Synthesis and characterization of hyperbranched associative polyacrylamide

Hydrophobically modified polyacrylamide with hyperbranched structure (HDPAM) was synthesized by water free-radical copolymerization based on functional hyperbranched polyamide-modified ultrafine silica as functional monomer and methacryloxyethyl-dimethyl cetyl ammonium bromide as hydrophobic monomer. The chemical and spatial network structure of HDPAM were investigated by means of FTIR, H-1 NMR, TGA and SEM, respectively. The rheological measurements indicated that the HDPAM solution was viscoelastic fluid. With the increase of HDPAM concentration, both intermolecular association efficiency of hydrophobic groups and apparent viscosity of HDPAM solution increased. HDPAM solution had good thixotropy and temperature tolerance property. Moreover, compared with HPAM, HDPAM demonstrated superior properties on the aspects of viscosification property, temperature resistance and salt tolerance.