Carbomer is tightly coiled acidic molecules powder, once the molecule is uncoiled, the viscosity will be increased.
Neutralization thickening is one kind of thickening mechanisms
Once dispersed in water, Carbomer begins to hydrate and the carboxyl groups of the acrylic acid backbone will ionize the hydrion, with the electrostatic repulsion force and the effect of hydrogen bonding, cross-linked polyacrylic acid will partially uncoil , forming a colloidal dispersion. Fig.1 shows the partially uncoiled state of Carbomer dispersion. The pH of 0.5% aqua dispersion is about 2.5-3.5. Once the dispersion is neutralized, the molecule is ionized and generated negative charges along the backbone of the molecule, and the electrostatic repulsion force of the carboxylate ionization of the polymer backbone will be much stronger, so the neutralized mucilage will swell and can swell even up to 2000 times their original volume and 10 times their original diameter to form gel. Fig.2 shows the thickening process and their molecule state.
Fig. 1 The crosslinked and partially uncoiled state of Carbomer dispersion
Fig. 2 The process of the neutralization and the Carbomer's molecule state
Article from Anhui Newman Fine Chemicals Co., Ltd. - professional carbomer manufacturer.
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