JAIC 1992, Volume 31, Number 2, Article 3 (pp. 175 to 197)

OBSERVATIONS ON THE DRYING OF PAPER: FIVE DRYING METHODS AND THE DRYING PROCESS

JANE E. SUGARMAN, & TIMOTHY J. VITALE

ABSTRACT—Three experiments were performed to examine the drying of paper. In the first experiment visual analysis was used to monitor change caused by five drying methods on the surface texture of 12 historic papers. Although all methods caused changes, the early restraint method was most successful, while the traditional method was least successful, at maintaining original surface texture. Some of the 12 historic papers altered more than others, but the characteristics of sizing, pressing, and fiber furnish could not be used to predict degree of change. In the second experiment papers were dried under laboratory conditions while water content and appearance were monitored. Papers were observed to pass through stages: flooded, glossy-dark matte, dark matte, light matte, onset of physical distortion, and white. The most important stage, onset of physical distortion, occurred at 63 � 3% solids in all papers and correlated with the start of hydrogen bonding between fibers and the shrinkage of fibers. These facts explain why the early restraint method is superior; it fixes the paper into a defined shape before the paper goes through the bonding and shrinkage process. In the third experiment the vapor humidification process was shown to result in 81 � 5% solids, which disrupts hydrogen bonds within fibers. It is unlike complete wetting, which, at 43 � 9% solids, disrupts hydrogen bonds both within fibers and between fibers.

Article Sections:

1. INTRODUCTION
2. OVERVIEW OF DRYING AND FLATTENING
3. GENERAL INTRODUCTION TO PAPER TEXTURE
4. EXPERIMENT 1: EVALUATION OF DRYING AND FLATTENING METHODS
5. EXPERIMENT 2: QUANTIFICATION OF THE DRYING PROCESS
6. EXPERIMENT 3: PROLONGED HUMIDIFICATION OF SEVEN PAPERS
7. CONCLUSIONS
1. APPENDIX 1
2. APPENDIX 2
a: Appendix , Notes , References , Author Information

Entire Article