ESTIMATING DEGRADATION BEHAVIOR AND MASS DEACIDIFICATION OF BAMBOO PAPER

摘要

To evaluate the degradation of paper made from bamboo pulp, accelerated aging tests (dry heat treatment at 105 °C, moist heat treatment at 80 °C and 65% RH, and heat treatment in a sealed tube at 100 °C) were performed. The results were used to predict the long-term effects of natural aging. Acid-free laboratory sheet prepared from bamboo pulp exhibited higher tearing strength and zero-span tensile strength, compared with sheets made from hardwood pulps. However bamboo sheet tended to degrade rapidly in accelerated aging tests. This might be related to the rapid reduction in the viscosity number of bamboo pulps during accelerated aging tests. Two mass deacidification techniques have been employed in Japan to suppress degradation of acidic paper: the Bookkeeper (liquid phase) and dry ammonia-ethylene oxide (gaseous phase) (DAE) processes. Both these mass deacidification processes increased surface pH of acidic bamboo and hardwood papers. These processes also suppressed reduction in surface pH and loss in paper strengths such as tearing strength, the zero-span tensile strength and folding endurance during the accelerated aging test in the sealed tube. The Bookkeeper process gave higher strengths than the DAE process after extended accelerated aging of bamboo paper.