Small‐Angle Neutron Scattering and Rheological Characterization of Aluminosilicate Hydrogels

Structure and formation of aluminosilicate hydrogels were investigated as a function of chemical composition. Oscillatory rheometry was used to measure the dynamic moduli, G ‘ and G “, of the gels during setting. The formation of aluminosilicate hydrogels was monitored over time as a function of the storage modulus for gels of low solids volumes, φ < 0.030. Overall gel strength correlated well to the fractal dimension, D , observed by neutron scattering. Scattering data were interpreted using the power law, and the Guinier relationship was used to determine the size of the constructing colloidal/gel particles. Aluminosilicate hydrogels were observed to consist of large fractal aggregates of indeterminable size constructed from smaller subunits of ∼45 Å in dimension. Structure and formation of the gels were highly dependent on [Al 2 O 3 ] and [Na 2 O] content.