The effect of N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate addition on washing properties of liquid laundry detergents

The use of colorimetric analysis based on a CIELab system to determine detergency of commercial liquid laundrydetergents before and after modification with SB3C14 sulfobetaine (N-tetradecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate) is presented. The EMPA 101 standard cotton fabric soiled with carbon black and olive oil was usedin washing tests under the following conditions: temperature 40°C, rotational speed 200 rpm, 30 minute washing cycle,water hardness 5.35 mval/l, the concentration of liquid laundry detergents 1.25–50 g/l. The physicochemical analysis ofcolour, form, odour, pH, density, viscosity and content of anionic surfactants showed compliance with the manufacturers’declarations. The studies demonstrated that with increasing laundry detergent concentration a gradual increase indetergency occurred. At the highest tested concentrations of 50 g/L, detergency of 18.1% and 22.2% for cheaper L1 andmore expensive L2 products was achieved, respectively. Modification with the 5% addition of the zwitterionicsulfobetaine SB3C14 led to an improvement of the washing properties by 4.7% on average. At a concentration of 50 g/l,the modified L1 and L2 solutions demonstrated the highest detergency equal to 22.8% and 35.3%, respectively. Thisproves the existence of synergistic effect by the interaction of all ingredients in the solutions with higher concentrations.Microscopic analysis of EMPA 101 fabrics before and after washing processes showed no serious damage to the fibres,only the presence of slight fraying of individual ones. The results suggest that the SB3C14 sulfobetaine can besuccessfully used in liquid laundry detergents due to its very favourable surface properties