Abstract

Paper material produced after about 1850 contains additives that cause progressive acidification of the cellulose matrix, which can result in severe degradation of the material and simultaneous deterioration in its strength properties. This problem has affected whole stocks of libraries and archives, in response to which the process of “mass deacidification” has been developed. In this study, the structure and chemistry of the active reagent used in the main variant of this process has been identified as magnesium n-propoxycarbonate. The reagent, introduced in an inert fluorinated solvent, neutralizes acids in the paper matrix and simultaneously deposits a reserve of alkaline magnesium salts that counteract re-acidification. At the same time, it is much less alkaline than the magnesium alcoholates so that alkali-induced degradation reactions of cellulose (β-alkoxy elimination) are avoided.