Extensional and viscoelastic properties of hydrophobically-modified alkali-soluble associative (HASE) polymer solutions

Abstract

The steady shear, dynamic and extensional properties of four model associative polymer solutions (HASE) were examined in this study. The model HASE systems consist of a co-polymer of methacrylic acid/ethyl acrylate (0.49/0.50 mole ratio) with 0.01 mole fraction of hydrophobes of either a CO, CI2, CI6 and C20 alkyl chains. The hydrophobe is extended from the backbone by a spacer chain of ~ 31 moles of polyethylene- oxide (PEO). At low pH, the polymer exists as insoluble latex particles, which dissolve upon neutralization to pH greater than 7. This gives rise to a large increase in the viscosity, which is attributed to hydrophobic associations and the expansion of the polyelectrolyte backbones.