Colloidal and film properties of carboxylated acrylic latices ‐ effect of surfactant concentration

Abstract

The effects of amount of conventional surfactant sodium dodecyl sulfate in the synthesis of carboxylated acrylic latices prepared by semicontinuous emulsion polymerization method were investigated. The properties considered were particle size and colloidal stability by addition of sodium chloride solution, on the latex system and water sorption, tensile strength at break and elongation, on latex films. It was found that the surfactant concentration had an important effect on the above mentioned properties. The particle size decreases with increasing surfactant concentration and the colloidal stability has a maximum value. The critical coagulation concentration value found in this work, seems to indicate an additional stabilisation of latex particles, due to a steric factor. The water uptake and the mechanical behaviour of latex films are affected considerably when SDS concentration rises. In conclusion, depending on the final use of latex, there is an optimal surfactant concentration for which the properties are appropriate.