Insight into the measurements for determining the ageing degree of ancient silk

Abstract

Evaluating the degradation degree of aged silk is a challenge but worthwhile to determine the structure change and stability of silk. To date, the characterizations of silk degradation are widely studied, however, it still remains a lack of systematic research on measuring and quantifying the degradation degree of silk with effective ageing indicators. In this research, ancient silk samples from two different ages and regions were investigated by means of X-ray diffraction, X-ray photoelectron spectroscopy, EPR spectroscopy and 13C CPMAS NMR in an attempt to provide numerical indicators for assessing their ageing degree. As a result, the crystallinity, oxidation and carbonization degree, variation of amino acid content and content of random coil were proved to be the valuable indexes for interpreting the distinct deterioration and fragility level of aged silk. This work may shed light on studying the ageing status and stability of historical silk and further providing evidence for the conservation and preservation of silk cultural relics.