3.3.3. Viscosity Index
The viscosity index values for the PKO biolubricant synthesized by
transesterification with trimethylolpropane (TMP) PKBLT,
synthesized by epoxidation-esterification PKBLE, and
petroleum lubricant are 139, 132 and 105, respectively. These values are
higher, though close to that of the petroleum lubricant value. Viscosity
index is defined as the property of a liquid that helps to resist
changes in viscosity with increases or decreases in temperature. In
lubricants, it is important to have higher viscosity index values. This
is because lubricants with higher viscosity index significantly resist
viscosity changes with changes in temperature. The viscosity index of
PKO is this work is 180. This value is slightly lower than 185, reported
by Alang et al. [1] for PKO. Also, this value was lower than the 233
viscosity index value for Jatropha oil, reported by Menkiti et al.
[4].