Synthesis and properties of soap-free poly(methyl methacrylate-ethyl acrylate-methacrylic acid) latex particles prepared by seeded emulsion polymerization

In order to obtain functional polymer latex particles with clean surface and with surface carboxyl groups, P(MMA-EA) seed particles with the diameter of 335 nm were first synthesized via soap-free batch emulsion polymerization of methyl methacrylate (MMA) and ethyl acrylate (EA), and then the seeded emulsion copolymerization of MMA, EA and MAA (methacrylic acid) onto the seed particles were performed in the absence of emulsifier. Influences of ingredients and conditions on polymerization, latex particle size (Dp) and its distribution were investigated. Results showed that most of the monomers polymerized onto the seed latex particles in the second step of polymerization by using drop-wise addition method, and Dp increased from 483 nm to 829 nm with the mass ratio of core/shell monomers [C]/[S] decreased from 1:2 to 1:15. It was found that Dp decreased with the increase of MAA and initiator amounts, and the size of the latex particles became uniform with the decrease of MAA amount and with the increase of [C]/[S] value.