Emulsion Polymerization of Acrylic Esters

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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.

Section: Effect Of the Emulsifiermentioning

confidence: 99%

“…Emulsions having excellent stability to friction can be made by the incorporation of 0.5% or more of a suitable agent, such as modified casein and alginic acid derivatives. These agents may be added before or during the polymerization (13).…”

mentioning

confidence: 99%

Emulsion Polymerization of Acrylic Esters and Other Vinyl Monomers

Mast¹,

Fisher²

1949

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“…of acrylic esters and dienes such as butadiene have been found (8,8) capable of undergoing vulcanization with sulfur and certain accelerators. It was observed subsequently (6,8) that halogen-containing acrylic resins, prepared conveniently (9) by copolymerizing 95 parts of ethyl acrylate with approximately 5 parts of either 3-chloropropyl acrylate or 2-chloroethyl acrylate, also can be vulcanized with sulfur and with certain other agents. Since polymeric ethyl acrylate is not sulfur-vulcanizable it was assumed that olefinic linkages and halogen atoms, respectively, are responsible for sulfur vulcanization of the ethyl acrylate-butadiene and ethyl acrylatechloropropyl acrylate copolymers.…”

Section: Copolymersmentioning

confidence: 99%

“…It was thought that, in order to be completely satisfactory for the preparation of vulcanizable ethyl acrylate copolymers, the chlorine-containing monomer should meet the following requirements: (1) It should be actually or potentially inexpensive and available commercially; (2) the boiling point at atmospheric pressure should be between approximately 50°and 200°C . ; (3) it should be capablé of distillation without decomposition or premature polymerization, and (4) capable of copolymerizing readily and satisfactorily with ethyl and other alkyl acrylates; (5) it should not lower the molecular weight of the copolymer seriously; (6) the copolymer formed should be capable of being vulcanized at a satisfactory rate by several different recipes; (7) it should not cause pitting, bubbling, or blowing during vulcanization; (8) it should not raise the brittle point appreciably; (9) it should not adversely affect the milling and processing ease of the copolymer; and (10) the vulcanizates should have satisfactory tensile, elongation, hardness, and other characteristics. This list of desirable characteristics was based on the properties of copolymers of ethyl acrylate and approximately 5% of the chlorine compound.…”

Section: Chlorine-containing Monomersmentioning

confidence: 99%

Vulcanization of Chlorine-Containing Acrylic Elastomers

Mast¹,

Fisher²

1948

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“…The field of acrylate elastomers has been recently reviewed by Riddle (IS), from the standpoint of both monomer synthesis and commercial utilization of the polymers. The preparation and properties of a large series of acrylate elastomers have been extensively investigated by the Eastern Utilization Research Branch, United States Department of Agriculture (6)(7)(8)11). To effect vulcanization, chlorine-containing monomers have been copolymerized with the acrylate monomer, as described by Mast and Fisher (5).…”

mentioning

confidence: 99%

Butyl Acrylate Elastomers Cast from Latex

Fram¹,

Szlachtun²,

Leonard³

1955

HE development of synthetic rubbers has progressed along T many divergent paths, yielding elastomers capable of meeting unusual requirements in many special applications. One application of an elastomeric material requiring an unusual combination of properties is the "cosmetic" glove used to cover a mechanical hand or an artificial restoration for an amputee. Among the many types of synthetic elastomers, the acrylates possess many of the exceptional properties that are demanded by the stringent technological requirements in this application.The field of acrylate elastomers has been recently reviewed by Riddle ( I % ) , from the standpoint of both monomer synthesis and commercial utilization of the polymers. The preparation and properties of a large series of acrylate elastomers have been extensively investigated by the Eastern Utilization Research Branch, United States Department of Agriculture (6-8, 11). T o effect vulcanization, chlorine-containing monomers have been copolymerized with the acrylate monomer, as described by Mast and Fisher ( 5 ) . Owen (10) and Semegen ( 1 6 ) have also discussed vulcanization methods that yield useful elastomeric compositions. The vulcanized products are reported to have outstanding flex life, good heat resistance, and resistance to oil, having applications as gaskets for automatic transmissions for gasoline engines. Furthermore, because of their low softening points, most of the acrylates are particularly suited to filmforming applications-for instance, textile processing (9)especially in the form of aqueous dispersions which are prepared readily by emulsion polymerization.The strength of acrylate elastomers was shown ( 2 , 4 ) to be significantly increased by copolymerizing the acrylate monomer with acrylonitrile, and also by loading with finely divided fillers. The choice of filler was limited in an application like cosmetic gloves by the requiremmt of a transparent to translucent composition. Among the noncarbon tvpe of fillers known to reinforce acrylate elastomers (%) were amorphous silica and certain poly(alky1 methacrylates). I n the present study a wide variety of poly(alky1 methacrylates) were prepared in latex form and evaluated as fillers in copolymers of butyl acrylate and acrylonitrile. EXPERIMENTALThe alkyl methacrylate monomers were obtained from the Monomer-Polymer Corp., Leominster, Mass., with the exception of methyl and ethyl methacrylates, which were supplied by the Rohm & Haas Co., Philadelphia, Pa. The monomers were freed of inhibitor by alkaline washings, followed by washings with deionized water until the aqueous phase was neutral to litmus paper. The washed monomers were dried over Drierite, filtered, and stored a t 5 " C. until ready for use.The approximate charge formula employed in the preparation of the latices is as follows: Recipe for Emulsion Polymerization of Alkyl Methacrylate MonomerIngredient Parts by Weight Monomer Water Santomerse D KC1 KZSZOS NazSeOs. 5H~0 100 121-129 1.8-4.0 0.14 0.011 0,011 Two of the latices used in this study were ...