THE EFFECT OF STRETCH DURING THE WET-SPINNING OF POLYACRYLONITRILE PRECURSOR FIBRES ON THE MECHANICAL PROPERTIES OF THE RESULTANT CARBON FIBRES.
ROYAL AIRCRAFT ESTABLISHMENT FARNBOROUGH (ENGLAND)
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Fibres of polyacrylonitrile were prepared by wet-spinning from a sodium thiocyanate solution and the amount of stretching in steam was varied between X5 and X13. These fibres were converted to carbon fibres by preoxidizing in air at 220C, followed by carbonization to 1000C in hydrogen and heat-treatment to 2500C in argon. The results of mechanical tests showed that the tensile strengths and the Youngs moduli of the carbon fibres increased with the amount of stretch thus reflecting a similar trend that had been present originally in the polymer fibres. The carbon fibres produced from the polyacrylonitrile fibres that had been steam-stretched X13 had an average Youngs modulus of 50 x 10 to the 6th 16sq in and an average tensile strength of 177,000 lbsq in after being heat-treated to 2500C. Author
- Refractory Fibers