Rheological properties of coal-tar pitches

Abstract

The viscosities of 21 coal-tar pitches with softening points in the range of 21.8 to 113.5/sup 0/C were determined in the temperature range from 60 to 220/sup 0/C. The applicability of two equation forms to these measured values was assessed. An equation relating the simple logarithmic viscosity to the second power of the difference between reciprocal absolute temperature and reciprocal softening point (absolute temperature unit) fits the results well. It is further shown that the reciprocal softening point is additive in binary pitch mixture.