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Polyurethanes (PUs) were prepared by condensation of isophorone diisocyanate and polypropylene glycol (PPG) using butane diol as a chain extender. Methoxy or methacrylic endgroups of PUs were obtained upon reacting the residual isocyanate group (NCO) moiety with either methanol or hydroxyethylmethacrylate (HEMA). The resulted PUs were dissolved in mixtures of acrylic monomers, and then the miniemulsion polymerization was conducted. These PUs were quite efficient hydrophobes for polyurethane (PU)-acrylate hybrid miniemulsion polymerization. It was also demonstrated from the results of differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) that the microphase separation of soft and hard phase of PUs in hybrid latexes was more significant than that of original PUs. The PU containing the methacrylic endgroup was almost fully cross-linked during miniemulsion polymerization, resulting in less hard–hard segment of PU hydrogen bond in the hybrid polymer. Some specific morphologies were also discussed from transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The mechanical properties of these films were studied from the strain–stress curves. Copyright © 2008 John Wiley & Sons, Ltd.

The styrene-acrylonitrile radical copolymerization kinetics have been studied for polymerizations carried out in two different solvents, toluene and dimethylformamide (DMF), in the whole range of monomer mixture compositions and at various dilutions. The copolymer prepared in toluene solutions are poorer in acrylonitrile than those prepared in bulk. The reverse situation is observed in DMF solution, where the polymerization rate is the highest. In the latter case, also for acrylonitrile rich mixtures, the relative polymerization rate of styrene tends to increase with conversion; this effect is attributed to preferential solvation of styrene. Possible explanation of these facts are briefly discussed.

A sample of poly(vinyl chloride) having a very good thermal stability and a high initial crystallinity was annealed between 80 and 260°C, either as it was or mixed with stabilizers, in sealed ampoules or in KBr pellets, and studied by X-ray and IR techniques. When the sample is treated in glass ampoules, practically no changes in IR spectra are observed up to 240°C; the X-ray diagrams, however, show an increase in the size of the crystallites but no increase in the amount of crystalline material. The melting point is observed by X-ray between 250 and 260°C. If the sample is heated in the KBr pellets, it undergoes some stress which causes an increase of the crystalline IR bands at 604 and 635 cm−1, but no change in the X-ray diagram. At higher temperatures, dehydrochlorination is enhanced by the KBr and involves chiefly the amorphous regions.

The earlier results concerning the kinetics of polymerization and initiator consumption, molecular weight distribution, and the nature of the chain ends in the polymerization of vinyl chloride initiated by tert-butylmagnesium chloride (tBuMgCl) in tetrahydrofuran and other solvents are rediscussed in terms of the simultaneous participation of an ionic mechanism and a radical mechanism. The former is operative mainly at the beginning of the process and gives very low molecular weight products. The latter is responsible for the formation of the high polymer. The radicals are generated from the organomagnesium compound giving a tert-butyl group as a chain end for every macromolecule. New experiments support the radical mechanism: comparison with radical polymerizations in the same conditions of temperature and solvent medium, inhibition by NO, copolymerization with vinylidene chloride. Also the high polymer is not obtained if the ionic mechanism is exalted by introduction of a powerful solvating agent, the dimethoxyethane.

Two kinds of hybrid acrylic–polyurethane (PUA) latexes are compared according to their synthesis and properties. The acrylic part is a copolymer of styrene, methyl methacrylate, and butyl acrylate. The PUAs are based on the polycondensation of isophorone diisocyanate and poly(propylene glycol) using butanediol and ethylene diamine as chain extenders. The first class result from the polymerization of miniemulsions of solutions of PU in the mixture of monomers using benzoyl peroxide as an initiator at 80°C. In the second class PUs modified by neutralized dimethylolpropionic acid are used as seeds and emulsifiers for emulsion polymerization of the monomer mixtures initiated with azobisisobutyronitrile at 75°C. The polymerization kinetics are compared, as well as the morphology of the latex particles. Films are obtained upon coalescence of these latexes, and the surface composition of these films and their tensile properties are studied. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3927–3941, 2006

Polyurethanes were prepared from reaction of isophorone diisocyanate (IPDI) with polypropylene glycol (PPG), with chain extension with butanediol (BDO). Their end groups are either methoxy, or methacrylic groups. These polyurethanes (PUs) are dissolved in mixtures of acrylic monomers (methylmethacrylate, MMA, and butylacrylate, BA). The solutions are sonicated to produce miniemulsion droplets, using sodium dodecyl sulfate (SDS) as surfactant, the PU being the hydrophobe. These miniemulsions were polymerized, with an oil-soluble peroxide initiator. Those latexes with methoxy end groups in the PU are fully soluble, while those containing the acrylic end groups are almost fully crosslinked, but can easily form smooth films. The mechanical properties of these films were studied from their stress–strain curves, and compared with those films formed from the uncrosslinked hybrid latexes. Copyright © 2005 John Wiley & Sons, Ltd.

