Changes in the chemical and physical properties of paper documents due to natural ageing

Abstract

The aim of this study was to assess the changes in chemical and physical properties of selected paper documents, dating from the 18th century to the present date. Paper documents from the 18th, 19th, and 21st centuries had a pH ranging from slightly acidic to alkaline values, whereas paper documents from the 20th century were more acidic. The contents of mannose, glucose, holocellulose, and lignin were significantly correlated with the pH of the paper. High contents of both carboxylic acids (acetic and formic) and the most durable monosaccharide (glucose) were found in the oldest examined paper documents originating from the 18th and 19th centuries. The lowest percentage of brightness was found in paper documents originating from 1920 and 1923. The lowest breaking length was associated with papers originating from 1920.