The potential loss of some polymeric materials, their sources and methods of manufacture, is a little recognized but consequential occurence. Examples of polymeric materials are presented as extinct or endangered substances. Chemical and working properties of the "lost" polymers are unmatched with today's equivalents. War, economics, scarcity of raw materials and loss of expertise are factors in the trend. Some rare polymers exist only in research settings. Nikawa, an animal glue, is vital to Japanese artistic production. Mechanization changed production methods; alternatives supplanted traditional raw materials. In 2014 the last traditional maker ceased production. Modern production methods both remove components and introduce contaminants that affect valued working properties. The technology is now thought to be lost. Isinglass is a proteinaceous substance derived from the swim bladders of Baltic sturgeon. Extirpated in its home waters, small extant populations are endangered. Used in icon production, as an adhesive and a binder, it is used by art conservators for the consolidation of flaking surfaces. Sources are extremely limited, of varying quality, and have been adulterated with synthetic resins. It is prized for its adhesive strength, optical properties, and long term stability. Dragon's blood, a tree resin, renowned for its brilliant red transparent color, was used in many artistic forms. Specimens from the island of Socotra are threatened by the current war in Yemen. Also used as a medicinal and described by Pliny, current pharmacoepic research may bolster its survival. Celullose acetate, a modified cellulose, will change irrevocably in composition. Phthalate plasticizers are being replaced with less toxic equivalents. It was used as a lamination film and in animation art. Polymers are themselves cultural heritage materials; their loss diminishes our understanding of many forms of human endeavor.

Extinct and endangered polymers in cultural heritage materials

256th National Meeting (2018)

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