Mass Deacidification of Paper

Abstract

Paper, the carrier of our written heritage, decays within a relatively short period of time mainly due to its acid content and the influence of air pollution. More than 50% of the records of our libraries and archives are already at risk. Mass deacidification allows this problem to be counteracted by significantly slowing down the deterioration of paper and thereby prolonging its life span. An overview of all relevant mass deacidification methods is given. As it was found that the 'papersave' method was the most suitable to meet Swiss requirements, a plant using an optimised version of this method was built and put into service in March 2000. Thanks to this optimisation, not only books and loose sheets but also documents in archival boxes could be mass-deacidified for the first time. Due to the necessity to analyse not only test papers but also original documents, new non-destructive testing methods had to be developed. Findings of basic investigations regarding treatment effects as well as results of routine quality control turned out to be very satisfactory.

Nonaqueous solution deacidification treatments to prolong the storage life of acidic books: A review of mechanistic and process aspects

“…Hon 1989;Clark et al 1998;Hubbe 2005 Completion By optimizing the moisture content of the paper or by equilibration of the treated paper with humid air, can one ensure that most or all of the organometallic agent gets converted to the hydroxide, oxide, or carbonate form during the course of the treatment? Hon 1989;Brandis 1994;Wittekind 1994a; Blüher and Vogelsanger 2001 By optimizing the level of organometallic agent, at a given moisture content, can one ensure that accessible acidic groups within the structure are neutralized during the course of the treatment? -Chemistryrelated issues Is there an ideal range of reactivity for an organometallic deacidification agent to be applied as a solution?…”

“…Commercially-demonstrated, solution-based nonaqueous deacidification practices will be introduced here, starting with a historical overview, then considering chemical aspects (focusing on the alkaline reagent and the solvent), then the procedural steps. Broad descriptions of the technology are given in the following sources (Smith 1987;Morrow 1988;Hon 1989;Schwerdt 1989;Blüher and Vogelsanger 2001;Baty et al 2010;Ahn et al 2012a).…”

“…HFC-134 (1,1,1,2-tetrafluoroethane) was later used in the Wei T'o system because it was found to be a good solvent for MMMC (Smith 2013). Hydrofluorocarbons have been specified as solvents or carriers for various deacidification systems (Leiner and Kifer 1995;Blüher and Vogelsanger 2001;Thomas and Diggs 2003;Banik 2005). Due to a concern about potential ozone depletion, specified chlorofluorocarbons have been used in place of earlier used versions of chlorofluorinated solvents for such systems (Smith 1977(Smith , 1982Green and Leese 1991;Clark et al 1998).…”

“…According to Couture (1999), the HFC solvents were found to provide excellent stability of the alkoxide-based reagent using the Wei T'o system. Nevertheless, some authors have asserted that chlorofluorocarbons are not to be regarded as a long-term option (Kelly et al 1977;Blüher and Vogelsanger 2001). Schwerdt (1989) stated that there was too much loss of such solvent when operating the Sable process, a French system described as being similar to Wei T'o.…”

“…At the heart of some of the most successful and important systems for the massdeacidification of books and archival materialto increase their useful lifetimesis a class of treatments employing organometallic agents dissolved in nonpolar solvents (Hon 1989;Porck 1996;Blüher and Vogelsanger 2001;Cedzova et al 2006;Ramin et al 2009;Baty et al 2010). Such systems have demonstrated high performance in maintaining paper strength when the documents were subsequently subjected to accelerated aging (Brandis 1994;Andres et al 2008;Ramin et al 2009;Ahn et al 2012a;Katuscak et al 2012;Hubbe et al 2017).…”