Process for converting multi-dimensional sheet-like structures consisting of polyacrylonitrile fibers into the thermally stabilized state

摘要

A process is claimed for the prodn. of multi-surfaced formed bodies consisting at least mainly of carbon fibres (CF) derived from polyacrylonitrile (PAN)-based starting material. The process comprises heating the corresp. body made of PAN fibres to 180-320 degrees C to convert the PAN into the infusible uncarbonised form and then passing gas contg. an oxygen-releasing substance through the body for 0.5-10 h, in amts. which are controlled so as to (a) maintain the necessary temp. for the chemical reactions required for thermal stabilisation of the fibres and (b) avoid overheating and consequent damage to the fibres. Also claimed are (i) formed bodies made of carbon fibres, obtd. by this process, and (ii) an appts. for the continuous thermal treatment of the above formed bodies made of PAN fibres.