2-Ethylhexyl acrylate, emulsion

ASA structural latexes have been synthesized in a two stage seeded emulsion polymerization. In the first stage, partially crosslinked poly(n-butyl acrylate) and poly( -butyl acrylate-sfaf-2-ethylhexyl acrylate) rubber cores are synthesized. In the second stage, a hard styrene acrylonitrile copolymer (SAN) shell is grafted onto the rubber seeds (16). 

The use of core-shell impact modifiers for sPS is also patented in EP 318793 [15] (see Table 19.1). These impact modifiers are usually prepared using the emulsion polymerization process, although other methods such as the microsuspension polymerization process are possible. The core usually consists of polymers prepared from an acrylate, especially butyl or 2-ethylhexyl acrylate or butadiene. These rubber particles are then grafted with vinyl monomers, where... 

Stable aqueous emulsions of poly(2-ethylhexyl acrylate) (PEHA) were also produced by RESAS from CO2 (68). In this case, a polymer suspension in CO2 was expanded instead of a dissolved solute. A C02-philic surfactant, Monasil PCA (PDMS-g-pyrrolidonecarboxylic acid), was utilized in dispersion polymerization to form a stable polymer suspension at 65°C and 345 bar. A hydrophilic surfactant, (e.g., SAM 185, Pluronic L61, or Pluronic L62), that is soluble in CO2 and CO2/2-EHA monomer mixtures as well as water was added to CO2 to stabilize the suspension after it had been rapidly expanded through a capillary into aqueous solution. The resulting aqueous emulsion with up to 15.6 wt % polymer content was stable for weeks with an average particle size of 2 to 3 pm. Another approach is to introduce the hydrophilic surfactant in the aqueous phase in addition to the surfactant in the CO2 phase. This approach is more general, since many hydrophilic surfactants are not soluble in CO2. During expansion of the suspension into an aqueous solution, the hydrophilic surfactant—for example, triblock Pluronic copolymers—dilfuses to the particle surface to provide stabilization. The resulting aqueous latexes were stable for 100 days for a polymer content reaching 12.7 wt %. 

A typical emulsion polymerisation formulation contains water, 50% monomer blended for the required glass transition temperature (T ), surfactant (and often coUoid), initiator, pH buffer and fungicide. Hard monomers with a high Tg used in emulsion polymerisation may be vinyl acetate, MMA, and styrene, while soft monomers with a low include butyl acrylate, 2-ethylhexyl acrylate, vinyl versatate,... 

Poly(vinyl acetate) latex is used in the production of water-based emulsion paints, adhesives, and textile and paper treatments. Emulsion paints are stable, dry quickly, and are relatively low cost. PVAC emulsion adhesives are used in labeling and packaging, and as the popular consumer white glue. Copolymers with dibutyl fumarate, vinyl stearate, 2-ethylhexyl acrylate, or ethyl acrylate are used to obtain compositions that are softer for emulsion use. As indicated above, a major use of poly(vinyl acetate) is in the production of poly(vinyl alcohol), which is itself the starting material for poly(viityl butyral) and poly(vinyl formal). 

A number of copolymers are known where vinyl acetate is the major component. In coatings, vinyl acetate is often used in copolymers with alkyl acrylates (line 2-ethylhexyl acrylate) or with esters of maleic or fumaric acids. Such copolymers typically contain 50-20% by weight of the comonomer and are usually formed by emulsion polymerization in batch processes. They are used extensively as vehicles for emulsion paints. 

Emulsions can be formulated with only hard monomer and plasticized at a later stage, but it is normal to internally plasticize the emulsion by copolymerizing some soft monomer. Vinyl acetate plasticized with an acrylate such as butyl or ethylhexyl acrylate, or a dialkyl maleate, are common combinations. Other hard (high Tg) monomers include methyl methacrylate, styrene, and vinyl chloride. Soft monomers include Vinyl Versatate (Shell Chemicals), ethylene, and vinylidene chloride (Figure 1). 

The effect of the Tg of the latex on the film-formation behaviour of a series of 2-ethylhexyl acrylate/methyl methacrylate emulsion copolymers was studied. Stage 1 of fihn formation was examined using a combination of DMA and conductivity measurements. Stages 2 and 3 were investigated using calorimehic compensation, DSC, dielectric spectroscopy and atomic force microscopy. Comparison of the results from the different methods employed led to a detailed model of the film-formation process in which the temp, used relative to the minimum film-formation temp, determined the effectiveness of the processes. The relative usefulness of the techniques used in their ability to characterise the various stages in the film-formation process was assessed for these copolymer systans. 23 refs. 

Four-stage emulsion copolymerization of styrene, 2-ethylhexyl acrylate, methacrylic acid, butyl acrylate, methyl methacrylate, and divinylbenzene [139]. 

In an autoclave are placed 140 gm of a 25% aqueous solution of sodium lauryl sulfate, 4200 ml of distilled water, and a solution of 46.5 gm of ammonium persulfate in 500 ml of water. The mixture is warmed to 80°C while, over a period of 1 hr, a monomer emulsion obtained by dispersing 3500 gm of 2-ethylhexyl acrylate and 70 gm of a 25% aqueous solution of sodium lauryl sulfate in 1-liter of distilled water is added. By the end of the addition period, the polymerization is substantially complete. The latex has a solid content of 37%, a surface tension of 56 dynes/cm, a pH of 2.0, and an average particle size between 0.03 and 0,06 jum. 

