Showing papers by "Gérard Riess published in 1994"
TL;DR: In this paper, a series of PS-PEO copolymers were labeled by the phenanthrene or anthracene groups at the block junctions, and the chromophore contents were determined by the absorbance spectroscopy using suitable model compounds.
Abstract: Micelle formation in THF-methanol, 1,2-dichloroethane-methanol, THF-water, and water solutions by PS-PEO diblock copolymers was studied by the fluorescence spectroscopy. For this purpose, a series of PS-PEO copolymers was labeled by the phenanthrene or anthracene groups at the block junctions. The chromophore contents in copolymers were determined by the absorbance spectroscopy using suitable model compounds. When micelles were present, intramicellar nonradiative energy transfer could be observed. For the PS-PEO copolymer (M n =114 000, 93 weight % PEO) we find the onset of micelle formation in water in the range of 10×10 -3 g/L (9×10 -8 M)
64 citations
TL;DR: In this article, a series of poly(styrene-b-ethylene oxide) copolymers were investigated as stabilizers for the dispersion polymerization of styrene in methanol.
36 citations
TL;DR: In this article, a block copolymers with poly(N-acetyliminoethylene) and vinyl sequences were obtained by a two-step synthetic approach, where the first stage macroinitiators were prepared.
Abstract: New block copolymers with poly(N-acetyliminoethylene) and vinyl sequences were obtained by a two-step synthetic approach. In the first stage macroinitiators of poly(N-acetyliminoethylene) type, with azo groups inserted in the main chain, were prepared. They were latter used in the radical polymerization of some vinyl monomers [styrene, methacrylic acid, methyl methacrylate, butyl methacrylate, β-(N-carbazolyl)ethyl acrylate, β-(methacryloyfoxy)ethyl 3,5-dinitrobenzoate]. The resulting block copolymers were characterized by spectral methods, elemental analysis, gel permeation chromatography, and electron microscopy. The kinetic study of the thermal and photochemical decomposition of the synthesized macroazoinitiators, as well as the polymerization data, suggest a dependence of their initiating efficiency on the length of the poly(N-acetyliminoethylene) segments. © 1994 John Wiley & Sons, Inc.
24 citations
Patent•
22 Dec 1994
TL;DR: In this article, stable emulsions comprising a continuous phase made up of a solution of elastomer in an organic solvent and a dispersal phase including at least one active chemical substance in a solvent which is not miscible with the solution, which are capable of being converted into elastomers and process for their preparation.
Abstract: Elastomer films in which active chemical substances such as anticorrosive agents, lubricants or medications such as biocides are uniformly dispersed in the form of liquid droplets, process for their preparation and their applications. Stable emulsions comprising a continuous phase made up of a solution of elastomer in an organic solvent and a disperse phase including at least one active chemical substance in a solvent which is not miscible with the solution of elastomer, which are capable of being converted into elastomer films, and process for their preparation. The said elastomer film includes a dispersion of droplets of a solvent b which is not miscible with the elastomer, laden with at least one active chemical substance, which dispersion is stabilized by a block or graft copolymer comprising polyB blocks which are miscible with the said droplets and polyA blocks which are not miscible with these droplets. `
18 citations
TL;DR: In this paper, the effect of the surface coverage of the polybutadiene seed latex by the surfactant and the latex composition on the interphase of PBut-PMMA core-shell latexes was examined.
Abstract: High-resolution solid-state 13C NMR and differential scanning calorimetry (DSC) were used to examine the effect of the surface coverage of the polybutadiene seed latex by the surfactant and the latex composition on the interphase of PBut-PMMA core-shell latexes. On the basis of the determination of the relaxation time (T1ρ(H)), glass transition temperature (Tg) and transition zone (ΔTg), information on the interphase was obtained, such as the fraction of the PMMA in the interphase and the interphase thickness. An optimum surface coverage of the PBut seed latex particles was found to lead to the largest amount of interphase.
10 citations
Patent•
22 Dec 1994
TL;DR: In this article, a method for converting stable emulsions into elastomeric films containing uniformly dispersed liquid droplets of active chemical ingredients such as anti-corrosive agents, lubricants or drugs such as biocides, and a preparation method therefor, and uses thereof, are disclosed.
