08-Mar-2018 - University College London (UCL)

What the Smell Can Tell

The degradation status of modern polymeric museum artifacts can be classified by their smell

Breath analysis in disease diagnostics is a promising research field, and the advances in instrumentation allows the accurate detection of metabolites. But not only the health status of patients, but also the preservation status of museum artifacts could be monitored. Heritage science researchers have investigated emissions of volatile organic compounds from plastics-based art objects and provided a first calibration scheme for polymer degradation in museum environment.

Everyone is familiar with the detection of volatile organic compounds (VOCs). They can be sensed by the nose and tongue, indicating several aspects of the current state of the emitting system—be it the mown grass in the backyard, the level of maturation of cheese or decay in fish, or even if a patient suffers from diabetes. But the emittance of marker chemicals is not restricted to living systems. Volatile degradation products can also be detected for polymers. Since the beginning of the 20th century, many plastics-based objects have found their way into museums, and conservators and heritage scientists are highly interested in assessing their preservation status, ideally without taking physical samples from the objects. Katherine Curran and her colleagues from the University College London (UCL) Institute for Sustainable Heritage, the University of Strathclyde, Glasgow, working in collaboration with several museums, libraries, and archives, now introduce a noninvasive gas-chromatography/mass-spectrometry detection system for marker VOCs emitted by several polymers contained in modern museum artifacts. They also developed a rough calibration system to classify three real objects from the Tate into two distinct decay states.

Every polymer leaves its own signature of degradation products. For example, degrading cellulose acetate emits acetic acid, which can be quantified over time. To assess the quality and quantity of VOCs from polymers, the scientists chose chemical markers for polymers common in museum artifacts such as cellulose-based polymers, polyurethane foam, poly(vinyl chloride), polystyrene, and polyethylene. As reference degradation states, they used modern polymeric samples exposed to heat for zero to 10 weeks. The aim was to find characteristic VOC patterns: “The VOCs detected provide an insight into the composition and ongoing chemical degradation processes of the objects studied,” the authors remarked.

Based on the detected VOCs, a rough classification scheme as “early stage” and “advanced degradation state” could be established for the different polymers—and tested for real museum objects based on these materials. For two cellulose-based objects from the Tate made in the 1920s and 1930s, the scientists reported a low degradation state, but one made in 1923–1924 was found in a more advanced decay. While this might be a matter of concern for the conservators, Curran and her colleagues think of expanding their analysis: A calibration scheme based on naturally aged samples would help reduce the current limitations, they argue.

More about University College London
  • News

    New material for longer-lasting fuel cells developed

    In the study, published in the journal Nanoscale, scientists produced graphene via a special, scalable technique and used it to develop hydrogen fuel cell catalysts. The research team, involving scientists from Queen Mary University of London and University College London (UCL), showed that ... more

    Fast-charging, long-running, bendy energy storage breakthrough

    A new bendable supercapacitor made from graphene, which charges quickly and safely stores a record-high level of energy for use over a long period, has been developed and demonstrated by UCL and Chinese Academy of Sciences researchers. While at the proof-of-concept stage, it shows enormous ... more

    Using neutrons and X-rays to analyse the ageing of lithium batteries

    An international team has used neutron and X-ray tomography to investigate the dynamic processes that lead to capacity degradation at the electrodes in lithium batteries. Using a new mathematical method, it was possible to virtually unwind electrodes that had been wound into the form of a c ... more

  • Videos

    Understanding how Lithium-ion batteries fail

    What happens when lithium-ion batteries overheat and explode has been imaged inside and out for the first time by a team led by UCL PhD student Donal Finegan (UCL Chemical Engineering) and Dr Paul Shearing (UCL Chemical Engineering).Understanding how Li-ion batteries fail and potentially ca ... more

More about University of Strathclyde
More about Angewandte Chemie
  • News

    Palladium Catalysts Can Do Its

    Palladium catalysts help synthesize key chemicals for many industries. However, direct reaction of two basic reagents, aryl halides and alkyllithium compounds, remains a challenge. Now, a team of scientists have found that a catalyst containing YPhos-type ligands can mediate this reaction e ... more

    On the road to conductors of the future

    Superconducting wires can transport electricity without loss. This would allow for less power production, reducing both costs and greenhouse gasses. Unfortunately, extensive cooling stands in the way, because existing superconductors only lose their resistance at extremely low temperatures. ... more

    Cascades with carbon dioxide

    Carbon dioxide (CO2) is not just an undesirable greenhouse gas, it is also an interesting source of raw materials that are valuable and can be recycled sustainably. In the journal Angewandte Chemie, Spanish researchers have now introduced a novel catalytic process for converting CO2 into va ... more