荆州楚墓和南昌明墓出土丝纤维老化降解状况分析

Research on ageing and degraded status of unearthed silk fibers from Jinzhou Chu Tomb and Nanchang Ming Tomb

荆州楚墓和南昌明墓出土的丝织品在年代上相差近2 000年,无论是从宏观上还是微观上,丝纤维的形态都有很大的变化。采用形貌分析、红外光谱分析、X-射线衍射分析、热重分析、氨基酸分析等测试方法对这2批出土丝织品的老化降解情况进行初步分析。结果表明:荆州楚墓出土的丝织品老化降解程度比南昌明墓严重,主要包括样品表面脆化糟朽不堪;丝蛋白肽链分子中部分氢键遭到破坏,致使酰胺I吸收峰发生红移;无卷曲成分增加,结晶度减小;长期的老化降解致使耐热性能下降;部分无定形区的氨基酸被降解,南昌明墓出土的丝纤维发生了水解老化,且主要发生在非结晶区。

There are big differences in the morphology either from microcosmic or macrocosmic aspects between two batches of silk products,one unearthed from the tomb of Chu Dynasty in Jinzhou and the other from Ming Tomb of Ming Dynasty which is nearly two thousand years after Chu Dynasty.The status of ageing and degradation of these products is analyzed using morphological analysis,infrared spectrum,X-ray diffraction,thermogravimetry,and amino acid analysis.The results indicate that the silk unearthed from Chu Tomb exhibits more serious ageing and degradation than that from Ming Tomb,including the brittle and decayed surface,the red shift of amideⅠ absorption peak caused by the damaged H-bond in fibroin peptide chain molecules,increase in non-crimped components and decrease in crystallinity,deteriorated heat resistance due to long-term ageing and degradation.Both display degraded amino acid in part of amorphous area.The silk from Ming Tomb shows hydrolytic ageing,mainly occurs in amorphous area.