Oxidation at the wet/dry interface in the deterioration of paper in library and archival collections in humid climatic conditions.
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Date
1998
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Abstract
Three primary mechanisms of paper deterioration in library and archival
collections are driven by climatic conditions of excessive relative humidity.
These are chemical reactivity, mechanical stress and biological deterioration. It is the view of the researcher that the role of chemical
reactivity has not been adequately assessed in relation to the deterioration
of paper. The significance of an autoxidative phenomenon, similar to the brown tideline staining at the wet/dry interface, has not been previously
recognised as a cause of deterioration as an accelerated function of time
under humid conditions of the macroclimate, and as a function of the
unstable equilibrium moisture content of materials in a microclimate, but has
been obscured by the accepted explanation of biological deterioration.
An analytical procedure was developed to enable the comparison of
oxidative degradation products found in stained areas of naturally aged
samples with those formed during a dynamic simulated ageing programme
to induce cellulosic discolouration. A relationship between the degradative
mechanism and humid climatic conditions was established. Based on the
findings of the analytical investigation, this study forms a contribution
towards the development of a theory of deterioration. Evidence is presented of a chemical process of degradation in the oxidation
of paper at the wet/dry interface, following the condensation and evaporation kinetics induced by cycling relative humidity (RH) driven by temperature fluctuations in diurnal and seasonal ranges. Sites of moisture accumulation at which the oxidative reaction readily take place, and which constitute a wet/dry interface, are identified at surface areas exposed to atmospheric exchange, in physical defects, in uneven adhesive lamination, in local wet treatments, in impervious storage enclosures or adjacent to an impervious surface which acts as a vapour barrier to the transudational force of capillary action. In advancing the theory of a chemical response of library and archival materials in the fluctuating moisture content as an explanation for the causation of cellulosic staining, the evidence of foxing is redefined. Librarians, archivists and conservators are thus assisted in the identification of the basic chemical reactions involved in the process of deterioration, and in recognising the role of oxidative degradation relation to environmental conditions.
Description
Thesis (Ph.D.)-University of Natal, Pietermaritzburg, 1998.
Keywords
Paper--Storage., Paper--Preservation., Library materials--Conservation and restoration., Archival materials--Conservation and restoration., Theses--Library and information science.