Systematic assessment of the silk deterioration behaviors for silk aging prediction

The silk cultural artifacts have suffered significant deterioration since their discovery, and the unsuitable conditions in the storage environment will further exacerbate this degradation. Systematically and quantitatively assessing the degree of deterioration of silk fabrics with multiple indexes is imperative. In this study, color difference, oxidation degree, crystallinity, and amino acid contents were employed to investigate the aging degradation process of silk fabrics. The results illustrated that both thermal and ultraviolet aging processes were accompanied by discoloration, increasing oxidation degree, decreasing crystalline degree, and amino acid contents reduction. Moreover, the aging level of silk fabrics deterioration behaviors varied across three different stages: (i) the initial stage was primarily marked by color changes, (ii) while oxidation degree and crystallinity alterations dominated in the intermediate phase, (iii) and a substantial reduction in amino acid contents prevailed during the final stage of aging. Therefore, the color difference could be identified as the early safety warning indicator for cultural relics preservation. The GM (1, 1) and GNNM (1, 1) forecasting models were utilized and the results suggested that GNNM (1, 1) outperformed GM (1, 1) in predicting the color properties of silk fabrics, indicating its potential for widespread use in predicting the deterioration of silk artifacts within collections. Collectively, this work comprehensively investigated the degradation process of silk fabrics and further achieved the prediction of color property changes during the simulated aging process, thereby providing a theoretical foundation for the conservation and protection of silk fabrics.