Analysis of audio magnetic tapes with sticky shed syndrome by ATR-FTIR

摘要

Audio magnetic tapes that are difficult to play may be affected by a form of degradation called "sticky shed syndrome" (SSS). SSS exhibits physical symptoms during playing such as squealing, not packing tightly on the reel and possible tape material loss during playing. This research investigated attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) to identify spectroscopic markers for SSS in audio magnetic tapes with poly(ester urethane) (PEU) binder layer. This article presents results for applying this technique to 50 audio magnetic tapes from the Library of Congress (LC) collections. This technique and analysis is intended to be used as a tool in identifying audio magnetic tapes with SSS from the mid 1970s through the 90s for improved preservation and to increase workflow in libraries and archives. This ATR-FTIR technique had a success rate of 71% for identifying SSS tapes and 86% for non-SSS tapes. The research also discusses spectral and chemical changes in the PEU binder layer between SSS tapes, non-SSS, and SSS tapes treated by baking including changes in hydrogen bonding of the carbonyl groups. The results support chemical/physical changes occurring in the soft segment of the PEU binder layer of SSS tapes. The absorption ratio of free to hydrogen bonded carbonyl groups was also correlated with SSS.