METHOD OF PRODUCING HIGH-MODULUS FIBRE FROM AVERAGE-STRENGTH CARBON FIBRE Russian patent published in 2010 - IPC D01F9/22 D01F9/21 D01F9/12 

FIELD: chemistry.

SUBSTANCE: starting material used is average-strength carbon fibre with linear density of 200-1600 tex and modulus of elasticity of 200-250 GPa. This fibre is twisted to 30-60 twists/m with finish agent content of more than 1%. The fibre is further finished with finishing agent content less than 1%. The twisted bundle undergoes primary thermal treatment at 2300-2500°C for 1-10 minutes until achieving at least 300 GPa modulus of elasticity of the carbon bundle. Second thermal treatment is carried out at temperature not lower than 3000°C for 1-20 s while pulling the bundle to 10% until modulus of elasticity of the carbon bundle increases to at least 450 GPa.

EFFECT: high quality is achieved owing to compact form of obtained carbon bundles, which ensures high content of carbon fibres in the composite material and maximum mechanical properties of the composite material.

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