VAPOR PHASE CONSOLIDATION OF BOOKS WITH THE PARYLENE POLYMERS
Bruce J. Humphrey
1 INTRODUCTION AND BACKGROUND INFORMATION
PARYLENE IS THE GENERIC NAME for the various members of a Polymer series developed by Union Carbide Corporation. (PARAXYLYLENES). Parylene has been in commercial use for about 20 years. The primary application for this polymer has been in the electronics industry where the process is becoming increasingly important as a means of protecting delicate microcircuitry from all forms of hostile environments.
To the best of the author's knowledge, parylene has not until recently been considered as a possible conservation material. The author's experience with parylene and its properties led to the investigation of potential applications for this polymer in the various conservation fields. Brittle books (books whose paper fractures after one or two folds) seem to be likely candidates. The fact that this polymer is deposited from the gaseous phase indicated that it might be possible to treat entire books without disturbing the binding.
It is the author's understanding that the acid content in paper eventually results in the cellulose fibers breaking into smaller and smaller units, thus causing the paper to become brittle. Consolidative treatments seek to reunite these fibers in order to regain some of the lost strength. It is the author's belief that the parylene family of polymer holds great promise for accomplishing this consolidation in bound books.
This paper is a brief account of the first tentative steps toward this goal. As stated earlier the process, on paper, is an irreversible polymerization reaction, so a great deal more will have to be learned prior to actual conservation use.
Exhaustive studies of parylene are now in progess at the J. Paul Getty Conservation Institute with an emphasis on qualification for ethnographic purposes. The Library of Congress is investigating the process described in this paper as a potential means of “mass consolidation” of that portion of their collection which has become brittle.
It is hoped that the results described here will stimulate further interest and research into the application of this polymer for conservation, and that readers will be informed about a new technology that may have some future impact on their various fields of endeavor.