Study on the Aging Mechanism of Textile Relics in Museum Collection Environment by Accelerated Aging Experiment

ABSTRACT

The protection of textile relics against environment-induced aging is vital when planning exhibitions or storing in the museum. To effectively avoid the deterioration of textile relics caused by improper preservation environment, this study accordingly examines different museum-collection environment (temperature, humidity, light sources, and their combination) in terms of the damage potential they hold for textile relics. Results showed the temperature, humidity, and light source of the museum-collection environment induced the performance of textile relics to varying degrees, among which the influence of temperature and light source was significantly greater than that of humidity, and appropriate humidity was also conducive to easing the performance aging of textile relics induced by the storage environment. In addition, it was found that regardless of the museum collection environment, the performance aging of protein textile relics was significantly greater than that of cellulose textile relics, indicating that the decline in the performance of textile relics was related not only to the museum-collection environment, but also to the fiber molecular composition of textile relics. Therefore, in the subsequent storage process of textile relics, the characteristics of textile relics should be fully considered and classified storage to minimize damage induced by the museum-collection environment.

摘要

在规划展览或在博物馆中储存时，保护纺织品文物免受环境引起的老化是至关重要的. 为了有效避免纺织品文物因保存环境不当而变质，本研究相应地考察了不同博物馆收藏环境（温度、湿度、光源及其组合）对纺织品文物的破坏潜力. 结果表明，博物馆收藏环境的温度、湿度和光源对纺织品文物的性能有不同程度的诱导作用，其中温度和光源的影响明显大于湿度，适当的湿度也有利于缓解纺织品文物因储存环境诱导的性能老化. 此外，研究发现，无论博物馆收藏环境如何，蛋白质纺织品文物的性能老化明显大于纤维素纺织品文物，表明纺织品文物性能的下降不仅与博物馆收藏环境有关，还与纺织品文物的纤维分子组成有关. 因此，在纺织品文物的后续存放过程中，应充分考虑纺织品文物的特点，分类存放，最大限度地减少博物馆收藏环境的破坏.

KEYWORDS:

• Textile relics
• aging mechanism
• museum collection environment
• color difference
• mechanical strength
• appearance morphology
• molecular structure

关键字:

• 纺织品文物
• 老化机制
• 博物馆收藏环境
• 色差
• 机械强度
• 外观形态
• 分子结构

Introduction

The report of the 19th National Congress pointed out: “Culture is the soul of a country and a nation.” (Nara 2020; Tao et al. 2017; Uring, Chabas, and Alfaro 2021). Textiles relics due to their exquisite and unique weaving style have become one of the precious heritages of inheriting history and culture, bearing splendid civilization, and maintaining national spirit (Akyuz et al. 2014; Liu et al. 2021). Moreover, textiles relics are also important physical evidences to reveal the evolution history of ancient textile technology. Thereby, textile relics have important historical, artistic and scientific values (An and Yeanok 2009; Yang et al. 2021). However, unfortunately, the macromolecular structure and properties of textile relics have changed obviously and even very fragile due to the long-term erosion of the underground environment (Chen et al. 2020; Chun and Hoon 2022; Gong et al. 2022). Additionally, after excavation, it is easy to appear the deterioration of textile relics’ properties, even debris, decay and other damage, because of the sudden change of the surrounding environment (Wei et al. 2022; Yang et al. 2021; Zhao et al. 2019). In other words, the significant difference between the storage/display environment of textile relics and the underground burial environment before the excavation also is unfavorable to storage/display textile relics, and even aggravates the further deterioration of the performance of unearthed textile relics (Farke, Binetti, and Hahn 2016). Moreover, textile relics belong to the key objects of promoting and displaying Chinese traditional culture and historical civilization (Farke, Binetti, and Hahn 2016; Gong et al. 2022; Zhao et al. 2021). Once damaged, the cultural and historical connotations of textile relics no longer exist, so it is our bounden duty to take good-care of textile relics (Jiwon et al. 2020; Kim and Wyeth 2009; Koperska et al. 2014).

However, the current researches mainly focus on the identification, digital restoration, reinforcement technology’s development of textile relics, etc., there were few researches on investigation of museum-collection environment (Grinder-Hansen et al. 2020; Liu et al. 2021; Tao et al. 2017; An and Yeanok 2009). Moreover, only few studies of museum-collection environment also belonged to the qualitative expression of the relationship between the preservation environment of textile relics and the deterioration of textile relics’ performance, the quantitative relationship between the preservation environment and the properties of textile relics and its mechanism were not systematically expounded (Grinder-Hansen et al. 2020; Uring, Chabas, and Alfaro 2019, 2021). At the same time, although there are many reports on the aging characteristics of textiles, but these studies are mainly for the protein fiber (silk and wool textiles), cellulose fiber (cotton and linen textiles) have not been reported (Mang and Yuan 2010; Mumenya, Tait, and Alexander 2010; Struszczyk et al. 2016). In addition, the current researches of textile aging mainly include hydrolytic aging in acid-base environment, thermal aging at fixed temperature and UV aging at different intensities (Jiang et al. 2022; Kamboj et al. 2022; Lin et al. 2017). The mechanism of deterioration of textile properties under the combination of temperature and humidity, different light sources, as well as their continuous or intermittent environment, is not discussed (Drouhet, Touchard, and Chocinski-Arnault 2022; Manjula et al. 2018; Wei et al. 2023).

