Material characterization and preservation guidance for a collection of prosthetic limbs developed since 1960

Abstract National Museums Scotland has collections relating to many areas of science and technology, including medical science. This paper considers technical and conservation issues of an important collection of more than 150 prosthetic limbs. Much of the collection is of prosthetics developed for children born lacking or with malformed upper limbs caused by the prenatal morning sickness drug Thalidomide. However, many other examples are represented and the collection showcases a timeline of bioengineering development covering the past five decades. A wide range of plastics and metals were observed within the pieces examined, with many visibly degraded and degrading. The identification and characterization of these materials and their condition are fundamental to interpreting the development of the collection, for deciding on treatment, and for setting a strategy for future preservation. In addition to visual inspection, three analytical techniques were used to examine the various parts of the selected examples: Fourier transform infrared spectroscopy for polymer identification and condition; X-ray fluorescence spectroscopy to identify the metals and alloys present, and X-radiography to reveal the internal mechanisms of the limbs. Interpretation of the results was greatly enhanced by documentation and conversation with engineers and scientists involved in research and development of the limbs. The combination of different materials, some with conflicting environmental requirements, makes storage and display challenging as the goal is to prevent degradation of any part the object. Some objects were found to be actively degrading and for these separate storage solutions have been recommended to slow the emission of volatile degradation products that would cause further damage throughout the collection.