The Chemistry of Paper Preservation:: Part 4. Alkaline Paper
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Henry A. Carter [1]
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[1] Department of Chemistry, Augustana University College
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- Localización: Journal of chemical education, ISSN 0021-9584, Vol. 74, Nº 5 (May), 1997, págs. 508-511
- Idioma: inglés
- Texto completo no disponible (Saber más ...)
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Resumen
The inherent instability of old papers is largely due to the presence of acids which catalyze the hydrolytic degradation of cellulose. The use of alkaline paper can minimize the problem of acidity for new papers. This study focuses on the chemistry involved in the sizing of both acid and alkaline papers and the types of fillers used. The waterproofing agent that is used in acid paper is alum-precipitated rosin size, which tends to spread and create a hydrophobic surfaces over the cellulose fibers. Alkaline paper uses the synthetic sizing agents, alkyl ketene dimers(AKD) and alkyl succinic anhydrides (ASA). These alkaline sizing agents become chemically bound to the cellulose fibers with hydrophobic chains pointing outward, producing a water repellent surface. The sizing reactions take place in a neutral-to-alkaline medium. Calcium carbonate can then be used as a filler to replace expensive titanium dioxide. Finally, the advantages and potential problems in alkaline paper making are discussed.
