Polymères thiocarboxyliques, 2. Synthèse par modification de polymères préformés

Dithioester groups were introduced into linear or crosslinked polystyrenes by Friedel-Crafts reaction with ClCH₂Si(CH₃)₃/CS₂ or with ethyl chlorodithioformate, as well as thioamide groups by reaction with ethoxycarbonyl isothiocyanate. Treatment of several copolymers of acrylonitrile with ethanethiol and hydrogen chloride and subsequently with H₂S led to copolymers with dithioester and thioamide groups in the side chains without cyclization. Most of these reactions occur without crosslinking.     

Synthèse et copolymérisation avec l'acrylamide de macromonomères d'acrylate de dodécyle

Graft copolymers of well-defined structure and composition were prepared by radical copolymerization of acrylamide and poly(dodecyl acrylate) macromonomers. The macromonomers were prepared by telomerization of dodecyl acrylate in the presence of 2-mercaptoethanol as a transfer agent, followed by reaction with acryloyl chloride. Poly(dodecyl acrylate) macromonomers with M _n = 1100, 1100, 2200 and 4600 were synthesized. The kinetics of the radical telomerization of dodecyl acrylate with 2-mercaptoethanol and AIBN was studied at 66°C in THF. Under these conditions we obtained the transfer constant C_T = 0,9. The graft copolymerization of acrylamide with the poly(dodecyl acrylate) macromonomer was carried out in the presence of the transfer agent C₆F₁₃C₂H₄SH. If C₀ = [AIBN]/[Acrylamide] = 0,01 and R₀ = [C₆F₁₃C₂H₄SH]/[Acrylamide] = 0,01, for acrylamide a DP _n = 160 was obtained in all cases, for the macromonomer of M _n = 1100 a DP _n = 2,5, and for the macromonomer of M _n > 1100 a DP_n = 1.     

Synthèse de cotélomères photoréticulables, 6. Utilisation de cotélomères biséquencés

Photocrosslinkable block cotelomers were synthesized in three steps. In the first step a monomer M₁ was telomerized with carbon tetrachloride or chloroform, in the second step a monomer M₂ with the resulting macrotelogen, and in the third step the hydroxyl groups were esterified by cinnamic acid or acrylic acid. These reactions were carried out with ethyl acrylate (M₁)/CCl₄ by redox catalysis and subsequently with vinyl acetate (M₂) by free radical initiation, or with vinyl acetate (M₁)/CHCl₃ by free radical initiation and subsequently with isoprene (M₂) by redox catalysis, or with 2-hydroxyethyl acrylate (M₁)/CCl₄ by redox catalysis, and subsequently with isoprene (M₂) by redox catalysis.     

Synthèse et transformations chimiques des télomères de l'undécène-10 oate de méthyle, 1

Redox of radical telomerizations of methyl 10-undecenoate (1) with different telogens such as CCl₄, CCl₃Br, CCl₃CF₃, HPO (OEt)P₂ or different adducts of CCI₄, on vinylidene chloride and chlorotrifluoroethylene, were studied. Chemical transformation of the end of the chains led to the corresponding difunctional compounds. Starting with these last compounds, polycondensation reactions were carried out.     

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.     

Recherche de télomères à activité pharmacologique potentielle, 2. Télomères de l'acide acrylique et greffage de composés hydroxylés

Several telomers of acrylic acid with carbone tetrachloride were prepared. Their average degree of polymerization, which was between 10 and 50, was determined by several analytical methods (elemental analysis, viscosimetry, and GPC). From the kinetic equations of telomerization a relation between DP _n of these telomers and the experimental conditions is established. Fixation of hydroxylic compounds through direct esterification was studied and it was found that the prepared telomers can be used as hydrosoluble carriers for drugs containing primary alcohol or phenol functions.     

