The use of utraviolet-visible spectrophotometry in the determination of average properties of nonylphenol ethylene oxide condensates

Ultraviolet spectrophotometry is usd in the determination of average molecular weight (M), average degree of polymerization (X), the hydrophilic-lipophilic balance (HLB) and ethylene oxide percentage of nonylphenol ethylene oxide condensates. The method is based on determination of the absorptivity a, expressed in g lt-1 cm−1, from the absorbances measured at 275 nm for a series of dilutions of an aqeuous ethanolic solution (60:40, v/v/) of a given product, followed by numerical interpolation of this value in the expression a = f(HLB), log a = f(log M), and log a = f(log X). These expressions are obtained from reference samples or samples previously analyzed. The proposed method gives relat…