Poly(acrylic acid) ( PAA ; trade name Carbomer ) is a polymer with the formula (CH 2 −CHCO 2 H) n . It is a derivative of acrylic acid (CH 2 =CHCO 2 H). In addition to the homopolymers , a variety of copolymers and crosslinked polymers, and partially deprotonated derivatives thereof, are known and of commercial value. In a water solution at neutral pH , PAA is an anionic polymer , i.e., many of the side chains of PAA lose their protons and acquire a negative charge. Partially or wholly deprotonated PAAs are polyelectrolytes , with the ability to absorb and retain water and swell to many times their original volume. These properties – acid–base and water-attracting – are the bases of many applications.
13-459: PAA, like any acrylate polymer , is usually synthesized through a process known as free radical polymerization, though graft polymerization may also be used. Free radical polymerization involves the conversion of monomers, in this case, acrylic acid (CH 2 =CHCO 2 H), into a polymer chain through the action of free radicals. The process typically follows these steps: The global market is estimated to be worth $ 3.4 billion in 2022. Polyacrylic acid
26-496: A compound by introduction of the ethyl group. The most widely practiced example of this reaction is the ethylation of benzene with ethylene to yield ethylbenzene , a precursor to styrene , which is a precursor to polystyrene . Approximately 24.7 million tons of ethylbenzene were produced in 1999. Many ethyl-containing compounds are generated by electrophilic ethylation, i.e. treatment of nucleophiles with sources of Et . Triethyloxonium tetrafluoroborate [Et 3 O]BF 4
39-492: A temperature of 150 °C. On the other hand, for the new type, the press curing time and follow-up vulcanization time are significantly reduced by combining metal soap and sulfur. It has no special characteristics. The rebound resilience and abrasion resistance of the new type are poor, and even its electrical characteristics are considerably poor compared with acrylonitrile-butadiene rubber and butyl rubber . Ethyl group In organic chemistry , an ethyl group (abbr. Et )
52-544: Is a weak anionic polyelectrolyte, whose degree of ionisation is dependent on solution pH. In its non-ionised form at low pHs, PAA may associate with various non-ionic polymers (such as polyethylene oxide, poly-N-vinyl pyrrolidone, polyacrylamide, and some cellulose ethers) and form hydrogen-bonded interpolymer complexes . In aqueous solutions PAA can also form polycomplexes with oppositely charged polymers such as chitosan, surfactants, and drug molecules (for example, streptomycin). Dry PAAs are sold as white, fluffy powders. In
65-466: Is an alkyl substituent with the formula −CH 2 CH 3 , derived from ethane ( C 2 H 6 ). Ethyl is used in the International Union of Pure and Applied Chemistry 's nomenclature of organic chemistry for a saturated two-carbon moiety in a molecule, while the prefix " eth- " is used to indicate the presence of two carbon atoms in the molecule. Ethylation is the formation of
78-430: Is as a superabsorbent . About 25% of PAA is used for detergents and dispersants. Polyacrylic acid and its derivatives (particularly sodium polyacrylate ) are used in disposable diapers . Acrylic acid is also the main component of Superabsorbent Polymers (SAPs), which are cross-linked polyacrylates that can absorb and retain more than 100 times of their own weight in liquid. The US Food and Drug Administration authorised
91-454: Is such a reagent. For good nucleophiles, less electrophilic reagents are employed, such as ethyl halides . In unsymmetrical ethylated compounds, the methylene protons in the ethyl substituent are diastereotopic . Chiral reagents are known to stereoselectively modify such substituents. The name of the group is derived from the Aether , the first-born Greek elemental god of air (and at that time
104-503: The consistency in flow of cosmetics. Carbomer codes (910, 934, 940, 941, and 934P) are an indication of molecular weight and the specific components of the polymer. For many applications PAAs are used in form of alkali metal or ammonium salts, e.g. sodium polyacrylate . Hydrogels derived from PAA have attracted much study for use as bandages and aids for wound healing. A few reports were made on PAA use as deflocculant (so called alkaline polyacrylates ) for oil drilling industry. It
117-454: The dry powder form of sodium polyacrylate , the positively charged sodium ions are bound to the polyacrylate , however, in aqueous solutions the sodium ions can dissociate. The presence of sodium cations allows the polymer to absorb a high amount of water. PAA is widely used in dispersants. Its molecular weight has a significant impact on the rheological properties and dispersion capacity, and hence applications. The dominant application for PAA
130-414: The slightly better water resistance of ANM there are no physical differences between the two types. The material is less resistant in terms of cold weather with a saturation point of −15 °C for old types and −28 °C to −30 °C for new types. In terms of vulcanization , the standard method for the old type is amine vulcanization. To minimize permanent deformation, the old type requires curing for 24 hours at
143-769: The use of SAPs in packaging with indirect food contact. Detergents often contain copolymers of acrylic acid that assist in sequestering dirt. Cross-linked polyacrylic acid has also been used in the production of household products, including floor cleaners. PAA may inactivate the antiseptic chlorhexidine gluconate . The neutralized polyacrylic acid gels are suitable biocompatible matrices for medical applications such as gels for skin care products. PAA films can be deposited on orthopaedic implants to protect them from corrosion. Crosslinked hydrogels of PAA and gelatin have also been used as medical glue. Other applications involve paints and cosmetics . They stabilize suspended solid in liquids, prevent emulsions from separating, and control
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#1733084859085156-481: Was also reported to be used for metal quenching in metalworking (see Sodium polyacrylate ). Acrylate polymer An acrylate polymer (also known as acrylic or polyacrylate ) is any of a group of polymers prepared from acrylate monomers. These plastics are noted for their transparency, resistance to breakage, and elasticity. Acrylate polymer is commonly used in cosmetics , such as nail polish , as an adhesive . The first synthesis of acrylic polymer
169-777: Was reported by G. W. A. Kahlbaum in 1880. Acrylic elastomer is a general term for a type of synthetic rubber whose primary component is acrylic acid alkyl ester ( ethyl or butyl ester ). Acrylic elastomer possesses characteristics of heat and oil resistance, with the ability to withstand temperatures of 170–180 °C. It is used primarily for producing oil seals and packaging related to automobiles. Acrylic elastomer can generally be characterized as one of two types. "Old" types include ACM ( copolymer of acrylic acid ester and 2-chloroethyl vinyl ether ) containing chlorine and ANM (copolymer of acrylic acid ester and acrylonitrile ) without chloride. "New" types do not contain chlorine and are less prone to mold-related staining. Other than
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