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.     

Synthesis of polymers containing pseudohalide groups by cationic polymerization, 3. Preliminary study of the polymerization and copolymerization of alkenyl monomers containing azide groups

The cationic polymerization or copolymerization of various alkenyl monomers was investigated in the presence of azide groups. The monomers were either of the n-π-donor type, such as vinyl ethers, or π-donors, such as isobutene (2-methylpropene) or styrene. The azide groups were introduced by a suitable comonomer, such as 2-azidoethyl vinyl ether (AEVE) or 4-azidomethyl-styrene (AMS). The initiator was TiCl₄. 3-Azido-2-methyl-1-propene (AMP) (methallyl azide) revealed to be not polymerizable. In the case of vinyl ethers, their cationic polymerization in the presence of azide groups requires high Lewis acid concentrations, according to the work previously carried out on oxetanes. In the case of the less nucleophilic monomers styrene and isobutene it was shown that cationic polymerization takes place provided that the initiator concentration is equal or higher than that of the azide group. This effect was assigned to a complexation between the Lewis acid and the azide group, and consequently the more nucleophilic the monomers (heterocyclics or vinyl ethers) are the lower the required Lewis acid concentration to observe cationic polymerization. Some evidence was found showing that the isobutene polymerization carried out in the presence of a molecular containing an azide group results in an azido-endcapped polyisobutene while in the case of styrene and vinyl ethers cationic copolymerization with comonomers containing azide groups was observed.     

Epoxydation de copolymères triséquencés styrène-isoprene-styrène par l'acide monoperoxyphtalique

Styrene isoprene styrene copolymers (SIS) modified by epoxidizing were investigated in order to obtain adhesive materials. Influences of experimental parameters (concentrations, solvents, compositions of SIS) are shown for epoxidation with monoperoxyphtalic acid at a yield of modification lower than 50%.     

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 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.     

Poly{[(Chloro-2 éathyl)-4 phéanyl]-1 éathylène}: Synthèse,caractérisations,dégradation thermique et modifications chimiques

Poly{1-[4-(2-chloroethyl)phenyl]ethylene} ( 3 ) was synthesized by bulk polymerization of 4-(2-chloroethyl)styrene ( 6 ) in two steps from commercial products. The polymer was characterized by means of GPC (weight-average molecular weight M?_w = 85 000 and number-average molecular weight M?_n = 63 500), ¹H NMR and ¹³C NMR spectroscopy. The first stage of thermal degradation begins at 290°C and ends at about 410°C. The overall activation energy was calculated to be 43 kcal · mol^?1 (180 kJ · mol^?1). The solid residue was crosslinked and insoluble. The volatile products, identified by gas chromatography-mass spectroscopy (GC-MS), were chiefly hydrogen chloride, dichloromethane and monomer. In a strongly basic medium, nucleophilic substitution of chlorine was achieved without elimination.     

Nouveaux copolymères alternés préparés à partir du dicyanure de propène-1 ylidène-1 avec le styrène et la vinyl-1 pyrrolidone-2

A trisubstituted ethylene, 1-propene-1-ylidene dicyanate has been prepared via Knoevenagel reaction of acetaldehyde and malonitrile with β-alanine as a catalyst. This product has been copolymerized in bulk — with 2,2′-azoisobutyronitrile as an initiator — with styrene and 1-vinyl-2-pyrrolidone. Preliminary ¹H and ¹³C NMR studies of the copolymers are in good agreement with an alternating structure besides minor proportions of homopolymers of styrene or 1-vinyl-2-pyrrolidone. The propagation mechanism has also been studied with ¹H-¹H correlation spectroscopy.     

Polymérisation et copolymérisation d'acétoxy-2 alcadiène-1,3: L'acétate de (cyclohexène-1 yle)-1 vinyle. Synthèse d'une δ-polycétone

1-(1-Cyclohexenyl)vinyl acetate ( 1c ) was polymerized in bulk under radical conditions. The homopolymers consist only of 1,4-units ( 4 ) which can be hydrolysed into δ-polyketone. Reactivity ratios in radical copolymerization with styrene and acrylic comonomers were determined. The photochemical degradation of the copolymer with styrene was studied in solution.     

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.     

