Shear Responsive Gelation of Aqueous Polyacrylic Acid-co-polyacrylamide: Molecular Mechanism and Tribological Applications

Abstract

This study reports the shear-responsive gelation of an aqueous solution of polyacrylic acid-co-polyacrylamide (PAA-co-PAM). Microstructure characterization and molecular dynamics simulation reveal that the shear action results in the ordering of the polymer chains, thus increasing the strength of hydrogen bonds between chains and forming gel. Friction tests reveal that the PAA-co-PAM aqueous solution effectively reduces the friction and wear of Si3N4 friction pairs via the in situ formation of a colloidal lubrication film which could cooperate with the silica gel layer generated on the Si3N4 surface. Owing to the shear gelation characteristics of the PAA-co-PAM aqueous solution, the hydrogel lubrication film could be continuously formed under shear action, thus overcoming the insufficient lifetimes of existing hydrogel lubricants.

The Effect of Silver Nanoparticles/Titanium Dioxide in Poly(acrylic acid-co-acrylamide)-Modified, Deproteinized, Natural Rubber Composites on Dye Removal

“…In this system, the grafting of PAA- co -PAM occurred at the natural rubber particle surface. The linkage of PAA- co -PAM chains during polymerization was obtained due to the addition of MBA, leading to the formation of a crosslinked network structure [ 27 , 28 ]. Consequently, the PAA- co -PAM chains can hold into the natural rubber-based structure, resulting in an increase in grafting efficiency and grafting percentage.…”