In addition, collections of museums are valuable scientific and cultural asset of country and are the basis for the publicity and education activities of historical culture and the crystallization of ancient laboring people’s wisdom (Grinder-Hansen et al. 2020; Wei et al. 2022; Weiss 1977). Museum was an important site for collecting, preserving and displaying for textile relics (Jin et al. 2022; Su et al. 2022). Additionally, some scholars also pointed out that the excessive high and frequent changes of temperature could cause the desorption of textile relics’ fiber adsorbing free water, make the feel of textile relics brittle and hard, strength reducing, and the long-term high temperature environment also results in textile relics fading/yellowing decomposition, especially the protein fiber’s textile relics (silk/wool) (Cho and Lim 2012; Grinder-Hansen et al. 2020; Jin et al. 2022). Humidity is the medium of chemical reaction. The excessive high humidity can lead to the expansion of textile relics’ fibers, and accelerate the harmful chemical reaction, and then appear a series of physical and chemical damage such as fading, degradation, embrittlement and splitting (Grinder-Hansen et al. 2020; Jin et al. 2022). Moreover, the appropriate humidity (40% - 50%) is also conducive to the growth of microbial reproduction, easy to cause biodegradation, mildew, moth-eaten of textile relics (Grinder-Hansen et al. 2020; Jin et al. 2022). On the contrary, the excessive low humidity can lead to the loss of water and brittle-fracture of textile relics’ fibers, and even carbonization (Grinder-Hansen et al. 2020; Jin et al. 2022). Long time or improper light illumination could cause the textile relics yellowing, the strength reduction (Grinder-Hansen et al. 2020). In addition, the secretions of microorganisms adhering to the surface of textile relics also grow rapidly and multiply under the appropriate temperature, humidity and light conditions, enriching on the surface of textile relics, causing pollution of textile relics, corrosion fiber, forming stains, long-term residing on textile relics, weave texture of textile relics becoming indistinct (Uring, Chabas, and Alfaro 2021). These findings indicted that the improper preservation and display, as well as an unfavorable natural environment, easily lead to the deterioration of textile relics’ properties, even debris/decay, and then the loss of artistic value and research value of textile relics. Thereby, it was easy to deduced that the museum-collection environment (temperature and humidity, light, air quality) has a direct relationship with the preservation life of textile relics. Moreover, the museum-collection environment belongs to a continuous and compound environment of temperature, humidity and light (Cho and Lim 2012; Grinder-Hansen et al. 2020; Jin et al. 2022). Obviously, this was significantly different from the current reports on accelerated aging of textiles, so the experimental conclusion of accelerated aging cannot be applied to the museum-collection environment of textile relics. Moreover, the existing literature on textile relics also pointed out that it is the primary task of textile relics’ protection to design the storage environmental parameters for textile relics to long-term preserve the original ornamental value of textile heritage and have no damage (Mang and Yuan 2010; Mumenya, Tait, and Alexander 2010; Pavlogeorgatos 2003). Consequently, it is necessary to explore the relationship between different environment of museum-collections and the properties of textile relics. Therefore, in this work, taking the alkali-treated substitute sample of textile relics as the object of study, the effects of museum collections’ environment (temperature, humidity and light source types) on the color difference, mechanical properties, appearance and secondary structure of textile relics are systematically investigated with the help of artificial accelerated aging experiment. Additionally, the aging mechanism of the museum collection’s environment of textile relics is also comprehensively explored. This work can not only provide data support for the design of museum collection’s environment, but also be beneficial to textile heritage resources to fully play their heritage of civilization, the promotion of each ethnic culture. Additionally, this study also assists understanding of the aging mechanism of textile relics, especially in museum-collection environments.

Experimental details

Materials

Cotton (100% Cotton, Plain, 240 × 250/10 cm, 148.52 g/m², 0.019 mm), linen (100% linen, Plain, 140 × 180/10 cm, 176.80 g/m², 0.020 mm), silk (100% Silk, Plain, 630 × 400/10 cm, 59.52 g/m², 0.009 mm) and wool (100% Wool, Fleece +Plain, 624.04 g/m², 0.165 mm) fabrics (Hefei, Anhui Tuoyan Experimental Materials Co., Ltd.) were selected and cut to the size of 300 mm × 500 mm as experimental materials. In addition, in the experimental study, 10 m/v% NaOH purchasing from Shanghai McLin Bio-chemical Technology Co., Ltd. was also used to obtain simulated samples of textile relics.

Preparation of simulated samples of textile relics

In order to ensure the reliability of the experimental results, the simulated samples of textile relics were prepared by alkali treatment of commercial fabrics {Cotton, linen, silk, and wool fabrics (Hefei, Anhui Tuoyan Experimental Materials Co., Ltd.)}. Detailed preparation of simulated samples of textile relics were listed as follows (see Figure 1): Firstly, in order to obtain simulated samples of textile relics, alkaline solution of pH ≈ 9 configured by 10 m/v% NaOH. The obtained alkali solution was used as a treatment solution for textile relics. Experimental materials was soaked in the configured alkaline solution of pH ≈ 9 for 24 h, according to the mass ratio of 30:1 (solution: material). In addition, the experimental materials were stirred every 4 h to ensure the uniformity of material treatment. Secondly, the alkalized material was removed and rinsed with deionized water to neutral. Finally, the rinsed neutral alkali-aged sample was dried at room temperature, simulated samples of textile relics were prepared for subsequent experiments. Moreover, it should be noted that the whole experiment was done under standard experimental conditions of temperature 20°C ±2°C and relative humidity 65 ± 2%, except for the natural light aging experiment.

Figure 1. The preparation flow chart of simulated samples of textile relics.

Accelerated aging experiments

It is well known that the aging reaction of the museum collection environment of textile relics is a long process (Akyuz et al. 2014; Chen et al. 2020; Drouhet, Touchard, and Chocinski-Arnault 2022). In order to shorten the time needed for the experiment, a rigorous artificial accelerated aging experiment was selected according to the principle of time-temperature equivalence. The specific experiments are as follows: The accelerated aging experiment of temperature (55 ± 2°C, 105 ± 2°C, 155 ± 2°C), humidity (10 ± 5%, 50 ± 5%, 85 ± 5%), light source (natural light, ultraviolet light, LED) was carried out. Description of the specific parameters of accelerated aging treatment were shown as follows: To study the effect of temperature, we set three temperatures (55 ± 2°C, 105 ± 2°C, 155 ± 2°C), under the condition of fixed relative humidity of 10 ± 5%; To study the effects of light sources, we set up three light sources (natural light, ultraviolet light, LED); In order to study the effect of humidity, we conducted three humidity (10 ± 5%, 50 ± 5%, 85 ± 5%) studies at 55 ± 2°C; To study the effects of intermittent processing, we set the low temperature and low humidity of 55 ± 2°C,10 ± 5% and the low temperature and high humidity of 55 ± 2°C,85 ± 5%, ultraviolet radiation, according to the treatment time and untreated time ratio of 1:2. Additionally, in order to explore the time-cumulative effect of the above treatment conditions, simulated samples of textile relics were treated for 48 h, 96 h, 144 h, 192 h respectively. In other words, samples were treated under the conditions of different temperature, humidity, light source, and taken out every 48 h, and for taking 4 times, and then separately put into the sample bag as an experimental sample for later testing. In addition, it must be pointed out that the whole experiments were carried out at the indoor environmental conditions of temperature 20°C ±2°C and relative humidity 65 ± 2%, except for the natural light experiments, to ensure the change of the performance of the test sample only owing to aging treatment.

Experimental testing indicators and methods

Color difference

In order to explore the relationship between the museum collection environment and the color retention of textile relics, color difference of textile relics after different accelerated aging treatments was measured with the help of spectrophotometer (DS-700C, color spectrum technology (Zhejiang) Co., Ltd.). During the testing process, Lab color model was used, and artificial-simulated textile relics were used as standard samples, the color difference of four different positions of each sample after different accelerated aging treatments was tested to ensure the stability and repeatability of the results, and the average value of their color difference was taken as the final color difference value of the tested sample. The color difference was calculated by the following formula:

(1) $\mathrm{\Delta }E=\sqrt{{\left(\mathrm{\Delta }{L}^{\ast }\right)}^2+{\left(\mathrm{\Delta }{b}^{\ast }\right)}^2+{\left(\mathrm{\Delta }{a}^{\ast }\right)}^2}$(1)

Where $\mathrm{\Delta }{L}^{\ast }$ is brightness index; $a^{\ast }$ is red-green color index; $b^{\ast }$ is yellow-blue color index; $\mathrm{\Delta }{E}_1$is color difference.

