Influence of plasticizer and biocide on the functional properties of gelatin-based adhesives used in painting consolidation

Abstract

The study presented herein focuses on the influence of glycerol and citronella oil, added to gelatin dispersions as plasticizer and biocide, respectively, on the mechanical, water barrier and other functional properties of gelatin-based adhesives used in treatments of painting consolidation. For this purpose, ATR-FTIR spectroscopy, gas chromatography mass spectrometry, atomic force microscopy analyses combined with tensile, water vapour permeability, water content and water solubility tests were performed on gelatin films prepared by adding glycerol and citronella oil. These two products were chosen for their low toxicity and eco-friendly properties. The modification in the behaviour of gelatin-based adhesives as a result of addition of glycerol and citronella oil was evaluated on the basis of changes of the three-dimensional structure of the protein molecules due to their interaction with glycerol and citronella oil. All these data were provided by the analytical techniques. In a second step, stability of the proposed adhesive to light was assessed to establish its suitability for painting consolidation. The results suggest that citronella oil enhances the effectiveness of glycerol to improve mechanical behaviour and reversibility of the gelatine-based adhesive. Light ageing of the specimens containing the proposed additives produced no remarkable changes in structure, mechanical, water barrier and other functional properties of the adhesives.