Preparation of polyoxyethylene(n) monodehydroabietates and their physicochemical properties

Abstract A series of nonionic surfactants, polyoxyethylene(n) monodehydroabietates (PEGylated DHAAs), were synthesized by an addition polymerization reaction between dehydroabietic acid (DHAA) and ethylene oxide (EO). The structures of PEGylated DHAAs were characterized by FTIR, UV–Vis and 1 H NMR, and their hydrophilic-lipophilic character and surface activities were evaluated by water titration and surface tension measurement, respectively. Meanwhile, the degree of polymerization of the PEG chain in the structure of PEGylated DHAAs was determined according to the results of 1 H NMR analysis, and its influence on the hydrophilic-lipophilic character and performance of the surfactant in aqueous solution was systematically investigated. The experimental results showed that the degree of polymerization of the PEG chain has a significant influence on the hydrophilic-lipophilic character, the critical micelle concentrations (CMCs) of PEGylated DHAAs and their surface tensions at CMC ( γ CMC ), while it had little effect on their minimum of surface tensions ( γ min ).