Effect of washing temperature on semi-solid oil removal from fabric surfaces

Abstract

The objective of this research was to examine the use of a single extended surfactant for detergency to remove semi-solid oil from fabric (a polyester/cotton blend) at various wahing temperatures. Extended surfactant [AlfoterrnR, C145-4(PO)] was used to form microemulsion systems with semi-solid oil (methyl pamitate) at different surfactant concentrations and different salinities. Dynamic interfacial tensions were also measured between the oil and surfactant soltions to select an optimum condition for further study. The highest oil removal of 65.6% was achieved at 30 C by 0.1 %w/v extended surfactant concentration and 3 %w/v sodium chloride. In addition, the redeposition of the oil was less than 5% This was due to the lowest dynamic interfacial tension at 30C which was slightly higher than the melting point of methyl palmitate. Interestingly, oil removal decreased substantially with decreasing washigh temperature below 30C since the methyl palmitate became solid, leading to lowering oil removal. The removal mechanism of solid oil depends on surfactant adsorption onto both surfaces of the oil and fabric, causing electrostatic repulsion force, while the removal of liquid oil increases with decreading interfacial tension between oil and washing solution.