Silane consolidant

Injecting epoxy, furan, or furan-formaldehyde resins into poorly consolidated formations to consolidate them was a common sand control practice for thin highly productive formations (44-46). Organic solvents (46) and silane coupling agents (47) are used to promote adhesion of the resin to the rock surface. Excess resin is flushed deeper into the formation to minimize resin hardening in the flow channels since this would reduce formation permeability. 

The deposition of the silane in the loading step has been studied. The surface loading was correlated to the specific surface area of the silica rather than the hydroxyl content. Part of the deposition, therefore, is non-hydroxyl specific. The above reaction schemes, however, indicate the crucial role of the hydroxyls in the consolidation of the silane coating on the surface. 

Due to the limited reversibility of consolidation treatments for ceramics, new consolidations are carried out only if the object is seriously endangered, e.g. when the ceramic body is crumbling or the surface decoration is flaking off the surface. Materials, such as Paraloid B72 (already mentioned for glass conservation) or silanes and siloxanes (used for stone conservation) can be applied by brush, injection, spray or by immersion. Vacuum impregnation might be useful to achieve deep penetration with the consolidant. 

Structural consolidation depends on placing the consoUdant where strengthening is required. Distribution of the solid consolidant in the object should be as uniform as possible to reduce stresses at interfaces. However, uniformity of distribution is not easily achieved and seems possible only if the consolidant can be immobilized where it is needed. This can be achieved using consolidants, which react by cross-linking with themselves or the object, for example silane consolidation of fossils but not the matrix (Davidson and Alderson, 2009). The consolidant can be immobilized by freezing it in situ, as in the poly(ethylene glycol) consolidation of waterlogged wood (Jensen and Jensen, 2006). The penetration of the consolidant into the smaller pores or molecular structure is... 

Silane coupling agents (Plueddemann, 1991) (Table 13.1) have been widely used to inaease the durability of the adhesion between an adhesive and glass this has been suggested as a pretreatment for consolidation of stone... 

TABLE 13.4 Silane Stone Consolidation Products continued... 

The effect of other organosilanes on deteriorated limestone was investigated. Particular attention was paid to the depth of penetration, effects on color, and the degree of consohdation. A solution of acryhc silane in methyltrimethoxysilane was found to be the most suitable consolidants for use on limestone (Bradley, 1987). It was also shown that organosilanes do not encapsulate salt in stone and that soluble salts could be removed by a poulticing technique following consolidation. 

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