Inverse emulsion polymerization is developing rapidly in recent years. The polymerization method has the following advantages, such as high polymerization rate, a highly decentralized and uniform size of polymerization particles. The water-oil inverse emulsion was prepared with the compounds of Span80 and Tween60 as emulsifier. It was investigated by way of electric conductivity that the types and stability of the inverse emulsion was affected by many kinds of factors such as emulsification time, rotate speed, HLB value and emulsifier concentration, ratio of oil to water, and the optimum conditions for forming stable water-oil inverse emulsion were attained as the emulsification time about 35 [KG*4]minutes, the [KG*4]rotate [KG*4]speed [KG*4]on 14 000 r/min, HLB value of mixed emulsifier at 5.0, the mass ratio of oil to water in 1∶1, and the content of the mixed emulsifier at 4%. Based on the experimental results, some aspects of the stability mechanism were explained.

The effects of ethylene-vinyl acetate copolymer（EVA） on the Zeta potential of wax crystals were studied by micro-electrophoretic equipment. The results show that when EVA content is low, the Zeta potential increases with EVA content. When EVA content reaches 600 μg/g, the Zeta potential（9.8 mV） doesn't increase with the increasing of EVA content. When the average carbon atom number of ethylene chain reaches 30 or so, the Zeta potential reaches the maximum 10.86 mV. When VA chain content reaches 45%, the Zeta potential reaches the maximum 15.0 mV. When the branch degree of EVA increases, the Zeta potential of wax crystals reduces. When the average molecular weight of EVA reaches 1.2×10 ⁴, the Zeta potential reaches the maximum 11.8 mV. 