Non-Destructive Identification and Characterization of Crystopal, A Novel Mid-Twentieth Century Plastic

Abstract

Crystopal is a mechanically strong yet highly decorative plastic with a translucent and crackled appearance that was produced in the 1960s by the artist and plastics engineer Armand G. Winfield (1919–2009) and his company, Crystopal, Ltd. Many of Winfield’s collected plastic objects are housed within the Syracuse University Libraries, but some lack complete archival descriptions, including plastic compositions. To address this, the non-invasive and non-destructive determination of the polymer identities in Winfield’s artifacts was performed by Raman spectroscopy. Our studies generally begin with the database matching of an artifact spectrum to that of a polymer standard, but when objects known to be fabricated from Crystopal were analyzed, a database of over 100 representative polymers failed to yield the chemical identity of the plastic. However, the Raman spectrum of Crystopal displayed a unique chemical fingerprint that revealed it to be composed of an unsaturated polyester crosslinked with styrene. This Raman spectrum was added to the database and used as reference for the unambiguous identification of Crystopal artifacts, distinguishing them from decorative plastics with similar appearances. The addition of Crystopal to the polymer database provides a pathway toward establishing artifact provenance and preserving objects crafted from this unique and decorative plastic.