Emulsion blends

Although many combinations of emulsion blends have been commercially utilized, the technical literature on properties/characterization of simple emulsion blends is limited. This is not the case, however, with a specific subset of emulsion blends referred to as core-shell polymers discussed earlier and will be detailed later in this section. The term emulsion used in this section refers to aqueous based emulsions, unless noted otherwise. 

Cast films of emulsion blends comprised of non-fluorinated acrylics and fluorinated acryhcs exhibited surface enrichment of the fluorinated acryhc upon exposure of the film above the film formation temperature of the fluorinated acryhc [546]. Similar results were observed for smaU particle size fluorinated acryhc copolymer emulsion blends with large particle size S-nBA copolymers [547]. The combination of low free energy and smaller size of the fluorinated acryhc particles (excluded volume/percolation) yielded much higher concentration of the fluorinated polymer at the surface than in the bulk film. 

A technique for compatibilization of emulsion blends involves separate partial polymerization of two different concentrated emulsions fohowed by mixing and optionally adding additional initiator and completion of the polymerization [548-550]. In one example, polystyrene and a small amount of acryhc add comprised one emulsion and PnBA or 

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Several hybrid epoxy emulsions have been commercially prepared. An epoxy emulsion blended with waterborne aliphatic urethanes exhibited peel strength on aluminum of 10 lb/in—1.5 times greater than with the polyurethane itself. The optimum concentration of urethane in the final emulsion was about 50 percent by weight.13 Epoxy-phenolic dispersions have also been developed to provide waterborne adhesive systems with high glass transition temperature and chemical resistance. 

Water Repellents 7jirconium/wax emulsion blend Cotton, Rayon, Acetate... 

The structural and rheological properties of emulsions, blends, and foams are of great importance in the food, cosmetics, oil-field, and packaging industries. By definition, such fluids are thermodynamically unstable or at best metastable. Hence, conditions of preparation are of extreme importance to both the scientific study and the engineering of these fluids. 

Defomax. [Toho Chem. Industry] Nonionic surfactant/wax emulsion blend andfoaming agent for rubbers and plastics. 

In spite of decades of commercial utility the fundamental relationships involved with emulsion blends has only recently begun to be smdied. This is a least partly due to the also recent interest in film formation. 

It was observed that intermediate compositions dried slower than the unblended constituents. The mechanical properties of latex blends comprising low and high particles, the film formation ability, and the comparison of results to classical theory of polymer blends containing hard particles have been reported by Lepizzera et al. [1997], This is one of the few studies in the literature that has attempted to correlate emulsion blend properties with empirical/theoretical relationships previously available in the open literature. 

Table 2.1 presents a summary of the information available in the scientific literature for C and OC dispersion in isoprene rubbers. The state of dispersion depends on the clay type, pristine or organically modified, and on the blending technology adopted. Table 2.2 shows that nanocomposites are formed with a pristine clay only through emulsion blending. In fact, the inorganic nature of clay layers hinders their compatibility with the rubber matrix. 

Table 2.3 summarizes what arises from the scientific literature for the emulsion blending of CNTs in NR latex. 

Table 2.3 Dispersion of CNT in NR matrix through emulsion blending.

Barrier properties of a rubber matrix are remarkably improved thanks to clay addition. The tortuous path model is proposed to explain this phenomenon. In a NR/Mt nanocomposite prepared from emulsion blending, 1, 2 and 3 phr of clay led to more than 35% and to about 45% and 50% reduction of oxygen permeability, respectively. " 3 phr of OC (Mt/ didodecyl methyl amine) gave a 50% reduction of the oxygen permeability and a 40% reduction of toluene absorption at 20 °C. About 10% and 15% reduction of oxygen permeability were obtained with 5 and 10 phr of OC, respectively, and 30% reduction of toluene absorption was achieved with 15% OC, at 30 °C. ... 

An excellent Mt dispersion, also at a level of 20 phr, was observed when emulsion blending was adopted, with both individual and stacking silicate layers with a thickness of about 10-30 nm. 

Journal of Applied Polymer Science 81, No.9, 29th August 2001, p.2109-17 EFFECT OF NETWORK MORPHOLOGY ON ADHESIVE PERFORMANCE IN EMULSION BLENDS OF ACRYLIC PRESSURE SENSITIVE ADHESIVES... 

Division 1.5—explosives that are very insensitive. Division 1.5 explosives have a mass explosion hazard but are very unlikely to initiate or detonate from burning under normal transportation conditions. Typical examples include blasting agents, ANFO, non cap-sensitive emulsions, blends, slurries, water gels, and other explosives that require a booster for initiation. 

Emulsion blends Crystalline-crystalline polymer blends... 

Figure5.20 AFM of an emulsion blend of poly(vinyl acetate) and a vinyl acetate-ethylene-vinylchloride terpolymer (as cast) (Reprinted from Robeson, L.M.and Hyder,. Z.,J.Appl.Polym.Sci.(2003) 90, p. 933, with permission of John Wiley Sons, Inc.)...

AFM has been utilized successfully to measure the film formation characteristics of emulsion polymers [116,117], including emulsion blends [118,119]. With emulsion blends comprised of a high Tg/lowTg immisdble emulsion blend, the individual high Tg particles are easily resolved for room temperature cast samples as shown in Fig. 5.20. With annealing, the high Tg particles coalesce with the structure shown in Fig. 5.21. 

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