Rubberlike materials, designated as Lactoprene, were prepared In earlier investigations by copolymerizing ethyl acrylate with small proportions of butadiene, Isoprene, or allyl maleate, compounding the resulting copolymers (assumed to have olefinic unsaturation) with sulfur and accelerators, and then curing the compounded products.

Effects of various agents on the emulsion polymerization of acrylic esters are described, and directions are given for preparing several types of resin emulsions. When emulsion polymerization is used merely to convert monomeric acrylic esters into polymers or copolymers of relatively high molecular weight, Tergitol Penetrant No. 4 and ammonium persulfate can be used satisfactorily as emulsifier and polymerization catalyst, respectively. The resulting emulsion is only moderately stable and can be coagulated readily by the addition of aqueous solutions of sodium chloride, acetic acid, or mixtures of the two. Triton K60 and hydrogen peroxide also can be used conveniently to produce emulsions of only moderate stability. Emulsions remarkably stable to electrolytes (but not to mechanical agitation or solvents such as acetone and ethanol) can be made with Triton 720 as the emulsifier. Triton 720 and Tergitol Penetrant No. 4 can be used together in various proportions to produce emulsions of almost any desired

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INDUSTRIALAND ENGINEERING CHEMISTRY hydrogen ions. The heterogeneous hydrolysis in the interface takes place only in the initial stage. Its speed is low compared with that of the homogeneous reaction._ 2. The reagents of both processes act similarly-that is, by dissolving in the oil phase as the reaction goes on, increasing the water solubility in it, and activating the water by liberating hydrogen ions. The requirements for a good reagent are strong solubility in fats and weak solubility in water, and the presence in the molecule of ions or functional groups which are strongly hydrated and capable of producing free hydrogen ions directly or indirectly.3. The rate of hydrolysis increases with temperature and amount of reagent. It. also depends on the nature of the reagent. 4. The reaction limit depends exclusively on the ratio of fat to water; it is greater when the proportion of water increases.

Acrylic ester copolymers containing vulcanrzable unsaturation were prepared by polymerizing methyl acrylate or ethyl acrylate with small quantities of polyfunctional monomers, such as butadiene, isoprene, and allyl maleate. Compounding the soft copolymers with sulfur and accelerators, followed by curing, produced rubbery vulcanize tes. Several abundant carbohydrates can be converted, through lactic acid as an intermediate, into approximately an equal weight of vulcanized acrylic resins. Because of the key role played by lactic acid in this transformation, the name "Lactoprene" is proposed for synthetic rubber of this type as described here.