Layer-by-Layer Self-Assembly for Reinforcement of Aged Papers

The hybrid films of reinforcing the aged papers have been employed via layer-by-layer (LBL) assembly deposition of the chitosan lactate/carboxymethyl cellulose complex previously modified with metal oxide. In order to reinforce the films, a vacuum infiltration was adopted in the LBL process. The mechanical properties and structure of the aged papers in relation to fiber morphology were investigated using SEM, FTIR, XPS, and tensile test. The well-dispersed coatings resulted in an excellent improvement in mechanical properties of the modified paper. After only three bilayers deposited, the measured tensile strength and folding endurance for modified aged newspaper samples increased up to 100% and 450%, respectively, as compared to the control sample. This high efficiency was kept even when the modified paper samples exposed to the moist-heat accelerated aging and UV irradiation. The pH of the paper rose to alkalescence rapidly, and the paper samples maintained their coloration close to the original after treatment.