The Determination And Analysis Of The Rheological Behavior Of Coal-tar Pitches

The differences among NDJ-79, NDJ-99 and NDJ-31 viscometers in constitution, performance and testing method have been analyzed. The viscosity transformation trend of coal-tar pitches with temperature can be characterized by means of NDJ-31 viscometer. The rheological behaviour of the modified pitch and medium pitch can be evaluated effectively by the viscosity determination. As determining the viscosity of coal-tar pitches by NDJ-31 viscometer, the temperature differences among heat-conducting oil with coal-tar pitches should been determined for reducing measurement error.The comprehensive evaluation indicated that the performances of modified pitch are superior to that of medium pitch. Through the viscosity test, the differences of rheological behavior of the modified pitch and medium pitch have been studied. The higher viscosity of modified pitch brings about a series of actual application problem. According to the viscosity variation rule of modified pitch with temperature, the process parameters of several modified pitches has been determined.The modification rule of the stearic acid,oleic acid and paraffin wax to modified pitch are systematically studied. Effect of content of the stearic acid,oleic acid and paraffin wax on the viscosity of modified pitch has been analyzed. The regularity of rheological behavior has been found. The differences of modification effect among stearic acid,oleic acid and paraffin wax have been comparatively investigated. The process parameters of the stearic acid modified pitch,oleic acid modified pitch and paraffin wax modified pitch have been pointed out.