Application de la réaction de métathèse à la synthèse de prépolymères α,ω-bifonctionnels, 2. Etude de possibilitiés d'application à la synthèse de prépolymères α,ω-dichlorés

The capability of chloroalkenes to undergo cometathesis with alkenes was investigated with the intention to check the possibility of applying the principle of the synthesis of α,omega;-difunctional polybutadienes to α,omega;-dichloropolybutadienes. The results obtained from the analysis of the reaction products resulting from 1,6-dichloro-3-hexene ( 1 )/4-octene ( 2 ) systems and WCl₆/EtAlCl₂ were compared with those obtained from 1-chloro-3-hexene ( 8 ) alone, 1 /1,5-cyclooctadiène ( 13 ), 5-chloro-1-pentene ( 6 )/ 2 , and 1,4-dichloro-2-butene ( 10 )/ 2 systems in the presence of WCl₆/EtAlCl₂. It was found that it is possible to apply the synthetic principle to α,omega;-bis-(δ-chloroalkenyl)polybutadienes.     

Télomères monofonctionnels du chlorure de vinyle, 2. Cinétique par amorçage radicalaire

Radical telomerizations of vinyl chloride with telogens R? CCl₃, containing alcohol and acid functions in the R group, were carried out. The molecular weights of the obtained products are between 1000 and 10 000. Transfer constants (C_T) were calculated for each case by studying the DP_n (10 to 50) variation as a function of the mole ratio (R) of telogen to monomer. In addition, the functionality of the resulting poly(vinyl chloride) was evaluated from the values of C_T and R.     

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.     

Oligo(thiophénylènes-1,4) α,ω-difonctionnalisés, 3. Oligomères α,ω-diaminés et copolyamides qui en dérivent

Polyamides 7a and 7b were prepared from α-(4-aminophenyl)-ω-aminopoly(thio-1,4-phenylene)s (3a) by reaction with 1,12-dodecanedioic acid (6) , tribloc copolymers 9 from 3a and 11 aminoundecanoic acid (8) , and multibloc copolymers 10 from 3a, 6 , and 8 . The properties of these copolymers were studied by DSC and compared with those of N, N'-lauroyl derivatives of 3a as model compounds. Phase separations were observed with products containing at least four phenylene units in the thiophenylene blocs. However, the T_g was found to increase with increasing number of phenylene units.     

Synthèse de composées photoréticulables, 7. Télomères des acides acrylique et méthacrylique gréffés par méthacrylate d'époxy-2,3 propyle

Telomers were prepared from acrylic or methacrylic acid and CCl₃Br, C₁₂H₂₅SH, C₁₈H₃₇SH or C₈F₁₇C₂H₄SH by initiation with 2,2'-azoisobutyronitrile. The transfer constant of CCl₃Br and the thiols, which are about 0,03 and 0,5, respectively, were determined. These telomers were used as supports of photopolymerizable functions, which were introduced by grafting of 2,3-epoxypropyl methacrylate, catalysed with dodecyldimethylamine. The reactions were followed by ¹H NMR, elemental analyses, tonometrie, and especially by GPC and titration of the acid functions. The grafting telomers, holding many acrylic functions which react upon UV and electron irradiation, give photoreticulated varnish coatings with very interesting properties.     

Cinétiques de télomérisation, 7. Calcul de k/kTe en polymérisation radicalaire de divers monomères

In contrast to the usual method of determination of the principle ratio in radical polymerization, k/k_Te, which is based on the comparison of the rate of polymerization with the concentration of initiator, a method was used consisting in the representation of log_e([M]₀/[M]) versus (1 ? e^?kd^t/2). The results obtained with styrene, vinyl acetate, acrylic acid, methacrylic acid, and 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorooctyl acrylate ( 1 ) were found to be in good agreement with those already obtained by the other method.     

Polymères porteurs de dérivés du glycérol, 1. Polymérisation du méthacrylate d'époxy-2,3 propyle et du méthacrylate-phényl-2 butyrate d'hydroxy-2 triméthylène

Radical polymerizations and copolymerizations of 2,3-epoxypropyl methacrylate ( 1 ) and its reaction product with 2-phenylbutyric acid ( 2 ), 2-hydroxytrimethylene methacrylate 2-phenylbutyrate ( 3 ), were studied using 2,2′-azodiisobutyronitrile, benzoyl peroxide, or H₂O₂ (with UV irradiation) as initiators, and also the influence of the experimental conditions (temperature, concentration, time) on the yield. Due to the reactivity of the oxirane moiety, poly(2,3-epoxy-propyl methacrylate) can easily be modified by ring opening reactions, e.g. with carboxylic acids.     

