The GREENART project: "green" and sustainable materials for cultural heritage conservation

European Cultural Heritage (CH) is a crucial resource that must be maintained, preserved and made accessible, to counteract degradation enhanced by unfavorable environmental conditions and climate changes. Some of the conservation methodologies nowadays available lack sustainability and cost-effectiveness, and are typically based on energy-consuming processes or non-environmentally friendly materials. This contribution will report on the main results so-far achieved in the EU-funded project GREen ENdeavor in Art ResToration (GREENART), coordinated by the Center for Colloid and Surface Science of the University of Florence (CSGI). Coping with the imperatives of EU Green Deal, the project proposes new solutions based on green and sustainable materials and methods, to preserve, conserve and restore CH. In particular, several innovative materials have been developed and tested:  1) Protective coatings based on green materials from waste and plant proteins, with self-healing and reversibility character, possibly functionalized with organic/inorganic nanoparticles to impart VOC capture, anti-corrosion and barrier behaviors. 2) Foams and packaging materials made by biodegradable/compostable polymers from renewable sources (polyurethanes and natural fibers) to control temperature and relative humidity. 3) Consolidants based on natural polymers from renewable sources, to mechanically strengthen weak artifacts. 4) Gels and cleaning fluids inspired by the most advanced systems currently available to conservators, which will be improved according to green metrics and circular economy requirements. 5) Green tech solutions for monitoring CH assets non-invasively against pollutants and environmental oscillations. Life Cycle Assessment and modeling favor the “safe-by-design” creation of affordable solutions safe to craftspeople, operators and the environment, and minimize energy-consumption in monitoring museum environments. Such holistic approach is granted in GREENART by a multidisciplinary partnership that gathers hard and soft sciences and engineering, including academic centers, innovative industries and SMEs, conservation institutions and professionals, museums whose collections hold absolute masterpieces in need of conservation, public entities and policy makers. Innovative materials and products have been assessed at the lab scale on representative mock-ups of works of art (remedial conservation), or in simulated museum/archive environments (preventive conservation). The project intends to transfer the most promising systems to field assessment on actual artefacts and museums/archives, in cooperation with conservator partners. The best products are also fed into a GREENART open repository and an App to illustrate the new solutions and involve citizens in good preservation practices. Constant feedback from conservators (internal or external to the partnership) can stimulate iterative refinement of the products, triggering a positive loop in this methodological approach. Covering these topics, we provide here an overview of the most advanced green materials for art conservation that can be useful to end-users in this field.