Additionally, digital camera (Sony, ZV-1F) was used to more vividly and realistically show the relationship between different museum-collection environments and color changes of textile relics.

Mechanical properties

To evaluate whether the mechanical properties of textile relics are affected by different museum collections environments, the tensile strength of textile relics before and after different accelerated aging treatments were tested using fabric strength tester (YG026HC). Testing methods and operations refer to ISO 13,934-1-2013 textiles, fabrics-tensile properties-part 1, determination of breaking strength and elongation at break (strip method). Additionally, in order to maintain the reliability of the data, each sample was measured six times (three longitude and three latitude), the average value of 6 times of was taken as the tensile strength of the sample. Loss rate of tensile strength was calculated by the following formula.

(2) $\mathrm{\Delta }T=\frac{T_0-T_a}{T_0}\times 100\mathrm{\%}$(2)

where $\mathrm{\Delta }T$ is the loss rate of tensile strength, %; $T_0$ is the tensile strength of artificial-simulated textile relics (alkali treatment); $T_a$is the tensile strength of textile relics after different accelerated aging treatments.

Appearance morphology

We investigate the effect of different museum environments on the morphology of textile relics, and reveal its mechanism of action, morphology of textile relics after different accelerated aging treatments was measured with the help of scanning electron microscopy (SEM) HitachS-4800 (Japan).

Fourier transform infrared spectroscopy (FTIR)

In order to analyze whether the museum collection environment influences the secondary structure of textile relics, infrared spectrum of textile relics after different accelerated aging conditions was carried out using a Fourier transform infrared spectrometer (Perkin-Elmer, USA). The samples were cut into powder, and then mixed with KBR and ground, pressed into thin disc, directly placed in the optical path for testing. Wavenumber scanning range was 4000–400 cm⁻¹, wavenumber as horizontal coordinate, percent transmittance as vertical coordinate, resolution 4 cm⁻¹, scanning times 32.

Results and discussion

In order to reveal the aging mechanism of textile relics in museum collection environment, the effects of (55 ± 2°C, 105 ± 2°C, 155 ± 2°C), humidity (10 ± 5%, 50 ± 5%, 85 ± 5%), light source (natural light, ultraviolet light, LED) and their composition on color difference, mechanical strength, appearance morphology and molecular structure of textile relics were analyzed and compared with the help of accelerated aging experiments.

Color difference analysis of textile relics

The variation of color difference of textile relics under the environments of different museum collections is illustrated in Table 1, Figures 2 and 3. As shown in Table 1, Figures 2 and 3, under the condition of constant humidity (10 ± 5%), comparing different temperatures (55°C, 105°C, 155°C), it is found that cotton textile relics have almost no color change at lower temperatures (55°C, 105°C), regardless of the length/short of treatment time. However, at higher temperatures (155°C), cotton textile relics yellowed slightly at 155°C for 96 h, and yellowing phenomenon slightly increased with the increase of storage time, but the trend of change was relatively slight. However, linen textile relics yellowed slightly at 105°C for 96 h, and yellowed obviously at 155°C for 48 h, and the yellowing increased obviously with the increase of treatment time. Silk textile relics yellowed slightly at 55°C for 96 h, and the yellowing increased slightly with the increase of storage time. At 105°C and 155°C for 48 h, yellowing appeared obviously, and the higher the temperature, the longer the treatment time, yellowing more obvious. Wool textile relics yellowed slightly at 55°C for 48 h, and the yellowing phenomenon increased slightly with the increase of treatment time. At 105°C and 155°C for 48 h, wool textile relics appeared yellowing, and with the increase of storage time, yellowing phenomenon obviously increased. At the same time, it also found that the yellowing phenomenon of cotton textile relics was less than that of linen textile relics at any temperature, which shows that the temperature of storage environment has a great influence on the color of linen textile relics. At lower temperature (55°C, 105°C), the color difference of silk textile relics was less than that of wool textile relics, and at higher temperature (155°C), the color difference of silk textile relics was more obvious than that of wool textile relics, which indicated that the silk textile relics only appeared yellowing phenomenon under the higher temperature. However, silk textile relics easily appeared under the condition of lower temperature (55°C, 105°C) for long treatment time. In addition, it was found that at low temperature (55°C), the yellowing of cotton, linen, and silk textile relics was local yellowing, but at high temperature (55°C, 105°C), these textile relics suffered uniform yellowing. Woolen textile relics experienced uniform yellowing regardless of collection environment. Moreover, the color difference of textile relics of protein fiber (silk, wool) was significantly greater than that of textile relics of cellulose fiber (cotton, linen) at any temperature. These findings also implied that these own properties of different textile relics should be fully considered to obtain a reasonable setting of storage environment for different textile relics, when the subsequent storage environment setting. Moreover, comparing the discontinuous low temperature (55°C) with the continuous low temperature, it was found that discontinuous or not had little influence on the color difference of any kind of textile relics. This was because the temperature of 55°C was too low to stimulate the color groups of textile relics, therefore, whether the heating treatment or intermittent, the color difference changes slightly. This shows that the museum should try to use the low-temperature environment for the preservation of textile relics to ensure the stability of color.

Figure 2. Appearance of cotton/linen textile relics in different collection environments.

Figure 3. Appearance of silk/wool textile relics in different collection environments.

Table 1. The relationship between museum collection environment and color difference of textile relics.