Using FT-MIR spectrometers equipped with ATR probes, Chatzi et al. [171], Kammona et al. [172], Hua and Dube [173], and Roberge and Dubd [174] obtained similar results for 2-ethylhexyl acrylate/styrene and VA/butyl acrylate/ MMA emulsion homo- and copolymerizations. Particularly, Hua and Dube [173] present a review about the use of FT-IR-ATR spectroscopy for kinetic studies in polymerization systems. In all cases, MLR or PLS calibration models were used for interpretation of spectral data. 

Chatzi EG, Kammona O, Kiparissides C. Use of a midrange infrared optical-fiber probe for the on-line monitoring of 2-ethylhexyl acrylate/styrene emulsion copolymerization. J Appl Polym Sci 1997 63 799-809. 

Cement emulsion Vinyl chloride 2-Ethylhexyl acrylate... 

These empirical relationships along with the glass transition temperature data estabhshed for homopolymers (Table 9.1) allow polymer chemists to determine the optimal position of the glass transition temperature and then design adequate emulsion polymer compositions to fulfill end-users requirements. n-Butyl acrylate (T = -54°C) and 2-ethylhexyl acrylate (Tg = -85°C), for example, are widely used as the major components of water-based pressure-sensitive adhesives. Vinyl acetate and n-butyl acrylate copolymer latexes with a weight ratio of about 80 20 Tg = 8°C) are a primary choice for inte-... 

References cited provide details of polymerization of the monomers indicated. Heterogeneous polymerizations (emulsion, miniemulsion) are indicated by the monomer being in italics. Monomer/RAF agent combinations that are relatively ineffective are indicated by the monomer being in parentheses. DMAM, A/,W-dimethylacrylamide EHA, 2-ethylhexyl acrylate HPMAM, /V-(2-hydroxypropyl) methacrylamide MAM, methacrylamide NIPAM, W-isopropyl acrylamide tBA, ferf-butyl acrylate VBz, vinyl benzoate. 

A limitation of external plasticizers of this kind is that they may eventually be lost by evaporation or by migration into the substrate, leaving an imperfect and brittle film. This limitation may be overcome by the use of copolymers and these are now widely used in surface coatings and other applications. Comonomers which may be employed for this purpose include butyl acrylate, 2-ethylhexyl acrylate, diethyl fumarate, diethyl maleate and vinyl esters of fatty acids (e.g. a branched Cio fatty acid). Typically, the copolymers contain 15-20% by weight of such comonomers. These copolymers are readily prepared by the emulsion polymerization techniques described previously for the homopolymer. 

One of the most common types of emulsion for decorative paint is based on vinyl acetate internally plasticised with about 20 parts of vinyl versatate. Di-butyl or di-octyl maleate or fumarate are also used as plasticising monomers for vinyl acetate, but butyl acrylate or 2-ethylhexyl acrylate are now preferred. Vinyl acetate homopolymers externally plasticised with di-butyl phthalate are still widely used. 

Up to now, poly(methyl methacrylate) and methyl methacrylate copolymers e.g. with styrene, butyl acrylate and dodecyl methacrylate) have been the most widely used acrylic polymers for nanocomposite preparation by emulsion and suspension polymerization. Less research has been based on other acrylic polymers, such as polyacrylonitrile, poly(butyl acrylate), " poly(butyl methacrylate), poly(2-ethylhexyl acrylate), poly(2-hydroxyethyl methacrylate), polyacrylamide, poly(lauryl acrylate)," poly(butyl acrylate-co-styrene)," " poly(acrylonitrile-co-styrene), poly(acrylonitrile-co-meth-acrylate)," poly(ethyl acrylate-co-2-ethylhexyl acrylate)" and poly(2-ethylhexyl acrylate-co-acrylic acid)," and sometimes small amounts of hydophilic acrylic monomers, such as hydroxyethyl methacrylate, methacrylic acid and acrylic acid, have been used as comonomers. " Therefore, it may be stated that, so far, the preparation of acrylic-clay nanocomposites has been based mainly on high glass transition temperature polymers, although nanocomposite materials with lower glass transition temperatures with improved or novel properties, which exhibit a balance of previous antagonistic properties, can also be achieved and are very desirable. Regarding nanocomposites of low glass transition temperature polymers, such as poly(butyl acrylate), poly(ethyl acrylate) and poly(2-ethylhexyl acrylate), which have been utilized as the main components of acrylic pressure-sensitive adhesives, little information is available. 

Neopentyl glycol Pentaerythrityl triallyl ether Terephthalic acid Tripropylene glycol comonomer, unsaturated polyesters Dipropylene glycol comonomer, vinyl acetate Bis (2-ethylhexyl) maleate Diisooctyl maleate comonomer, vinyl emulsion polymers Bis (2-ethylhexyl) maleate comonomer, vinyl resins Dibutyl fumarate Dibutyl maleate comonomer, vinyl/acrylic resins Benzyl methacrylate... 

Di-n-octyltin bis (2-ethylhexyl maleate) stabilizer, wax emulsions Cl 3-15 pareth-20 stabilizer, wax systems Lanolin acid stabilizer, waxes Acrylates copolymer stabilizer, wine Bentonite... 

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