A rigid polyimide (PI) was dissolved in acrylic monomers (methyl methacrylate, n-butyl acrylate) as a hydrophobe to form miniemulsions stabilized by a mixture of sodium dodecyl sulfate and Triton®, with droplets size in the range 100–300 nm, and PI concentration up to about 30% by weight, which corresponds to its limit of solubility. Upon polymerization initiated with ammonium persulfate, the particle size tends to decrease to the range 80–250 nm. From these hybrid latexes, clear yellowish films were obtained with two glass transitions: one close to that of polybutylacrylate (Tg = −50 °C) and the second between 15 and 40 °C, depending on PI concentration. PI causes a reinforcement of the mechanical properties at room temperature. This reinforcement is enhanced through an appropriate thermal treatment. Copyright © 2004 Society of Chemical Industry

We carried out the suspension polymerization of styrene, initiated with benzoyl peroxide at 80°C, in the presence of the simultaneous polymerization of acrylic acid in the water phase, initiated by potassium peroxidisulfate (KPS) at the same temperature. The polymerization in the water phase was started at certain times after the beginning of the polymerization of styrene. Then, a continuous addition of KPS was carried out at a given landing rate and during variable feeding times. The water-phase polymerization actually produced a copolymer of styrene and acrylic acid, which displayed surface-active properties. The particle size distribution depended on the variables mentioned earlier (starting time, KPS feeding rate, and addition time), being controlled by the molecular weight, and on the composition of the copolymer produced and its availability at the increasing conversion of styrene. A second distribution of submicronic particles was produced. Both families of particles had about the same molecular weight. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3271–3285, 2002

Emulsion Polymerization was carried out in the presence of inorganic pigments such as TiO2, black FexOy, yellow FexOy, and red FexOy, and NP 30 as surfactants, and water soluble AZO compounds or KPS as initiator. Monomers with specific hydrogen bonding interaction must be used in the initial steps of polymerisation, methylmethacrylate and vinylacetate being the most convenient. Then a semi continuous feed of a mixture of monomers was carried out in starved conditions. In order to make the covered pigments water-redispersible a mixture of hydrophobic and hydrophilic monomers should be chosen with proper pH conditions. The amount of surfactant has to be chosen so that no agglomeration of the covered pigments take place. The covered pigments were dried upon lyophylisation, then formulation of powder paints was carried out using commercial powder binders and other additives. Good properties of the paints, such as brightness were obtained in that way.

In the context of a European union-supported network on “Reactive Surfactants for Heterophase Polymerization,” different polymerizable surfactants (surfmers) have been synthesized and engaged in the emulsion polymerization of styrene, butyl acrylate, and acrylic acid. The thermomechanical properties of films cast from these different latices are reported in this article. The evolution of the mechanical properties with temperature and the effect of water molecules on these properties are studied. We observed that the studied surfactants do not influence the properties of the dry films. However, some differences due to grafting of reactive surfactants appeared when the films were wet. The amount of water uptake is drastically decreased when only reactive surfactants are present in the film. Concerning the mechanical behavior of the wet films, a decrease of the plastic flow stress is observed for all the samples whatever the nature of the surfactant (reactive or conventional). Hence, calorimetric measurements and dynamic mechanical analysis are used to identify the possible mechanisms that induce the change in the mechanical behavior of the latex films. In the case of reactive surfactant grafted to the polymer, the very low value of water uptake is accompanied by a plasticization of the polymer. In contrast, no plasticizing effect is observed in the case of nonreactive surfactant, even if the amount of water is very large. Finally, the tensile behavior of the styrene–butyl acrylate copolymer versus temperature is analyzed in the frame of the quasi point defects (qpd) model. Both rubber elasticity and chain orientation effects are taken into account to describe the behavior laws at large extensions (i.e., ϵ ≈ 1.2). © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1686–1700, 2002; DOI 10.1002/app.10548

