Influence of Paper Raw Materials and Technological Conditions of Paper Manufactur on Paper Ageing

The Influence of Unbleached Pulp Content on the Permanence and Durability of Archive and Library Materials on Paper

“…pH by aqueous extraction, Kappa number, degree of polymerisation (limit viscosity of the copper ethylene diamine -CED -solution) and Copper number 5,6,7 . pH by aqueous extraction, Kappa number, degree of polymerisation (limit viscosity of the copper ethylene diamine -CED -solution) and Copper number 5,6,7 .…”

“…By checking the change of viscosity and Copper number (representing the amount of reductive groups) we determined the hydrolytic and oxidative degradation of the cellulose molecule, microbiological contamination, chemo-mechanical decomposition together with the depolymerization, which all lead to a lower average molar weight or degree of polymerisation and in an increased Copper number 4,5 .…”

“…The higher Cu numbers indicate a higher degree of oxidation 4,5 . The higher Cu numbers indicate a higher degree of oxidation 4,5 .…”

“…The effect of accelerated ageing on optical characteristics was studied by checking whiteness, brightness and yellowness, colour according to the CIE-L*a*b* system, opacity, scattering and diffusion/absorption of light according to the Kubelka-Munk method 5,7,8 .…”

“…Such reactions are furthered by increased temperature 4,5 . The process is promoted by light and high temperature and is increased by high relative humidity.…”