NO.	Cotton	Linen	Silk	Wool	NO.	Cotton	Linen	Silk	Wool
1#	0.89	0.83	4.81	5.76	23#	7.99	3.09	9.91	8.23
2#	1.23	1.02	6.87	8.98	24#	8.06	4.87	10.21	8.99
3#	1.35	1.04	7.23	9.04	25#	4.99	2.98	13.98	8.14
4#	1.87	1.56	9.76	10.23	26#	5.98	5.99	16.56	11.22
5#	0.23	0.11	3.78	4.54	27#	7.87	9.45	24.18	14.98
6#	0.87	0.29	4.22	5.99	28#	8.34	11.09	29.87	15.21
7#	1.12	0.65	4.34	6.27	29#	0.32	0.23	1.77	1.65
8#	1.22	0.78	4.87	6.65	30#	0.48	0.34	1.98	1.77
9#	0.29	0.08	2.73	4.34	31#	0.77	0.65	2.21	1.89
10#	0.76	0.32	3.12	4.89	32#	0.98	0.78	2.74	2.02
11#	0.88	0.67	3.84	5.21	33#	0.48	0.33	0.75	0.38
12#	1.12	1.01	4.56	5.27	34#	0.97	0.67	1.23	0.91
13#	3.09	3.45	10.89	12.98	35#	1.12	0.93	1.36	1.23
14#	3.34	4.76	11.32	14.33	36#	1.27	1.04	1.59	1.28
15#	3.89	5.23	12.87	15.08	37#	0.23	0.05	4.09	3.99
16#	4.02	5.67	16.09	17.98	38#	0.74	0.22	5.67	4.02
17#	5.12	10.67	21.78	32.12	39#	0.84	0.54	6.98	4.76
18#	7.56	16.22	29.34	39.35	40#	1.07	0.98	8.96	4.87
19#	9.98	18.43	36.88	40.23	41#	0.99	2.79	10.01	5.99
20#	12.65	21.67	43.23	43.59	42#	1.92	3.04	12.34	9.56
21#	3.28	5.98	7.31	6.45	43#	2.08	5.07	13.54	10.65
22#	3.87	4.34	8.65	7.35	44#	3.12	5.89	15.02	11.27

Unit of color difference is %. Additionally, the accuracy of the test data was controlled in the range of ±1%.

Additionally, compared with the environment of different relative humidity at 55°C, it was found that regardless of the type of textile relics, the color difference of textile relics decreased with the increase of relative humidity. This suggested that the appropriate increase of humidity reduced the color difference of textile relics due to the addition of humidity. This was because textile relics are the materials with good hygroscopicity. When the humidity of the storage environment is higher, the moisture regain rate of the fabric is higher. There is a lot of binding water in or between the fibers, and even forming a layer of water film. When textile relics are attacked by the outside environment, the bound water first reacts with external environment. In other words, to a certain extent, the adsorbed binding water prevents the destruction of fiber molecules of textile relics induced by external environment. At the same time, the binding water or water film on the surface of textile relics also has a certain reflection effect on the outside unfavorable factors. This further reduced the deterioration of textile relics properties induced by the external environment. At the same time, compared with the continuous/intermittent high-humidity environment (85 ± 5%), the intermittent high-humidity treatment was more beneficial to relieve yellowing caused by temperature, compared to continuous high-humidity. But their difference was not significant.

In addition, comparing different light sources, it was found that no matter what kind of textile relics, the change in the color of textile relics after the irradiation treatment of ultraviolet light and nature light was relatively obvious. The longer the exposure time, the more obvious the yellowing phenomenon, especially silk, and wool textile relics. Moreover, the influence of ultraviolet light on the color difference of textile relics was much greater than that of nature light. However, the irradiation treatment of LED, did not cause the color change of textile relics, no matter how long the illumination, which indicating that LED was more suitable light source for textile relics, instead of ultraviolet light and nature light. At the same time, by comparing the continuous ultraviolet light irradiation with the intermittent ultraviolet light irradiation, it was found that the intermittent ultraviolet light irradiation greatly reduced the yellowing phenomenon of textile relics caused by the ultraviolet light irradiation, which indicated that in the museum collection environment, intermittent short-term use of ultraviolet light was feasible, instead of long-term use. At the same time, according to the report of the Environmental Health Organization, ultraviolet light irradiation has a good sterilization and disinfection function. Therefore, when designing the light source of museum for textile relics, we should take all factors into full consideration to reasonably select light source.

Mechanical properties analysis of textile relics

Table 2 shows in detail the effect of museum collection environment on the mechanical properties of textile relics. As shown in Table 2, the decline in strength of silk/wool textile relics was significantly greater than that of cotton/linen textile relics, regardless of the museum collection environment. This is because that silk and wool textile relics belong to protein fiber textile relics, which are mainly composed of amino acids that are easily affected by the external environment such as temperature, moisture and light, while cotton and linen textile relics belong to cellulose fiber textile relics, it is mainly composed of polysaccharides with stable properties in heat, humid and light environment. This conclusion implies that the strength loss of textile relics in museum collection environment is not only related to the museum-collection environment, but also to the fiber-molecular composition of textile relics.

Table 2. Relationship between museum collection environment and mechanical strength of textile relics.

NO.	Cotton	Linen	Silk	Wool	NO.	Cotton	Linen	Silk	Wool
1#	1.41	1.87	2.51	2.99	23#	6.49	6.87	12.17	8.32
2#	2.89	2.89	3.92	3.77	24#	8.07	8.99	20.17	9.91
3#	3.21	4.03	4.21	4.65	25#	10.98	12.21	20.19	11.06
4#	4.23	4.64	5.51	4.87	26#	13.32	29.87	42.28	28.98
5#	2.89	2.98	6.91	5.23	27#	14.67	32.98	53.39	35.18
6#	3.23	3.82	9.47	8.87	28#	16.01	37.23	54.18	40.32
7#	4.35	4.77	10.19	10.11	29#	0.09	0.12	1.02	0.23
8#	7.87	5.91	12.11	11.34	30#	0.21	0.48	1.33	0.76
9#	5.02	6.52	7.09	14.21	31#	0.67	0.77	1.51	0.99
10#	8.02	8.55	13.76	24.44	32#	0.89	0.98	1.61	1.22
11#	9.28	9.92	18.98	27.98	33#	1.02	1.07	1.02	1.07
12#	10.98	11.77	23.08	28.77	34#	1.34	1.45	2.12	2.43
13#	12.12	16.98	23.01	22.91	35#	1.67	1.89	3.07	3.34
14#	16.56	18.92	39.87	26.71	36#	2.03	2.23	3.99	4.03
15#	19.98	20.39	44.78	28.19	37#	5.76	6.82	12.09	20.09
16#	20.65	23.97	48.99	30.21	38#	8.99	9.23	24.76	32.19
17#	20.09	27.98	56.23	55.98	39#	10.45	10.61	29.98	42.98
18#	27.34	30.91	67.49	56.23	40#	12.09	15.12	34.99	43.09
19#	29.89	33.12	73.48	68.87	41#	1.76	3.43	14.09	4.76
20#	32.62	34.23	79.29	70.87	42#	3.01	12.87	20.08	7.08
21#	2.98	3.09	6.17	5.43	43#	4.07	17.09	22.12	14.23
22#	4.34	4.91	9.14	7.97	44#	5.44	19.87	26.18	20.03

Unit of loss rate of tensile strength is %. Additionally, the accuracy of the test data was controlled in the range of ± 1%.

