Susceptibility of printed paper to attack of chewing insects after gamma irradiation and ageing

In the context of a larger research project on the recovery of books and documents stored in libraries and archives and further of an analogous work related to cellulose just published, three different types of printed paper (newspaper, magazine paper, "permanent durable" paper) were submitted to two different experimental trials. In the first the papers were irradiated by gamma rays, while in the second they were also subjected to thermal accelerated ageing. The assessment was made by observing the extent of the damage that the Periplaneta americana (American cockroach) was able to do to the different and differently treated papers, in the form of erosion during the following storage period. The results indicate that the papers irradiated with doses up to 10 kGy do not show greater erosion damage compared to the untreated papers. The same is true for papers subjected to the combined treatment of irradiation + ageing. In the case of very high irradiation dose (100 and 200 kGy) a relationship between the quantity of radiation absorbed by the paper and the "desirability" for the chewing insects was observed. This effect is significantly higher after the combined treatment, at least for two of the papers. Finally considerations on the practical importance of these phenomena are presented.