Ageing of ancient paper: A kinetic model of cellulose degradation from Raman spectra

In this study, the degradation of cellulose is investigated with particular attention to the breaking of glucose chain units. Based on the analysis of the Raman spectra of experimental samples, public and private collections of books covering a period of seven centuries (XV-XXI), and literature data on cellulose, a successful kinetic model was proposed with the intention to correlate an estimated ageing time with the degradation process of cellulose. Raman spectra were collected by means of portable non-destructive NIR mu-Raman spectroscopy (B&W TEK i-Raman Ex integrated system), a valuable characteristic for monitoring documentary heritage. The model was successfully applied to study the conservation conditions of books of a public library, evidencing how conservation conditions and use affect the ageing. The kinetic model promotes Raman spectroscopy as a very useful tool for conservation and restoration of ancient books and papers.