Abstract: The invention concerns a process for preparing a block or comb copolymer comprising at least one hydrophilic portion and at least two hydrophobic portions, by anionic solvent-free polymerization of a prepolymer selected from a polyethylene glycol and a polyvinyl alcohol, and of a lactone or dilactone monomer. The process is carried out in the presence of an alkaline-earth metal hydride, in an inert atmosphere, and the polymerization step is not carried out under vacuum. The invention also concerns copolymers obtained by this process.

Abstract: The invention concerns a process for preparing a block or comb copolymer comprising at least one hydrophilic portion and at least two hydrophobic portions, by anionic solvent-free polymerization of a prepolymer selected from a polyethylene glycol and a polyvinyl alcohol, and of a lactone or dilactone monomer. The process is carried out in the presence of an alkaline-earth metal hydride, in an inert atmosphere, and the polymerization step is not carried out under vacuum. The invention also concerns copolymers obtained by this process.

Abstract: Substrates, e.g., silicon wafers, coated with a UV-curable organopolysiloxane composition including a crosslinking catalyst therefor (e.g., a platinum group metal compound) and an amount of a crosslinking inhibitor (e.g., an azodicarboxylate) which is effective at ambient temperature, but ineffective to prevent crosslinking on exposure of the composition to ultraviolet radiation, are well adapted for the imaging of negative intelligence patterns thereon.

Abstract: Photosensitive film which is photosensitive in a given wavelength range comprises at least one silicon-containing polymer, at least one salt which can be converted into a Brunsted acid by irradiation and optionally at least one photosensitizer. The silicon-containing polymer-based photosensitive film can be used as a masking resin in a lithography process for producing electronic components.

Abstract: Photosensitive film which is photosensitive in a given wavelength range comprises at least one silicon-containing polymer, at least one salt which can be converted into a Brunsted acid by irradiation and optionally at least one photosensitizer. The silicon-containing polymer-based photosensitive film can be used as a masking resin in a lithography process for producing electronic components.

Abstract: The invention relates to a doped polyacetylene film for forming an organic semiconductor or even a conductor of a metallic type. It serves to make the doping more homogeneous and improves the stability over a period of time. The process consists of using as the dopant a salt of an element such as chrome, nickel, iron, titanium, tungsten, or molybdenum belonging to the transition metals, or a salt of an element such as europium or ytterbium belonging to the lanthanides. Doping takes place by immersing the film in a solution having a low dopant concentration, e.g. in toluene, and maintaining the system at low pressure and ordinary temperature for a period of a few days, as a function of the desired doping level and conductivity.

Abstract: A process for the anionic polymerization or copolymerization of olefinic monomers, dienic monomers, vinyl monomers and heterocyclic monomers is described which comprises reacting at least one monomer which is an olefinic monomer, a vinyl monomer or an heterocyclic monomer with a catalyst capable of inducing anionic polymerization and an aprotic macroheterocyclic cryptant, said at least one monomer being the only medium for the reaction.The macroheterocyclic complexing agent has general formula ##STR1## in which: R.sub.1 is hydrogen, a hydrocarbon radical or alkoxycarbonyl, or the two R.sub.1 together can form a group of the general formula: ##STR2## in which A is a hydrocarbon radical,D is oxygen, sulfur, or a hydrocarbon radical, with the proviso that at leat two of the D groups are oxygen or sulfur and that if R.sub.1 is hydrogen, a hydrocarbon radical or alkoxycarbonyl, one of these two D groups is oxygen or sulfur and the other is oxygen, andn and p are integers from 1 to 3 and m is 2 or 3.

Abstract: A novel process for polymerization or copolymerization of monomers is described, according to which the reaction is carried out in the presence of an anionic initiator and a macroheterocyclic complexing agent of formula ##STR1## in which: EACH R.sub.1 is a hydrogen atom, a hydrocarbon group or an alkoxycarbonyl group, or the two R.sub.1 together can form a group of the general formula: ##STR2## THAT IS TO SAY FORMING A THIRD BRIDGE BETWEEN THE TWO NITROGEN ATOMS IN THE MOLECULE, A is a hydrocarbon group,D is an oxygen or sulfur atom or a hydrocarbon group, with the proviso that at least two of the groups D are oxygen or sulfur atoms and that, if each R.sub.1 is hydrogen, a hydrocarbon group or an alkoxycarbonyl group, one of these two groups D is oxygen or sulfur and the other is oxygen,n and p are integers ranging from 1 to 3, andm is 2 or 3.