Lamination of fragile documents as preliminary intervention to aqueous mass deacidification. A study on reversibility effects.

Paper lamination is a widely known method to consolidate fragile and brittle documents. Since the loss of mechanical strength of paper documents is almost completely due to their acidity, the procedure generally adopted by restorers consists of an aqueous treatment of deacidification followed by consolidation. The drawback of this method is due to the loss of paper fragments during the deacidification step, that must be therefore accurately controlled. Some preliminary experiments showed that a better and faster practice would be the lamination of paper documents with a water-resistant sheet before their immersion in the deacidification bath. The aim of this work is to evaluate the permeability, chemical stability and reversibility of the lamination sheets coated with two commercially available acrylic resins. From both gravimetric and FTIR analyses it appeared that slight modifications of the acrylic monomers led to different properties, and this behaviour can be exploited to improve the properties of lamination sheets in order to set up a reliable method of aqueous mass deacidification.