Поли (акриловой кислоты)

Описание

Poly (acrylic acid) (PAA) is hygroscopic, brittle and colorless in nature with Tg at nearly 106oC. At temperatures above 200 to 250oC, it loses water and becomes an insoluble crosslinked polymer anhydride. Solubility of dried PAA in water increases with rise in temperatures. Concentrated solutions of PAA in water is thixotropic in nature.
Polyacrylic acid (PAA) is a hydrophilic colloidal solution, similar in properties to water-soluble natural gums. It is a clear, colorless, viscous stable solution. Applications include the modification of aqueous formulations for such end uses as cleaners, binders, adhesives, and emulsion paints. The sodium, potassium, and ammonium salts are effective thickeners and dispersants useful in both natural and synthetic latex systems. PAA in ceramic applications improves dry strength, dispersant action, and improved workability of the clays. PAA is stable to hydrolysis and is not susceptible to bacterial degradation.

Химические свойства

white powder

Использование

Applications of PAA may include: · to study solute diffusion in Polyvinyl alcohol/PAA copolymer hydrogel · synthesizing poly(N-isopropylacrylamide)-block-PAA copolymer which responds to both temperature and pH stimuli · in preparing block copolymer of oligo (methyl methacrylate)/PAA for micellar delivery of hydrophobic drugs · as thickening agent for adhesives

Определение

ChEBI: An acrylic macromolecule, composed of acrylic acid repeating units.

Методы производства

Carbomers are synthetic, high-molecular-weight, crosslinked polymers of acrylic acid. These acrylic acid polymers are crosslinked with allyl sucrose or allyl pentaerythritol. The polymerization solvent used previously was benzene; however, some of the newer commercially available grades of carbomer are manufactured using either ethyl acetate or a cyclohexane–ethyl acetate cosolvent mixture. The Carbopol ETD and Carbopol Ultrez polymers are produced in the cosolvent mixture with a proprietary polymerization aid.

прикладной

Poly acrylic acid and its derivatives are used in disposable diapers,ion exchange resins and adhesives. They are also popular as a thickening, dispersing, suspending and emulsifying agents in pharmaceuticals, cosmetics and paints. PAA inactivates the antiseptic chlorhexidine gluconate.

Общее описание

Poly(acrylic acid) solution (PAA) is an anionic polymer that can be synthesized by the free radical polymerization of acrylic acid. It has a swelling nature that tends to absorb and retain the water. Its high ion exchange capacity makes it useful in the formation of membranes.

Несовместимости

Carbomers are discolored by resorcinol and are incompatible with phenol, cationic polymers, strong acids, and high levels of electrolytes. Certain antimicrobial adjuvants should also be avoided or used at low levels. Trace levels of iron and other transition metals can catalytically degrade carbomer dispersions.
Certain amino-functional actives form complexes with carbomer; often this can be prevented by adjusting the pH of the dispersion and/or the solubility parameter by using appropriate alcohols and polyols.
Carbomers also form pH-dependent complexes with certain polymeric excipients. Adjustment of pH and/or solubility parameter can also work in this situation.

Регуляторный статус

Included in the FDA Inactive Ingredients Database (oral suspensions, tablets; ophthalmic, rectal, topical, transdermal preparations; vaginal suppositories). Included in nonparenteral medicines licensed in Europe. Included in the Canadian List of Acceptable Nonmedicinal Ingredients.