AGING OF NEWSPAPER SINCE 1959 UNDER ARCHIVE CONDITIONS - A QUANTIFICATION OF DIFFERENT EFFECTS USING FT-IR SPECTROSCOPY

Aging of newspaper under archive conditions was investigated. The experimental design included issues of all the decades since 1959 to 2015. Newsprint and white parts of colored pages were characterized. The yellowed border and the area in the middle of the pages were characterized using ATR-FTIR spectroscopy. Principal component analysis (PCA) revealed two processes of paper aging: cellulose modification, which results in an increase of carboxyl/carbonyl content; and lignin degradation reactions, which is the main cause of paper yellowing. Cellulose aging was loaded on the first principal component (PC), accounting for about 90% of data variability. Yellowing effects were loaded on the second PC with an explanation rate of 5%. Yellowing was even found in newspapers from the year 2015 with only slight changes over time, whereas cellulose aging proceeded quite continuously. The effects were found for both newsprint and colored pages. Additionally, five samples from newspapers that had been buried in a sanitary landfill were included into the dataset. The organic bands followed the same aging process as in the archives; microbial degradation obviously had a minor effect on the aging process studied.