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.