Polyurethane in contemporary Italian design: the case of “Pratoni” in the Triennale Museum, Milan

Since it was synthesised in 1864 by C.A. Wurtz, Polyurethane (PUR) has been widely used for industrial purposes thanks to its great versatility. For this reason, it has been chosen also by designers and artists as a versatile material for the creation of works of art and daily-life objects. PUR, however, is one of the synthetic materials which are subjected to deterioration phenomena in shorter time if compared to historical and traditional art materials. This study takes into consideration three examples of “Pratone”, belonging to the “Multipli” series by the Italian brand Gufram srl and conserved in the Triennale Museum in Milano. “Pratone” is a sofa which reproduces on a higher scale a portion of grass; it was firstly projected in the 1970s using polyurethane foam painted in green colour to recall the natural element. These design objects, although produced in the last 10 years, were already interested by degradation processes. Therefore, they were analysed by optical microscopy, SEM-EDS, FTIR-ATR and TG-DSC techniques in order to obtain information on the compositional materials and the degradation observed and to give information for their conservation in terms of restoration practice and environmental storage conditions. The results pointed out that the three Pratoni were produced using ether-based polyurethane foams, in which additives (such as inorganic fillers, anti-flames retardants, dyestuff, etc) were introduced in the PUR composition. The green paint appeared to be a polyisoprene-based latex. The only difference among the Pratoni consists in the protective layers: two examples were covered by polymetacrilate-based varnish, while the third one was treated with polyetheretherketon (PEEK). The main deterioration processes (yellowing and brittleness of the alveolar structure) were largely due photo-oxidation and humidity problems. This research aims also to stress the importance of studying and understanding what is happening to contemporary art materials and to elaborate preventive conservation plans for their maintenance.