Earlier studies of paper kept in cycling humidity conditions found an accelerated degradation of the cellulose possibly induced by the physical stresses of the cellulose chains as they respond to moisture changes.  The response of cellulose to physical stresses from the cycling humidity prompted us to investigate how the physical manipulations of the cellulose can create local regions of stress that are a potential for increased chemical degradation.  This relates to situations where an artifact is placed under stress when displayed, such as for paintings where the canvas is stretched, tapestries which are hung, or historic clothing that is displayed on mannequins.  We plan to apply physical stresses on cotton fibers and monitor the chemical degradation that may occur.  Understanding the mechanism of degradation will provide insight into ways of minimizing or redistributing the physical tensions on the material to slow down the induced degradation.

Current research focuses on:

• Developing methodology for putting stress on cotton fibers and monitoring the chemical changes by gel permeation chromatography (GPC) and physical damage by mechanical testing.
• Determining the parameters required to create induced stress degradation and detecting the extent of damage.
• Establishing the chemical kinetics for stress induced degradation.
• Determining preservation steps required to minimize the effects of localized physical stressors on artifacts.

Presently, threads from cotton yarn are being strung with weights as a means of simulating the physical tensions on artists materials.  Current methodologies for dissolving paper using a DMAC/LiCl solvent system have been adopted to dissolve the high molecular weight cotton fibers from mercerized yarn and allow for analysis by GPC.  Natural and accelerated aging of the fibers with and without weights is being monitored by both GPC to follow molecular weight changes as well as by mechanical testing to follow strength loss.  This project, while in its infancy, has great potential for better understanding the damage created by stress induced chemical degradation.

Back to the top