As part of a study to evaluate the potential of hydrocarbons from South-eastern Turkey for carbon fiber production, samples from Raman-Dincer crude oils were processed by vacuum distillation to produce pitch precursor for carbon fibers. Structural characterizations of the distilled pitches were examined by elemental analysis, thermogravimetric analysis (TGA and DTG), softening point (SP), gel permeation chromatography (GPC), FT-TR and solution H-1, C-13 NMR spectroscopies. Vacuum distillation markedly decreased atomic WC ratio and increased aromaticity as well as SP. The softening of the distilled pitches could be raised to about 250 degrees C, giving a yield of 17%. The pitches distilled at 400 degrees C for 1 h showed excellent spinnability into thin fibers of about 15 mu m in diameter. The resulting fibers were stabilized by oxidation with air. The morphology of the stabilized fibers was studied by scanning electron microscopy (SEM). (C) 2000 Elsevier Science Ltd. All rights reserved.