J. Drelich et al., SURFACE-TENSION OF TOLUENE-EXTRACTED BITUMENS FROM UTAH OIL SANDS AS DETERMINED BY WILHELMY PLATE AND CONTACT-ANGLE TECHNIQUES, Energy & fuels, 8(3), 1994, pp. 700-704
The surface tension values for toluene-extracted bitumens from Whitero
cks, Sunnyside, PR Spring, Asphalt Ridge, and Circle Cliffs oil sands
were measured with the Wilhelmy plate technique and found to vary from
20.6 to 31.2 mN m-1 at 333 K. A linear relationship between the bitum
en surface tension and temperature was observed in the temperature ran
ge 310-356 K, which allowed for the calculation of the temperature coe
fficients of surface tension. The temperature coefficients were found
to vary among the bitumens from -0.063 mN m-1 deg-1 to -0.097 mN m-1 d
eg-1. Also, the surface tensions of these bitumens at room temperature
were calculated from contact angle measurements using Neumann's equat
ion-of-state. Satisfactory agreement between the results for bitumen s
urface tensions as determined from contact angle data and direct surfa
ce tension measurements with the Wilhelmy plate technique were obtaine
d for the Whiterocks, Sunnyside, and PR Spring bitumens. However, larg
e discrepancies, 6.4-9.4 mN m-1, were observed between the bitumen sur
face tension data obtained from Neumann's equation-of-state and the bi
tumen surface tensions determined by direct Wilhelmy plate measurement
s for the Asphalt Ridge and Circle Cliffs bitumens.