Improving the flexibility and durability of aged paper with bacterial cellulose

Ancient paper with irreplaceable value was severely acidified and aged due to poor storage conditions and the degradation of its own components. The restoration of ancient paper in deacidification and reinforcement was imperative. Bacterial cellulose (BC) with good fiber aspect ratio and rich hydroxyl groups was suitable to enhance aged paper. However, the utilization of BC for paper reinforcement was limited with its dispersion due to the highly aggregated state. In this paper, stable BC solutions were prepared by dissolving BC in NaOH/urea, and its application in ancient paper restoration by ultrasonic atomization was proposed. BC was uniformly bridged on the fiber surface and between the fibers, which played a good role in strengthening the aged paper. After treatment, the mechanical strength of the paper was notably improved, the paper processed for 60 min using 0.6% BC solution exhibited a high folding resistance of 28 times, which was 2.15 times of the untreated paper. Besides, the pH value and alkali reserves of the repaired paper were successfully achieved at 8.12 and 0.4 mol/kg. Even after hot-humid aging for 30 d, the repaired paper retained about 50% of its initial strength. This suggested the repair fluid based on BC had potential applications in the field of paper reinforcement with high performance and durability.

Automated summary

This paper proposes the use of stable bacterial cellulose (BC) solutions in ultrasonic atomization for the restoration of ancient paper. It effectively strengthens the aged paper, improves its mechanical strength and chemical properties.