DISCOLOURATION OF PLASTIC OBJECTS: INVESTIGATION INTO COMPOSITION USING VARIOUS ANALYTICAL TECHNIQUES
BY SUZAN DE GROOT
Few would argue that scientific research will continue to play a crucial role in the study, documentation and conservation of modern and contemporary art and design. There seems to be a never-ending number of new materials, and techniques in application, being incorporated into works of art, each of which would presumably require the development of appropriate analytical methods capable of identifying them. At the Cultural Heritage Agency of the Netherlands (RCE) in Amsterdam, research has been carried out into the conservation of plastics used for and applied in modern and contemporary art and modern design objects. For the conservation of modern and contemporary works of art and design objects made of plastics, the composition of the main component including additives of a plastic object should be known. Various analytical techniques exist for the identification of the composition of plastics; moreover, a non invasive technique is preferred. Mostly the main components are identified; additives and colorants have not been researched in detail. More and more colored plastic objects, especially the red colored ones, show fading due to discoloration of pigments. Which pigments are responsible for this phenomenon has not been researched yet. So for this reason, the synthetic organic red pigments were researched. Various red synthetic organic pigmentsfs from the RCE reference collection have been analysed with several analytical techniques: Raman spectroscopy, Fourier Transform Infrared spectroscopy (FTIR), Pyrolyses Gaschromatography Mass Spectrometry (Py-GCMS) and X-Ray Diffraction (XRD). Using the resulting reference data, different red synthetic organic pigmentsfs in plastics could be identified.