Degradation of 'Lumarith' Cellulose Acetate

Abstract

Objects manufactured from cellulose acetate comprise one of the most problematic groups of plastic in the collections of the Smithsonian Instititution's National Museum of American History (NMAH). To understand better cellulose acetate degradation, a 'salesman's sample kit' of 'Lumarith' brand, injection-molded, cellulose acetate color samples, manufactured by the Celluloid Company in the early twentieth century and now in the NMAH collection, was studied using minimally invasive analytical techniques at the Smithsonian Institution's Museum Conservation Institute (MCI). The kit includes 49 plastic coupons that vary in color, transparency, chemical composition and current state of degradation. Results of analysis were compared with Celluloid Company records at the NMAH Archives Center and Celanese Corporation in Narrows, Virginia, in order to determine the causes for their current level of preservation or degradation. The possible reasons for the degradation of some coupons are discussed; methods are proposed for identifying cellulose acetate objects that are at risk and for early detection of degradation.