CHARACTERISTICS OF KMNO4-MODIFIED PAN FIBERS - ITS INFLUENCE ON THE RESULTING CARBON-FIBERS PROPERTIES

Polyacrylonitrile precursor has been chemically impregnated with aqueo us solution of KMnO4 under varying conditions of temperature and time. FTIR of the as-modified PAN fibres shows a clear peak at 2340 cm-1 co rresponding to MnO4-C=N conjugation. Such conjugation helps not only a s catalyst for cyclization reaction, but also as plasticizer. Calorime tric studies show that activation energy for cyclization reaction for KMnO4-treated fibres is reduced from 119 KJ/mole to 90 KJ/mole. Experi mental results show that the tensile strength of carbon fibres prepare d from chemically modified samples goes up to 4.2 GPa, compared to 2 G Pa obtained from unmodified samples. More importantly, elongation to b reak for such carbon fibres is pushed up to 1.82%, compared to 0.9% ac hieved with unmodified samples. Surface morphology of the treated and carbonized samples has also been investigated using SEM.