A new means of producing high solids content latices with low viscosity is presented. The replacement of water-soluble initiators that decompose to give charged free radicals is shown to perturb the stability of highly concentrated latices. Their replacement by an oil-soluble initiator during particle growth, then by an activated, water-soluble system to remove residual monomer has been shown to help significantly reduce the number of stable particles generated by homogeneous nucleation. Latices with 73% (v/v) solids have been produced with a bimodal particle size distribution (PSD) consisting of 900 and 110 nm particles. The viscosity of these latices can be as low as 300 mPa s−1 at 20 s−1. Despite the presence of water-soluble monomers, excellent control over the evolution of the PSD allows one to obtain highly reproducible results. In addition, latices produced with the new initiator system have a much lower water uptake and their viscosity is much less sensitive to changes in pH than is the case for latices produced using standard emulsion polymerization techniques. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 1935–1948, 2002; DOI 10.1002/app.10514

In the synthesis of latexes for use in waterborne coatings, the benefits of using reactive surfactants are now well known. Improvements are obtained in the stability of the latexes, due to the fact that they are not desorbed from the particle surface. The film properties are also better, chiefly if the films are exposed to humidity, where the water rebound is decreased significantly. This lecture summarises some recent progress obtained in that field through a European programme, including the participation of 10 academic and industrial laboratories. Four topics are considered. The first one is dealt with a series of anionic surmers (polymerizable surfactants) prepared upon reacting a polymerisable alcohol with either maleic, or succinic, or sulfosuccinic anhydride. One of these products, resulting from the addition of Hydroxyethylmethacrylate on maleic anhydride is now available commercially. From maleic anhydride one get bifunctional surfmers with 2 polymerisable groups, while the two other anhydride lead to monofunctional surfiners. All these products are engaged in seeded core-shell polymerisations, resulting in film-forming latexes quite stable during and after the polymerisation. However, because they are simply anionic, they do not provide steric stabilization and the latexes flocculate upon addition of strong electrolytes or in freezing tests, except if they are engaged in miniemulsion polymerisations initiated with KPS. The second topic is concerned with a series of nonionic block copolymer surfmers. A hydrophilic sequence of ethylene oxide units, produced upon ring opening living anionic polymerisation, is followed by a hydrophobic sequence of propyleneoxide, and the living polymer is killed with a polymerisable group attached on a reactive halogen atom. A variety of polymerisable groups have been used: styrenic, methacrylic, vinylic, allylic and maleic. The HLB balance is controlled through the lentgh of the hydrophilic and hydrophobic sequences. The more reactive, associated with an adequate HLB balance allows to prepare core-shell latexes with an excellent steric stabilisation at solid contents up to 40%. It is not the case for the less reactive maleic or allylic, the behaviour of which is close to that of a non reactive surfactant with the same structure. Transurfs, with an addition-fragmentation mechanism, is the subject of the third topic. A first study was carried out by the group of Eindhoven, who produced a new surfactant on the basis of a MMA dimer condensed on a long chain bromoalcohol and then sulfonated. This transurf was engaged in a MMA emulsion polymerisation, and compared with SDS; the polymerisation rate was lower and the molecular weight was broader. Optimisation of the incorporation of the transurf was achieved upon using starved feed conditions. We have carried out styrene miniemulsion using controlled RAFT process with a surfactant belonging to the first family reported above together with a RAFT agent. Finally we have used a RAFT agent derived from the nonionic block copolymer surfactants. The last topic was done in cooperation with the group of the MPI in Golm, who have studied a family of reactive dienic polymeric surfactants able to be grafted onto the polymer particles from the residual double bonds. These polymeric surfactants are working by an electrostatic stabilization mechanism, being flat onto the particle surface.

Macromonomer with styrenic polymerizable group was synthetized by anionic polymerization of ethylene oxide initiated by potassium vinylbenzyl alcoholate, p-Vinylbenzyl-terminated polyoxyethylene macromonomer (PEO-VB) was then copolymerised with styrene in water/alcohol continuous phase. The resulting polymer is chiefly non soluble in that medium, and the final state is polymer particles in the range 500-1000 nm in diameter stabilized by a macromonomer-rich copolymer. The conversion time curve consists of three regions. The length of nucleation period was inversely proportional to the volume ratio ethanol/water (E/W). The dependence of the polymerization rate (Rp) vs. conversion is described by a curve with two-rate intervals. The rate of polymerization increased with increasing PEO-VB and initiator AIBN concentration but was nearly independent of the volume ratio E/W. The particle number slightly increased with increasing PEO-VB and AIBN concentration. The molecular weight of graft copolymer increased with increasing the volume fraction of water, PEO-VB and AIBN concentration.

