Ternary pressure sensitivity

As with pressure sensitive adhesives, general purpose water-borne adhesives often involve blend combinations to yield the desired balance of properties for a myriad of applications. An evaluation of three emulsions (acrylic, epoxy and a urethane) (using a simplex blending study) was conducted for polyester/LLDPE, polyester/nylon and A1 foil/polyester lamination [142]. In each lamination, a ternary blend gave the optimized performance when a number of properties were considered. 

If the azeotrope is not sensitive to changes in pressure, then an entrainer can be added to the distillation to alter in a favorable way the relative volatility of the key components. Before the separation of an azeotropic mixture using an entrainer is considered, the representation of azeotropic distillation in ternary diagrams needs to be introduced. 

AF Compounds. The stmctures of the dkali fluorides are all of the NaCl type however, the sensitivity to moisture for the K, Rb, and Cs compounds and their high-pressure phase transitions to the CsCl type show an increasing tendency to adopt the higher coordination number 8 with increasing ionic radius. In ternary compounds, it is mostly easier to adopt a more suitable coordination sphere of fluoride ligands Li+ may have tetrahedral coordination such as in scheelites LiMp4 and a few other compounds (see Section 3.2.13) but has normally CN 6. Na+ shows CN 6-8 with a certain favoring of CN 7. K+ clearly prefers CN 8, and Rb+ and Cs+ CN 10 to 12, in some cases up to 18. 

Jenner and Kellou recently studied the pressure effect on azeotropy in free-radical terpolymerization of MA with acrylonitrile, dielthyl fumarate, methyl acrylate, methyl methacrylate, methyl vinyl ketone, vinylidene chloride, norbornene, a-methylstyrene, indene, and vinyl acetate, with styrene as the second comonomer common in all cases. It was found that ternary azeotropes were only possible for those systems where the first comonomers had positive e values, i.e., diethyl fumarate, acrylonitrile, methyl acrylate, methyl methacrylate, methyl vinyl ketone, and vinylidene chloride. Surprisingly, the coordinates of the ternary azeotropes were very little affected by variations of the pressure from 1-3,000 bars. Since reactivity ratios in multi-component polymerizations are sensitive to pressure, causing terpolymer composition to also be pressure dependent, a shift of the ternary azeotropic point would be expected. Why this occurs awaits further clarification. 

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