METHOD OF MAKING CARBON FIBRES HAVING IMPROVED STRENGTH AND MODULUS BY MULTI-STEP STRETCHING OF THE PRECURSOR FIBRE

摘要

The invention also provides a method for making carbon fibers having high tensile strength and modulus of elasticity. The method comprises advancing a precursor fiber through an oxidation oven wherein the fiber is subjected to controlled stretching in an oxidizing atmosphere in which tension loads are distributed amongst a plurality of passes through the oxidation oven, which permits higher cumulative stretches to be achieved. The method also includes subjecting the fiber to controlled stretching in two or more of the passes that is sufficient to cause the fiber to undergo one or more transitions in each of the two or more passes.