Rhone-poulenc S.a.

Rhone-poulenc Industries

Maurice Balme

Max Gruffaz

Jean-Louis Locatelli

Jean Gattus

Bernard Gerard

Novel imido copolymers, useful for the production of a variety of shaped articles, e.g., by molding, are prepared by reacting an oligoimide with an aromatic compound bearing labile hydrogen atom(s) on the nucleus thereof, or by co-reacting such oligoimide and aromatic compound with a polyamine.

Imido copolymers from oligoimide and phenolic compound

Polyamines possessing imide groups are obtained by heating at least one unsaturated polyimide of the general formula: ##STR1## WITH AT LEAST ONE POLYAMINE OF THE GENERAL FORMULA:

Polyamines with imide groups

Compositions are provided which consist of a solid suspension of:

Thixotropic aqueous polyimide compositions

A suspension of a maleamic acid is provided by reacting maleic anhydride with an appropriate diprimary diamine in an organic diluent in the presence of a tertiary amine. The suspension has a low viscosity and the maleamic acid can readily be recovered from it.

Preparation of suspensions of maleamic acids

An improved process for the dehydration of bis-maleic acids to bis-maleimides is provided which comprises heating the bis-maleamic acid with a lower carboxylic acid anhydride in acetone, in the presence of 0.2 to 1 mol of tertiary amine per mol of bis-maleamic acid and of a soluble nickel derivative and 0.1 to 10 mols of water per mol of bis-maleamic acid and precipitating the resulting bis-maleimide by the addition of water. The addition of water to the starting materials reduces the proportion of by-products produced and increases the degree of cyclodehydration.

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Sainte Foy Les Lyon, France

Maurice Balme