A series of new anionic surfactants were prepared by reacting a polymerizable alcohol with either maleic or succinic anhydride, as well as sulfosuccinic anhydride, resulting in either bireactive or monoreactive surfactants, either carboxylated or sulfonated. The synthesis presented and the critical micelle concentration (CMC) determined. These compounds were engaged in the emulsion polymerization of styrene in batch and also in semi-batch seeded copolymerization producing core-shell latexes. The core was a polystyrene seed prepared using sodium dodecyl sulfate (SDS), thoroughly purified through ion exchange resins. The seed was then swollen overnight with a small amount of a 1 : 1 mixture of styrene and butyl acrylate, and finally fed with the same mixture together with the reactive surfactant. The amount of monomer was calculated so that, from a seed with a diameter of 100 nm, a core-shell latex of 150 nm was obtained. The amount of surfactant was such that a coverage of 80% was aimed for. The calculated solid content was 9%. Using 3.5 wt.-% of surfactant (versus monomer), the conversion reached about 90%, the floc being limited most often to less than 2%. The target diameter of the core-shell latex was nearly obtained. The latexes were stable only with limited amounts of added electrolytes and failed the test of freeze-thawing. About 40–50% of the surfactant were located on the surface.

This work is relative to attempts for obtaining acid-thiol supported polymers that may be used as solid bifunctional catalysts, active in the Bisphenol A synthesis. Five approaches are tested with modified sulphonic styrene-based polymers obtained either by multi-polymerisation in one or several steps and derivatization. The objective is to get simultaneously sufficient capacity and high selectivity, by using an adequate acid/thiol ratio, and enhanced sites accessibility via an optimisation of the morphology. Reactivity results are favourably compared to those obtained in a homogeneous process.

This study deals with the influence of a copolymerizable surfactant on the stability of lattices. Two main reactive surfactants, one anionic and one nonionic, both containing a reactive part issued from maleic anhydride, were engaged in seeded emulsion polymerizations of styrene-co-butyl acrylate-co-acrylic acid. The importance of the polymerization conditions clearly appears through the incorporation yield of the surfmers: When good conditions are used, this yield can be as high as 80%. Once stable lattices are synthesized, with a great incorporation of the surfactant, the stability of the colloid (against freeze–thawing cycles or in the presence of concentrated divalent electrolyte solutions) is then largely improved. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2768–2776, 2000

Polymerizable styrenic surfactants (surfmers) and nonreactive analogs, have been applied in emulsion copolymerization of acrylic monomers in a seeded semibatch process. Stable core-shell latexes with low levels of coagulum and controlled particle size have been obtained; some of them, with either steric or electrosteric stabilization, display excellent stability to electrolytes, freeze–thaw cycles, and shear flocculation. In addition, the reactive surfactants lead to films with superior performance due to reduced migration of surfactant to the surface (contact angle measurements) and dimensional stability when the films are dipped in water, as well as less water uptake. Some differences also appear in particle morphologies. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 4205–4217, 1999

Core–shell lattices with a polystyrene core and a polystyrene/butyl acrylate shell with more than 40% solid contents were produced using a combination of sodium dodecyl maleate hemiester as anionic surfactant and styrenic block copolymer of butylene oxide and ethylene oxide as nonionic surfactant. Stable lattices able to resist rather high concentrations of electrolytes can be obtained, provided a careful protocol of the addition of surfactants is used. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 2251–2262, 1999

Hemiesters and hemiamides of maleic acid with different chain lengths of the hydrophobic alkyl group (R = C8H17, C10H21, C12H25, C16H33) have been synthesized and used as surfactants in the emulsion polymerization of styrene and butyl acrylate. The same polymerization experiments were also carried out using nonreactive surfactants with an analogous succinic structure. The chemical structure of the surfactants was confirmed by 1H nuclear magnetic resonance. The melting point and critical micelle concentration of the reactive surfactants described herein were measured. All of the surfactants studied provided good stability of styrene/butyl acrylate latexes, when compared with a reference latex of a styrene/butyl acrylate copolymer prepared with a surfactant sodium dodecyl sulfate. The amount of surfactant grafted onto the particles of the final latex was estimated by conductimetric titration. Between 33 and 68% of surfactant used in emulsion polymerization was found on the surface of latex particles. Electrolyte addition at high concentration and freeze/thaw cycle cause flocculation of latexes. Copyright © 1999 John Wiley & Sons, Ltd.

