Poly consolidant

Poly(acrylic acid) and its salts have been known to have useful binding properties for some thirty years they have been used for soil consolidation (Lambe Michaels, 1954 Hopkins, 1955 Wilson Crisp, 1977) and as a flocculant (Woodberry, 1961). The most interesting of these applications is the in situ polymerization of calcium acrylate added to soil (de Mello, Hauser Lambe, 1953). But here we are concerned with cements formed from these polyacids. 

Podol skii IYa, Kondrat eva EV, Shcheglov IV et al. (2002) Fullerene C60 complexed with poly(N-vinylpyrrolidone) prevents the disturbance of long-term memory consolidation. Phys Solid States. 44 552-554. 

Sintering - Consolidation and densification of poly-tetrafluoroethylene particles above its melting temperature is cdlleA. sintering. See also Coalescence. 

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... 

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. 

If consolidation is required only for surface layers of an object, application by brushing may be suflScient. Consolidant may be applied in several coats, but eventually a saturation of surface layers will lead to formation of undesirable glossy films. More resin can be introduced by application of many coats of low-concentration solutions than by use of solutions in high concentration, because the latter lead to early gloss formation (9). Barclay (7), for example, used a 5% solution of poly(vinyl butyral) resin (Butvar B90) in ethanol for brush treatment of parts of an English fire engine. 

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). 

Traditional Methods. Traditional approaches to strength and integrity restoration center around consolidation systems. These consist of natural or synthetic resins that are impregnated into the wood. The natural resins are usually waxes or oils. Synthetic resins are either thermosetting (based on epoxy s, polystyrene, or a poly methyl methacrylate) or thermoplastic (such as poly(vinyl acetate)s, poly(vinyl butyral)s, or acrylics). In general, all of these consolidation systems do not penetrate the cell wall because they are not polar enough or because their molecular size is too large. 

Zhang, J. M. and Peijs, T., Self-reinforced poly(ethylene terephthalate) composites hy hot consolidation of Bi-component PET yams . Composites Part A Applied Science Manufacturing, 2010,41(8), 964. 

All-PPTA, tri-dimensional foamed consolidated FRP composite was prepared by embedding Kevlar 49 fibers in poly(A,A-di-sec-butyl-p-phenylene terephthalamide) resin [95]. The latter, on heating in the presence of benzenesulfonic acid catalyst, was dealkylated to form the PPTA matrix. In this way, Kevlar 49/PPTA molecular composites containing fiber fractions in the range of 8-40% by volume, having densities in the range of 0.2 to 1.2 g/cm, were prepared and their thermal and mechanical properties characterized. It has been pointed out that such all-PPTA composites mimic natural materials, e.g., the foamed composites prepared in this work had a remarkable resemblance to wood, with the advantages of flame and rot resistance. 

The film stacking method is a technique where the fiber reinforcement is sandwiched between films of the same polymer, and then hot pressing is apphed to consolidate them together. Note that the melting of the matrix-giving film should start at lower temperature than the reinforcement. This technique has been apphed to a wide range of polymers, such as poly (ethylene terephthalate) (PET) [6-7], polypropylene (PP) [8-11], polyethylene (PE) [10,12] and polylactic acid (PLA) [13]. 

Zhang J M and Peijs T (2010) Self-reinforced poly(ethylene terephthalate) composites by hot consolidation of bi-component PET yarns, Compos Part A 41 964-972. 

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... 

Poly(vinyl formal) was tried as a consolidant for textiles (Geijer, 1961b Leene, 1963) bnt conld not be redissolved, presnmably because of cross-linking with acid and aldehyde gronps on the degraded textile. 

Wolbers, R. C., McGinn, M., Duerbeck, D. (1998). Poly(2-ethyl-2 oxazoline) a new conservation consolidant. In V. Dorge, F. C. Howlett (Eds.), Painted wood History and conservation (pp. 514-527). The Getty Conservation Institute. 

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