Influence of crosslinker amount on swelling and gel properties of hectorite/poly(acrylamide/itaconic acid) nanocomposite hydrogels

A new hectorite/poly(acrylamide/itaconic acid) nanocomposite hydrogel was synthesized by inverse microemulsion polymerization. The effects of crosslinker amount on water absorbency and salt absorbency, swellability, pH-sensitivity, gel strength, temperature-and shear-resistance were investigated. Water and salt absorbencies, pH-sensitivity and swellability decreased, while gel strength and temperature-and shear-resistance increased with increasing crosslinker amount. Nanocomposite hydrogels had good thermal stability with onset decomposing temperature of 252 A degrees C. The as-synthesized hydrogel particles were regular and spherical-like and had an average particle size of 43 nm in the range of 30-65 nm. Hectorite clay platelets were exfoliated and transformed into amorphous structure.