Use of low‐temperature differential scanning calorimetry for determination of ethylene oxide content in some nonionic surfactants

Abstract Low‐temperature differential scanning calorimetry studies on ethoxylates of hydrogenated castor oil and 12‐hydroxystearic acid show endothermic transformations that could be ascribed to melting of ethylene oxide (EO) components of the surfactant molecule. The ethoxylation process also results in formation of free polyethylene glycol (PEG). Separation of free PEG followed by area under the curve measurements enabled estimation of EO content of the product formed during manufacture. The melting endotherm provided additional information on the chain‐length distribution of polyoxyethylene units in the surfactant.