Ethyl Acrylate emulsion polymerization

Aqueous emulsions of styrene, methyl methacrylate, methyl acrylate, and ethyl acrylate were polymerized with y-radiation from a Co source in the presence of sodium dodecyl sulfate or sodium laurate. The continuous measurement of conversion and reaction rate was carried out dilato-metrically. The acrylates polymerized fastest and the over-all polymerization rate increased as follows styrene < methyl methacrylate < ethyl acrylate methyl acrylate. The effects of radiation dose, temperature, and original monomer and emulsifier concentrations were studied with respect to the following factors properties of polymer dispersions, number and size of polymer particles, viscometrically determined molecular weights, monomer-water ratio, and kinetic constants. 

Svoboda et al. [160] investigated the emulsion copolymerization and ter-polymerization of VC with vinyl accetate, butyl acrylate and/or ethyl acrylate. The polymerizations proceeded under batch and continuous conditions and were initiated by peroxodisulfates. Anionic emulsifiers (sodium dodecyl sulfate, sodium dodecylbenzene sulfonate,..) and blends of anionic and non-ionic emulsifiers (mostly polyoxyethylene type) were used. Copolymer latexes prepared with emulsifier blends were much more stable than those with an anionic emulsifier. As expected, the copolymers prepared by continuous polymerization gave copolymers with homogeneous composition. In the batch copolymerizations, the shift in the copolymer composition with conversion was observed and particles with broader size distribution were prepared. For example, the batch VC/ethyl acrylate polymer latexes gave particles with a diameter from 180 nra to 320 nm. 

Vinyl resins - In the coatings industry, vinyl resins usually refer to either poly(vinyl chloride) (PVC) or poly(vinyl acetate) (PVAc) which is widely used in interior and exterior latex paints. Produced usually by emulsion polymerization, a PVAc homopolymer is too hard to allow its colloidal latex particles to coalesce well into a continuous film at ambient temperatures. Most PVAc emulsions used in the paint industry are copolymers with a plasticizing monomer such as dibutyl maleate, 2-ethyhexyl acrylate, n-butyl acrylate, dibutyl fumarate, isodecyl acrylate, or ethyl acrylate. By polymerizing under pressure, copolymers of vinyl acetate and ethylene are also produced for latex paints. External plasticizers such as dibutyl phthalate are used as well. All these methods not only soften the polymer to allow the latex particles to coalesce into a continuous film, but also impart the film flexiblity needed in exterior house paints. 

Emulsion Polymerization. Emulsion polymerization is the most important industrial method for the preparation of acryhc polymers. The principal markets for aqueous dispersion polymers made by emulsion polymerization of acryhc esters are the paint, paper, adhesives, textile, floor pohsh, and leather industries, where they are used principally as coatings or binders. Copolymers of either ethyl acrylate or butyl acrylate with methyl methacrylate are most common. 

Polymerization processes are characterized by extremes. Industrial products are mixtures with molecular weights of lO" to 10. In a particular polymerization of styrene the viscosity increased by a fac tor of lO " as conversion went from 0 to 60 percent. The adiabatic reaction temperature for complete polymerization of ethylene is 1,800 K (3,240 R). Heat transfer coefficients in stirred tanks with high viscosities can be as low as 25 W/(m °C) (16.2 Btu/[h fH °F]). Reaction times for butadiene-styrene rubbers are 8 to 12 h polyethylene molecules continue to grow lor 30 min whereas ethyl acrylate in 20% emulsion reacts in less than 1 min, so monomer must be added gradually to keep the temperature within hmits. Initiators of the chain reactions have concentration of 10" g mol/L so they are highly sensitive to poisons and impurities. 

Hydrophobic polymers with some hydrophilic groups can be obtained with an emulsion polymerization technique. Suitable monomers are nitrogen-containing acrylics and methacrylics allyl monomers such as dimethylamino-ethyl methacrylate, dimethylaminopropyl methacrylamide, diethylamino-ethyl methacrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate and nitrogen-containing allyl monomers (e.g., diallylamine and N,N-diallyl-cyclohexylamine) [225,226]. 

Fig. 31. Polymerization of ethyl acrylate by wool swelling at 25° C using water as a swelling agent (60% aquesous emulsion with 3.2% Triton X-405) (105)...

Among the polyesters that are used for PVC, the copolymers of butadiene with ethyl fumarates and ethyl acrylates deserve mention. They have been produced by Badische Anilin-und Sodafabrik (BASF) under the commercial name Palamoll. Palamoll I consists of 75% diethyl fumarate and 25% butadiene Palamoll II contains equal parts of butadiene and ethyl acrylate. In combination with the same amount of liquid plasticizers (such as DOP), films with cold resistance down to — 60°C. can be produced. These products are especially important for cable insulation because of their good dielectric properties. The Palamoll products are produced by emulsion polymerization and can be directly combined with emulsions of PVC. 

