2-Acrylamido-2-methylpropane sulfonic acid (AMPS) was a Trademark name by The Lubrizol Corporation. It is a reactive, hydrophilic, sulfonic acid acrylic

monomer In chemistry, a monomer ( ; '' mono-'', "one" + ''-mer'', "part") is a molecule that can react together with other monomer molecules to form a larger polymer chain or three-dimensional network in a process called polymerization. Classification ...

used to alter the chemical properties of wide variety of anionic polymers. In the 1970s, the earliest patents using this monomer were filed for acrylic fiber manufacturing. Today, there are over several thousands patents and publications involving use of AMPS in many areas including

water treatment Water treatment is any process that improves the quality of water to make it appropriate for a specific end-use. The end use may be drinking, industrial water supply, irrigation, river flow maintenance, water recreation or many other uses, inc ...

, oil field, construction chemicals,

hydrogels A gel is a semi-solid that can have properties ranging from soft and weak to hard and tough. Gels are defined as a substantially dilute cross-linked system, which exhibits no flow when in the steady-state, although the liquid phase may still dif ...

for medical applications, personal care products,

emulsion An emulsion is a mixture of two or more liquids that are normally immiscible (unmixable or unblendable) owing to liquid-liquid phase separation. Emulsions are part of a more general class of two-phase systems of matter called colloids. Altho ...

coatings,

adhesives Adhesive, also known as glue, cement, mucilage, or paste, is any non-metallic substance applied to one or both surfaces of two separate items that binds them together and resists their separation. The use of adhesives offers certain advant ...

, and rheology modifiers.

Production

AMPS is made by the Ritter reaction of

acrylonitrile Acrylonitrile is an organic compound with the formula and the structure . It is a colorless, volatile liquid although commercial samples can be yellow due to impurities. It has a pungent odor of garlic or onions. In terms of its molecula ...

and

isobutylene Isobutylene (or 2-methylpropene) is a hydrocarbon with the chemical formula . It is a four-carbon branched alkene (olefin), one of the four isomers of butylene. It is a colorless flammable gas, and is of considerable industrial value. Producti ...

in the presence of sulfuric acid and water. The recent patent literature describes batch and continuous processes that produce AMPS in high purity (to 99.7%) and improved yield (up to 89%, based on isobutene) with the addition of liquid isobutene to an acrylonitrile / sulfuric acid / phosphoric acid mixture at 40°C.

Properties

* Hydrolytic and thermal stability: The geminal dimethyl group and the sulfomethyl group combine to sterically hinder the amide functionality and provide both hydrolytic and thermal stabilities to AMPS-containing polymers. * Polarity and hydrophilicity: The sulfonate group gives the monomer a high degree of

hydrophilicity A hydrophile is a molecule or other molecular entity that is attracted to water molecules and tends to be dissolved by water.Liddell, H.G. & Scott, R. (1940). ''A Greek-English Lexicon'' Oxford: Clarendon Press. In contrast, hydrophobes are no ...

and anionic character at wide range of pH. In addition, AMPS is absorbing water readily and also imparts enhanced water absorption and transport characteristics to polymers. * Solubility: AMPS is very soluble in water and dimethylformamide (DMF) and also shows limited solubility in most polar organic solvents. * Inhibition of divalent cation precipitation: Sulfonic acid in AMPS is a very strong ionic group and ionizes completely in aqueous solutions. In applications where the precipitation of mineral salts is undesirable, the incorporation of a polymer containing even a small quantity of AMPS can significantly inhibit the precipitation of divalent cations. The result is a significant reduction in the precipitation of a wide variety of mineral salts, including calcium, magnesium, iron, aluminum, zinc, barium and chromium. * Determining viscosity-average molecular weight (Mark-Houwink constants) * Reactivity ratio: AMPS reacts well with a variety of vinyl monomers. M₂= AMPS or ^† sodium salt of AMPS

Applications

Acrylic fiber Acrylic fibers are synthetic fibers made from a polymer (polyacrylonitrile) with an average molecular weight of ~100,000, about 1900 monomer units. For a fiber to be called "acrylic" in the US, the polymer must contain at least 85% acrylonitri ...

