Suspension properties of Gemini surfactant, polyethylene glycol diester alpha sulfonated stearic acid disodium salt, on 15% thiram/carbofuran/triadimefon seed coating agent of maize, 17% carbendazim/carbofuran/triadimefon seed coating agent of wheat and 15% carbendazim/thiram/triadimefon seed coating agent of cotton were studied. Under these conditions, Gemini surfactant had a good suspension property by itself and an excellent synergistic effect with some nonionic surfactant such as OP‐10, Tween 80, and AEO‐7. Also, it can be mixed with attapulgite clay to provide a better suspension property than suspension system without attapulgite clay. Its suspending rates on three kinds of seed coating agents mentioned above are, respectively, up to 97%, 95%, and 98% for 90 days. In comparison with traditional surfactant suspending agent of LAS and SDS, Gemini surfactant had less changes in suspending efficiency at high temperatures, and in viscidity in impact tests. In a germination experiment, cotton seeds coated with Gemini surfactant suspending agent have an 88% germination rate for 10 days and a 69% excavation rate, which was higher than those bare seeds, and grow fully.
The authors are grateful for the financial support received from the Natural Science Fund Key Project of Anhui Educational Committee of China (contract: 2006KJ045A).