Pseudo-ternary Phase Behaviour of Palm - Based Microemulsion Insecticides

This research aimed to characterize microemulsionsystem of palm methyl ester (PME) andwater/ mixed surfactants (Tween®80 and Dehydol®LS 2)/ 1-propanol via a pseudo-ternaryphase behaviour study. The microemulsion system with a hydrophilic-lyphophilic balancevalue of 12.33 was prepared using the constant composition method. The phases included anemulsion, a gel/viscous phase and a transparent microemulsion which were tested at differenttemperatures to examine their stabilities. Microemulsion samples were evaluated to obtain theircolloid characteristics, such as particle size, viscosity, pH and conductivity. The optimumformulation of palm-based insecticide consisted of 48% water, with 20% PME, 20% mixedsurfactants and 12% 1-propanol. The particle size of the microemulsion was 84.20 nm. The pHvaluewas 6.6, the conductivity was 0.00951 μ S/cm, and the viscosity was 20.44 cP. Theresults indicated that different amounts of surfactants and co-surfactant in the emulsionexhibited different phase behaviour in the pseudo-ternary phase diagram. Palm-basedmicroemulsion potentially could be an alternative to replacing petroleum-based solvents ininsecticides.