Effect of Neutralizing Amine on Stability of Emulsions Prepared with Carboxy Vinyl Polymers

Synopsis The influence of chain length and concentration of neutralizing amine on the stability of carboxy vinyl polymer stabilized emulsions was studied. Stability was based on the per cent of oil released under centrifugation at 13,000 rpm. Whereas the short chain length butylamines and the longer chain length amines (C s or higher) generally yielded poor emulsions, hexylamine and 2-ethylhexylamine gave stable emulsions over a wide pit range. The stability of these emulsions is discussed in terms of orientation of the polymer at the droplet-continuous phase interface. The degree of adsorption seems to l>e dependent on the 1)•fiy•m'r conformation and hydrophilic-lilmphilic balance. i NTRODU CTION Stirface active cmulsifiers that orient at the droplet continuous phase interface and that produce a more or less rigid film serve to reduce markedly the rate of coalescence. They prevent the droplets of the internal phase from losing their discreteness, even upon close approach. It should be noted that these surface active agents may not influence the rate of cream-ing to any significant degree. Some hydrophilic polymers which act by modifying the rheological properties of the dispersion medium, i.e., viscosity and yield value, may further increase the stability of such emulsions. These polymers act by decreasing the rate of creaming without, in many instances, influencing directly the rate of coalescence