MODELING OF DETERGENCY PERFORMANCE FOR SOME TECHNICAL NONIONIC SURFACTANTS

The detergency behaviour towards nonpolar soil was modelled for seven technical nonionic surfactant as a function of surfactant concentratio n, washing time and washing temperature. The detergency experiments we re carried out according to a central composite circumscribed statisti cal experimental design. Second order polynomial functions were used f or the modelling. It was possible to establish good models for all sur factants except one. For three of the surfactants the models predicted a detergency maximum. The detergency effects of these surfactants wer e examined at the variable settings predicted to give maximum detergen cy. The results obtained were in good agreement with predictions. The surfactant concentration giving maximum detergency is not directly lin ked to the c. m. c. The temperature for maximum detergency corresponds to the cloud point of the washing solution with the surfactant concen tration giving maximum detergency. The cloud point has to be determine d with the soil present. This indicates that a microemulsion has to be present to obtain maximum nonpolar soil removal.