Eutectic effect during mesophase formation in co-carbonization of ethylene tar pitch and polystyrene

Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The characteristics of mesophase pitches were examined using polarized light optical microscopy, apparent viscometry, Fourier transform infrared spectrometry, 1H nuclear magnetic resonance spectrometry, and X-ray diffractometry. The properties of the mesophase pitch were greatly improved because of the eutectic effect. The soluble content increased from 5% to 56%, the mesophase itself increased from 32% to 100%, and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch. The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization. The increased number of alkyl groups, which are mainly methylene groups, altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.