Über polymere koronanden auf der basis von 18-krone-6 enthaltenden vinylmonomeren

Vinyl group containing derivatives of 18-crown-6 were synthesized and copolymerized with styrene and p-divinylbenzene of p-divinylbiphenyl. The selectivity of the alkali metal cation complexation of one of the polymers was investigated. The prepared polymers were applied as catalysts in several nucleophilic substitution reactions. The influence of the crosslinking agent as well as the degree of crosslinking on the catalytic activity of the polymers was studied.     

IUPAC. International symposium on macromolecules,Helsinki, Finland,July 2.–8. 1972

The radical copolymerizations of ethyl vinyl sulfoxide (EVSO) with various vinyl monomers were investigated. The copolymerizations of EVSO with styrene, methyl methacrylate and acrylonitrile gave copolymers having minor amounts of EVSO. Vinyl chloride and vinyl acetate, however, did not give any homopolymer and copolymer. From the copolymerization with styrene, EVSO was evaluated as an electron-accepting and non-conjugative monomer: Q = 0.13 and e = 0.61. The effects of LEWIS acids (LiCl, ZnCl₂) and proton donors (phenols, alcohols) on the monomer reactivity of EVSO were also investigated. These additives were found to enhance the monomer reactivity of EVSO. From the spectroscopic studies, it was concluded that the rate enhancement in monomer reactivity was attributable to the formation of a complex or to a hydrogen bond formation between the EVSO monomer and these additives.     

Étude du pouvior émulsifiant des copolymères séquencés polystyrène/chlorure de polyvinyl-2 pyridinium et polyisoprène/chlorure de polyvinyl-2 pyridinium

The emulsifying effect of polystyrene/poly(2-vinylpyridinium chloride) and polyisoprene/poly(2-vinylpyridinium chloride) block copolymers has been intensively studied. It has been shown that, in the presence of two non-miscible liquids, each of them being a selective solvent of one of the blocks, it is possible to obtain oil in water or water in oil emulsions, depending upon the molecular characteristics of the copolymers. More precisely, in the case of copolymers with high 2-vinylpyridinium chloride content, only oil in water emulsions have been obtained, whereas in the case of copolymers with a high styrene (or isoprene) content water in oil emulsions have been preferentially obtained.     

Préparation de polystyrène de masse éalevée à chaîcne aliphatique ou noyaux aromatiques deuteriés

Isotopically substituted styrene, (phenyl-²H₅) styrene ( 3 ), and selectively labled styrene, [alpha;, beta;-²H₂] styrene ( 6 ), were prepared by the classical two step synthesis, starting with the correspondingly labeled compounds. By anionic polymerization in an inert atmosphere labeled high molecular weight polystyrences 10 and 11 were prepared.     

Étude de la polymérisation du styrène en émulsion inverse

The polymerization of reversed emulsions water in styrene prepared with polystyrene-polyethyleneoxide block copolymers (Cop PS-POE) has been studied. The kinetics of this polymerization has been studied as a function of the parameters: type and concentration of initiator, phase ratio water/styrene, concentration of Cop PS-POE, molecular characteristics of Cop PS-POE. The type of the emulsion can be regulated by the characteristics of the Cop PS-POE and by the phase ratio water/styrene. The initiation of the polymerizations can be achieved by water soluble initiators (K₂S₂O₈). Correlations could be established between the rate of polymerization and the initiator concentration, the amount of water in the reversed emulsions and the concentration of Cop PS-POE. It was shown furthermore that the rate of polymerization increases with the POE content of two-block copolymers and that three-block copolymers are more appropriate for the polymerization in reversed emulsions. Finally the main influence of the water/styrene interface was demonstrated which regulates the transfer of radicals from the aqueous into the organic phase.     

Approche de la microstructure d'une résine copolymère de monomères vinyliques et diéniques

The present work deals with a general framework of the kinetics and the microstructure (sequence distribution of monomeric units, network parameters…) of resins constituted of vinyl and diene monomers based on the theory of Markov chain propagation. As a matter of example, calculations were applied to the copolymerization of styrene with p- and m-divinylbenzene.     

