The effect of fullerene C60 additives on the density of o-xylene

Abstract

The results of the experimental study of the density of o-xylene/ fullerene C60 solutions in the concentration range 0-0.55 wt.% and temperatures 283-343 K are presented. The density was measured by a pycnometric method with an extended uncertainty of 0.07%. The concentration and temperature dependences of the density of o-xylene/ fullerene C60 solutions were obtained. It was shown that the temperature dependences of the density form a family of almost equidistant straight lines. At the same time, the concentration dependences of the density have a peculiarity that indicates probable structural transformations in the base fluid when a small amount of fullerene C60 is added. It was shown that all concentration dependences of the density of the studied solutions have a minimum in the vicinity of the fullerene concentration of 0.05 wt.% in the entire investigated temperature range. In addition, these dependences consist of two branches with different behavior. Of interest is the phenomenon of the density reduction in the region of small fullerene C60 additives to o-xylene. It is proposed to use an extended scaling model with a universal for non-associated substances crossover function for predicting the density of o-xylene/ fullerene C60 solutions in a wide range of state parameters. Within this model, the pseudocritical parameters of o-xylene/ fullerene C60 solutions were calculated. The authors note that the concentration dependences of the pseudocritical parameters also have a minimum in the vicinity of the fullerene concentration of .0.05 wt.%. The density of o-xylene/ fullerene C60 solutions calculated according to the proposed equations are consistent with the experimental data within the extended uncertainty. The excess molar volume of o-xylene/ fullerene C60 solutions was calculated.