Acrylic coatings hydrolysis

Acrylics. Acetone is converted via the intermediate acetone cyanohydrin to the monomer methyl methacrylate (MMA) [80-62-6]. The MMA is polymerized to poly(methyl methacrylate) (PMMA) to make the familiar clear acryUc sheet. PMMA is also used in mol ding and extmsion powders. Hydrolysis of acetone cyanohydrin gives methacrylic acid (MAA), a monomer which goes direcdy into acryUc latexes, carboxylated styrene—butadiene polymers, or ethylene—MAA ionomers. As part of the methacrylic stmcture, acetone is found in the following major end use products acryUc sheet mol ding resins, impact modifiers and processing aids, acryUc film, ABS and polyester resin modifiers, surface coatings, acryUc lacquers, emulsion polymers, petroleum chemicals, and various copolymers (see METHACRYLIC ACID AND DERIVATIVES METHACRYLIC POLYMERS). 

Vinyls, finyl esters are usually used in waterborne coatings in the form of copolymer dispersions. Typical vinyl esters are vinyl acetate, vinyl propionate, vinyl laurate, and vinyl versatate. Acrylic, maleic, and fumaric acid esters are used as copolymers, finyl acetate is lower in cost compared to (meth) acrylic esters. Although vinyl acetate coatings are inferior to acrylics in both photochemical stability and resistance to hydrolysis, this does not prevent them from being used for exterior... 

The hardcoat is a silicone-silica composite prepared by hydrolysis of alkoxysilanes in the presence of water and colloidal silica, and can contain an alkoxysilylated UV absorber for protection of the polycarbonate. Adhesion of the topcoat to polycarbonate is provided by a primer, which is a solution of acrylic polymer. The primer is coated on polycarbonate and air dried to a 0.5 pm thick film. The topcoat is applied over the primer layer and air dried before curing at 130 °C for at least 30 min. 

A technique for the extraction of total filterable phosphorus from seawater using iron (ni) hydroxide-coated acrylic fibres was described by Lee et al. (1992). These fibres had previously been shown to adsorb adenosine 5 -triphosphate, DNA, glucose 1-phosphate and glucose 6-phosphate, and were used to preconcentrate large volumes (>1000 1) of seawater. While workers such as Baldwin et al. (1995, 1996) have demonstrated that hydrolysis of organic phosphorus can occur at mineral surfaces, only a small amount of hydrolysis (<3%) was observed in these studies. 

Acrylic acid is produced by oxidation of acrolein or hydrolysis of acrylonitrile. It is used in the manufacture of plastics in paints, polishes, and adhesives and as coatings for leather. 

It is the purpose of this paper to further characterize the changes in crosslink structure that occur on weathering. In particular, a detailed study of the dependence of the rate of methoxy disappearance on humidity and light intensity is presented which verifies the photoenhancement of hydrolysis. The effect of changes in the composition of the acrylic/melamine coating and the effect of common photostabilizers on the rate of photohydrolysis has been determined. Finally, possible mechanisms for photoenhanced hydrolysis are discussed. 

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