Abstract: A new kind of non-ionic polymeric surfactant, the dimeric fatty acid (DFA)/polyethylene glycol (PEG) polyester terminated with rosin acid, was prepared with rosin acid and a polyester which was synthesized from DFA and PEG 400, and its surface activities were studied. The optimum reaction conditions of esterification were as follows:molar ratio of DFA/PEG 400 1:1.20, stannous chloride as the preferable catalyst at amount 0.30% of DFA, reaction temperature 200℃, reaction time 6 h, the conversion can reach 98.11%. Number-average molecular weight (M_n) of the product is 6 135. Weight-average molecular weight (M_w) of the product is 7 438. The coefficient of distribution of molecular weight (M_w/M_n) is 1.212, which indicates a narrow distribution of molecular weight. Orthogonal experiment results of rosin acid terminated reaction of dimeric fatty acid polyethylene glycol polyester showed that optimum reaction conditions were as follows:molar ratio of materials n(DFA/PEG polyester):n(rosin acid) 1:1.30, dosage of catalyst SnCl₂ 0.20% of polyester, reaction temperature 215℃. After 2.8 h, termination ratio of the end hydroxyl groups of polyester reached 62.75%. Rosin acid terminated DFA/PEG polyester surfactant has excellent emulsification properties, emulsification stability, power to disperse calcium soap as well as performances of defoaming and inhibiting foaming.

Key words: rosin acid terminated dimeric fatty acid/polyethylene glycol polyester, dimeric fatty acid, rosin acid, non-ionic polymeric surfactant