This paper summarizes the work carried out during 3 years in a Network of the program "Human Capital and Mobility" of the European Union CHRX 93-0159 entitled "Reactive surfactants in heterophase polymerization for high performance polymers". A series of about 25 original papers will be published in the open literature under the general title of this feature article from Part I to Part XXV.The synthesis of selected surfactants either anionic or non ionic, and as well inisurfs (both initiators and surfactants), transurfs (both transfer agent and surfactants) or surfmers (both comonomers and surfactants) is shortly described. They were applied in emulsion polymerization and dispersion polymerization, and their behavior in shortly discussed. Finally films have been produced from a few of them, mainly from surfmer with maleic reactivity, and the main properties, and interests of such films are discussed.

Polymer lattices with a multimodal particle size distribution (PSD) polymer latex were prepared by introducing additional surfactants during the semicontinuous emulsion polymerization of styrene, butyl acrylate, and methacrylic acid. The polymerization was investigated by following the variation of the particle size, the size distribution, the number of particles, the Tg of the different particle sizes, and the total conversion at different steps of the polymerization process. The results show that bimodal and trimodal PSD polymer lattices can be obtained by this method and that the secondary generation of particles is greatly influenced by the nature and the amount of additional surfactants, as well as the moment when they are introduced. When the amount of additional surfactants is increased, the diameters of both the small and large particles decrease and the number of particles in each of the populations increases. Earlier introduction of these surfactants favors the generation and the growth of the small particles and thereby leads to a reduction of the relative fraction of large particles in the final latex. On introduction of 7 wt % of additional surfactants, based on the total monomers, 100% of the monomers of the second-stage polymerization were consumed to form the small particles. This fraction decreases with a decreasing amount of the additional surfactants. These results were further demonstrated by measuring the Tg's of both the large and the small particles of two lattices, in which the Tg's of the copolymers produced in each of the stages were different. High solid content (>65%), low viscosity, and coagulum-free lattices have been obtained through secondary nucleation, and a minimum in viscosity was found when the weight fraction of the large particles was around 80%. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 70: 2667–2677, 1998

A new strategy was developed for producing a polymer latex with trimodal particle size distribution by adding a second seed of polymer particles and some additional surfactants during polymerization. The polymerization was investigated by following the variation of the particle size, the size distribution, the number of particles, the surface tension and surfactant surface coverage at different stages of the polymerization process. The results showed that both the size and the size distribution can be easily controlled by varying the amount of additional surfactants and the second seed of polymer particles. The secondary nucleation was achieved when the surface coverage of particles was over 70%, and the amount of small particles formed increased with increasing amount of additional surfactants. The introduction of the additional surfactants had no significant effect on the size and number of middle particles, but reduced the size of large particles and caused the number of large particles to remain more stable because of the suppression of limited flocculation. Copyright © 1998 John Wiley & Sons, Ltd.

Dodecylhemiester of maleic anhydride is a very good anionic stabilizer for the emulsion polymerization of styrene. Rather high solid contents may be produced. Up to about 70% of the surfactant can be grafted onto the surface of the particles. Upon floculation with calcium salt, only 3% of the surfactant is left in the washing water. © 1997 John Wiley & Sons, Inc.1 J Appl Polym Sci 65: 2289–2296, 1997

SUMMARY Emulsion polymerization of ethyl acrylate was carried out in the presence of different kinds of functionalized and non-functionalized silica particles. 3-(Trimethoxysily1)propyl methacrylate, 2-hydroxyethyl methacrylate and 3-(triethoxysily1)propanethiol functionalization agents were examined. It is demonstrated that use of the first two coupling agents results latexes able to give films which display remarkable mechanical properties similar to those of vulcanized elastomers reinforced with solid particles. A qualitative model is then set up to give account for these properties. It is proposed that a part of the polymer is covalently bound to silica as tight loops, giving rise to a set of strong entanglements with the non-grafted polymer during film formation. This model is supported by stress-strain measurements. Some validation experiments are described using the third grafting agent of the series. ZUS AMMENFAS S UNG : Die Emulsionspolymerisation von Ethylacrylat wurde in Gegenwart verschiedener funktionalisierter und nicht funktionalisierter Siliziumdioxid-Teilchen durchgefiihrt. Als Funktionalisierungsagens dienten 3-(Trimethoxysilyl)propylmethacrylat, 2-Hydroxyethylmethacrylat und 3-(Triethoxysi1yl)propanthiol. Mit den beiden erstgenannten Agentien wurden latexartige Materialien erhalten, aus denen Filme mit bemerkenswerten mechanischen Eigenschaften, vergleichbar denen von vulkanisierten und mit Feststoffen verstiirkten Elastomeren, hergestellt werden konnten. Ein qualitatives Modell zur Erklarung dieses Verhaltens wird vorgestellt, nach dem Polymermolekiile in Form von engen Ringen kovalent an Siliziumdioxid-Teilchen gebunden sind und wahrend der Filmbildung starke Verschlaufungen mit den ungepfropften Polymermolekiilen bewirken. Dieses Modell wird durch Ergebnisse von Zug-Span

