Modifications of the Mesoscopic Structure of Cellulose in Paper Degradation

Paper is the main component of a huge quantity of cultural heritage. It is primarily composed of cellulose that undergoes significant degradation with the passage of time. By using small angle neutron scattering (SANS), we investigated cellulose’s supramolecular structure, which allows access to degradation agents, in ancient and modern samples. For the first time, SANS data were interpreted in terms of water-filled pores, with their sizes increasing from 1.61 nm up to 1.97 nm in natural and artificially aged papers. The protective effect of gelatine sizing was also observed.

Figure 1

Neutron scattering intensity versus scattering vector $q$ from all the samples exposed to ${\mathrm{D}}_2\mathrm{O}$ atmosphere (listed in Table ) are reported. Curves are arbitrarily shifted for clarity.

Figure 2

The SANS scattering intensity profiles (open triangles) and that obtained from AFM image analysis (crosses) from the $\mathrm{F}{6}_{\mathrm{D}}$ sample. The data curve with open squares is the difference between the SANS curve and the low $q$ background. Guinier (dashed line) and a fractal (continuous line) least-squares fits are also included. In the upper inset SANS profiles from samples $\mathrm{F}{6}_{\mathrm{D}}$ (circles), $\mathrm{F}{6}_{\mathrm{H}}$ (downwards triangles), and $\mathrm{F}{6}_{\mathrm{HD}}$ (upward triangles) are also reported. The dotted line is the nonlinear square fitting with a power law in the low $q$ region. In the lower inset an AFM image of a single fiber from $\mathrm{F}{6}_{\mathrm{D}}$ is reported.

Figure 3

The mean radius of the pore sizes for samples investigated is reported. In the inset, $R_g$ of the ancient samples are plotted versus their PC1 values as obtained by optical spectroscopy. Degradation increases by decreasing PC1 [5].