Features of the Hydration of Consolidated Methyl Silica and a Composite Based on It and Succinic Acid

A procedure is developed for bringing hydrophobic nanosilica (neat and modified with succinic acid) into a wet state where the amount of the water bound to the material is comparable to the weight of the silica, and the apparent density is 0.7-1 g/cm(3). The obtained composite is studied via low-temperature H-1 NMR spectroscopy, X-ray powder diffraction analysis, and thermogravimetry. It is shown that the bonding of water to hydrophobic silica is more efficient than the bonding of water to a water-based composite with hydrophilic succinic acid. It is concluded that under mechanical loads, small (less than 10 nm) clusters of water form in the intergranular gaps in silica and interact with the hydrophobic surface via van der Waals interactions.