Consolidants soluble resins

Most soluble resins that are being used as consolidants in conservation today are also used in picture varnish. Thus these resins have a history of satisfactory use that, in the case of poly(vinyl acetate), extends over almost 60 years (6). Consolidants can cause some darkening of wood surfaces much in the way wetting them with water deepens their color, but with proper technique they will not leave a shiny surface film (7). Because excessive... 

Consolidation treatments with soluble resins can be considered reversible in principle, but it has been questioned (i, 9) whether this reversibility would ever be practically feasible. Experiments with an acrylic and a poly(vinyl butyral) consolidant showed that most of the resin could be removed from treated wood, and that the acrylic could be removed more readily than the poly (vinyl butyral) (15). In another study, a consolidation treatment of archaeological wood with Acryloid B72 in toluene could be substantially but not completely extracted again, as evidenced by scanning electron microscopic examination (22). 

Schniewind, A. P. (1988). On the reversibility of consolidation treatments of deteriorated wood with soluble resins. In Wooden Artifacts Group Specialty SessUm, New Orleans, June 5, 1988 Papers. American Institute for Conservation. 

Schniewind, A. P., Eastman, P. Y. (1994). Consolidant distribution in deteriorated wood treated with soluble resins. Journal of the American Institute for Conservatim, 33(3), 247-255. 

Sand has been treated with oil-soluble organosilicon compounds to form a hydrophobic proppant (77). A double layer resin coating has also been developed. The inner layer coating the sand particle is a cured gamma-aminopropyltriethoxvsilane - hexamethylenetetramine. The outer layer is an uncured mixture of the same two chemicals which cures within the fracture to form a consolidated permeable mass holding the fracture open (78). 

Materials used as consolidants may be classified as either natural or synthetic in origin. Natural consolidants include water-soluble glues such as hide glues, solutions of natural resins such as shellac, molten waxes such as beeswax, and drying oils such as linseed oil (2). These natural materials have their advantages and limitations, and are still used as consolidants, but will not be discussed further here. 

According to Grattan (9), the most common polymers used in solvent-resin consolidant systems are acrylics, poly(vinyl acetates), poly(vinyl butyrals), and soluble nylon. Of these, soluble nylon has since been shown to be unsuitable because it inevitably cross-links and embrittles within as little time as a few weeks (iO). The others are known to have excellent longterm stability (9). Most likely the stability of polymers placed inside the wood may be even better, because they would be protected from light-catalyzed degradation reactions. Possible wood-polymer interactions, however, are unknown at this time. 

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