Plasma treatment - an increasing technology for paper restoration?

An important part of our cultural heritage consists of paper materials, whi ch are stored in archives and libraries. Deterioration of written cultural relics is attributed to several causes, such as microbial contamination, ox idation, acidification, and others. It is therefore desirable to focus rese arch activities on conservation and restoration techniques to develop appro priate treatments. A new technology in the field of restoration could be pl asma treatment, which is a well-established technique in a number of other processes, such as plasma cleaning, etching and coating. The main aim of th is project is the removal of microbial contamination combined with an incre ase in paper strength using a plasma-based treatment. Therefore, a special after-glow plasma reactor was constructed to enable careful paper treatment . Current experiments work with oxidising and reducing process-gases to tre at naturally aged groundwood paper. A positive effect on the paper stabilit y was achieved by varying treatment parameters, such as flow, pressure, pow er and time. An overall increase in paper stability of up to 20% was possib le. Parallel investigations using plasma treatment for microbial cleaning w ere carried out. Certain amounts of different fungi and bacteria were sprea d on naturally aged paper. After plasma treatment, the reduction in microor ganisms was measured. This proved the fungicidal and bactericidal action of the after-glow plasma treatment. Nevertheless, optimisation with regard to different microorganisms and kinds of papers must be considered. (C) 2001 Elsevier Science B.V. All rights reserved.