The effect of temperature on bitumen viscosity Tiopronin significant and the same behavior is observed for mixtures with low n-heptane concentrations. Fig. 8 shows the impact of temperature on the mixture viscosities at 10 MPa. The mixture viscosities show a linear variation with temperature at high n-heptane concentrations in a semi-log plot. At low n-heptane weight fractions, similar trend as bitumen for viscosity variation with temperature is golden brown algae observed.