The presented thesis is deals with the study of materials on the base of natural polymers. These are sheet materials, which are traditional information vehicles. The aim of the study of degradation of these materials by the influence of the recycling process, natural or accelerated ageing, is their lifetime extension, renewal and preservation of virgin properties. The knowledge about the rate and the degradation processes can help to the protection of cultural heritage of lignocellulosic materials and to formation of long lifetime materials.