Cultural heritage objects are precious witnesses of the past, so our mission is not only to preserve them for future generations, but also make them available or open to the public. Among most fragile historic materials are paper-based materials. They are susceptible to various forms of damage and deterioration, and their preservation presents a challenging task for conservators. In recent years, the use of advanced materials with unique properties has been growing at an increasing rate, even in the traditionally slow-changing cultural heritage sector. This study models how historic paper would be affected by application of multiple coating layers containing different quantities of cellulose nanocrystals (CNCs). In our study, a 4 % CNCs aqueous suspension was used to treat the samples. In order to form a uniform layer, bar-coating method was used, and in addition, a specific layer thickness was formed in both single and multiple passes. The prepared samples were analysed for their optical properties (colour coordinates, yellowness, opacity, gloss), physical properties (Taber stiffness, weight, thickness) and surface properties (roughness). An increase of wet film deposit thickness (single layer applications) resulted in an increase of paper thickness, grammage, gloss, opacity, yellowness, the ΔE value and Taber stiffness, while its average surface roughness decreased. Multi-layer applications have gradually decreased paper thickness, while Taber stiffness remained unchanged.

The aim of this study was to stress the importance of investigating the prop- erties of preservation enclosure materials in order to identify the ones that are able to protect their contents more efficiently. Since not all information on materials is covered by international standards and technical specifica- tions, nine paper-based materials used for making preservation enclosures (file folders, passepartouts, boxes etc.) were investigated. A selective analysis of the materials' properties was carried out to determine smoothness, water absorptiveness, water wettability, water vapor permeability, tensile strength, folding endurance, bursting strength, puncture strength, as well as loss of bursting strength caused by dry heat and 100% RH. Results obtained from measuring smoothness, water absorptiveness, water wettability and water vapor transmission rate indicate that a material outside of ISO 16245:2009 grammage requirements for making file covers can exhibit more desirable properties than the one that meets multiple standards for storage and preservation. Additionally, results showed that bursting strength of enclosure materials was significantly affected by both extreme microclimate condi- tions. However, 100% RH had affected bursting strength of the investigated materials more than dry heat. The presented procedure proved to be a useful indicator of materials’ properties within the context of heritage collections preservation and storage.

In heritage conservation, paper deterioration can be slowed down by controlling the environmental conditions surrounding heritage objects and stabilizing the materials these objects are made of. As conservation materials can also cause optical, chemical, and physical changes in the object, their application should be safe, minimalistic, and purposeful. This paper aimed to observe the functional applications of three biopolymers used in paper conservation. For that purpose, a model paper was coated with methylcellulose (MC), cellulose nanocrystals (CNCs), and wheat starch (WSP) using different wet film deposits. The prepared samples were characterized by determining their physical, optical, and surface properties. The results show that changes in the wet film deposit thickness influenced paper properties. With CNCs, the increase has caused a drastic change of colour properties, with MC hydrophobicity increased and with WSP grammage and thickness increased. All coatings (except CNC24) have contributed to the preservation of the colour properties of the paper from the damage caused by thermal ageing.

The UV radiation causes inks to fade. The ink fading will lead to the degradation of the visual appearance of printed imprints making them less attractive to the user. To deal with this that phenomenon, one of the solutions is to create a coating that could challenge these issues. In order to create efficient protective coating against UV induced degradation, nano scaled titanium dioxide (TiO2) wasl added to the commercial water-based varnish. To determine influence of the amount of TiO2, was homogenized in various weight ratios. The prepared nanocomposites were applied onto offset (lithography) prints made in accordance with Fogra PSO, i.e. ISO 12647-2:2013 on gloss coated paperboard. The samples have been subjected to artificial UV induced aging for 30 hours. The protective properties of the nanocomposite TiO2 coating was determined by calculating colorimetric and densitometric change on full tone and determining tone value change of half tones. The results showed that the prepared nanocomposite coating has relatively little effect on the printed colour of the samples. However, some coating compositions exceed the allowed tolerance ΔEab> 5, however in those cases the initial colorimetric value of WB (ΔEab) was close to the FOGRA PSO border value. The coatings with TiO2 will increase resistance to accelerated ageing on full and halftone. To conclude, this research has provided the new perspective on modulation possibilities of commercially available varnishes in order to cope a designated problematics and downsides of coatings which was, in this case, UV induced fading and degradation of visual appearance. The further research should investigate the applicability of this kind of modulated varnish in other coating techniques as well the use of other kind of nano sized compounds.

Although the primary role of packaging is to protect its content, it also acts as the carrier of both relevant information and visual identity. To enhance its properties, packaging materials are often coated with material which could provide barrier against chemicals, atmospheric conditions, or electromagnetic radiation. This paper focuses on the change of surface properties, i.e., wetting of a coated cardboard surface when packaging material is exposed to light induced accelerated ageing. Prepared printed cardboard was coated with nanocomposites composed of commercial water-based varnish and defined mass concentration of nanosized TiO2. The prepared samples were subjected to accelerated ageing in a light chamber equipped with Xenon lamp. The characterization of the samples included determining contact angles with liquids of known surface tension and calculating surface free energy, determining water vapour transfer rate and performing burst resistance tests (Mullen burst test). It can be concluded that the UV radiation influenced the cardboard substrate and varnished samples where AcA made some changes in the polar component due to forming of new oxidation products, which are less polar from its -OH group. However, with the introduction of nanoparticles, the UV influence was lowered in terms of surface parameters. The smallest TiO2 weight ratio (0.25%) lowers the WVTR by 56%. Moreover, with increase of TiO2 nanoparticles weight ratio, water permeability decreases significantly where the 0.5% TI/NC provided the best result (decrease of63%). Regarding the mechanical properties, although bursting strength of samples coated with nanocomposites is higher than the one coated by WB, there is no visible dependence between mechanical properties and weight ratio of nanoparticles. This research showed that addition of TiO2 nanoparticles will improve commercial varnish and will increase protection against UV radiation in terms of adhesion to the substrate and water vapour barrier.