The conservation of rapid prototyping (RP) materials is an emerging need of many important collections and museums. RP technology has revolutionized manufacturing, gaining popularity among designers and artists. The base materials in RP technologies range from inorganic (metals, ceramics) to plastic and rubbery materials (ABS, PVC, silicone rubber). In addition, pigments, dyes, fillers and infiltrants are used, leading to the resulting object being extremely complex. RP objects have found their way into collections, often representing one of the most unstable material types, prone to rapid discolouration and dimensional change, representing a significant conservation challenge, not only due to the number of RP processes available (and constantly on the increase) but also due to the fact that artists continuously experiment with treatments and applications in postproduction. Surprisingly, there is very scarce existing research on RPs degradation and conservation. Surface alteration depends both on intrinsic features (chemical composition, manufacturing techniques) and environmental factors related to the conservation context (climatic conditions, temperature, UV, humidity, presence of external or museum atmospheric pollutants). A systematic approach to identification, degradation and conservation/protection studies was urgently required, looking at the processes of curing and degradation, and at development of conservation materials and solutions that impart greater dimensional stability and surface protection (coatings, impregnants).
Long-term protection of surfaces is also needed for the preservation of modern/contemporary metal artifacts. The anti-corrosion protection of metals (e.g. bronze) has been already largely studied in the past; however, the aim of NANORESTART was to develop enhanced protective systems going beyond the commonly used traditional protection based on the use of an inhibitor embedded in an acrylics or wax films against environmental aggressive agents.
Atmospheric pollutants from the urban environment or inside museums (due to inadequate cleaning of the spaces, aeration system without filters, excessive number of visitors, construction materials and furniture) can irreversibly compromise the conservation status of the artifacts, leading to the formation of alteration products and reactive compounds such as chlorides, oxy-chlorides, sulfides and sulfates on Cu-based alloys. The corrosion process induced by these species can modify the entire object surface either uniformly or locally in the form of spots. In particular, the presence of copper oxy-chlorides as alteration products can suggest the presence of the most harmful and nearly inexorable degradation phenomenon of Cu-based alloy objects i.e. the “bronze disease” that is based on the cyclic copper corrosion.
These conservation challenges were addressed through the application of removable self-healing green nanocomposites and coatings and through nanoparticles-mediated release of protective agents or corrosion inhibitors, as described in WP4.