METHOD OF PRODUCING POLYIMIDE COMPOSITE FIBRE BASED ON CARBON REINFORCED BY NANOSTRUCTURED SILICON CARBIDE Russian patent published in 2018 - IPC C04B35/83 D01F6/00 C08G73/10 C08K3/34 C08K9/06 C08L79/08 

FIELD: chemistry.

SUBSTANCE: invention relates to the production of nanocomposites based on nanostructured silicon carbide and carbon fibre with a polyimide matrix, which can be applied in various fields of engineering, in particular in the manufacture of construction materials used in rocket engineering, in the aviation and space industries. The described method of producing a polyimide composite fibre based on carbon reinforced with nanostructured silicon carbide, comprising the initial step of producing a polyimide composite reinforced polymer and subsequent stage of processing to the formation of fibres, characterized in that the polyimide composite polymer reinforced by nanostructured silicon carbide or silicon carbide, modified organic silanes, is produced by condensation reaction of dianhydrides of aromatic polycarboxylic acids with aromatic diamines and in the presence of 0.2-10 wt % of nanostructured silicon carbide (by weight of binder) carried out in current of inert gas, in the dry environment of the polar organic solvent and under the influence of ultrasound. The starting materials are introduced in a certain sequence: first, nanostructured silicon carbide, both modified and unmodified, is mixed in a polar organic solvent with diamine, then cooled to 1-15°C, and an equimolar (relative to diamine) number of dianhydride is added in portions with stirring to the resulting reaction mass and, after stirring at room temperature for 3 to 8 hours, under ultrasound exposure through the resulting polyimide reinforced composite polymer, a carbon fibre is stretched at a speed of 1-10 cm per minute, which is pre-treated prior the stretch at a temperature of 200-600 °C, followed by drying the resulting fibre in an inert gas stream or at a reduced pressure of 10 to 150 mm Hg with stepwise heating according to the following scheme: from 70 to 90 °C for 3-8 hours, from 120 to 180 °C for 0.5-2 hours, from 190 to 230 °C for 0.5-2 hours, from 240 to 280 °C for 0.5-2 hours, from 290 to 300 °C for 0.5-2 hours, from 340 to 400 °C for 0.1-1 hour, followed by cooling in an inert gas stream or at a reduced pressure of 10 to 150 mm Hg.

EFFECT: cheaper and technological process for the production of a composite fibre made of polyimide and nanostructured silicon carbide is proposed.

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