Acrylic acid latex

Progress in Organic Coatings 42, Nos.1-2, June 2001, p.110-5 THICKENING OF BUTYL ACRYLATE/ STYRENE/2-HYDROXYETHYL METHACRYLATE/ACRYLIC ACID LATICES WITH AN HEUR ASSOCIATIVE THICKENER Quadrat O Horsky J Mrkvickova L Mikesova J Snuparek J... 

Vinyl acetate/vinyl Versatate 42-00 FILM FORMER Methyl methacrylate/ethyl acrylate/acrylic acid latex 26-00... 

Figure 6.6. AFM images of films cast from a butyl acrylate-styrene-acrylic acid latex stabilized by sodium dodecyl sulfate (a) before rinsing with water (b) after rinsing with water x- and y-axes, 0.500 gm/division z-asis, 25.000 nm/division. (From A.-C. Hellgren et al. Prog. Org. Coatings, 903, 1 (1999) Reprinted with permission from Elsevier Science)...

The mechanisms involved in monomer removal by post polymerisation were studied. Three redox initiator systans which generate radicals with different hydrophobidties were investigated tert-butyl hydroperoxide, hydrogen peroxide and potassium persulphate. Ascorbic acid was used as a reductant in all cases. The efficiency of these initiator systems for the removal of residual monomers from commercial latexes was studied. The examples exauuued were removal of unreacted vinyl acetate from a vinyl acetate/butyl aerylate/acrylie acid latex, methyl methacrylate from a methyl aaylate, butyl aaylate/acryhc acid latex and butyl acrylate from a butyl aaylate/styrene/ acrylic acid latex. Efficieucy of monomer ranoval by post polymerisation increased with the hydrophobidty of the radical formed from the initiator system and this was independent of the water solubihty of the residual monomer. Reasons for the observations were discussed. 35 refs. 

Film formation of latexes can be followed by s-NMR experiments. Three different kinds of water were found in poly(butylacrylate)/polystyrene/ poly(acrylic acid) latex films free water, mobile water bound to the polymer and immobilised water inside the polymer [750]. The effects of water and DEP plasticiser on the molecular motion of cellulose acetate (CA) have been examined by H, and CP/MAS NMR [751]. 1-NMR relaxation... 

Poly(acrylic acid) is insoluble in its monomer but soluble in water. It does not become thermoplastic when heated. The sodium and ammonium salts have been used as emulsion-thickening agents, in particular for rubber latex. The polymer of methacrylic acid (Figure 15.13 (VI)) is similar in properties. 

Paine et al. [99] tried different stabilizers [i.e., hydroxy propylcellulose, poly(N-vinylpyrollidone), and poly(acrylic acid)] in the dispersion polymerization of styrene initiated with AIBN in the ethanol medium. The direct observation of the stained thin sections of the particles by transmission electron microscopy showed the existence of stabilizer layer in 10-20 nm thickness on the surface of the polystyrene particles. When the polystyrene latexes were dissolved in dioxane and precipitated with methanol, new latex particles with a similar surface stabilizer morphology were obtained. These results supported the grafting mechanism of stabilization during dispersion polymerization of styrene in polar solvents. 

PABA, 1,6-7, 11, 70. See also para-amino benzoic acid PABA esters, 6-7 padimate A, 7 padimate O, 7 pain relievers, 158,170-189 paints, 44, 70, 112, 129 acrylic, 234 latex, 232, 236, 237 oil, 94... 

A modified latex composition contains a phosphorus surface group. Such a latex is formed by emulsion polymerization of unsaturated synthetic monomers in the presence of a phosponate or a phosphate which is intimately bound to the surface of the latex. Thus, a modified latex containing 46% solids was prepared by emulsion polymerization of butadiene, styrene, acrylic acid-styrene seed latex, and a phosphonate comonomer in H20 in the presence of phosphated alkylphenol ethoxylate at 90°C. The modified latex is useful as a coating for substrates and as a binder in aqueous systems containing inorganic fillers employed in paper coatings, carpet backings, and wallboards [119]. 

There are numerous applications where the development of high viscosity is necessary in a finished product. For example, thickeners, mainly based on poly(acrylic acid), are used to give body to so-called emulsion paints. Emulsion paints are not formulated from true emulsions (Le. stable dispersions of organic liquids in water), but are prepared from latexes, that is, dispersions of polymer in water. Since latexes do not contain soluble polymers, they have a viscosity almost the same as pure water. As such, they would not sustain a pigment dispersion, but would allow it to settle they would also fail to flow out adequately when painted on to a surface. Inclusion of a thickener in the formulation gives a paint in which the pigment does not settle out and which can readily be applied by brush to a surface. 

Polymers of acrylic acid and methacrylic acid have been tested for their gel-formation ability [1396]. They are used with gel-forming additives similar to those described for polyacrylamides. Also, mixtures of latex with methacrylate-methacrylic acid copolymer as an additive have been described as plugging agents [1041]. 