Additionally, it was also found that the strength loss of textile relics increased with the increase of temperature, humidity, and time of heat-humid environment/light environment, regardless of the type of textile relics. Therefore, it is inferred that the research of temperature – humidity of museum collection environment and light source setting are very important for the preservation of textile relics. It also found that there were differences in the declining trend and extent for different type of textile relics after the same treatment of museum collection environment. Specifically, comparing the cotton and linen textile relics, it was found that the strength of cotton textile relics decreased only under high temperature (155°C) environment and sunlight and ultraviolet radiation environment, and increased slightly with the increase of treatment time, but the strength loss was slightly under other museum collection environment environments. On the contrary, linen textile relics, in the long-term low temperature and high humidity environment (55°C, 85 ± 5%, 192 h), high-temperature environment (155°C) and sunlight and ultraviolet radiation environment, occurred more obvious strength loss, which indicated that the long-term storage for linen textile relics was more difficult than cotton textile relics. Moreover, it was also found that the strength loss of cotton textile relics was less than that of linen textile relics regardless of collection environment, which further confirmed that the preservation of linen textile relics in the later period should be more careful. Additionally, this is to a certain extent reveals the reason why the ironing temperature of cotton fabric is higher than that of linen fabric in the daily-ironing care.

Comparing the cotton and linen textile relics, it was found that the strength loss of silk textile relics increased linearly with the increase of treatment time, the longer the treatment time, the greater the strength loss. On the contrary, the strength of wool textile relics decreased rapidly in a short time (48 h or 96 h). Beyond the range of this time, the loss rate of strength became slow. This indicates that the loss of strength of wool textile relics mainly occurs in the initial stage of adjustment to the balance between the unearthed environment and the museum collection environment, instead of museum collection environment. Consequently, it is very important for the preservation of textile relics to systematically study the tomb environment and set up the museum collection environment which is consistent with the tomb environment as far as possible. In addition, it also found that the strength loss of silk textile relics was significantly greater than wool textile relics in any other collections environment, except for the high humidity environment (continuous and intermittent heat-moisture treatment with relative humidity of 85 ± 5%, namely 9 # - 2 #, 36 #- 40 #). This may be the reason that the small molecules of amino acids in the surface of wool textile relics was taken away, owing to the water vapor reflux. Moreover, the scale structure of wool fibers in hot and humid environment leads to external water molecules enter the fiber through scale gap, resulting in scale layer exfoliation/damage and the keratinocytes of wool medulla dehydration, and thus the scale structure of wool textile relics was more susceptible to moisture.

Comparing different light sources, it was found that no matter what kind of textile relics, the strength loss of textile relics after ultraviolet light irradiation was the largest, that of textile relics after natural light irradiation was middle, and that of textile relics after LED light irradiation was slight, almost no change. This means that LED is more suitable for textile relics, instead of the ultraviolet light and natural light. This is because ultraviolet light and natural light contain high-energy ultraviolet light that is easy to damage to organic relics (cotton and linen silk and wool textile relics), so the strength loss rate of textile relics irradiated by ultraviolet light and natural light is greater than that of LED. In addition, it was also found that the irradiation of intermittent ultraviolet light significantly reduced the damage of textile relics caused by ultraviolet light radiation. This was because ultraviolet light had higher energy and acted as a catalyst to accelerate textile relics’ fiber photocatalytic reaction, resulting in chemical bond fracture, protein degradation and denaturation. In addition, relevant environmental science or medical reports also pointed out that ultraviolet light was helpful for the sterilization of the environment, so appropriate ultraviolet light exposure was beneficial for the sterilization of textile relics, but the irradiation time should be controlled reasonably. This finding also further confirmed the scientific and rationality of the research of museum collections environment of textile relics.

Moreover, it also found that regardless of textile relics, the damage of textile relics caused by continuous dry-heat treatment (1#–4#) and ultraviolet-light treatment (25#–28#) was greater than that caused by intermittent dry-heat treatment (33#–36#) and ultraviolet-light treatment (40#–44#). This is because that the intermittent treatment provides buffer time for the damage of textile relics caused by museum collection environment, and then reduces its cumulative damage. On the contrary, the strength loss of textile relics after intermittent wet-heat treatment was obviously higher than that after continuous wet-heat treatment. This change may be due to the continuous swelling-shrinkage deformation. These results implied that the humidity of museum collections environment should be kept at a relatively stable level, otherwise it is easy to cause secondary damage to textile relics and shorten their exhibition life. However, the intermittent high-humidity (85 ± 5%) treatment leaded to a significant decline in the strength of textile relics base on the subsequent strength test. Consequently, it was concluded that the environment with constant humidity and not frequent changes has a certain positive effect on the textile relics resistance to adverse external environment. In other words, it was advantageous to preserve textile relics by keeping the humidity of museum collection environment constant and not changing frequently.

Appearance morphology analysis of textile relics

The relationship between museum-collection environment and micro-morphology of textile relics was clearly given in Figures 4–7. As illustrated in Figures 4–7, the effect of museum-collection environment on micro-morphology of different textile relics was significantly different.

Figure 4. Relationship between museum-collection environment and micrograph of cotton textile relics.

Figure 5. Relationship between museum-collection environment and micrograph of linen textile relics.

Figure 6. Relationship between museum-collection environment and micrograph of silk textile relics.

Figure 7. Relationship between museum-collection environment and micrograph of wool textile relics.

In particular, for cotton textile relics, only high-temperature environment of 150°C and ultraviolet radiation for longer time (more than 96 h), the surface morphology of cotton textile relics, aroused cracks, splitting, and other damage phenomena. On the contrary, under other conditions, the morphology changed slightly, which was related to good heat resistance of cotton fiber. This indicates that the storage environment requirements of cotton textile relics are relatively less stringent, compared with other textile relics. At the same time, this also partly explained the reason why the change in color difference and strength of cotton textile relics was always the least in different museum collection environments. In addition, compared with the different humidity, the distortion of cotton textile relics’ fiber was reduced and the fiber was fuller under the higher humidity environment, which may be caused by the humidity entering the fiber. Moreover, comparing different textile relics, it was also found that no matter what kind of collection environment, the change in appearance of cotton textile relics after being stored in the same museum-collection environment was always the least, followed by linen textile relics, wool textile relics and silk textile relics. This implied that different textile relics undergo different changes in appearance when subjected to the same treatment conditions. Additionally, comprehensive considering the preceding analysis of color difference and strength, it was easy to deduced that the best storage environment for different textile relics was different. Therefore, it was recommended to store and display them separately according to the fiber types of textile relics, which effectively protected textile relics and save the cost of environmental maintenance. This also implied that the setting of the collection environment was a complex and systematic work, and thus the setting of the subsequent collection environment should comprehensively consider all factors. Moreover, this further confirmed the practical value of this study.