Substituted vinylindolizines sometimes polymerize spontaneously and also copolymerize with styrene. Polymers of similar structure have been prepared by formation of indolizines on the polymer chain using methods outlined in Sections 3.08.3 and 3.08.6 (see Scheme 36 for an example). Moreover, indolizine dyes such as (214) have been bound to an ethyl acrylate/acrylic acid copolymer by heating to give dyes that do not migrate in photographic colour film emulsions. 

Example C-tn-18 AE(50EO) for t ie emulsion polymerization of ethyl acrylate... 

Most of the reactive surfactants used for emulsion polymerization have the reactive group at the end of the hydrophobic moiety of the molecule, on the assumption that the polymerization process takes place in the latex particle. Work of Ferguson et al. [14] shows indeed a lower stability of lattices produced with Surfmers with an acrylate group attached to the end of the hydrophilic chain than those produced with the equivalent terminated with an ethyl ester group. 

Emulsion polymerization with the chain transfer agent l-benzyl-2,5-cyclohexadiene-1-carboxylic acid was also used to prepare poly(ethyl acrylate-co-methacrylic acid). Poly(N-vinylpyrrolidone) was prepared using the chain transfer agent l-i-propyl-2,5-cyclohexadiene-1 -carboxylic acid. 

In order to gain evidence for interfacial initiation, the redox initiator system was compared with a water-soluble initiator (VA-044) in terms of the emulsion polymerization behavior of butyl acrylate (BA)/[2-(methacryloyoxy)ethyl] trimethyl ammonium chloride (MAETAC). It was found that for the water-soluble initiator system, only homopoly(MAETAC) was formed and BA did not polymerize at all. In the case of VA-044, it was suggested that it may be difficult for polymeric free radicals in the aqueous phase to penetrate the viscous surfactant layer to initiate the polymerization of the BA monomer. On the other hand, it has also been found that BA could be rapidly polymerized under the same conditions if VA-044 is replaced with CHP/TEPA, indicating that radicals are formed in the interface, where they do not need to penetrate through viscous surfactant layer. 

Some two stage emulsion graft copolymer materials synthesized and characterized by DMS include) the series poly (methyl methacrylate)/poly(n-butyl acrylate) (PMMA/ PnBA) synthesized by Dickie (14) and the series poly(ethyl methacrylate)/poly(n-butyl acrylate) (PEMA/PnBA) synthesized by Sperling et al. (1) The present study will continue the development of the PEMA/PnBA damping materials by incorporating a common comonomer) ethyl acrylate (EA)) in both stages of the emulsion polymerization. 

Stalagmometric determination of the SDDS adsorption at the aqueous solution-ethyl acrylate interface dependence on the rate of drop formation (volume 0.03 cm ) were carried out in our laboratory by Vasilenko. The measurements showed that establishment of adsorption equilibrium at the CMC occurs at drop formation periods of 15-20 sec, ije., at surface formation rates not exceeding 10 m sec. Adsorption kinetics acquires considerable importance in analysis of the mechanism of particle formation during emulsion polymerization, when tbe rate of organic phase formation and the rate of adsorption layer formation may be commensurate. 

Ethyl Acrylate (EA). Figure 7 shows the over-all reaction rate plotted logarithmically vs. time in case of the y-emulsion polymerization of EA. The function shows a very simple form from the beginning v r increases rather fast (in 6.5 minutes at 200 rad per hour) up to a maximum, and then decreases slowly without a period of zero order, following with considerable accuracy the first-order law with respect to [M]. At high conversions and very low reaction rates (about 0.05 mg. per minute per gram of emulsion), the curve falls less steeply. 

Styrene, methyl methacrylate, ethyl acrylate, and methyl acrylate are easily polymerized in aqueous emulsion under the action of Co y-radiation. The maximum over-all reaction rate increases in the sequence given above. Using a dose rate of 200 rad per hour, the doses required to obtain a conversion of 80 to 90% amount to about 10 rad. This dose is far lower than the doses required for a measurable degradation or cross linking of the polymers formed. The G value of formation of polymer molecules was found to be orders of magnitude higher than the Gr (H2O) values referred to in the literature. 

Emulsion polymerization typically refers to the polymerization of a nonaqueous material in water. The polymerization of a water-soluble material in a nonaqueous continuum has been called inverse emulsion polymerization. The inverse emulsion polymerization technique is used to synthesize a wide range of polymers for a variety of applications such as wall paper adhesive, waste water fiocculant, additives for oil recovery fluids, and retention aids. The emulsion polymerization technique involves water-soluble polymer, usually in aqueous solution, emulsified in continuous oil phase using water in oil emulsifier. The inverse emulsion is polymerized using an oil- or water-soluble initiator. The product is a colloidal dispersion of sub-microscopic particles with particle size ranging from 0.05 to 0.3 pm. The typical water-soluble monomers used are sodium p-vinyl benzene sulfonate, sodium vinyl sulfonate, 2-sulfo ethyl acrylate, acrylic acid, and acrylamide. The preferred emulsifiers are Sorbitan monostearate and the oil phase is xylene. The proposed kinetics involve initiation in polymer swollen micelles, which results in the production of high molecular weight colloidal dispersion of water-swollen polymer particles in oil. 

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