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Latex complexes, solubilized

Formation of solubilized surfactant-latex complexes can influence the properties and performance of vinyl acrylic latexes prepared with NaLS and other penetrating type anionic surfactants. Such complexes seem to affect glass transition temperature and film coalescence process (12). [Pg.232]

Recent investigations have shown that the behavior and interactions of surfactants in a polyvinyl acetate latex are quite different and complex compared to that in a polystyrene latex (1, 2). Surfactant adsorption at the fairly polar vinyl acetate latex surface is generally weak (3,4) and at times shows a complex adsorption isotherm (2). Earlier work (5,6) has also shown that anionic surfactants adsorb on polyvinyl acetate, then slowly penetrate into the particle leading to the formation of a poly-electroyte type solubilized polymer-surfactant complex. Such a solubilization process is generally accompanied by an increase in viscosity. The first objective of this work is to better under-stand the effects of type and structure of surfactants on the solubilization phenomena in vinyl acetate and vinyl acetate-butyl acrylate copolymer latexes. [Pg.226]

Lower molecular weight (300-800) anionic surfactants such as NaLS and Alipal EP-110 adsorb at a vinyl acrylic latex in a complex C-type adsorption isotherm, leading to penetration and solubilization of latex. [Pg.232]

However, the preparation of latex particles may be perceived as having reached a level at which the potential for a fundamental breakthrough in the final materials per se is rather limited. Pioneering efforts may instead be expected in the development of polymeric microcompartmentalized materials. This development, in a limited form, may be exemplified by the work of Gan and colleagues [28], who polymerized organic monomers solubilized in bicontinuous microemulsions and obtained microporous organic polymers. This area is, of course, of future interest, but the problem of lack of correlation between the microemulsion colloidal structure and the microstructure of the final material may result in a focus on the polymerization of liquid crystalline material where even complex systems [29,30] have been shown to retain their microstructure after polymerization. This area of polymerization has been further developed and systematized by Antonietti [31,32], Antonietti et al. [33], and Fendler [34]. [Pg.835]

Aqueous dispersions of charged copolymer latexes are active supports of cobalt catalysts for autoxidations of tetralin by cobalt-pyridine complexes and of 2,6-di-rm-butylphenol and 1-decanethiol by CoPcTs. Since these reactants are insoluble in water, a simple explanation of the catalytic activity is that the organic polymer serves to solubilize the reactants in the phase that contains the cobalt catalyst. All three reactions have initial rates that are independent of substrate concentration, as determined by absorption of dioxygen from a gas buret. All three reactions appear to proceed by different mechanisms. Tetralin autoxidation is a free radical chain process promoted by the CoPy complex, whereas the CoPcTs reactions are not free radical chain processes. The thiol autoxidation is reported to involve hydrogen peroxide, whereas the 2,6-di-re/t-butylphenol autoxidation apparently does not. [Pg.170]

To prepare stable PVC latexes by emulsion polymerization of VC, considerable attention must be paid to the choice of a proper emulsifier. The emulsifier greatly affects the reaction kinetics and the physico-chemical and colloidal properties of the final polymer product and/or the dispersion [98]. The choice of the proper emulsifier is a complex problem because of its manifold functions, e.g. the surf ace tension of the aqueous solution, emulsification or solubilization of oil-soluble monomers or additives, and the protection of latex particles against flocculation [99]. [Pg.166]

Surfactant—polymer systems have additional technological significance since surfactants are normally used in the emulsion polymerization of many materials, often involving the solubilization of monomer in micelles prior to polymerization and particle formation. Surfactants have also been shown to increase the solubility of some polymers in aqueous solution. The combined actions of the surfactant as a locus for latex particle formation (the micelle) in some cases, particle stabilization by adsorbed surfactant, and as a solubilizer for monomer permit us to expect quite complex relationships between the nature of the surfactant and that of the resulting latex. [Pg.242]

The ability of surfactants to form complexes with polymer chains may also affect the ultimate properties and stability of the resulting polymer, especially when the macromolecule exhibits some affinity for or reactivity with water. Perhaps the best documented case of the effect of surfactant on latex stability is that of polyvinyl acetate. The stability of PVAc latexes has been found to vary significantly depending on the surfactant employed in its preparation. It has also been found that PVAc could be dissolved in concentrated aqueous solutions of SDS and that it did not precipitate on dilution. The results suggest that, in this case at least, solubilization did not occur in the micelle, but that extensive adsorption of surfactant onto the polymer chain was required. They also indicate that a strong, stable PVAc-SDS complex is formed that produces a water-soluble structure that is essentially irreversible, imlike normal micelle formation. Cationic and nonionic surfactants had little or no solubilizing effect under identical conditions, indicating the specific nature of many, if not most, polymer-surfactant interactions. [Pg.242]


See other pages where Latex complexes, solubilized is mentioned: [Pg.628]    [Pg.289]    [Pg.232]    [Pg.238]    [Pg.14]    [Pg.543]    [Pg.2358]   
See also in sourсe #XX -- [ Pg.231 ]




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Solubilization complexation

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