Effects of Fluctuating Environments on Paper Materials—stability and Practical Significance for Preservation

Jean-Louis BIGOURDAN and James M. REILLY Image Permanence Institute Rochester Institute of Technology Rochester, New York, USA ABSTRACT The effect of changing environments on paper stability was studied using three types of paper (acid-processed 100% cotton, acid-processed groundwood, and buffered groundwood). The study was based upon three cycling situations. The effect of humidity cycling alone was investigated at 90°C, 70°C, and 50°C by exposing the paper samples to three humidity conditions: 60% RH, 80% RH, and cycling humidity between 40% and 80% RH (with a two-week cycle). The effect of temperature cycling was studied using two separate experimental procedures: 1) exposing the sample to constant RH and 2) keeping samples at constant moisture content in sealed bags. The temperature cycling included three incubation temperatures: 80°C, 70°C, and daily cycling temperature between 60°C and 80°C. The rates of paper deterioration were monitored using three indicators of decay: paper discoloration, MIT folds, and tensile properties. Data developed during this study indicated that the rate of paper decay was faster under cycling conditions than at the steady mid-range conditions of the cycles. The data also indicated that the paper decay rate was slower under cycling conditions than it was at the upper limits of the cycles. These observations were consistent for all sets of incubations investigated. These data failed to demonstrate that cycling environments are inherently detrimental to chemical stability in paper. Within the limited framework of this study, the deterioration rates observed with cycling conditions offer no evidence that transitions from one temperature to another or one RH to another provoke a new mechanism of decay or accelerate decay more than would be expected by current thermodynamic models.