New heterogeneous catalytic systems for anionic ring opening polymerization of oxygenated heterocycles are obtained by grafting alkylaluminium moieties on porous silica. Adding alcohol in excess causes the formation of aluminium alkoxides and allows a rapid exchange reaction between the grafted active centers and the free alcohols remaining in the solution, so that more polymer molecules than the number of metal atoms used are produced. An interesting feature is the facility to obtain functionalized oligomers because these exchange reactions lead to polymer chains end-capped by moieties derived from the alcohol molecules. The kinetic behaviour was investigated for different monomer, alcohol and aluminium concentrations. An activation is observed for a well-defined alcohol concentration range which is interpreted in terms of the enhancement of the nucleophilic reactivity of the oxygen atom of the alkoxide due to the coordination of the free alcohol onto the active centers and the share of the acidic vacancy of the aluminium atom.

Two methods of analysis, potentiometry and capillary electrophoresis, were used to study the decomposition of potassium persulfate (KPS) in aqueous solutions. The experiments were carried out in a glass reactor equipped with continuous control of temperature and pH during the reaction. The effect of the pH on the decomposition of KPS was investigated. The rate of KPS decomposition in the presence of a variety of additives (surfactants, inhibitor, monomer-like molecules, and monomers), which are used in emulsion polymerization recipes, was also studied over the temperature range of interest. The rate of disappearance of the persulfate ion was greatly increased in the presence of hydroquinone, but changed very little in the presence of surfactants. © 1996 John Wiley & Sons, Inc.

Low-molecular-weight stat-poly(ethylene oxide-co-propylene oxide) polymers have been prepared anionically using a new heterogeneous catalytic process previously reported. They were fully characterized by 1H and 13C NMR spectroscopy in order to determine the distribution of the ethylene oxide (EO)-centered triads, as well as the average lengths of poly(ethylene oxide) (PEO) sequences. Low degrees of crystallization were determined by DSC. These copolymers have been successfully used for applications in the solid polymer electrolytes field and high levels of conductivity at room temperature have been measured. The results are in good agreement with those obtained from a Monte Carlo simulation method using the copolymerization terminal model developed for radical polymerization. Durch anionische Polymerisation nach einem bereits beschriebenen neuartigen heterogen-katalysierten Prozes wurden statistische Poly(ethylenoxid-co-propylen-oxid)-Copolymere mit niedrigen Molekulargewichten hergestellt. Die Copolymeren wurden mit 1H NMR-und 13C NMR-Spektroskopie charakterisiert, um zum einen die Verteilung der um eine Ethylenoxid-Gruppe gebildeten Triaden und zum anderen die durchschnittliche Lange der Poly(ethylenoxid)-Sequenzen zu bestimmen. DSC-Messungen ergaben niedrige Kristallisationsgrade. Die so erhaltenen Copolymeren wurden erfolgreich als polymere Feststoffelektrolyte eingesetzt und zeigen bei Raumtemperatur hohe Leitfahigkeitswerte. Die Ergebnisse stimmen gut mit den Resultaten einer unter Verwendung des fur die radikalische Polymerisation entwickelten Copolymerisations-Terminal-Modells durchgefuhrten Monte Carlo-Simulation uberein.

Polypropylene is the polymer with the fastest-growing usage rate, owing to its low price combined with properties that have been improved over recent years. However, because it does not carry any functional groups, it has little interaction with useful components of many systems, and it is difficult to paint. Recently, a certain number of attempts have been made to modify this polymer, either through direct copolymerization with reactive monomers, or after chemical modification of the polymer itself or some of its copolymers. The paper is a review of these different approaches, with emphasis on two points: (a) the new possibilities offered by the metallocene family of catalysts and (b), the work carried out in the author's laboratory, based on various functionalizations of copolymers of propylene and dienes.

