Polyethylene terephthalate (PET) films, aka Mylar® or Melinex®, are widely used materials within conservation. One of the most common uses of these films is for encapsulation. Our studies have shown that water can permeate through the PET whereas formic acid vapor permeates at a much slower rate and acetic acid vapor permeates even more slowly, if at all. The rate of permeation is dependent upon the molecular diameter of the vapor. The varying rates of penetration have a two-fold impact. One, they can act as a protecting layer against some hazardous volatile compounds within polluted environments. Two, they can trap hazardous volatile compounds within enclosures, creating a microenvironment which maybe hazardous to cultural heritage objects.The data suggests that deacidification should be performed prior to encapsulation.
Professor/Educator, Johns Hopkins University, Milton S. Eisenhower Library
Dr. McGuiggan obtained her Ph.D. in Chemical Engineering from the University of Minnesota. During her Ph.D., she was a research scholar in the Applied Mathematics Department at the Australian National University working with Richard Pashley. She spent 3 years as a postdoctoral... Read More →
Student, Johns Hopkins University, Milton S. Eisenhower Library
Andrea Hall is Senior Research Specialist at Heritage Science for Conservation in the Department of Conservation and Preservation at Johns Hopkins University where she is working on physical property testing of heritage materials, environmental monitoring, studying conservation testing... Read More →
Molly K. McGath is the Research Scientist at The Mariners' Museum and Park. McGath received her doctorate from the University of Arizona in Materials Science and Engineering with a focus in Conservation Science. Her current research includes studying the deterioration mechanisms of... Read More →
In 2014 Bill was hired as the Senior Book Conservator for the Penn State University Libraries, a position funded by a challenge grant from the Andrew W. Mellon Foundation.