For linen textile relics, at lower temperatures (55°C), the surface roughness, fracture and burr of the fibers were slightly increased compared to the textile relics without treatment. With the increase of treatment time and humidity, the surface roughness and burrs of the fibers increased, which indicated that linen textile relics also suffered minor damage at lower temperature (55°C), which was also the reason why the strength of linen textile relics decreased at lower temperature (55°C). When the humidity was fixed (10 ± 5%), comparing different temperatures (55°C, 105°C, 155°C), it is found that with the increase of temperature, the surface burr, roughness, and split of the fiber increased significantly, and a large number of brittle fracture also appeared (see Figure 5). This implied that high temperature had a great influence on linen textile relics, and it also revealed the reason why the linen textile relics’ strength decreased significantly at higher temperature (105°C, 155°C). By comparing different light sources, it was found that under the same radiation time, the order of the surface roughness, burr, split and broken ends of linen textile relics was ultraviolet light > natural light > LED, which indicated that the damage of ultraviolet light irradiation to fiber was more serious, this was also the reason why the decline in the mechanical properties of textile relics after ultraviolet light irradiation was always most significant under three kinds of light sources. This is because the radiation energy of ultraviolet light is highest in the three types of light sources studied, therefore its damage to the textile relic is biggest. At the same time, compared with the continuous/intermittent treatment, it was found that the intermittent dry-heat and ultraviolet light irradiation could significantly reduce the surface roughness, fracture, and broken ends of the fiber compared with the continuous dry-heat and ultraviolet light irradiation. However, intermittent hygrothermal treatment could significantly increase the damage of textile relics, which was due to the repeated swelling and volume changes of fibers caused by intermittent hygrothermal treatment. This once again confirms the importance of maintaining a stable collection environment for the long-term preservation of textile relics.

For silk textile relics, by comparing the SEM images of silk textile relics treated with 55°C, 105°C and 155°C respectively, it was found that a small number of residual filaments, slight cracks, and even fibrilization would appear in silk textile relics treated with 55°C for longer time (144 h, 192 h). Additionally, with the increase of temperature and time, more residual filaments and cracks appeared on the surface of the filaments. At 155°C for 144 h, a large number of filaments were broken. This is because the interlaminar forces maintained by the hydrogen-bonded and Johannes Diderik van der Waals forces of silk molecules are destroyed with the increase of temperature, and the number of amino ends of the broken or free segments of the macromolecular chains caused by thermal oxidative cracking, therefore, the higher the temperature, the longer the treatment time, the greater the damage. To some extent, this also explained why the strength of silk relics decreased significantly with the increase of environmental temperature and treatment time. Comparing different humidity, it found that when the temperature was fixed, with the increase of the ambient humidity, the residual filaments rolled up on the surface and edge of the filaments slightly increased, but the range of change was not obvious, which implied that in the constant humidity environment, relative humidity had slight effect on textile relics. However, the increase of treatment time increased the number of pits and rolled filaments on the surface, which implied that long-time higher moisture treatment had great effect on silk textile relics, instead of short-time higher moisture treatment. Compared with different light sources, it was found that silk relics emerged more fiber fragments and breaks under ultraviolet and sunlight, and the longer the treatment time, the greater the damage. Led had little influence on the morphology of silk textile relics, but it was slightly higher than other textile relics (cotton, linen, wool). This was due to the poor light resistance of silk fibers. Comparing with discontinuous treatment and continuous treatment, it was found that the continuous heat and ultraviolet irradiation treatment caused more grooves, cracks, small fragments, and crimp of fiber residues, instead of discontinuous treatment. On the contrary, the intermittent hygrothermal treatment significantly increased fiber grooves, cracks, small fragments, residual yarn crimp. This suggests that the subsequent storage environment settings should try to ensure the constant level and avoid frequent changes of humidity.

For wool textile relics, compared with different temperature environment (55°C, 105°C and 155°C), it was found that in the environment of 55°C, the scale was intact, rarely appeared passivation, peeling off, and with the extension of treatment time, the overall scale edge and angle was still clear, no obvious damage. At 155°C for 48 h, the fibers were loose and the surface scales were broken. At 155°C for 96 h, the overlapping of scales was no longer regular and compact, the scales were no longer smooth and clean, and there were etchings on the surface with scale fragments, but the edges and angles of the whole scales were still clearly visible. However, as the treatment time continued to increase (144 h and 192 h), the scale on the surface of the fiber was flaking and passivation in a large area, and the fiber was also broken in a large area, the damage tendency of the surface of the fiber was increasing, such as passivation, peeling off and peeling off. At the same time, compared with the different humidity environment, it was found that the surface wool textile relics emerged material adhesion, and the greater the humidity, the more serious the adhesion, which may be due to the settlement of small molecules along with the recirculation of water vapor. However, the edge of the scale remained sharp. This indicated that it was suitable to effectively alleviate the yellowing of wool textile relics by an appropriate increase in environmental humidity. Compared with different light sources, it was found that under the three light sources, the scale passivation and peeling off of wool textile relics irradiated by ultraviolet light was the most serious, and some white deposits appeared. This may be due to oxidation of the endocortical layer and the ectocervical B layer in the scale layer of wool fiber. The appearance morphology of wool textile relics after LED radiation for no matter how long, almost no changed. The appearance morphology of wool textile relics after natural light radiation for short-term, was also no change, but long-term radiation, fiber appeared a certain degree of scale passivation or peeling. Additionally, it was also found that the longer the treatment time of ultraviolet light was, the more the white material deposited, indicating that in the ultraviolet light irradiation environment, wool textile relics would suffer greater damage; therefore, we should try to avoid ultraviolet light exposure in the subsequent preservation and display of textile relics in the environment. By comparing discontinuous and continuous treatment, it was found that discontinuous dry-heat and discontinuous ultraviolet radiation could effectively reduce the scale of textile relics’ fibers passivation or spalling. This was because intermittent treatment effectively alleviated the external-adverse environment leaded to the fiber damage. However, intermittent hygrothermal treatment resulted into wool textile relics’ fibers being more closely interlaced together, fiber plumpness declining, the fracture and adhesion increasing.

FTIR analysis of textile relics

Figure 8 clearly shows the infrared spectra of the textile relics before and after different processing environments. As shown in Figure 8a, no matter what kind of museum collection environments, the infrared spectrum of crystalline bands (1376 cm⁻¹,1430 cm⁻¹) and non-crystalline bands (2900 cm⁻¹, 897 cm⁻¹) of cotton textile relics did not change obviously, compared to untreated substitute sample of textile relics. This is because the macromolecular structure of cotton fiber belongs to the asymmetric six-ring structure, also known as oxygen-hexane, this structure is relatively stable; thus, chemical degradation was less, the molecular functional groups did not change much. At the same time, combined with the test results of color difference and strength, it was inferred that although the physical properties of cotton textile relics changed obviously, such as the decline of the strength of the fiber, but the chemical property did not change significantly because of the stability of oxygen-hexane. Therefore, it was also inferred that cotton textile relics in inappropriate storage environment for a long time, more prone to the decline in physical performance, instead of chemical structure.

Figure 8. Relationship between museum-collection environment and secondary structure of textile relics. (a) cotton, (b)Linen, (c) silk, (d) wool.

