B72 acrylic resin/methyltrimethoxysilane (YMTMOS) mixtures are frequently employed as consolidants for deteriorated limestones, sandstones and marbles- The addition of B72 to MTMOS imparts adhesive properties to the consolidant but it is not known to what degree the B72 affects the reactions which MTMOS must undergo to form a solid polymer network. This paper examines the following chemical, physical, and mechanical properties in order to better understand B72/MTMOS systems: 1. viscosity 2. vapor pressure 3. reaction mechanism and kinetics 4. chemical nature of polymer solids 5. rupture moduli of polymer solids and 6. rupture moduli of stone/consolidant composites.

SiCI4 was tested in both the liquid and vapor state for its suitability as a monolithic gel precursor. Samples with molar ratios of H2O/SiCl4 ranging from 4 to 400 were investigated. Several advantages of using SiCl4 over the classic organometallics such as tetraethylorthosilicate and tetramethylorthosilicate were observed. Gelation of the SiCl4-H2O sol is more rapid. Also, greater purity is achieved with SiCl4 vapor as the starting material. In addition to the SiCl4 experiments, GeCl4 was also investigated as both a dopant and in the pure state for its gelation characteristics. Higher dopant concentrations were achieved using this technique than are possible with other monolithic gel methods, but pure GeO2 gels were not formed. The gel made by the vapor phase method has been named vapogel.