés

Poly(p-trimethylsiloxystyrene) (1a) , poly[p-(tert-butyldimethylsiloxy)styrene] (1b) , poly[p-(trimethylsiloxy)-α-methylstyrene] (1c) , poly[p-(tert-butyldimethylsiloxy)-α-methylstyrene) (1d) and poly{p-[2-(tert-butyldimethylsiloxy)ethyl]styrene]} (1e) were prepared by free-radical or cationic polymerization of the corresponding monomers. Poly{[p-[2(trimethylsiloxy)ethyl]styrene]-co-[p-(2-hydroxyethyl)styrene]} (2a) was synthetized by anionic polymerization of the corresponding trimethylsilylated monomer, followed by acid hydrolysis of the resulting polymer. Poly{[p-[2-(trimethylsiloxy)ethyl]styrene]-co-[p-(tert-butoxycarbonyloxy)styrene]} (2b) were prepared by free-radical polymerization of the corresponding monomers.     

Synthèse et caractérisation de copolymères séquencés poly(vinyl-2 pyridine)/poly(oxyéthylène)

Hydrophobic-hydrophilic poly(2-vinlypyridine)/poly(ethylene oxide) block copolymers were synthesized by anionic polymerization in tetrahydrofuran in vacuum with diphenylmethylpotassium as initiator. The resulting polymers were fractionated from benzene solution by progressive precipitation with 2,2,4-trimethylpentane at 35°C. Gel permeation chromatography, light scattering, osmometry, and ¹H NMR were used to characterize the fractions. The copolymers, thus prepared, were found to have a well defined structure and a low polydispersity in both molecular weight and chemical composition.     

Synthèse et caractérisation de réticulats-modèle de polyisoprène

Polyisoprene model-networks were synthesized by an “endlinking” process: an efficient bifunctional initiator, developped recently, was used to polymerize isoprene to a bifunctional “living” precursor polymer. The living sites were subsequently used to initiate the polymerization of a small amount of divinylbenzene, whereby a model network is formed, the elastic chains of which are of known length and low polydispersity. Equilibrium swelling data and stretching moduli were measured. Unfortunately no reproducible results could be obtained on unswollen networks. Qualitative experience was obtained on the degree of association of lithium organic sites in benzene solution: the value of 2 is to be considered as plausible.     

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 par voie radicalaire de polymères à extrémités hydroxylées, 14. Synthèse de copolymères butadiène-vinylferrocène

Hydrogen peroxide, thermally cleaved into hydroxyl radicals, was used as initiator of butadiene-vinylferrocene copolymerization. The influence of different parameters like temperature, pressure, proportion of hydrogen peroxyde and addition of a solvent with weak transfer capability was studied.     

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 caractérisation de quelques poly-ε-caprolactones

The presence of a certain degree of crystallinity in poly(1.2-dichloroalkamer)s, obtained by addition chlorination of a homologous series of stereoregular polyalkenamers, ranging from polybutenamer to polydodecenamer, may suggest a chain mechanism for chlorine addition. Three different approaches have been used in order to support such a mechanism by experimental evidences: Determination of the relative velocities of chlorine addition to the two double bonds of different dienes, used as model compounds of polyalkenamers. Investigation of the demolition products of partially chlorinated polyalkenamers. Examination of the DTA thermograms of partially chlorinated polyalkenamers.     

SynthèSe de copolymères triséquencés polybutyramide-polystyrène et polybutyramide-polyisoprène

The synthesis of triblock copolymers with crystalline outer blocks of polybutyramide and a central block of polystyrene or polyisoprene was performed. First polystyrene (or polyisoprene) fitted at both ends with acyllactam functions were obtained. In a second step these endstanding functions promote the lactame polymerization to yield the polyamide blocks. A careful characterization of the resulting samples was carried out. The behaviour of these block copolymers is typically that of a thermoplastic elastomer, whereby the crystalline blocks constitute the physical crosslinks in the samples.