Note: OS represents simulation sample of textile relics before museum collection storage; LTD represents textile relics stored in museum-collection environment of 55±2°C, RH≈10±5%, 192 h; LTH represents textile relics stored in museum-collection environment of 55±2°C, RH≈85±5%, 192 h; HTD represents textile relics stored in museum-collection environment of 155±2°C, RH≈10±5%, 192 h; SL represents textile relics stored in museum-collection environment of natural light; UL represents textile relics stored in museum-collection environment of ultraviolet light; LED represents textile relics stored in museum-collection environment of led light source.

In addition, by comparing the long-term placement of samples in different museum collection environments, it was found that linen textile relics were placed in humid and heat environment, continuous dry-heat environment and ultraviolet radiation environment for a long time, the characteristic peaks (3339 cm⁻¹,1430 cm⁻¹,1056 cm⁻¹, 896 cm⁻¹, respectively) decreased in different degrees, but the intensity of the absorption peak changed slightly (see Figure 8b). This showed that the heat and humid environment, continuous dry-heat and ultraviolet light and other harsh environment caused -OH expansion and contraction of the vibration, -CH₂ outside the swing, -OH bending, C-O-C stretching vibration and-OH plane bending vibration in linen textile relics materials, and the longer the treatment time, the greater the change. At the same time, it was also found that the decreasing range of the characteristic peak value was different in different treatment environment, the humid-heat environment > the continuous dry-heat environment > the ultraviolet radiation environment, which implied that the humid and hot environment had a great influence on the linen textile relics, next was the continuous dry-heat environment, the ultraviolet radiation environment. The humidity of museum collection environments should be controlled reasonably in the subsequent museum-collection of linen textile relics to reduce the performance degradation caused by environmental humidity.

Additionally, it was found that the peak value of amide I band and amide II band amide V did not change significantly in the collection environment of low temperature and dry-heat (55 ± 2°C, RH ≈ 10 ± 5%, for 192 h). Under the collection condition of high temperature and dry heat (155 ± 2°C, RH ≈ 10 ± 5%, for 192 h), the peak values of amide I band and amide II band amide V shifted to higher wavenumber than the original samples, and the peak values were also weakened, showing a random trend (see Figure 8c). This was because the amide bonds (amide I, amide II, amide V) of silk textile relics were broken, the molecular chain was cut to short, and reacted with hydrogen bonds. At the same time, it was found that the characteristic peak intensity at 996 cm⁻¹ of the silk textile relics placed at high temperature (155 ± 2°C) showed a downward trend, which implied that the β-type silk fibroin chain of silk textile relics placed at high temperature had a tendency to disappear. It also means that the excessive higher ambient temperature can lead to the deterioration of the aggregation structure of silk textile relics and the transformation of β-type molecular bond structure to α-type. This also explained the dramatic decline in the strength of silk textile relics at high temperatures. Furthermore, the vibrational absorption peak intensity of phenol hydroxyl group of tyrosine at 1160 cm⁻¹ at high temperature also decreased significantly. This was because the tyrosine was oxidized and decomposed under high temperature, and the yellowing substance was formed, so the intensity of its absorption peak decreased obviously. Additionally, this was also reasons of silk textile relics emerged yellowing more serious in the high temperature environment. Moreover, it was found that the characteristic peaks of the silk textile relics after long-term placement in hot and humid environment, including the 1623 cm⁻¹ amide I band and 1517 cm⁻¹ amide II band decreased, however, the strength of amide v peak at 1068 cm⁻¹ increased, which indicated that the stretching vibration of N-H bond, the C=O stretching vibration (amide I band) and the bending vibration of N-H bond (amide II band) of silk textile relics in hygrothermal environment, tended to weaken, while the O-H group vibration tended to strengthen. And the peak value of the silk textile relics placed in hot and humid environment moved to higher wavenumber than the original sample (not stored), showing a trend of irregularity. This was because of the oxidation of silk textile relics in the hygrothermal environment, the formation of hydroxyl structure in the fiber macromolecular chain, so the number of O-H groups increased. Comparing different light sources, it was found that compared with the natural light and LED, the intensity of C=O absorption peak (amide I) at 1637.6 cm⁻¹ in silk textile relics was significantly decreased under UV irradiation, the peak values of amide I band and amide II band moved to higher wavenumber than the original sample. This may be due to the destruction of amino acids in the amorphous region and the looser structure of the crystalline region by UV irradiation, the break of peptide bonds and production of small molecules such as (NH₃). The attenuation of C-N stretching vibration absorption peak at 1230 cm⁻¹ and out-of-plane rocking vibration absorption peak at 700 cm⁻¹ further confirmed this conclusion. In addition, it was found that the intensity of the alcohol hydroxyl absorption peak at 1060 cm⁻¹ of silk textile relics irradiated by UV light was decreased, which may be due to the disruption of the alcohol hydroxyl groups of threonine and serine with alcohol hydroxyl groups during UV light irradiation, the conjugated double bond system with yellowing was formed by removing 1 molecule of water. This was also the cause of serious yellowing of silk textile relics under ultraviolet radiation. At the same time, the peak values of amide I and amide II bands of silk relics also moved slightly toward high wavenumber under natural light irradiation, and their structures tended to be irregular conformations, but the changes were obviously lower than those of the samples irradiated by ultraviolet light, it was inferred that the damage of secondary structure of silk textile relics by long-term ultraviolet radiation was much greater than that by natural light radiation. However, under LED irradiation, its characteristic peak was close to the original, no obvious changes, indicating that long-term irradiation of LED did not cause damage to silk textile relics, so it can be used as light source for the display/display/storage of textile relics.

