Jane Down and Elzbieta Kaminska
Although cyanoacrylate (CA) adhesives are widely used for fossil preparation, a controversy exists as to whether they should be used for this purpose. Currently, little conservation research on CAs has been done. In 2003, Jane Down from the Canadian Conservation Institute (CCI) won the Preparator’s Award from the Society of Vertebrate Paleontology (SVP) to do preliminary research on the suitability of CA adhesives for fossil material.
Most CA adhesives sold in North America, including those used for fossil preparation, are ethyl CAs. However, the medical profession uses butyl CAs for tissue closure and bone fracture repair. This is because medical research, which is currently the largest body of research on CAs, indicates that butyl CA degrades more slowly than ethyl CA. Thus, toxic degradation products (eg., formaldehyde) from the butyl CA can be absorbed by the body better than from ethyl CA causing less dermatitis and carcinomas. Medical research also indicates that CAs tend to degrade more in alkaline and moist conditions, and under UV light.
The CCI research investigated the degradation (ie., formation of formaldehyde) of various CAs (eg., ethyl, butyl, etc) in the presence and absence of fossil material. The fossil material was obtained from several different sites in North America (ie., Dinosaur National Monument, Royal Tyrrell Museum, Mammoth Site and Badlands National Park) and varied in pH, moisture content, ash content, porosity, and mineral/elemental composition.
This presentation will outline some CA properties, advantages/disadvantages of CAs, and the results of the CCI research. The research confirmed that butyl CA degrades more slowly than ethyl CA, whether fossil is present or not. The results also suggest that acidic fossil material retards the degradation of CAs, while neutral and alkaline fossil materials increase it. How this degradation relates to actual bond failure and fossil composition has yet to be determined and will be the focus of future work.