Are cellulose ethers safe for the conservation of artwork? New insights in their VOC activity by means of Oddy testing

Abstract Cellulose ethers, like methyl cellulose (MC) or hydroxypropyl (HPC), are widely used in conservation. They also occur as additives and rheology modifiers various products dispersions gels. Do such release harmful volatile organic compounds (VOC) during their accelerated aging? A mass testing series utilizing the Oddy test of 60 commercial ethers ranks safe for permanent use (P, no corrosion), only temporary (T, slight unsuitable at all (F, heavy corrosion). Results show that 55% passed whereas 33% corrosion occurred on least one metal coupon 11% failed test. Raman measurements identified oxides massicot, litharge, cuprite, tenorite among carbonates (hydrocerussite, plumbonacrite), acetates basic lead acetate, acetate trihydrate well formate main phases. For example, commercial, industrial Klucel® G (HPC) scored a T rating through coupon. Basic other phases indicates presence acetic acid. Additional sample with thermal desorption GC–MS BEMMA scheme confirm high acid outgassing reveal small amount formaldehyde.