Stability of PVC latices

Figure 3. Mechanical stability of PVC latices. Effect of particle size and emulsifier level. Polymer 45% by weight. Na 0.01 mol/l.

Poljmierisation to high solids content has been described in the patent literature (12). However for emulsion polymers a serious problem is one of mechanical stability during polymerisation. Palmgren (22) has studied the mechanical stability of monodisperse PVC latices as a function of particle size, emulsifier concentration, electrolyte concentration and residual monomer content. The mechanical stability of PVC latices of different particle size containing different surface concentrations of SDS emulsifier is shown in Fig 4. At a given emulsifier coverage on the latex, these data indicate that the latex stability decreases with increasing particle size. Latex... 

Our understanding of the formation and stability of monomer emulsions which can be subsequently polymerised has been advanced considerably by the work of Ugelstad, both in general terms (14) and specifically in relation to PVC (9). These reveiws have suggested several new methods by which PVC latices may be prepared ... 

Water-soluble EMA resins and derivatives of these materials function very well as dispersants (Table A.3). For example, the amide-salt derivative exhibits excellent dispersant properties for pigments in waterborne synthetic latice systems. Dispersants for the coatings, rubber, leather, cosmetic, ceramics, photographic film, and agricultural field have been claimed for EMA resins. The linear derivatives are especially useful as dispersants and stabilizers for emulsion bead polymerizations. For example, EMA-type dispersants (emulsifiers) are very useful for PVC production. The resins also function well as macromolecular dispersants for the suspension copolymerization of a-olefins and aromatic vinyl compounds with MA. ... 

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