Rheological Study of Polymer--Colloid Complexes of Aluminoxane Particles with Weakly Charged Polyelectrolytes in Semidilute Aqueous Solutions

摘要

Viscoelastic properties of hydrogels based on polymer-colloid complexes of aluminoxane particles with acrylamide-acrylic acid copolymers were studied. Rheometric measurements were performed with an MFR 2000 Fourier microrheometer (GBS, Australia) under the regime of oscillating loads with the use of the dynamic mechanical analysis. It is shown that, with copolymer concentrations above the crossover point, the phase angle decreases abruptly; that is, the elastic characteristics of the gels decline. The maximum elastic properties of the gels for all copolymers are attained at the molar ratio of reagents Z ? 1. The effect of strain rate on relaxation processes in the gels was investigated. It is found that, at low strain rates, irreversible deformations (flow) can take place, and with an increase in frequency, the strength of physical networks formed with participation of aluminoxane particles tends to increase.