Dégradation photochimique de polymères cétoniques, 2. Etude sur modèles de la photodégradation de copolymères cétoniques à groupes carbonyles en chaǐne

Three linear phenyl ketones, 4-methyl-1,7-diphenyl-3-heptanone ( 6a ), 2,8-diphenyl-4-nonanone ( 6b ), and 5-methyl-2,8-diphenyl-4-nonanone ( 6c ), and four cyclic ketones, 1-phenethyl-2-(3-phenylpropionyl)cyclopentane ( 4a ), 1-(3-phenylbutyryl)-2-(2-phenylpropyl)cyclopentane ( 4b ) and their cyclohexane homologues ( 5a and 5b ), were synthesized as models of styrene copolymers bearing carbonyl groups in the chain, and their photochemical degradation was studied in various solvants at wavelengths > 280 nm. This study has shown that both Norrish mechanisms, i.e., the type I scission in α-position of the carbonyl and the type II photoelimination, which occur with the models, take place in a similar fashion with the copolymers. The relative part and the efficiency of each photodegradation depend on the solvent, the linear or cyclic character of the chain, as well as on the substitution. Photodegradation studies of the models have also allowed us to explain the photochemical behaviour of the particular copolymers and especially the faster fragmentation of linear chains, and to elucidate the mechanisms involved in the degradation of these polymers.     

Polymerisationsauslösung mit substituierten ethanen, 8. Polymerisation von styrol

The free radical polymerization of styrene initiated by 1,1,2,2-tetraphenyl-1,2-diphenoxyethane (TPPA) can be described as a kind of dead end polymerization. At the beginning of the polymerization, mainly oligomers are formed by primary radical chain termination. These oligomers can be characterized by thin layer and gel permeation chromatography and by mass spectroscopy. With increasing conversion and decreasing initiator concentration the molecular weight of the polymers is increasing. Contrary to the polymerization of methyl methacrylate with the same initiator, in the case of styrene the formed oligomers are not able to initiate once more the polymerization because the end groups formed by initiator radicals and styrene units are rather stable at normal polymerization temperatures (60 – 100°C).     

Amorceurs radicalaires fonctionnels, 2. Macroinitiateurs à partir de l'α-hydrogeno-ω-hydroxypoly(oxyéthylène) et des acides tert-butyldioxycarbonylbenzoïques

Modified polystyrenes were obtained by free radical polymerization of styrene using the macroinitiators α-tert-butyldioxyterephthaloyl(or phthaloyl)-ωtert-butyldioxyterephthaloyl(or phthaloyl)poly(oxyethylene) ( 3 and 4 ), which were synthetized. To examine the stability of such compounds, thermolysis kinetics of model compounds, OO-tert-butyl O-methyl monoperoxyphthalate ( 6 ) and terephthalate ( 7 ) were studied by differential scanning enthalpimetry. Suspension polymerization of styrene applying the industrial method, showed that the macroinitiator is able to initiate the process. A polystyrene containing up to 4% by weight oxyethylene units was obtained.     

Nature des espèces «vivantes» en polymérisation anionique des diènes conjugués

The nature of “living” propagating species in the anionic polymerization of conjugated dienes was studied by nuclear magnetic resonance. A judicious choice of monomers affords a glimpse of electronic and steric effects on the observed structures. It is shown that the “living” oligomers contain only 4,1 and/or 1,4 (cis and trans) structures, and that the active species can be described by a delocalized π-allyl structure. Association seems to be the fundamental point in the mechanism of the reaction of the initiator with the diene. The internal association of the lithium organic compound disappears or alters to an external association with any electron donating agent. The nucleophilic function can also be taken by the diene itself. A mechanism is proposed based on the concept of association.     

Le poly(α-acétoxystyrène) et les copolymères de l'α-acétoxystyrène avec le styrène et styrènes substitués obtenus par polymérisation thermique. Etude de la microstructure et de la stabilité thermique des polymères

The microstructure of poly(α-acetoxystyrene), prepared from α-acetoxystyrene by bulk thermal polymerization, was studied by ¹H and ¹³C NMR spectroscopy. Anomalies observed in the NMR spectra could be ascribed to fragmentations with formation of benzoxy and acetoxy radicals followed by re-initiation. The thermal degradation of the polymer, resulting in the formation of polyphenylacetylene, rules out certain types of transfer. α-Acetoxystyrene was copolymerized with styrene or substituted styrenes and the NMR study (¹H and ¹³C) was limited to α-acetoxystyrene. The composition of the copolymer could be ascertained by means of the resonances of the quaternary carbons of the aromatic cycle. The copolymers were characterized by viscometry, GPC, and thermal degradation. Their compositions, except that of poly(α-acetoxystyrene-co-styrene) were determined by elemental analysis.