Dr. Katherine Curran tests plastic sample using Near Infrared (NIR) spectroscopy at the UCL Institute for Sustainable Heritage (all images courtesy Katherine Curran)
According to new research, a special smell test can help museums sniff out artifacts on the verge of irreversible degradation. UK chemists say their method could help conservators rescue everything from plastic sculptures to cellulose film to decomposing paper.
In a recent roll-out of their methods, the researchers — based at University College London and the University of Strathclyde — even followed their noses to the Tate, where they tested three decades-old plastic sculptures.
The testing technique starts with a particular type of chemicals found in the air: VOCs, or volatile organic compounds. VOCs are all around us, and they produce countless familiar smells. Formaldehyde and benzene are two well-known examples. Others come from automobile exhaust, solvents, and even human breath.
Gas samples being tested for volatile organic compounds at the Heritage Science Laboratory at UCL’s Institute for Sustainable Heritage
By analyzing which VOCs — and therefore which smells — show up in a particular sample, scientists can figure out which chemical processes are at play. For example, doctors can diagnose certain diseases by analyzing the compounds present in human breath.
“If you’re analyzing somebody’s breath, you get quite a complex mixture of compounds,” Katherine Curran, the lead author of the new research, told Hyperallergic. “It’s a method that can handle complexity.”
As it turns out, the same tactic can work in a museum setting. For example, Curran and her colleagues at the UCL’s Institute of Sustainable Heritage found camphor around cellulose film that’s starting to disintegrate. Similar results came from paper samples and a wide range of materials that contain polymers, from old combs and jewelry boxes to vinyl records and dolls.
A historic plastic comb from the Historic Plastic Reference Collection at the UCL Institute for Sustainable Heritage
In all, Curran’s team used chemical sensors to detect VOCs edited from 25 objects that were deliberately degraded in a hot and humid chamber. With between 50% and 83% accuracy — and, crucially, without actually touching the specimens — they were able to detect by-products of chemical degradation. Their findings were published in the German chemistry journal Angewandte Chemie.
This technique could have big implications in art institutions. It may one day help conservators quickly identify objects that have started to decay, allowing them to prioritize the artifacts that most urgently need the attention of experts. Though plastics have become a key material in modern art, and modernity itself, they are notoriously difficult to conserve.
As part of her research, Curran also examined three sculptures in the collection of the Tate, including a plastic model of Aphrodite, created in 1927 by the Russian-born sculptor Antoine Pevsner. Her research found that it, too, was emitting VOCs that could be analyzed to describe its state of degradation.
Curran hopes that her team’s method will empower museums to better preserve modern artifacts, whether plastic artworks, old film reels, and even paper. “These are really interesting materials, really impressive scientific achievements,” Curran said. “They tell a story about modern history.”
Chemical tests being conducted on gas samples that were gathered from plastic samples, at the Heritage Science Laboratory at UCL’s Institute for Sustainable Heritage
Very interesting article. For years I have known that I could smell the “breaking down” of chemical components when I kept a lotion (or similar product) in a plastic container. Although a negligible amount of air could have gotten inside of my plastic bottle, the smell told me that the plastic might be degrading. Such an effect did not occur when a lotion was kept in a glass container.