Über die polymerisation des 2-chlor-2-oxo-1.3.2-dioxaphospholans

Polymerization by ringopening of 2-chloro-2-oxo-1.3.2-dioxaphospholane ( I ) may lead to polymers of two different structures: (i) a polymeric acid chloride possessing a polyester structure of the main chain ( II ) and ( ii ) a β-chloroethyl ester of polyphosphoric acid, i.e. a polymer with a pure inorganic main chain ( III ). I is transformed into a polymer with a t least 90% of structure I11 and with at most 10% of structure I1 by heating or more rapid by and under more gentle conditions with various catalysts (e.g. NaF, AlCl₃, N(CH₃)₄Cl, tetraphenylphosphonium salts, triphenyl-phosphine, triphenylphosphine oxide). The product is branched and crosslinked. Kinetic measurements show that the spontaneous polymerization follows another mechanism than the catalytic reaction. The results are compatible with the assumption that the pure thermal reaction proceeds by successive independent steps, whereas the catalytic process advances via an ionic chain reaction. The effect of the various catalytic active substances consists in the direct or indirect production of chloride ions, which are on their part the real catalytic species.     

Application de la réaction de métathèse à la synthèse de prépolymères α,ω-bifonctionnels. 1: Cométathèse entre le cyclooctadiène-1,5 et l'hexène-3 dioate de diméthyle

α,ω-Dimethoxycarbonyl substituted polyenes were synthesized by co-metathesis between 1,5-cyclooctadiene ( 1 ) and dimethyl 3-hexenedioate ( 2 ) by use of the catalytic system WCl₆/Sn(CH₃)₄. The ability of 2 for co-metathesis with 1 was proved by determination of the distribution of low molecular weight products in terms of reaction time and 2/1 mole ratio. For these studies, high values of 2/1 ratios (0,5–4) were chosen in order to obtain lowest molecular weight co-metathesis products ( 3b–3e ). Metathesis involved preferentially the double bonds in the neighbourhood of the ester groups. At lower values of the 2/1 ratio (0,012–0,061) α,ω-difunctional prepolymers ( 3i ) were synthesized.     

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.     

Etude de la réaction de télomérisation d'un monomère tensioactif anionique

The synthesis of a new anionic polymerizable surfactant is described. It is obtained by reaction between methacryloyl chloride and 5-phenyl-1-pentanol. In a last step, the aromatic group is alkylated with succinic anhydride in order to obtain an ionic group. All products were characterized by ¹H nuclear magnetic resonance and the transfer constant C_T with C₈H₁₇C₂H₄SH and the ratio k_p²/k_t were determined. C_T is in agreement with that of classical acrylates whereas k_p²/k_t is lower because of the long methacryloyl chain which reduces the propagation rate.     

Oligomérisation anionique de l'éthylène, 5. Fonctionalisation des oligomères vivants par action directe de l'oxygène

Living oligomers of ethylene obtained by sec-butyllithium complexed with tetramethylethylenediamine (TMEDA) were deactived by oxygen. NMR and mass spectrometry, coupled with gas chromatography of the resulting product allowed us to follow the influence of TMEDA towards functionalization. The two products were characterized. Apparently the ratio [TMEDA]/[sec-BuLi] does not seem to influence the functionalization reaction.     

Recherche de télomères à activité pharmacologique potentielle, 4. Réactions sur les télomères de l'alcool vinylique

Chlorides of carboxylic acids were grafted on telomers of vinyl alcohol. The yields of grafting were improved by increasing the temperature and the concentration of the reactants. In the range investigated, they do not depend on the DP_n of the telomers, nor on the stoichiometric rates of the reactants. Therefore, the grafting rates are directly related to the initial conditions of the reaction. Modification of the telomers by treatment with ethylene oxide provides more soluble substances, but it does not affect the behaviour of the telomers in grafting reactions. Grafting of 1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolacetic acid ( 9 ) (indomethacin), an antiinflammatory drug, leads to potentially pharmacologically active telomers.     

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.