A whiff of plastic art reveals degradation

Art can be timeless, but no piece of art can resist time’s ravages: Stone crumbles, paint cracks, and plastics break down, chemical bond by chemical bond. Polymer decomposition can be invisible to the naked eye, so conservators who work with plastic pieces don’t always know how much an object has degraded until it’s too late to do anything to protect it. Chemists have now developed a noninvasive method to measure just how much particular polymers have degraded. The team, from University College London and University of Strathclyde, led by Katherine Curran and Matija Strlič, analyzed different types of polymers found in museum collections by studying the gases they give off during degradation (Angew. Chem. Int. Ed. 2018, DOI: 10.1002/anie.201712278). The chemists analyzed the plastics for volatile organic compounds using solid-phase microextraction gas chromatography and mass spectrometry. They then artificially degraded the polymers by heating them to 80 °C for up to 10 weeks and reanalyzed them. Polymers gave off different amounts and types of organic compounds, depending on how much they’d degraded. The researchers then analyzed three works of plastic art from Tate museums’ collections. One piece, Antoine Pevsner’s “Head” (1923–24), showed advanced degradation. Information gleaned from such analyses can help conservators make decisions about what protective measures to take.