Abstract: Multicellular materials having excellent heat-resistance are provided by preparing granules of1. a prepolymer obtained from:A. a product containing an imide group, which isA. a bis-imide of the formula: ##STR1## in which D represents a radical of the formula: ##STR2## WHEREIN Y represents H, CH.sub.3 or Cl, m is 0 or 1, and A represents a divalent organic radical containing 2 to 30 carbon atoms, orB. a mixture comprising a bis-imide of formula (I) and a mono-imide of the formula: ##STR3## in which D is as defined above and R represents a hydrogen atom or a monovalent organic radical containing 1 to 20 carbon atoms, andB. an amine product which isA. one or more polyamines containing from 2 to 5 primary or secondary amino groups, at least one of these groups being primary, orB. a mixture comprising one or more polyamines as defined under a) and one or more primary and/or secondary monoamines and/or one or more secondary polyamines,2. a pore-forming agent and3.

Abstract: A thermosetting composition is provided which comprises the reaction product of (a) at least one N,N'-bis-imide of an unsaturated dicarboxylic acid, of general formula ##STR1## in which T represents a divalent organic radical containing a carbon-carbon double bond and Q is a divalent organic radical of 2 to 30 carbon atoms, (b) at least one polyamine of general formulaR (NH.sub.2).sub.xin which x is an integer at least equal to 2, and R represents an organic radical of valency x, the bis-imide being present in an amount of 0.55 to 25 mols per molar --NH.sub.2 group of the polyamine, and (c) at least one monomer other than a bis-imide of formula (I), which contains a carbon-carbon double bond and is heat-polymerizable.

Abstract: Thermosetting compositions are provided which are particularly suitable for use in the form of solutions, in making laminates. The compositions comprise (a) a prepolymer possessing imide groups derived from a polyimide and ammonia and (b) an unsaturated polyester.

Abstract: Thermosetting polymers, both prepolymers and cured resins, are produced by reacting ammonia with a polyimide of the formula: ##EQU1## IN WHICH A IS A NUMBER FROM 2 TO 4, Y represents an organic radical of valency a, and A and T, which may be identical or different, each represent hydrogen, chlorine or methyl, the proportions of polyimide and ammonia being such that there are at least 2 imide groups per mol of ammonia. These polymers find utility in the production of materials liable to undergo severe heat stresses.