Polyelectrolytes provide excellent stabilisation of colloidal dispersions when attached to particle surfaces as there is both a steric and electrostatic contribution, i.e. the particles are electrosterically stabilised. In addition the origin of the electrostatic interactions is displaced away from the particle surface and the origin of the van der Waals attraction, reinforcing the stability. Kaolinite stabilised by poly(acrylic acid) is a combination that would be typical of a paper-coating clay system. Acrylic acid or methacrylic acid is often copolymerised into the latex particles used in cement sytems giving particles which swell considerably in water. Figure 3.23 illustrates a viscosity curve for a copoly(styrene-... 

In commercial latex dispersions this is often a mixture of acrylic acid and butyl and ethyl acrylates. 

Because the viscosity of neoprene latex at a given solids content is less than that of natural rubber latex, thickeners are generally needed with the former. Methylcellulose and the water-soluble salts of poly(acrylic acid) are the two most commonly used thickeners. Natural and synthetic gums are also used. 

Poly(acrylic acid) is water soluble. Because of its water solubility and its ability to increase the viscosity of water, it is used as a thickener. It is also a good flocculent for sewage treatment and is added as a pigment dispersant in latex paints, and is used in binders and adhesives. Polymers and copolymers containing acrylic or/and methacrylic acid are manufactured at a rate of about 2,000,000 metric tons yearly. 

Acrylics. There are two principal classes of acrylic sealants latex acrylics and solvent-release actylics. High molecular weight latex acrylic polymers are prepared by emulsion polymerization of alkyl esters of acrylic acid, The emulsion polymers are compounded inlo sealants by adding fillers, plasticizers, freeze-thaw stabilizers, thickeners, and adhesion promoters. As is true of the silicone lalex sealants, die acrylic latex sealants are easy to apply and clean with water. 

The emulsifier-free emulsion terpolymerization of PEO-MA macromonomer, BA, and acrylic acid (AA) led to the formation of graft copolymers and stable latexes [101]. At the beginning of terpolymerization, the PEO-MA macromonomer polymerized more quickly than BA or AA. Conversion of the macromonomer increased with increasing initiator concentration and with decreasing mo-... 

The foregoing methods developed for the preparation and characterization of monodisperse polystyrene latexes to be used as model colloids can also be applied to the characterization of industrial latexes. The recipes used for the preparation of these industrial latexes are complex, and most contain a small amount of a functional monomer, e.g., acrylic acid, 2-sulfoethyl methacrylate, or N-methylolacrylamide. These functional monomers are often predominantly water-soluble, so that their use may have several results (i) the monomer may polymerize in the aqueous phase to form a water-soluble polymer that remains in the serum ... 

A 62 35 3 ethyl acrylate-methyl methacrylate-acrylic acid copolymer latex was prepared by continuous addition of the monomer mixture over a 4-hour period at 80° (22). The emulsifier was a sodium lauryl ether sulfate-nonylphenol polyoxyethylene adduct (20 moles ethylene oxide) mixture, the initiator a potassium persulfate-sodium hydroxulfite mixture, and the buffer a sodium bicarbonate-potassium hydroxide mixture. The final latex of pH 6.5 contained 40% solids, and the Tg of the copolymer was 13°. 

Figure 3. Expansion characteristics of model acrylic latexes as determined by sedimentation ((%) 2% acrylic acid—Stage II no acid)...

The lower curve in Figure 6 shows the sedimentation behavior of a PMMA latex containing 2% acrylic acid added in Stage II in the same manner employed to make the model carboxylic acrylic latex. A contraction of approximately 75 A was observed at pH = 11. 

Figure 6. Expansion characteristics of PMMA latexes containing 2% ((%), d0 = 0.10 pm) and 3% (YH)> = 0.11 pm) acrylic acid (Stage II) as determined by...

In order to compare the PMMA results with those obtained with the carboxylic acrylic latex, the concentration of surface carboxyls must be determined. Acid location analysis (5 was carried out for this purpose. Briefly, the latexes were titrated conductometrically with 0.1N NaOH followed by a titration of the aqueous phase from which the particles had been removed by centrifugation. The difference in the two titrations provided the distribution between surface and soluble acid. The deficit between the total acid thus determined and the concentration of acrylic acid used in the polymerization was termed "buried". Although some drift occurred in the conductance with time, an equilibration time of approximately 10 minutes per addition of sodium hydroxide was generally sufficient to yield stable readings. 

A second PMMA latex was prepared, with 3% acrylic acid (Stage II), in an effort to match the surface acid concentration of the standard acrylic latex. The acid location results in Table II show that the surface acid of this latex was indeed close to that of the standard acrylic. The sedimentation curve for this latex is shown in Figure 6 in which an apparent expansion maximum of about 60 A... 

Wide angle light scattering is used as the principal probe to examine the core-shell structure proposed for certain acrylic acid acrylate ester copolymer latexes. Additional techniques were sedimentation and photon correlation spectroscopy. 

Ethylhexyl acrylate manufacture represented about 15 percent of domestic consumption of the alcohol. The acrylate is the longest chain acrylate ester produced by esterification of acrylic acid. The monomer is used in acrylic copolymers for pressure sensitive adhesives, PVC impact modifiers, and as a comonomer with vinyl acetate and vinyl chloride in latexes for paints and textiles. Growth over the next 5 years is estimated at 6 percent per year. 

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