Poly(acrylic acid) (PAA; trade name Carbomer) is a polymer with the formula (CH₂-CHCO₂H)_n. It is a derivative of acrylic acid (CH₂=CHCO₂H). 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.

Poly(acrylic acid)

Names
IUPAC name Poly(acrylic acid), poly(1-carboxyethylene)
Other names PAA, PAAc, Acrysol, Acumer, Alcosperse, Aquatreat, Carbomer, Sokalan
Identifiers
CAS Number	9003-01-4 Y
ChEBI	CHEBI:51133
ChemSpider	none
ECHA InfoCard	100.115.375
EC Number	618-347-7
KEGG	C19501 N
UNII	73861X4K5F (8000 MW) N
CompTox Dashboard (EPA)	DTXSID50873988
Properties
Chemical formula	(C3H4O2)n
Molar mass	variable
log P	0.25700
Hazards
GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
NFPA 704 (fire diamond)	0 0 0
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references