Abstract:

Lauric acid polyglycol ester （LAE-R） was synthesized by the reaction of lauric acid with the polyethylene glycol recycled from waste crystal-silicon-cutting liquid. The surface tension （γ_cmc）, critical micelle concentration （cmc）, wetting power, emulsifying power, foaming performance and detergency were measured, as well as the degreasing rate in a dishwashing detergent. These properties were compared with those of AEO-9 and lauric acid polyglycol ester （LAE-I） which had been synthesized from industrial-grade PEG400 and lauric acid. The results show that LAE-R has high surface activity （γ_cmc is 28.9 mN/m and cmc is 60.4 mg/L, which are lower than those of LAE-I and AEO-9）. The emulsifying power of LAE-R on diesel oil and soybean oil is similar to that of AEO-9, but slightly lower than that of LAE-I. The wetting power and foaming power of LAE-R are lower than those of LAE-I and AEO-9. Therefore, LAE-R is a low-foam surfactant. LAE-R has the same comprehensive cleaning ability to carbon black cloth and sebum cloth as LAE-I, but its cleaning ability to carbon black cloth is lower than that of AEO-9. The degreasing rate of LAE-R is basically the same as those of LAE-I and AEO-9 during applied in a dishwashing detergent formula, however, LAE-R has a certain competitive advantage in cost performance due to its low raw material cost.

Key words: silicon cutting waste liquid, recycled polyethylene glycol, polyethylene glycol laurate