THE INFLUENCE OF DEACIDIFICATION ON THE DETERIORATION OF PAPER
J.S. Arney, A.J. Jacobs, & R. Newman
1.1 Precision of Determination of Xd/Xu and Yd/Yu
ALTHOUGH THE GRAPHIC METHOD of determining Xd/Xu and Yd/Yu is theoretically sound and intuitively easy to understand, it does not allow a rigorous analysis of the precision of the determinations. A more suitable analysis of the data involves equations (1) and (2). These equations may be derived from the geometry of Figure 2 or from the kinetic model suggested in our previous publication.7 From these equations, the data in Table III may be calculated directly. In addition, an analysis of variance of the data in Tables I and II (not shown) allows an error estimate of the data in Table III. The error limits shown in Table III are the 95% confidence intervals assuming a gaussian error distribution of Xd/Xu and Yd/Yu.
1.2 Speculation on Mechanisms of Degradation
THE TERMS “oxygen-independent” and “atmospheric oxidation” describe experimental manifestations only. They do not define uniquely the mechanism of degradation. In a kinetic study of this kind, one measures only the rate controlling process. Thus, the “atmospheric oxidation” process may involve any chemical mechanism whose overall rate is determined by reactions with oxygen. For example, an oxidative tendering of cellulose, catalyzed perhaps by transition metal impurities,5 might be followed by a fast hydrolysis. Such a mechanism would manifest itself as “atmospheric oxidation” if the oxidative tendering were, as one might suspect, rate controlling. Nevertheless, the actual loss of strength might be a direct result of the follow-up hydrolysis reaction.
Numerous mechanistic scenarios of this kind might be envisioned that would be consistent with the kinetic data. Thus, one should not consider the determination of i and j as mechanistically conclusive.
THIS INVESTIGATION was made possible by grants from the Andrew W. Mellon Foundation and the National Endowment for the Arts. The authors also express their thanks to Dr. R. L. Feller, Director of the Center on the Materials of the Artist and Conservator, for invaluable consultation and discussion.
Recent discussions and bibliographies on deacidification techniques are to be found in: (a) “Preservation of Paper and Textiles of Historic and Artistic Value,” Adv. in Chem. Series No. 164, edited by J. C.Williams, ACS, 1977, and (b) Anne F.Clapp, “Curatorial Care of Works of Art on Paper,” 3rd edition, Intermuseum Conservation Association, Oberlin, Ohio, 1978.
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J. S.Arney and A. J.Jacobs, Preprints, p. 3, AIC Annual Meeting, Fort Worth, Texas, June, 1978.
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