Bookbinding and the Conservation of Books
A Dictionary of Descriptive Terminology

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catalyst

1. A substance that changes the rate of a chemical reaction without itself being changed. A catalyst may increase the rate (positive catalyst), or decrease the rate (negative catalyst). The final state or equilibrium of the reaction is not changed by the catalyst. only the rate of approaching the final state is changed. Examples of catalytic action in the field of archival preservation include the impurities in paper, such as iron or copper, minute particles of which may inadvertently be introduced into the paper pulp in the beater operation. According to some authorities, these can act as catalysts in the formation of sulfuric or hydrochloric acid in paper. by assisting in the conversion of sulfur dioxide to sulfuric acid, or the chlorine frequently used in bleaching paper pulp, into hydrochloric acid. Leather, also, may contain minute particles of metals which may speed up the formation of sulfuric acid. 2. A chemical substance added to thermosetting resinous adhesives to speed up the cure time of such adhesives. to increase the cross linkage of a synthetic polymer, or to accelerate adhesive drying. (221 , 235 , 309 )




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