Evaluation of Thermal Properties of Modified Acrylic Fibers Precursor for the Fabrication of Carbon Fibers

Acrylic fibers are recognized as the most widely used precursor for the fabrication of carbon fibers. The process of fabrication composed of two steps including oxidative stabilization at low temperature and carbonization at high temperatures in an inert atmosphere. The chemistry of the stabilization process is complex, but consists of cyclization of the nitrile groups (C≡N) and cross-linking of the chain molecules followed by dehydrogenation and oxidative reactions. This study is focused on post spinning treatment of acrylic fibers with 5%wt. Potassium Permanganate (KMnO4) solution under different impregnation times. The evaluation of initial and modified acrylic fibers by differential scanning calorimetry (DSC) showed that treatment of acrylic fibers with KMnO4 solution can result in the change of chemical structure and thermal behavior of fibers. The recorded DSC thermograms of modified samples indicated that with increase of impregnation time, onset temperature of cyclization reaction decreased. Also there was a progressive increase in the difference of onset and endset temperature (ΔT) of chemical reactions in the DSC peak. In this work, defined the optimum conditions of impregnation for achieve to carbon fiber precursor with suitable thermal properties

Keywords:

Acrylic Fibers , Carbon Fibers , KMnO4 , Thermal Properties