Abstract: Elastomeric films containing uniformly dispersed liquid droplets of active chemical ingredients such as anti-corrosive agents, lubricants or drugs such as biocides, a preparation method therefor, and uses thereof, are disclosed. Stable emulsions comprising a continuous phase consisting of a solution of an elastomer in an organic solvent, and a dispersed phase including at least one active chemical ingredient in a solvent which is non-miscible with the elastomer solution, said emulsions being convertible into elastomeric films, and a preparation method therefor are also disclosed. Said elastomeric film includes dispersed droplets of a solvent (b) which is non-miscible with the elastomer and loaded with at least one active chemical ingredient, the resulting dispersion being stabilised by means of a block or graft copolymer comprising poly B sequences which are miscible with said droplets, and poly A sequences which are not miscible therewith.
7 citations
TL;DR: In this article, poly(methylmethacrylate)-poly(4-vinylpyridine) diblock copolymers were synthesized by sequential anionic polymerization.
6 citations
TL;DR: A series of poly (methyl methacrylate) PMMA polymers with low polydispersity was synthesized anionically using sterically hindered (1-(9-phenanthryl)-1-phenyl-3-methylpentyl) lithium as an initiator as discussed by the authors.
Abstract: A series of poly (methyl methacrylate) PMMA polymers with low polydispersity was synthesized anionically using sterically hindered (1-(9-phenanthryl)-1-phenyl-3-methylpentyl)lithium as an initiator. Results of absorption spectroscopy and gelpermeation chromatography (GPC) analyses were used to discuss the initiator efficiency.
3 citations
Patent•
22 Dec 1994
Patent•
22 Dec 1994
TL;DR: Films d'elastomere, dans lesquels sont dispersees uniformement, sous la forme de gouttelettes de liquide, des substances chimiques actives, telles que des anti-corrosifs, des lubrifiants ou encore des medicaments tels que des biocides, leur procede de preparation ainsi que leurs applications as discussed by the authors.
Abstract: Films d'elastomere, dans lesquels sont dispersees uniformement, sous la forme de gouttelettes de liquide, des substances chimiques actives, telles que des anti-corrosifs, des lubrifiants ou encore des medicaments tels que des biocides, leur procede de preparation ainsi que leurs applications. Emulsions stables comportant une phase continue formee d'une solution d'elastomere dans un solvant organique et une phase dispersee comprenant au moins une substance chimique active dans un solvant non miscible avec la solution d'elastomere, aptes a etre transformees en films d'elastomere, et leur procede de preparation. Ledit film d'elastomere inclut une dispersion de gouttelettes d'un solvant b non miscible avec l'elastomere, charge en au moins une substance chimique active, laquelle dispersion est stabilisee par un copolymere bloc ou greffe, comportant des sequences poly B, miscibles avec lesdites gouttelettes et des sequences poly A, non-miscibles avec ces gouttelettes.
Patent•
22 Dec 1994
TL;DR: In this article, a method for converting stable emulsions into elastomeric films containing uniformly dispersed liquid droplets of active chemical ingredients such as anti-corrosive agents, lubricants or drugs such as biocides, and a preparation method therefor, and uses thereof, are disclosed.
Abstract: Elastomeric films containing uniformly dispersed liquid droplets of active chemical ingredients such as anti-corrosive agents, lubricants or drugs such as biocides, a preparation method therefor, and uses thereof, are disclosed. Stable emulsions comprising a continuous phase consisting of a solution of an elastomer in an organic solvent, and a dispersed phase including at least one active chemical ingredient in a solvent which is non-miscible with the elastomer solution, said emulsions being convertible into elastomeric films, and a preparation method therefor are also disclosed. Said elastomeric film includes dispersed droplets of a solvent (b) which is non-miscible with the elastomer and loaded with at least one active chemical ingredient, the resulting dispersion being stabilised by means of a block or graft copolymer comprising poly B sequences which are miscible with said droplets, and poly A sequences which are not miscible therewith.