The Effects of Natural Dye and Iron Gall Ink on Degradation Kinetics of Cellulose by Accelerated Ageing

ABSTRACT

Iron gall inks have a destructive effect on paper supports due to their acidic and transition metal-containing nature. For the chemical stabilization of paper-based objects, conservation studies include both antioxidant and deacidification treatments. In order to evaluate the effectiveness of the treatments, accelerated ageing experiments are performed and changes during ageing are measured. Historical manuscripts may contain colored papers and since only natural dyes and pigments were available until the development of modern chemistry in the nineteenth century, the palette was limited. Organic dyes mainly consisted of colourants obtained from plants and insects. In this study, colored papers of manuscripts from the fifteenth century which belong to the collections of Millet Library, İstanbul were analyzed via high-performance liquid chromatography. According to the results, model papers were dyed with Rheum ribes L. (rhubarb), and then an iron gall ink, prepared according to a historical recipe, was applied to them. Due to acid and transition metal content, a stabilization treatment including alkali and an antioxidant was applied on a set of samples and after 12 days of accelerated ageing, changes in pH, degree of polymerization, and optical properties of the samples were monitored. A viscometer, a useful tool to monitor the efficiency of a treatment, was employed for the determination of degree of polymerization values. Data obtained from viscometric measurements were used to evaluate the degradation rate constants of the samples. Comparison of rate constants showed that treatment had a beneficial effect.

KEYWORDS:

• Cellulose
• natural dye
• degradation kinetics
• polymer stability
• iron gall ink

Acknowledgements

We are grateful to Prof. Recep Karadağ and Emine Torgan from Turkish Cultural Foundation for conducting HPLC analyses. We thank Prof. Gülnur Mertoğlu Elmas for her valuable efforts to make viscometric analyses possible. We also would like to acknowledge conservator Özlem Uzun for her assistance during sample preparation and Nil Baydar, head of Manuscript Conservation and Archive Department of Turkey Manuscript Institution, for encouraging the studies.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by the Research Fund of the Yıldız Technical University with DOP Project: [2014-07-01-DOP03].