The two main processes of cellulose degradation are acid hydrolysis and oxidation. Paper degradation occurs gradually over time when viewed in the human timescale. For better understanding of the process of degradation it is possible to accelerate it by exposing the paper to extreme conditions (such as elevated temperature). Accelerated degradation is usually performed by exposing the paper to circulating air inside the chamber. However, most of the paper stored in archives and libraries are isolated from the surrounding air because it is stored in the shape of books or surrounded by other materials. I studied whether the accelerated degradation of paper freely exposed to air inside the chamber is different from accelerated degradation of paper inside a book. I found that samples, which are surrounded by other papers, degrade 44 % faster than those which are exposed to surrounding air.
The role of lignin with cellulose degradation is still not yet fully explained. With the use of size exclusion chromatography, I have determined the degradation constants of paper samples with different lignin content. With multiple linear regression analysis I have determined the influence of individual variables on the degradation constants. It turns out that lignin has no direct effect on degradation constant while temperature has the largest effect.
Spectroscopic methods are employed to observe the changes in paper during the process of accelerated ageing. With imaging it is possible to produce chemical maps, which show the location of individual components in paper. I have produced chemical maps, which show lignin distribution as well as the distribution of oxidation products within the cross-section of paper. The results show that even if oxidation of cellulose is (directly or indirectly) caused by lignin, such influence is not localised.
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