Emulsifying agents from natural products

Table 3 Emulsifying agents derived from natural products and finely divided solids...

Emulsion Adhesives. The most widely used emulsion-based adhesive is that based upon poly(vinyl acetate)—poly(vinyl alcohol) copolymers formed by free-radical polymerization in an emulsion system. Poly(vinyl alcohol) is typically formed by hydrolysis of the poly(vinyl acetate). The properties of the emulsion are derived from the polymer employed in the polymerization as weU as from the system used to emulsify the polymer in water. The emulsion is stabilized by a combination of a surfactant plus a coUoid protection system. The protective coUoids are similar to those used paint (qv) to stabilize latex. For poly(vinyl acetate), the protective coUoids are isolated from natural gums and ceUulosic resins (carboxymethylceUulose or hydroxyethjdceUulose). The hydroHzed polymer may also be used. The physical properties of the poly(vinyl acetate) polymer can be modified by changing the co-monomer used in the polymerization. Any material which is free-radically active and participates in an emulsion polymerization can be employed. Plasticizers (qv), tackifiers, viscosity modifiers, solvents (added to coalesce the emulsion particles), fillers, humectants, and other materials are often added to the adhesive to meet specifications for the intended appHcation. Because the presence of foam in the bond line could decrease performance of the adhesion joint, agents that control the amount of air entrapped in an adhesive bond must be added. Biocides are also necessary many of the materials that are used to stabilize poly(vinyl acetate) emulsions are natural products. Poly(vinyl acetate) adhesives known as "white glue" or "carpenter s glue" are available under a number of different trade names. AppHcations are found mosdy in the area of adhesion to paper and wood (see Vinyl polymers). 

The net effect of this questionable attitude thrust upon FDA was that sucrose esters went into commercial production in Japan rather than in the land of their discovery. In Japan they go into cake mixes as emulsifying agents, and so far they have hurt no one. The process of digestion splits the sucrose ester into fatty acid and invert sugar, compounds that are normally present in the body. More recently I have seen reports that the French are using sucrose esters in animal feeds. The results of experiments synthesizing sucrose esters from acid anhydrides, to be reported later in this symposium, are, naturally, of great interest to me. 

Aluminum is present naturally in tea and some vegetables. Aluminum is introduced into grain products and processed cheese from aluminum-containing food additives. These products are used as acidifiers, buffers, leavening agents, emulsifiers, stabilizers, thickeners, and anticaking agents. For example,... 

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