Study of the Photochemical Stability of Paper Deacidified with Dispersions of Ca(OH)2 and Mg(OH)2 Nanoparticles in Alcohols

The photochemical stability of lignocellulosic and purely cellulosic paper deacidified with five dispersions of Ca(OH)(2) and Mg(OH)(2) nanoparticles in alcohols was studied. The hydroxide particles were produced either by "slaking" of CaO in an appropriate aqueous solution (two dispersions) or by homogeneous phase reactions of magnesium or calcium salts with NaOH (three dispersions). To evaluate the protective effect of deacidification of paper with these dispersions, artificial ageing with exposure to UV radiation at 280 nm at constant temperature (25 degrees C) and constant relative humidity (50%) were employed. The physicochemical, optical and mechanical properties of the tested paper indicate that the proposed deacidification method can ensure a quite satisfactory photochemical stability of paper. The present work continues a previous study concerning the evaluation of the same deacidification method using accelerated thermal ageing (Restaurator 28).