Uniform latex particles

In this chapter, the polymerization methods used for the production of uniform latex particles in the size range of O.I-lOO /Ltm are described. Emulsion, swollen emulsion, and dispersion polymerization techniques and their modified forms for producing plain, functionalized, or porous uniform latex particles are reviewed. The general mechanisms and the kinetics of the polymerization methods, the developed synthesis procedures, the effect of process variables, and the product properties are discussed. 

Table 5 Typical Dispersion Polymerization Recipes Providing Uniform Latex Particles...

Another group of uniform latex particles were prepared by the dispersion polymerization of acrolein in an aqueous medium by Margel and coworkers [96], A typical polymerization was conducted in the aqueous alkaline medium having a pH of 10.5, which was obtained by the aqueous NaOH solution. Polyglutaraldehyde-NaHS03 conjugate was synthesized by the reaction of... 

Multistage emulsion polymerization techniques are usually applied for (1) the synthesis of large uniform latex particles, (2) the introduction of functional groups into the uniform latex particles, or (3) the synthesis of macroporous uniform latex particles. 

Multistage emulsion polymerization has been proposed by Ugelstad et al. [108,109] for the synthesis of large uniform latex particles. In general, the multistage emulsion polymerization techniques include two main... 

The specific resistances obtained are independent of applied load, suspension concentration and membrane type, as expected for non-compressible filter cakes. Tests with uniform latex particles have given permeabilities in very good agreement with Equation 2, using a value of 5 for the Carman-Kozeny constant. 

The major distinction between the model of La Mer and that developed for uniform latex particles lies in the incorporation of colloidal stability of small particles. The La Mer model assumes that each nucleus is colloidally stable and survives at the end of the reaction at the center of a particle. The aggregation models argue that stabilizing primary small particles is difficult, but aggregation does not necessarily result in a broad particle-size distribution. When schemes for control of particle-size distribution are developed, the result of accepting the notion that colloidal stability can play an important role is that attention is focused away from the length of the nucleation period and towards the colloidal properties of the growing particles. 

The papers by Okada et al. (1990a, 1990b) can be estimated as an important novelty in the experimental investigation of the elementary microflotation act and the role of hydrodynamic and surface forces. The mean diameter of bubbles fed into the cell was 33pm. Three kinds of uniform latex particles of different diameter (0.9,2.9, and 6.4pm) were used as model particles. In order to change the surface charges of bubbles and particles three types of surfactants (cationic, anionic and nonionic) and AlCl, were used. The electrokinetic potentials of bubbles... 

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