SPIN PROBES IN STRUCTURE STUDIES OF PETROLEUM MESOPHASE PITCH

The ESR spectra of petroleum pitch labeled with the stable copper-porp hyrin complex and changes in the spectra due to pyrolysis are analyzed . If is concluded that the functions of carriers and traps for unpaire d electrons in mesophase pitch are performed by anisotropic associates or crystallites sized about 2.0 nm. The intermolecular interactions b etween the parallel layers of anisotropic associates may be significan t. They increase when the molecular associates pass to the paramagneti c state and determine the preferable packing of the paramagnetic cryst allites one over another.