Synthesis and Charaterized of Thickener by Soap-Free and Seeded Emulsion Polymerization *

A kind of acrylates copolymer thickener was prepared by soap-free and seeded emulsion polymerization. In order to obtain functional polymer latex particles with clean surface and with surface carboxyl groups, Poly(sty- rene-methacrylic acid) (P(St-MAA)) seed particles with the diameter of 250 - 300 nm were synthesized via soap-free emulsion polymerization. Then the seeded emulsion copolymerization of ethylacrylate (EA), lauryl methlacrylate (LMA), St and MAA onto the seed particles were performed in the absence of emulsifier. The content of LMA effected for the particles size and the stability of the emulsion was studied. The thickening performance of this polymer latex was quite good with the high thickening performance, good suspension ability, good transparence and easy to use. The factors of the copolymerization and the properties of the emulsion were discussed. Its structure and morphology were characterize by fourier transform infrared spectrometer (FT-IR) and transmission electron microscope (TEM).