Natural esters have high viscosity in their triglyceride form. Transesterification reduces their
viscosity but lowers their flash point. In this paper, we proposed an optimal blend of natural
esters, having the better compromise between flash point and viscosity, for use in power
transformers. Mixtures of two components, refined and methyl esters of palm kernel oil
(RPKO and MEPKO), were investigated by simplex lattice design (SLD). For each sample,
the viscosity, flash/fire points, neutralization number and biodegradability in an aqueous …