Polymer structure of acrylic polymer

Acrylic polymer

The structural formula of acrylic acid is: its alpha and beta hydrogens can be substituted; its carboxyl group can be derived from ester groups (including diesters, polyesters), amides, acid chlorides, acid anhydrides, etc .; nitrile can also be regarded as carboxyl derivative. Therefore, its derivatives can be polymerized a lot, which is a more important class of olefinic monomers.
Polyacrylic acid monomer is acrylic acid, which is mainly produced by the catalytic oxidation of propylene or acrolein in the industry. It is a liquid with a melting point of 12 ° C and a boiling point of 142 ° C. Usually, polymerization is performed in an aqueous solution state.

Its polymerization rate in water is greatly affected by pH, and it is faster in acidic media than in alkaline media. The aqueous solution of polyacrylic acid PAA is a polyelectrolyte, and its viscosity changes abnormally due to pH, that is, the viscosity increases abnormally when pH> 7. This is because the carboxyl group of polyacrylic acid ionizes to form negative ions, which results in electrostatic repulsion, which causes the polymer chain to assume a more relaxed conformation in solution. Polyacrylic acid can be used as a thickener due to its high viscosity. Polyacrylic acid can be cross-linked with ZnO or the like to form a so-called ion-crosslinked polymer, which is a new filling material.
Polymethylmethacrylate monomer α-methacrylic acid is a liquid with a melting point of 15 ° C and a boiling point of 162-163 ° C; it can dissolve about 18% in water at room temperature. The properties of polymethacrylic acid are basically similar to polyacrylic acid.