Thermoplastic polyimides
AssigneeRhodia Operations
InventorsStephane Jeol, Vincent Mollet, Benjamin Paci
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Abstract
The present invention relates to thermoplastic polyimides and to the synthesis thereof. The invention relates in particular to a method for manufacturing semi-aromatic thermoplastic polyimides by means of the solid-state polymerization of a solid ammonium carboxylate salt formed from an aliphatic diamine and an aromatic tetracarboxylic acid, thereby enabling powders having controlled particle sizes to be produced.
Claims20
A process for producing solid particles of semicrystalline and semiaromatic (co)polyimide (I), having a median diameter D50 of between 0.01 and 2 mm, said polyimide being thermoplastic and having a melting temperature of between 50 and 350° C., the process comprising:
- (a) charging a reactor with a salt formed by reaction of at least one aliphatic diamine with at least one aromatic tetracarboxylic acid;
- (b) polymerizing the salt from step (a) in the solid state to give the (co)polyimide (I), at an absolute pressure of between 0.005 and 1 M Pa and at a temperature T which obeys the following relation:
- Tf of the salt from step (a)>T>Tg of the (co)polyimide (I) to be obtained;
- (c) recovering the solid (co)polyimide (I) particles.
Solid particles of semicrystalline and semiaromatic (co)polyimide (I), having a median diameter D50 of between 0.01 and 2 mm, said polyimide being thermoplastic and having a melting temperature of between 50 and 350° C., said (co)polyimide being obtained from the polymerization of a salt formed by reacting at least one aliphatic diamine with at least one aromatic tetracarboxylic acid.
A salt of tetracarboxylic acid and aliphatic diamine, further comprising a chain transfer agent and/or exhibiting a stoichiometric imbalance.
Dependencies are inferred from the claim text.