Sustainable conservation treatments for large-scale artworks made of polyurethane ether foam in art and design

Polyurethane (PUR) foams have been among the most popular plastics used by artists and designers since the early 1960s. However, they react chemically with oxygen to discolour, collapse and eventually crumble. Conservation treatments for degraded PUR foams aim to strengthen and consolidate weakened foams so that they can withstand handling and resist further degradation. To date, there is only one evaluated and established conservation material that has proved effective in consolidating and coating crumbling PUR ether foams. However the consolidant, Impranil DLV solution, contains toxic chemicals, which require that it must be sprayed or nebulized in an enclosed area fitted with air extraction facilities. During a two-year project, completed in March 2017, water-based protein and carbohydrate solutions and acrylic dispersions were applied to new, thermally and photolytically aged model rigid and flexible foams and their appearance, texture, friability, recovery from impact and chemical stabilities evaluated and compared with those treated with Impranil DLV. Within the framework of this study, it may be concluded that Aquazol 500 (1.5%) and Agar (0.5%) offer superior consolidation, more sustainable and less toxic alternatives to Impranil DLV when applied by spray to soft foams. By contrast, Plextol B500 performed best on hard foams, although they were more complex to treat and to evaluate than soft. Keywords: Polyurethane, degradation, sustainability, consolidation, conservation, foam