Characterization of purified bacterial cellulose focused on its use on paper restoration

• The alkaline treatment renders layers of remarkable properties.
• The thermal treatment renders layers of similar quality to non-treated ones.
• Aging causes an increment in crystallinity and a diminution of pore volume.
• BC is highly stable over time contributing to the reinforcement of degraded paper.
• This study suggests that BC is a promising material for restoration of documents.

Bacterial cellulose (BC) synthesized by Gluconacetobacter sucrofermentans CECT 7291 seems to be a good option for the restoration of degraded paper. In this work BC layers are cultivated and purified by two different methods: an alkaline treatment when the culture media contains ethanol and a thermal treatment if the media is free from ethanol. The main goal of these tests was the characterization of BC layers measured in terms of tear and burst indexes, optical properties, SEM, X-ray diffraction, FTIR, degree of polymerization, static and dynamic contact angles, and mercury intrusion porosimetry. The BC layers were also evaluated in the same terms after an aging treatment. Results showed that BC has got high crystallinity index, low internal porosity, good mechanical properties and high stability over time, especially when purified by the alkaline treatment. These features make BC an adequate candidate for degraded paper reinforcement.