3.3.4. Pour Points
The temperature, at which oil solidifies enough to resist flow, is the
pour point of the oil sample [42]. The pour point reduced from 18 °C
for PKO to – 11 °C and – 12 °C for biolubricants after double
transesterification and epoxidation-esterification processes,
respectively. However, the pour point of the petroleum lubricant is –
20 °C. Hence, these results show that the pour point of the
biolubricants and petro-lubricant are good enough for to permit their
use at low temperatures. This was possible because, in the
biolubricants, the products thermal resistance was greatly enhanced, due
to the fact that the thermally fragile glycerol in the PKO triglycerides
are replaced by the trimethylolpropane backbone and the elongated chain
obtained during epoxy ring opening, which are thermally stable.
Therefore, the significant thermal stability and cold properties of the
PKO biolubricants, compared to the PKO. Similar results were obtained by
Alang et al. [1] and Musa [42] for the synthesis of biolubricant
using PKO; as well as by Bello et al. [45], for the synthesis of
biodiesel from PKO.