The degradation of poly(vinyl acetate) as a material for design objects: A multi-analytical study of the effect of dibutyl phthalate plasticizer. Part 1 Francesca Toja a , Daniela Saviello a , Austin Nevin b , Daniela Comelli c , Massimo Lazzari d , Marinella Levi a , Lucia Toniolo a, * a Politecnico di Milano, Dipartimento di Chimica Materiali e Ingegneria Chimica, Piazza Leonardo da Vinci, 26 e 20133 Milano, Italy b Consiglio Nazionale delle Ricerche, Istituto di Nanotecnologie e Fotonica (CNR -IFN) Dipartimento di Fisica, Piazza Leonardo da Vinci, 32 e 20133 Milano, Italy c Politecnico di Milano, Dipartimento di Fisica, Piazza Leonardo da Vinci, 32 e 20133 Milano, Italy d Department of Physical Chemistry, Faculty of Chemistry and Centre for Research in Biological Chemistry and Molecular Materials (CIQUS), University of Santiago de Compostela, 15782 Santiago de Compostela, Spain article info Article history: Received 24 February 2012 Received in revised form 29 June 2012 Accepted 4 July 2012 Available online 20 July 2012 Keywords: Poly(vinyl acetate) Fluorescence spectroscopy FTIR spectroscopy Thermal ageing Photo-oxidative ageing Design objects abstract The influence of dibutyl phthalate (DBP) plasticizer on poly(vinyl acetate) (PVAc) degradation was investigated. A multi-analytical approach (combining FTIR and Fluorescence spectroscopy, NMR and DSC analyses) was used to study how thermal- and photo-oxidative ageing treatments act on the polymer and assess the role of the additive in the degradation pattern. Standard and plasticized PVAc films were artificially aged at 60  C in a thermal regime and irradiated at wavelengths above 290 nm in a photo- oxidative ageing regime, with exposure between 100 and 2000 h. The two types of ageing differ mainly in the formation of C]C double bonds along the polymer backbone, enhanced by thermal ageing, and the formation of aldehydic structures, following photo-oxidative treatment and in the degree to which plasticizer is lost. The integration of results from different analytical methods highlights the utility in combining complementary analyses for the study of PVAc degradation. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction Plastic compounding is a fundamental process since polymers require chemical modifications to optimize their chemical and physical properties which include resistance to surfactants, strain, high temperatures, oxidation, impact, and ultraviolet radiation. Therefore, plastics are available in a wide range of formulations where base polymers are mixed with both organic and inorganic materials which include additives, metal powders and glass fibers [1]. Additives are fundamental components which provide stability to polymers, ensuring good mechanical properties, performance and long-term use and can prevent or delay degradation of the composite plastic formulation [2,3]. Each additive has a different effect on the properties and the ageing of materials and can play a key role in the success or structural failure and chemical degra- dation of objects in plastic [4,5]. It is well known that additives highly influence the pattern of degradation because of their loss, evaporation and migration to the surface, and also due to their reactivity with environmental agents [6e8]. The assessment of the role of additives in polymers degradation is a critical aspect for the conservation and preservation of artefacts made in plastic In fact, polymers are increasingly used to create artworks, and objects partially or completely made of plastics may be found in international collections [9]. Cellulose-based materials, plasticized PVC, polyether-based polyurethanes as well as polyvinyl esters are among the most widely used materials in this field. Nevertheless, plastics have shorter lifetimes than traditional materials (for example wood) because polymers, due to their nature, are much more susceptible to chemical degradation reac- tions [10]. Because of excessive exposure to light, heat, moisture, chemicals and gaseous pollutants, objects made in plastics may degrade very quickly and, in some cases, may have a useful lifetime of only a few decades [11]. In order to find effective ways to preserve these objects, conservation scientists need to carry out systematic studies with artificial or accelerated ageing [12]. Accelerated ageing tests are important to verify in an accessibly short time the relative chemical and physical stability of materials in museum-type conditions [13]. * Corresponding author. E-mail address: lucia.toniolo@polimi.it (L. Toniolo). Contents lists available at SciVerse ScienceDirect Polymer Degradation and Stability journal homepage: www.elsevier.com/locate/polydegstab 0141-3910/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.polymdegradstab.2012.07.018 Polymer Degradation and Stability 97 (2012) 2441e2448