Abstract: A method for detachably gluing at least one porous substrate to another material using at least one layer of a detachable adhesive comprising an ungluing admixture adapted for generating gases which, by gas expansion or gas migration towards at least one of the interfaces of the detachable adhesive layer, weakens the adhesive bond when heated by a detaching control, the aforementioned method including, before gluing, applying a metal sealing coating onto at least one of the substrates.

Abstract: The invention relates to the production of composite materials having a fibrous reinforcement and matrix obtained by the polymerization of acrylic monomers.These acrylic monomers are tetraacrylates of formula: ##STR1## in which R.sup.1 and R.sup.2, which can be the same or different, represent H or CH.sub.3, and Z is a divalent group having 1 or 2 aromatic or aliphatic cycles.For example, Z is a group derived from bisphenol A and R.sup.1 and R.sup.2 represent H.The composite materials can be prepared by injection moulding.

Abstract: Process for the hardening, curing or setting of a bis-maleimide resin and a composite material using said resin.The setting process according to the invention of a basic resin A having at least one bis-maleimide monomer consists of adding to the basic resin A, prior to the use thereof, at least one reactive diluent B consisting of a monomer having a copolymerizable vinyl termination with the basic resin A when subjecting the mixture of the basic resin A and the diluent B to the action of ionizing radiation (34), the total quantity of the diluent B being such that the maleimide functions of the basic resin A are consumed following the ionizing radiation action and being chosen in the range 10 to 50 parts by weight for 100 parts by weight of the basic resin A. This resin is more particularly intended for the production of a composite material (16, 18) having a fibrous reinforcement (26, 28, 30, 32) by filamentary winding.

Abstract: Process for the preparation of a polysilane crosslinked by ioning radiation and process for the production of a composite material having a polysilane matrix. The preparation process consists of subjecting to ionizing radiation chosen from among X-rays and an electron bombardment, a formulation crosslinkable by ionizing radiation incorporating at least one polysilane having at least one vinyl termination.

Abstract: Prepolymers having imide groupings and process for their preparation, for use in the production of resins capable of hardening under ionizing radiation. The prepolymers are derived from the reaction in a homogeneous liquid medium, at a temperature of between 50.degree. and 250.degree. C. of, firstly, imide grouping-generating reagents consisting of a least two specific maleimides of different kinds, and, secondly, two additional reagents, composed of a specific acrylate reagent and a specific vinyl compound other that an acrylate.

Abstract: According to the invention, the reactive lubricating product of carbon fibres for embedding in a resin which can be hardened by X or beta radiation according to a radical mechanism is constituted by a monomer having at least one functional group (F.sub.1) able to form a covalent chemical bond with the hydroxyl sites of the carbon fibres and an ethylene unsaturation (F.sub.2) able to crosslink with the resin during its hardening under irradiation.