Study On Ultraviolet Deterioration And Protection Measures Of Aged Silk Fabrics

Silk cultural relics are an important part of organic cultural relics.Due to their fragile texture,silk cultural relics have been seriously aged and deteriorated after being excavated from the burial environment,and are susceptible to sudden changes in the surrounding environment,especially ultraviolet rays.Research on ultraviolet deterioration mechanism and protection measures of aging silk is of great significance for inheriting Chinese excellent history and culture.Due to the aeration of soil,the influence of oxygen cannot be completely isolated in the underground burial environment.Except the arid areas in northwest China,silk fabrics are mostly affected by groundwater and environmental pH in underground burial environment,especially in southern China.Oxygen,pH and other factors in underground burial environment have different damage mechanisms on silk fabrics,so aging silk fabrics deteriorate differently under ultraviolet light.In this study,the aging pretreatment samples were prepared to simulate the burial environment with different tightness and PH,and then the samples were subjected to ultraviolet aging,to explore the influence of ultraviolet light on the deterioration of the aging silk fabrics in the burial environment with different tightness and PH.In the process of underground burial,the silk fabric cultural relics unearthed in Hubei and other humid areas in the south are greatly affected by oxygen and pH.Therefore,three silk fabric cultural relics unearthed in Hubei area of different ages are taken as the research object to evaluate the preservation status of the cultural relic samples and predict the deterioration trend of silk fabric cultural relics combined with the results of artificial simulation of aging.Finally,based on the conclusion of artificial aging simulation and cultural relic sample analysis,reasonable suggestions are put forward for the preservation conditions of silk fabrics museum,and scientific reference is provided for the preservation conditions of excavated aged silk fabrics in different burial environments with different airtightness and pH.In this paper,thermal aging and hydrolytic aging were firstly used to simulate the influence of oxygen and pH on silk fabrics in underground burial environment,and then the samples were aged by ultraviolet light in different ways.By testing the surface morphology,color difference data,mechanical properties,thermal stability,secondary structure and amino acid content of aging pretreatment samples under UV light,the ultraviolet degradation difference of silk fabrics excavated under different burying environments with different airtightness and pH was studied.The results show that ultraviolet light has different effects on the degradation of silk fabrics in different burial environments with different tightness and pH,and the damage is more serious in aerobic burial environment and alkaline burial environment.In addition,the decrease of the temperature of the maximum thermogravimetric decomposition rate of silk fabrics has a linear relationship with the UV irradiation time,which can be used to quantify the deterioration degree of silk fabrics.On the basis of artificial simulation of aging,the deterioration degree of silk fabric relics in wet areas was characterized.A large number of holes and cracks existed on the surface of the samples except the samples at the southern foot of Lianhuashan in the Ming Dynasty.Hearle type 6 fractures were found on the surface of the samples at Mashan and Lianhuashan,indicating that the burial process may be affected by hydrolysis.There are a lot of particles on the surface of the three cultural relics samples,which are composed of soil and crystalline salt.The non-crystalline zone of the samples has been seriously degraded,and both the crystalline zone and the non-crystalline zone of the samples from the No.1 tomb of Chu in Mashan,Jiangling have been seriously degraded.The L*values and surface color changes of three silk artifacts were as follows:No.1 Chu Tomb in Mashan,Jiangling,No.1 Han Tomb in Xijiaqiao,Ezhou,southern foot of Lianhua Mountain;The contents of glycin were as follows:the Ming Dynasty samples from Mashan No.1 Tomb of Chu,Xijiaqiao No.1 Tomb of Han,and the southern foot of Lianhua Mountain.The deterioration degree of three cultural relics and the presumed susceptibility to ultraviolet radiation:Silk fabrics from the No.1 Tomb of Chu in Mashan,Jiangling,>Silk fabrics from the No.1 Tomb of Han in Xie Jiaqiao,>Silk fabrics from the Ming Dynasty at the southern foot of Lianhua Mountain.Attention should be paid to the UV protection of the three cultural relics,especially the silk fabric of the No.1 Tomb of Chu in Mashan,Jiangling.This provides data support for the research of silk fabric protection in humid area of Hubei province.Finally,combined with the study on the degradation of silk fabrics unearthed in the simulated burial environment with different tightness and pH and the characterization of cultural relics degradation,the influence of various aging factors on silk fabrics was clarified and suggestions for protection were put forward.Silk fabrics in aerobic and alkaline burial environments are more prone to brittle fracture.Yellow change obviously;The breaking strength decreases faster;Secondary structure degradation rate is faster;Tyrosine and macrolateral amino acids decreased more rapidly.Therefore,attention should be paid to the collection and utilization of information about the airtightness and pH of the buried environment in archaeological sites.To strengthen the scientific and technological analysis and conservation research of cultural relics,the temperature of the maximum decomposition rate of TG can be used as a quantitative index indicating the deterioration of silk fabrics.The preservation conditions of silk fabrics in museum collections should be further refined according to the airtight burial environment and the difference between acid and alkali,especially to strengthen the UV protection of silk fabrics unearthed in alkaline environment and aerobic environment.In addition,research on UV protection agents and light stabilizers should also be strengthened to minimize the effects of UV and to deal with the phenomenon of "photobleaching" of aged silk fabrics.