POLYMER WITH IMPROVED CHARACTERISTICS AND METHOD FOR PRODUCTION THEREOF Russian patent published in 2019 - IPC C08K3/00 C08J3/18 C08J3/24 C08J3/28 C08L79/08 C08G73/10 

FIELD: technological processes.

SUBSTANCE: invention relates to a method of treating polyimide used for such products as fibers, films, sheets, blocks and other configurations. Treatment is carried out by temporarily increasing mobility of polyimide chains during the polyimide curing cycle after initiation of polyimide hardening and before the curing cycle. Temporary mobility of polyimide chains is ensured by introducing a plasticiser selected from CO₂ and H₂O, either by exposure to a pulsed electric field, or by exposure to ultrasonic irradiation.

EFFECT: said methods of treating thermosetting polyimide produce polyimides with thermal-oxidative stability less than or equal to 2_2 % of weight loss at 650 °F (343 °C) at atmospheric pressure for 1,000 h, glass transition temperature in dry conditions greater than or equal to 700 °F (371 °C) and glass transition temperature in hot / humid conditions greater than or equal to 690 °F (366 °C).

4 cl, 1 dwg