: A number of enhanced performance characteristics are imparted to acrylic, modified-acrylic, polypropylene and polyvinylidene fluoride fibers: dye receptivity, moisture absorbency, and static resistance. * Coating and adhesive: Its sulfonic acid group gives the monomers ionic character over a wide range of pH. Anionic charges from AMPS fixed on polymer particles enhance the chemical and shear stabilities of polymer emulsion and also reduce the amount of

surfactants Surfactants are chemical compounds that decrease the surface tension between two liquids, between a gas and a liquid, or interfacial tension between a liquid and a solid. Surfactants may act as detergents, wetting agents, emulsifiers, foaming ...

leaching out of paint film. It improves the thermal and mechanical properties of adhesives, and increases the adhesive strength of pressure-sensitive adhesive formulations. * Detergents: Enhances the washing performance of surfactants by binding multivalent cations and reducing dirt attachment. * Personal care: Strong polar and hydrophilic properties introduced to a high molecular weight AMPS homopolymer are exploited as a very efficient lubricant characteristic for skin care. * Medical hydrogel: High water-absorbing and swelling capacity when AMPS is introduced to a hydrogel are keys to medical applications. Hydrogel with AMPS showed uniform conductivity, low electrical impedance, cohesive strength, appropriate skin adhesion, and biocompatible and capable of repeated use and have been used to electrocardiograph (ECG)

electrodes An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte, a vacuum or air). Electrodes are essential parts of batteries that can consist of a variety of materials dep ...

, defibrillation electrode, electrosurgical grounding pads, and iontophoretic drug delivery electrodes. In addition, polymers derived from AMPS are used as the absorbing hydrogel and the

tackifier Tackifiers are chemical compounds used in formulating adhesives to increase the tack, the stickiness of the surface of the adhesive. They are usually low-molecular weight compounds with high glass transition temperature. At low strain rate, they p ...

component of wound dressings. Is used due to its high water absorption and retention capability as a monomer in superabsorbents e. g. for baby diapers. * Oil field applications: Polymers in oil field applications have to stand hostile environments and require thermal and hydrolytic stability and the resistance to hard water containing metal ions. For example, in drilling operations where conditions of high salinity, high temperature and high pressure are present, AMPS copolymers can inhibit fluid loss and be used in oil field environments as scale inhibitors, friction reducers and water-control polymers, and in polymer flooding applications. * Water treatment applications: The cation stability of the AMPS-containing polymers are very useful for

processes. Such polymers with low molecular weights cannot only inhibit calcium, magnesium, and silica scale in cooling towers and boilers, but also help corrosion control by dispersing iron oxide. When high molecular weight polymers are used, they can be used to precipitate solids in the treatment of industrial effluent stream. *Crop protection: increases in dissolved and nanoparticulate polymer formulations bioavailability of pesticides in aqueous-organic formulations. *Membranes: It increases water flow, retention and fouling resistance of asymmetric

ultrafiltration Ultrafiltration (UF) is a variety of membrane filtration in which forces such as pressure or concentration gradients lead to a separation through a semipermeable membrane. Suspended solids and solutes of high molecular weight are retained in the ...

and

microfiltration Microfiltration is a type of physical filtration process where a contaminated fluid is passed through a special pore-sized membrane filter to separate microorganisms and suspended particles from process liquid. It is commonly used in conjunction ...

membranes and is being studied as an anionic component in polymer fuel cell membranes. * Construction applications:

Superplasticizer Superplasticizers (SPs), also known as high range water reducers, are additives used in making high strength concrete. Plasticizers are chemical compounds that enable the production of concrete with approximately 15% less water content. Superplast ...

s with AMPS are used to reduce water in

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...

formulations. Benefits of these additives include improved strength, improved workability, improved durability of cement mixtures. Redispersible polymer powder, when AMPS is introduced, in cement mixtures control air pore content and prevent

agglomeration Agglomeration may refer to: * Urban agglomeration, in standard English * Megalopolis, in Chinese English, as defined in China's ''Standard for basic terminology of urban planning'' (GB/T 50280—98). Also known as " city cluster". * Economies of ag ...

of powders during the spray-drying process from the powder manufacturing and storage. Coating formulations with AMPS-containing polymers prevent calcium ions from being formed as

lime Lime commonly refers to: * Lime (fruit), a green citrus fruit * Lime (material), inorganic materials containing calcium, usually calcium oxide or calcium hydroxide * Lime (color), a color between yellow and green Lime may also refer to: Botany ...

on concrete surface and improve the appearance and durability of coating.

References

* Composition analysis of AMPS-vinyl amide copolymers. J.polym. materials 8(1991)287-289 * Synthesis and characterization of AMPS copolymers with vinylamides by Solution and thermal studies J.polym. materials 11(1994) 207-210. * High Temperature Molecular relaxations in EMA-AMPS copolymers. recent advances in Polymer Science. Vol.-II 879-(1994)allied publishers. * Thermoluminescence in probing molecular relaxations and degradation studies of MMA-AMPS copolymers. Bulletin of Electro Chemistry 9(2 & 3) feb. March 1993,pp. 143–145 {{DEFAULTSORT:Acrylamido-2-Methylpropane Sulfonic Acid, 2- Monomers Polyelectrolytes Sulfonates Anionic surfactants Vinyl compounds

Production

Properties

Applications

See also

References