Comparing the infrared spectra of wool textile relics in different temperature and humidity environments, it was found that compared with the original, the amide I absorption peak of α-helix structure at 1650 cm⁻¹ (caused by C=O stretching vibration) of wool textile relics placed at 55°C192 h and 85 ± 5%, 55°C,192 h, The characteristic absorption peak of amide II at 1540 cm⁻¹ (caused by N-H bending vibration and C-N stretching vibration), and the characteristic peak of amide III (caused by C-C stretching vibration and C=O bending vibration) at 1230 cm⁻¹ were basically unchanged (see Figure 8d). It implied that the low-temperature storage environment did not destroy the protein structure of wool textile relics, and thus did not cause the change of its characteristic peak. However, after 90%, 55°C,192 h, a small ester bond peak appeared at 1172.5 cm⁻¹. This may be due to the amino acid residues forming ester caused by bonds the addition of humidity. It also implied that long-term exposure to high humidity caused the breakage of molecular chains, the increase of amino acid residues and the formation of ester bonds. After 155°C,192 h, the red shift in the direction of low wavenumber of characteristic absorption peak of amide III region at about 1227 cm⁻¹ appeared, the characteristic absorption peak of cystine oxide at 1076 cm⁻¹ appeared, and the S-O symmetry stretching vibration absorption peak of cystine oxidation product sulfoalanine at about 1040 cm⁻¹ appeared. These results portended that disulfide bond breaking, amino-acid oxidation, fiber aging degradation and even embrittlement, was observed, when the wool textile relics stored/exhibited in high temperature for a long time. At the same time, the comparison of wool textile relics placed in different light sources for 192 h, it was found that the wool textile relics irradiated by natural light and ultraviolet light, the characteristic peak intensities in the 1648.2 cm⁻¹ of amide I region, 1541.8 cm⁻¹ of amide II region and 1223.1 cm⁻¹ of amide III region decreased in different degrees. The absorption peak of cystine monoxide at 1086.2 cm⁻¹ was observed. The phenomenon including coupling band of the bending vibration of N-H at 1414 cm⁻¹ and the stretching vibration band of C-N, broadening of peak width, strengthening of peak intensity and two peaks were observed. These results implied that the surface protein of wool textile was degraded, the amide bond was broken and the amino acid was oxidized. Moreover, the peak intensity at 1086.2 cm⁻¹ of wool textile relics irradiated by ultraviolet light was obviously higher than that irradiated by natural light, which indicated that the oxidation of cystine on the surface of wool textile relics irradiated by ultraviolet light was more serious, so the peak was stronger. On the contrary, the infrared spectrum of wool textile relics radiated by LED for 192 h did not change, which illustrated that LED was more suitable for the radiation of wool textile relics in the museum environment.

Conclusion

Textile relics not only witness the development of national history, but also play an important role in inheriting historical civilization. At the same time, textile relics are composed of cellulose or protein organic matter, which are easily affected by temperature, humidity and light source. However, at present, there are few reports on the aging mechanism of textile relics in the museum-collection environment. Therefore, in this study, the relationship between different museum-collection environments and color difference, strength, morphology and secondary structure of textile relics was systematically studied and analyzed to reveal the aging mechanism of textile relics in museum collection environment. Results showed that no matter what kind of textile relics, there was a trend that the yellowing phenomenon, strength decline, micromorphology damage and secondary structure change became more obvious with the increase of environmental temperature and the extension of occurrence time, suggesting the temperature of museum-collection environment was the main factor affecting the yellowing, strength decline, micromorphology and secondary structure change of textile relics, especially the protein textile relics. Additionally, comparing different humidity of museum collection environment, it was found that the increase of appropriate humidity in the museum-collection environment alleviated the phenomena of yellowing, strength decline, fiber microstructure damage and secondary structure change of textile relics to a certain extent. This was because the increase of humidity causes a certain amount of bound water to exist on the surface of textile relics. When confronted with harsh environment such as high temperature or ultraviolet radiation, the bound water was the first to react with the adverse environment. Therefore, to a certain extent, the performance deterioration caused by adverse environment was alleviated. But excessive humidity leaded to a sharp decline in the strength of textile relics.

Additionally, it was also found that different light sources significantly affected the yellowing, strength decline, fiber microstructure damage and secondary structure change of textile relics, ultraviolet radiation was the main factor affecting the yellowing, strength decline, fiber microstructure damage and secondary structure change of textile cultural relics. Long-term sunlight radiation also caused slight yellowing of textile relics, strength decline, fiber microstructure damage, secondary structure changes, but long-term LED radiation did not cause any changes in textile relics, so LED was the most suitable for textile relics in museum-collection environment. Intermittent ultraviolet radiation significantly reduced the performance damage caused by persistent ultraviolet radiation, so it was feasible to use intermittent short-time ultraviolet radiation for disinfection and sterilization of textile relics in the subsequent protection process. In addition, it was found that for cellulose textile relics (cotton and linen textile relics), only in the museum-collection environment of high temperature (105°C or 155°C) and ultraviolet radiation, the yellowing, strength reduction, morphology damage and secondary structure changes occurred, and the aging degree of linen textile relics > cotton textile relics. However, protein (silk and wool) textile relics experienced a certain degree of yellowing, strength decline, morphological damage and secondary structure changes under (55°C) low-temperature environment. With the increase of temperature and the extension of storage time, the performance deterioration increased significantly, especially for wool textile relics. This finding indicated that there were significant differences in the degree and amplitude of performance aging of different textile relics, and their performance aging depended on the properties of textile relics and the occurrence environment, which further confirmed the necessity of conducting research on the environmental aging mechanism of different textile relics. In conclusion, the study not only revealed the characteristics of temperature, moisture, and light irradiation during the preservation stage of the unearthed textile relics, but also provided a primary source and scientific basis for the preventive protection of the unearthed relics, it also provided reference for the formulation of environmental standards for the subsequent collection of textile heritage to better preserve textile heritage and prolong its life.

Research Highlight

• The relationship between the museum-collection environment and performance degradation of textile relics was quantitatively investigate.

• The most significant factors affecting the aging properties of textile relics in the museum collection environment has been found.

• The storage method of classifying and storing textile relics according to fiber types has been proposed in order to minimize the aging of textile relics induced by storage environment.

• This study provided a theoretical basis for the anti-aging of ancient textile relics and setting standards for temperature, humidity, and light source in the storage environment to effectively prolong the preservation life of textile relics.

Acknowledgments

This study is financially supported by The Open Project Program of Anhui Province College of Anhui Province College Key Laboratory of Textile Fabrics, Anhui Engineering and Technology Research Center of Textile (2021AETKL20); 2022 Anhui Polytechnic University -Jiujiang District Special Fund for Industrial Synergy and Innovation (2022 CYXTB7); Industry-university-research cooperation project of Anhui Polytechnic University (KH10002479); Humanities and Social Sciences project of the Ministry of Education, China (No. 22YJAZH064), the Later Funded Project of Philosophy and Social Science Research of the Ministry of Education, China (No. 22JHQ008), the National Endowment for the Arts, China (2018-A-05-(263)-0928) and the Youth Innovation Team of Shaanxi Universities, China.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the The Open Project Program of Anhui Province College of Anhui Province College Key Laboratory of Textile Fabrics, Anhui Engineering and Technology Research Center of Textile [2021AETKL20]; 2022 Anhui Polytechnic University - Jiujiang District Special Fund for Industrial Synergy and Innovation [2022 CYXTB7]; Humanities and Social Sciences project of the Ministry of Education, China [No. 22YJAZH064]; Humanities and Social Sciences project of the Ministry of Education, China (No. 22YJAZH064), the Later Funded Project of Philosophy and Social Science Research of the Ministry of Education, China [22JHQ008]; the National Endowment for the Artsand the Youth Innovation Team of Shaanxi Universities, China. [2018-A-05-(263)-0928]; Industry-university-research cooperation project of Anhui Polytechnic University [KH10002479].