INFLUENCE OF FUNCTIONAL COMONOMERS ON THE STABILITY OF EMULSIFIER-FREE ACRYLATE LATEXES

The influence of functional comonomers of varying degrees of solubilit y in the aqueous phase and containing groups capable of forming crossl inked structures on the stability of emulsifier-free acrylate latexes was studied. This study was carried out in order to develop a basis fo r the synthesis of a film-forming latex of high quality. Stability of the particles was estimated in terms of electrostatic and structural f orces of the particle interactions. Hydrophilic-hydrophobic properties of the functional comonomers were shown to affect zeta-potential of t he particle surface and the coefficient of the structural forces of at traction K-a. The latter was calculated with account for the stability , size, and number of particles. A decrease in stability of the latexe s with an increase in hydrophobicity of functional comonomers was demo nstrated to correlate with a drop of zeta-potential of the particle su rface and with an increase in coefficient K-a. The proposed approach t o estimating the stability indicates the possibility of synthesis of s table, modified, concentrated latexes under concentrations of function al comonomers controlled by their hydrophilic-hydrophobic properties. Hydrophilic comonomer improves the stability of particles in compariso n with an unmodified system due to a decrease in the structural forces of attraction and an increase in the electrostatic forces of repulsio n, thus making it possible to increase the concentration of this comon omer in the latex recipe, Hydrophobic comonomer reduces the stability of particles as compared to an unmodified system due to the opposite e ffect on the electrostatic and structural factors. Therefore, smaller amounts of these comonomers are required to achieve stability of the d ispersions and adequate parameters of the film-forming latexes.