Acrylic solutions

A Corynebacterium propinquum microbial cell catalyst was employed to convert acrylonitrile to ammonium acrylate, where the final concentration of product was 10-20% and the concentration of unconverted acrylonitrile was <30 ppm [81], The ammonium acrylate solution was concentrated to 40-60% by falling film evaporation, the resulting solution acidified, and the acrylic acid extracted with diethyl ether at 0-10 °C to obtain high-purity acrylic acid. 

Because of the high rate of the cycloadditlon reaction it is very important that the cyclopentadiene solution enter the reaction flask and mix with the acrylate solution at as low a temperature as possible. For this reason it is beneficial to use a short cannula and to introduce the cyclopentadiene solution onto the wall of the flask that is deeply immersed in a solid CO2 bath. 

If the methyl acrylate solution has stood for some time, it is advisable to use a x0 per cent excess, since the solution slowly deteriorates. A low yield of bromo ester is usually caused by insufficient methyl acrylate. 

The analysis of the obtained data shows that the use of urea and vinyl acryl solutions fails to provide sufficiently strong granules (11 to 30% of the granules were disintegrated). For this reason, impact loads were applied to granules obtained by the use of water, polyethylene oxide, and several original preparations of agglomerating liquid. 

The type of initiator utilized for a solution polymerization depends on several factors, including the solubility of the initiator, the rate of decomposition of the initiator, and the intended use of the polymeric product. The amount of initiator used may vary from a few hundredths to several percent of the monomer weight. As the amount of initiator is decreased, the molecular weight of the polymer is increased as a result of initiating fewer polymer chains per unit weight of monomer, and thus the initiator concentration is often used to control molecular weight. Organic peroxides, hydroperoxides, and azo compounds are the initiators of choice for the preparations of most acrylic solution polymers and copolymers. 

Solution Polymers. Acrylic solution polymers are usually characterized by their composition, solids content, viscosity, molecular weight, glass-transition temperature, and solvent. The compositions of acrylic polymers are most readily determined by physicochemical methods such as spectroscopy, pyrolytic gas—liquid chromatography, and refractive index measurements (97,158). The solids content of acrylic polymers is determined by dilution followed by solvent evaporation to constant weight. Viscosities are most conveniently determined with a Brookfield viscometer, molecular weight by intrinsic viscosity (158), and glass-transition temperature by calorimetry. 

Potential health and safety problems of acrylic polymers occur in tlieii manufacture (159). During manufacture, considerable care is exercised to reduce the potential for violent polymerizations and to reduce exposure to flammable and potentially toxic monomers and solvents. Recent environmental legislation governing air quality has resulted in completely closed kettle processes for most acrylic polymerizations. Acrylic solution polymers are treated as flammable mixtures. Dispersion polymers are nonflammable. 

Type Acrylic solution Appearance Straw colored solution pH 7.1... 

The quantity of amine added is 63% of theory based on the titrated acidity. Both the amine and the melamine resin were dissolved in the acrylic solution prior to the addition of the water which was accomplished in the same manner as for the epoxy ester. During preliminary studies the hexamethylolmelamine was omitted and the water correspondingly reduced. The electrodeposited films were baked for Vz hours at 175°C. 

Acrylic solution polymers. aoytic and vinyl polymer emulsions, water-soluble resins (acrytamide/acryfic add copolymers. poiyacryiicaad and saJuL. 

Curing acrylic adhesives are distinctly different from anaerobics, cyanoacrylates, and acrylic solution adhesives and emulsions. These related chemistries use different formulating materials, cure via different curing mechanisms, and often possess minimal high performance properties over long periods of time, or when exposed to aggressive environments. 

As stated above, conventional synthetic fibres may be rendered inherently flame retardant during production by either incorporation of a flame retardant additive in the polymer melt or solution prior to extrusion or by copolymeric modification before, during, or immediately after processing into filaments or staple fibres. Major problems of compatibility, especially at the high tanperatures used to extrude melt-extruded fibres like polyamide, polyester, and polypropylene and in reactive polymer solutions such as viscose dope and acrylic solutions, have ensured that only a few such fibres are commercially available. A major problem in developing successful inherently flame retardant fibres based on conventional fibre chemistries is that any modification, if present at a concentration much above 10wt% (whether as additive or comonomer), may seriously reduce tensile properties as well as the other desirable textile properties of dyeability, lustre and appearance, and handle, to mention but a few. 

Newer adhesives of the acrylic, anaerobic or radiation-curable types must, if they are structural, have a relatively high degree of toughness and durability if they are to compete with or challenge epoxy adhesive systems. Likewise, newer radiation-curable, pressure-sensitive adhesive systems must exhibit the properties of permanence largely associated with cross-linked adhesive masses deposited from an acrylic solution polymer base. Epoxy resin structural adhesives largely define the existing area on the one hand the cross-linked acrylics deposited on plastic or metallic films the other. 

A 10-mL, flamed-dried, round-bottomed flask was charged with 10.0 mg of chloro(l,5-cyclooctadiene)rhodium(I) dimer (0.02 mmol), 33.0 mg (/ )-BINAP (0.053 mmol), and 500 (iL of 1,2-dichloroethane. The resulting solution was stirred at room temperature for 1 h. After 1 h, 481 pL of 1,2-dichloroethane and 174 pL of diethylmethylsilane (0.97 mmol) were added to the mixture, and the reaction vessel was stirred for 30 min. Next, 1.15 mL of stock benzaldehyde/phenyl acrylate solution (0.07 M in aldehyde and 0.84 M in acrylate, 0.81-mmol aldehyde, 0.97-mmol acrylate) was added dropwise to the solution. The vessel was then sealed and allowed to stir for 24 h. Solvent was then evaporated from the reaction mixture and 1 mL each of THF, MeOH, and 4 N HCl were added. This mixture was stirred at room temperature for an additional 30 min. Ethyl acetate was then used to extract the product (3x7 mL). The combined organic layers were washed with a saturated aqueous sodium bicarbonate solution (2 x 20 mL), dried over anhydrous MgS04, and filtered. The solvent was removed by rotary evaporation to yield crude product, which was purified via flash chromatography (9 1 then 5 1 hexanes ethyl acetate) to yield the product 298. 

Acrylics Solutions and aqueous emulsions Both thermoplastic and thermoset formulations available Very wide adhesion range Excellent resistance to discolouration, hght, and oxidation Curing types are available that have wash and dry-cleaning resistance Pressure-sensitive adhesives Laminating adhesives... 

Acrylics have been nsed to impart impact strength and better substrate adhesion to cement (228). The ceramics indnstry uses both acrylic solution and emulsion pol5nners as temporary binders, deflocculants, and additives in ceramics bodies and glazes (229) (see Ceramics). 

The reaction system was made more viscous by adding poly(hexyl acrylate) to the mixture. The poly(hexyl acrylate) was prepared by bulk polymerizing a 1% Luperox 231/ 99% hexyl acrylate solution in an oil bath at 110 °C for 30 minutes. The reaction mixture consisted of 20% of the polymer, 5% Aliquat persulfate, 2% Luperox 231, and 73% hexyl aciylate. 

Acrylate and Methacrylate Polymers. Poly(ethyl acrylate) and poly(butyl acrylate) solutions and emulsions are important raw materials for pressure-sensitive adhesives. Copolymers of various esters, which give films of tailor-made hardness and which may additionally contain functional groups (carboxyl, amide, amino, methylol, hydroxyl), are used for pressure-sensitive adhesives to improve the adhesion properties or to enable the adhesive layer to be cross-hnked to a limited extent. 

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