In seed polymerization, a part of monomers are first polymerized to obtain the core (seed) of the emulsion, and then other polymerization monomers and initiators are added again to continuously polymerize on the original core to obtain the shell of the emulsion, thus preparing latex particles with narrow distribution and core/shell structure.Yu[1] et al. prepared a series of polymer emulsions with MMA/BA interpenetrating polymer network (IPN) structure by seed polymerization. The particle size of the obtained emulsion is between 150nm and 250nm. Fourier transform infrared spectroscopy (FT-IR) analysis confirmed that the obtained polymer was a crosslinked copolymer. Acrylonitrile (AN)-St-AA emulsion was synthesized by Tolue[2] et al. through two-step emulsion polymerization. The obtained core layer T is-49.7-58.7% C, and the shell layer Tg is about 104℃. Kan[3] et al. studied the emulsion copolymerization of MMA ethyl acrylate (EA) and MA seeds. The results showed that in the second stage, the particle size of the emulsion increased from 483nm to 829nm, and the ratio of most core/shell monomers decreased from 1: 2 to 1:15.