Plastics, preservation and prosthetic limbs: three months in the department of Conservation & Analytical Research

In June, I began a year’s Institute of Conservation (ICON) internship as a Science Conservation Intern, funded by Heritage Lottery Fund. The first three months were spent at the analytical research labs of the Conservation and Analytical Research Section (CAR) in Granton.  Having been a research chemist for 18 years prior to my internship, where I worked on a variety of multidisciplinary projects, the skills acquired during that time have helped me enormously in my new role.

In recent decades, museums have become aware that objects made from plastics (polymers) are subject to degradation from heat, light and moisture as well as physical damage. Sometimes termed modern materials, these objects can be anything from an acrylic sculpture to a PVC raincoat.  This has resulted in concern regarding their lifespan within the heritage sector and therefore significant research on their properties, degradation and long-term storage is a key issue for museums with significant object collections of modern materials.  While at National Museums Scotland, most of my time was spent working on these modern materials.

Projects

Examing, detailing and photographing the Plastics Handling Collection

This collection contains a huge variety of plastic objects, primarily manufactured in the 20th century, illustrating the development of plastics from the semi-synthetic to the synthetic. This allowed a database of these objects to be created, which will be used in the future to monitor degradation and inform curators of likely areas of concern specific to each polymer. All these objects had been photographed in 2000, although not described in detail, and visual comparisons were made using this photographic record to their current condition.

FT-IR Polymers Library

Modern materials such as polymers can be identified and their condition determined using Attenuated Total Reflectance/Fourier Transform Infrared (ATR/FT-IR). This technique creates a spectrum which provides a unique fingerprint of the polymer based on the vibrational energies of the molecules present in it. The technique allows objects (if small enough) or parts of larger objects to be studied non-destructively. The technique is very fast as no sample preparation is required and scans can take as little as one minute depending on the detail required.

CAR has an extensive collection of polymer samples obtained in the 1990s from companies such as BASF, BP and Courtaulds. Using these polymers I created libraries which can now be used in the future to identify unknown materials.

Conservation
Working in the Conservation & Analytical Research lab.

Prosthetics

National Museums Scotland recently obtained a collection of prosthetic limbs which are fabricated from a variety of polymers and metals and cover a period of prosthetic research and development in Edinburgh from the 1960s to the present day. The driver for such prosthetic development was to fit children born with no or shortened limbs due to the anti-nausea drug thalidomide.

My part in this project has been to assess the current condition of a selection of prosthetic limbs and to determine the materials they have been constructed from. I have done this by using three analytical techniques: Fourier Transform Infrared (FT-IR) (used for polymer identification and quality) and X-ray Fluorescence (XRF) (used to identify metals) to identify the materials and X-rays to determine the internal mechanisms present in the limbs. The subsequent analysis showed that the metal used in the mechanism was stainless steel. The prosthetics also frequently have fabric fastenings and coverings and in older samples leather is sometimes used.

Examining a prosthetic limb in the lab
Examining a prosthetic limb in the lab.

Jean Muir Collection

National Museums Scotland holds a variety of jewellery, hats and buttons by Jean Muir, which form part of a larger collection relating to this iconic designer. The jewellery in the main is made from plastic (polymers), some transparent and others pieces colored. In addition there were some silver pieces.

The conservation reporting and creation of new accessible storage solutions for these objects was carried out by Clare Berthommier, a visiting intern. As part of her task she wished to identify the materials these objects were made from, as this would help her to decide how they should be stored. Clare and I worked together on identifying the plastics, and we also found that some of the jewellery was made from silver. Some of the bracelets were flat discs, which were ideal for FT-IR scanning using the ATR attachment. Of the pieces analysed all were identified as poly(methyl methacrylate) (PMMA) often known by names such as  Perspex or Plexiglass.

Visits and seminars

While at National Museums Scotland I accompanied a group of scientists and curators on a visit to the Clinical Research Imaging Centre at the Royal Infirmary Edinburgh. Work had been carried out there on the scanning of mummies from the collection.

I attended the Getty funded Research Network Meeting on Modern Materials in June. The purpose of the meeting was to create ideas for future projects in the understanding and preservation of modern materials. Delegates from a variety of countries attended this event.

On 28 July Dr Jim Tate and I visited Dr Andrea Hamilton at the Centre for Materials Science and Engineering at Edinburgh University to view and discuss the capabilities of the Atomic Force Microscope (AFM) they have within their department. Our application was to use AFM to monitor the degradation of the surface of plastics as an aid to understanding the degradation process in addition to other techniques.

I visited Hampton Court on 17 August with other ICON interns. The day kicked off with a talk by Miriam Langford, the Treatment Conservation Manager. In it she described the projects we would view, which included the conservation on a tapestry based on a design by Raphael, Queen Anne state bed and Queen Victoria’s dolls. The rest of the day was spent viewing the studios and as a scientist it was very enlightening to see conservators at work: it highlighted the dedication, skill and patience required by them.

On 23 August I visited the Liverpool museums. In the morning a tour of the conservation centre took place, where we viewed the conservation and restoration of model ships, of which the museum has many as a result of Liverpool’s famous shipping past. After lunch we were taken on a visit to the recently opened Museum of Liverpool, designed by the Danish architects 3XN. It has an eclectic mix of objects ranging from Liverpool’s sea trading past to Beatles memorabilia.

Reflection

The three months of my internship have been busy, varied and motivating. I feel privileged to have been given the opportunity to be part of the HLF Internship program. My time at National Museums Scotland has given me a real insight into the museum sector and how it operates. It has been a mix of lab work, research reading, visits, being part of meetings and planning future work. From day one I felt part of the team and I hope that I contributed to the CAR department. I anticipate that the relationships I have made here will continue throughout my internship and perhaps beyond.

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