Thiol-ended polyethylene oxide (I) has been prepared from the esterification of thioglycolic acid with monomethylether of polyoxyethylene glycol. Emulsion polymerization of styrene (and, in a few cases, methylmethacrylate as comonomer) was carried out in the presence of I using either water-soluble azo initiator or t-butylhydroperoxide. In the former case, bimodal particle size distribution was obtained while monodisperse latexes could be prepared in the latter case. Then a redox system was formed from I and t-BuOOH so that I was both an initiator and a transfer agent. Good steric stabilization of the latexes was observed. The polyethylene oxide sequence of I was partly incorporated at the surface of the latex particles, but the incorporation yield remained limited (between 7 and 18%). Most of the resdue of I remained in the serum.

Among the variety of possible structures for polymerizable surfactants, it seems clear that the most interesting should be those with the reactive group located in the hydrophobic part of the molecule. We report here a study based on such a surfactant. Its general formula is A set of surfactants has been produced with m varying from 23 to 48 and n = 6 or 12. The compounds have been characterised by 1H-NMR (nuclear magnetic resonance), size exclusion chromatography, surface tension measurements and turbidimetry. These surfactants have been copolymerized with styrene in emulsion polymerization. The coagulum is rather important, except if m is large enough. Although the incorporation of the surfactant in the latex is rather high. Most of the anchored surfactant remains at the surface and is not too buried inside. The particle size decreases with both the amount of surfactant and the length of its hydrophilic part. The use of these polymerizable surfactants leads to an excellent stability of the latex against the addition of electrolytes, and also against freeze-thawing constraints.

A precise description of the active site for heterogeneous stereospecific catalysts for propene polymerization has not been achieved, taking into account the effect of all the components of the catalytic system. A new model is proposed based on the following facts: the active Ti is directly bonded to the support MgCl2; it is bridged with an Al atom of the alkylaluminium; the latter is complexed with the external Lewis base; the more efficient Lewis bases are known to be dialkoxy dialkyl (or aryl) silane containing at least one bulky alkyl group; it is suggested that the two alkoxy groups are complexed, one with the aluminium atom, the second with the titanium atom. The structure of such a site has been built using a Chem 3D software and starting from an octahedral Ti and a bipyramidal Al. Both are bridged with the polymer chain. The silane is located so that each oxygen atom is just above each of the two metal atoms; the bulky alkyl group covers the vacancy of the Ti octahedre being in agostic interaction with the Ti. Such a tight geometry imposes the isospecific coordination of the monomers before its insertion in the polymer chain. The model is flexible enough to allow for the transition state, the insertion of the incoming monomer and the rotation of the new bridge, the driving force being the agostic interaction. The successful replacement of the silane with a diether with 3 carbons atoms in between the oxygen atoms is easily explained by the model, as well as the effect of the structure of the alkoxy and of the alkyl groups of the silane.

New heterogeneous catalysts for ring opening oligomerization are obtained by grafting alkyl aluminium moieties on silica. Adding alcohol in excess causes the formation of aluminium alkoxides and allows the catalytic mode, because of a rapid exchange reaction between the grafted active centers and the free alcohols present in the medium. All the polymer chains are end-capped by these alcohol molecules, which give functionalized oligomers.

The thermal conversion of poly(p-xylyidene tetrahydrothiophenium) chloride into polyparaphenylene vinylene has been studied by Fourier transform infrared spectroscopy (FT-IR), thermogravimetry, and HCl and tetrahydrothiophene analyses, in the temperature range 20–250°C. Using this system, almost complete elimination can be obtained after only 1 hr heating at 180°C. A side reaction, with the transient formation of C–Cl bond is observed during the heat treatment. After doping with oleum, a stable conductivity is obtained that is not very-sensitive to the elimination temperature.

Suspended emulsion is a new polymerization process in which a water phase containing the initiator is suspended in an organic phase containing the monomer; the polymer formed is insoluble in both the organic and water phase. The final morphology of the polymer is a powder of grains (around 100–300 microns) formed with agglomerates of primary particles (around 1 micron). This article describes the effects of small amounts of either suspending agents (water-soluble polymers) or surfactants. These effects concern mainly the morphology (grain and particle size), but also the polymerization kinetics. A rather homogeneous distribution of grains and particles inside the grain may be obtained by using a cellulosic polymer as the suspending agent and an anionic surfactant such as sodium dodecyl sulfate. © 1994 John Wiley & Sons, Inc.

