AIC's 52nd Annual Meeting

Cultural heritage conservation commonly uses solvents for the application and removal of polymeric resins in object disciplines from wall paintings and stone to easel paintings, ceramics and glass, ethnographic objects, and others. Polymeric resins carried in solvent are applied in a variety of object treatment schema. The most common of which are: 1) consolidants, fixatives; 2) coatings, lacquers or varnishes; 3) adhesives; 4) binding media of paints and fillers used for restoration, and 5.) barrier layers on porous surfaces.

Conservators prefer solvents that minimally impact health and the environment, typically those with low/no odor. Thus, identification and selection of safer solvents with the required solvation and final film properties for resins of interest are of great importance to the field. This work is developing a repository of solvents that both meet specific GHS-defined safety criteria and readily solvate the specific resins of interest. Two bespoke computer assisted systems from Dow were used in the solvent identification and selection process: CHEMCOMP™ Service and a custom CAS Sci-FinderN portal. (CHEMCOMP Service is a series of computerized solvent modeling programs: Evaporation Rate Program, Solvent Blend Program, VOC Program, Flash Point Estimator, and Hansen Solubility Parameter Sphere Estimator.) This CHEMCOMP™ Service is built upon an internally developed database of solvents and polymeric resins supplemented with a few additional materials commonly used in cultural heritage conservation. The CHEMCOMP™ solvent database was analyzed using the CAS Sci-FinderN tool that identified those solvents that met physical, health and environmental GHS Hazard Phrase requirements outlined by the team. The Hansen Solubility Parameter Sphere Estimator functionality within CHEMCOMP Service then provided computational predictions for which safer solvents solvate the resins included in this pilot study. The solubility predictions of interest have and continue to be validated at the bench and in silico. Physical and mechanical properties of the resulting polymeric resin films cast from a sub-set of the safer solvents & solvent blends will be reviewed to provide an initial assessment of the functional performance of the polymers in use. The full solubility data will be disseminated once thoroughly developed and vetted by those appropriately skilled and qualified in art conservation practices.