Emulsion polymerization in the presence of polymerizable emulsifiers and surface active initiators

Abstract

A survey is given of recent developments in emulsion polymerization regarding improved auxiliary materials, e.g. vinyl tensides and surface active initiators. Results of the emulsion polymerization of styrene are presented with 3‐(alkyloxycarbonyl‐acryloyloxy)propanesulfonates (2) as polymerizable emulsifiers and with surface active azo initiators. The results show, that the content of water soluble surface active compounds in the latexes can be reduced. Investigations of the molecular weight of the polymers show the great importance of the initiator‐emulsifier system. Azo initiators leading to higher molecular weights than persulfate. Under the same conditions the highest molecular weights were obtained with a surface active azo initiator.

Interaction between Polyelectrolytes and Latices with Covalently Bound Ionic Groups

“…Since the amount of bound polycations could not be calculated from the increase of the mass of the latex particles, we tried to determine it from the concentration change of free polycations in the original solution and after the mixing with latex. PEC formation offers a very sensitive method for a quantitative analysis , c A° = 5 10~5 g cm' 3 ) at different degrees of conversion (Figure 7). While the scattering curves up to X = 0.9 are quite similar, a sharp transition to a highly aggregated system occurs at full conversion, which is indicated by a change of the scattering intensity of about a factor 50 and a strong curvature of the scattering curve.…”

“…The latex was synthesized by emulsion polymerization employing a non-ionic initiator and a monomer emulsifier with sulfonate groups (2,3), which is primarily incorporated at high degrees of conversion (Figure 1), leading to high charge density on the surface of the latex particles. Conditions of polymerization see Table 1.…”

“…, 8 mL latex with concentrations of c L = 5 10' 4 g cm' 3 and 1 10" 3 g cm' 3 respectively, corresponding to 22% and 44% of the charges of polycations. After separation of the coated latex by ultracentrifugation, the PC concentration was determined by PEC formation with NaPSS (c A = 5 10" 5 g cm' 3 ) in comparison with a pure PC solution.…”

“…After separation of the coated latex by ultracentrifugation, the PC concentration was determined by PEC formation with NaPSS (c A = 5 10" 5 g cm' 3 ) in comparison with a pure PC solution. The titration curves are given in Figure 8.…”

“…The titration curves are given in Figure 8. Curve 1 corresponds to the titration of 8mL pure PC solution of a concentration c c = 2.5 10" 5 g cm 3 . The full lines mark the points of 1:1 stoichiometry, taking into account the binding of polycations on the separated latex.…”