Polypropylene ionomers have been prepared by sulfonation of copolymers of propene and 7 methyl, 1-6 octadiene, followed by neutralization to cesium salts. Both WAXS and SAXS were used to study the morphology of the samples, while their thermal properties were studied by DSC and their mechanical properties by DMTA. The sulfonation process is shown to cause a further drop in crystallinity in addition to the effect of comonomer incorporation. Ion clustering is observed when the extent of sulfonation is high enough, the limit being dependent on the copolymer composition. The ion pairs which are not incorporated into the cluster cause a small-angle upturn in the WAXS pattern. The mechanical properties are strongly affected by the drop in crystallinity, but may be partly recovered due to ion clustering. No disruption of the ion clusters is observed before thermal decomposition of the polymer.

Upon copolymerization of propene and butadiene, using the recent generation of high mileage stereospecific MgCl2 supported TiCl4AIR3 catalytic systems, it is possible to incorporate a small proportion of butadiene units in polypropene, keeping reasonable, although strongly reduced, activity. The isospecificity of the catalysts for the propene polymerization is not affected, and even may be improved upon butadiene incorporation. The butadiene is incorporated in blocks of trans-1,4 units. The amount of incorporation is dependent on the temperature, on the presence and then on the nature and concentration of a silane compound as an external Lewis base, and also on the nature of the alkylaluminium cocatalyst. The silane causes a small amount of 1,2-butadiene units to be incorporated. The molecular weights of the polymers are strongly decreased but the crystallinity is only slightly affected.

Copolymerization of propylene and nonconjugated dienes such as 1–9 decadiene (α–ω symmetric) and 7-methyl-1,6 octadiene (asymmetric) is carried out in the presence of highly active isospecific catalysts for propene polymerization. The incorporation of the diene is random and does not affect the isospecificity of the catalytic system. For a low amount of diene, whatever its structure, an activation effect is observed. For the symmetric diene, the reactivity of the second double bond gives rise to crosslinking. Derivatization through hydroboration or epoxydation is carried out in suspension, using a toluenetetrahydrofuran solvent mixture that is able to swell the polypropylene and dissolve the reactants. After hydroboration the copolymer is transformed into hydroxylated polymer through oxidation in a phase transfer condition. The epoxydized copolymer shows excellent adhesive properties on anodized stainless steel.

The main part of the paper is dealing with 4 routes used to anchor chloromethyl groups to polymer grafted onto porous silica. The most efficient route involves first, grafting of a coupling agent bearing one function active in radical polymerization as initiator, comonomer or transfer agent, and then polymerization of vinylbenzyl chloride. The grafting efficiency, the homogeneity of the grafting process and the conformation of the grafted polymer are discussed, depending on the experimental conditions. Other grafted polymers are 1,2-polybutadiene and poly(phenylsiloxane). For catalytic applications, chloromethyl groups are reacted with ephedrin and the resulting solid is used for benzaldehyde alkylation with diethylzinc. On the other hand, grafted poly(phenylsiloxane) is sulfonated and used for esterification and phenol alkylation by dodecene.

The reaction was studied at 5,25,40,60 and 70°C. The initial rate obeys an Arrhenius law from 25 to 60°C, with an activation energy of 70 kJ/mol. Conversion limits are observed which strongly depend on the temperature. The stereoselectivity of the reaction with respect to the configurational triads does not depend on the temperature: the distribution of configurations is only dependent on the conversion. Assuming an S N 2 substitution mechanism governed by steric factors, the Monte Carlo simulation procedure described in a prior study is shown to give a good account for all temperatures above 40°C.

In the sulfonation of polynorbornene in dilute solution, the nature of the sulfonation agent mainly influences the reaction rate, according to its strength and also affects some side reactions (chain scission and crosslinking). The sulfonation can be carried out in suspension after swelling the highly porous powder in dichloroethane up to a 55% sulfonation ratio with preservation of the initial particular nature of the polymer; the latter may be then either partly or totally water soluble, depending on the initial size of the particles. Partial sulfonation, leading to ionomers, may be carried out in bulk at moderate temperature, in a mixing chamber, after gelification of the polymers, plasticized with CCl4.

Pellicular ion exchangers are obtained by grafting styrene or vinyl benzyl chloride onto commercial polypropylene (PP) beads (280 μm) previously peroxidized by an air-ozone mixture. Appropriate chemical modification of the grafted homopolymer follows to provide supported sulfonic acids of improved accessibility. The amount of grafted monomers has been varied from 0.3 to 30 wt %. Ion exchange capacities up to 2 meq H+/g were obtained. The thickness of the sulfonated grafted shell onto the polypropylene beads after swelling in water can exceed 200 μm.