Abstract: The invention concerns a multilayer structure based on polyamides, particularly suitable for making tubes or conduits for transporting liquid fluids such as alcohol's, liquid fuels, fuel containing oxygen-containing compounds such as, for example alcohol's or refrigerating fluids. The multilayer structure comprises two superposed layers: at least one internal layer and at least one external layer.

Abstract: The invention concerns a thermoplastic copolyamide and composition comprising as matrix said thermoplastic copolyamide, and a method of making such thermoplastic copolyamide. More particularly it concerns a copolyamide of the statistical tree type resulting from the reaction between a plurifunctional monomer comprising at least three reactive functions to form an amide function, said functions being two different types, and bifunctional monomer conventionally used in making linear polyamides. The resulting copolyamide has a very low softness index in molten state compared to the linear polyamide and improved shock-resistant properties. The invention also concerns with methods for making these copolyamides and composition for molding, extruding or injecting parts. Said compositions comprise fillers and additives and said copolyamide as a matrix.

Abstract: The invention concerns a polyamide comprising macromolecular chains having a star-shaped configuration, a method for making said polyamide and compositions comprising same. More particularly, the invention concerns a method for making a polyamide comprising linear macromolecular chains and star-shaped macromolecular chains with control of the star-shaped chain concentration in the polymer. Said control is obtained by using besides the polyfunctional polymers and amino acids or lactams a polyfunctional comonomer comprising either acid functions or amine functions. The resulting polyamide has optimal mechanical and rheological properties for improving the speed and quality of mould filling and producing mouldable compositions comprising high filler factors.

Abstract: The invention relates to a polyamide, a method for its manufacture and compounds containing it. It involves, specifically, a polyamide obtained through polymerization of an aminoacid or lactam such as caprolactam in the presence of a compound having at least three functions capable of generating an amide function by reacting either with an amine function or with an acid fonction. The polyamide obtained in this way has at least part of these molecular chains in a star formation, the other part being in linear form. This polymer is useful, inter alia, in the manufacture of compounds that are to be molded, since it has minimal viscosity in a melted medium while still retaining the mechanical properties of a linear polymer.

Abstract: A thermoplastic composition with improved properties for making fuel containers, e.g. for fuel oil, petrol, diesel oil or alcohol, and specifically for making fuel lines for feeding fuel to a fuel tank or engine. The thermoplastic composition includes a thermoplastic polymer matrix and at least one compound that enhances the resilience of thermoplastic compositions. Said matrix consists of a mixture of: at least one first thermoplastic copolymer produced by copolymerising .epsilon.-caprolactam with at least one monomer selected from the group which includes an amino acid having at least nine carbon atoms, or the corresponding lactam, and a mixture of hexamethylediamine and a diacid having at least nine carbon atoms, the weight ratio of the .epsilon.-caprolactam to the total amount of hexamethylenediamine and diacid being 4-9; and at least one second thermoplastic polymer or copolymer produced by polymerising monomers having at least nine carbon atoms.