ISO 6295 Petroleum products - Mineral oils - Determination of interfacial tension of oil against water - Ring method
1 Scope and field of application
This International Standard specifies a method for the measurement, under non-equilibrium conditions, of the interfacial tension of mineral oils against water, which has been shown by practice to give a reliable indication of the presence of hydrophilic compounds.
2 Reference
ISO 3170, Petroleum products - Liquid hydrocarbons - Manual sampling.
3 Principle
Interfacial tension is determined by measuring the force necessary to detach a planar ring of platinum wire from the surface of the liquid of higher surface tension, that is, upward from the water-oil interface. To calculate the inter-facial tension, the force so measured is corrected by an empirically determined factor which depends upon the force applied, the densities of both oil and water, and the dimensions of the ring. Measurements are made under rigidly standardized non-equilibrium conditions in which the measurement is completed within 1 min after formation of the interface.
