Embrittled Betallop sample and preparation method thereof

Abstract

The invention discloses an embrittled beetle sample and a preparation method thereof, and belongs to the technical field of cultural relic repair and protection. The method comprises the following steps: step 1, selecting palm plant leaves, cutting the palm plant leaves to obtain a beetle sample, soaking the beetle sample in water, heating the beetle sample to remove surface impurities and internal soluble substances, and enabling the beetle sample to be in a saturated water state; 2, preparing a sulfuric acid solution, and soaking the pretreated Betashes in the sulfuric acid solution through a sample to realize different degrees of cellulose degradation and embrittlement effects; and 3, washing the sample with deionized water, repeatedly soaking the sample treated in the step 2 until the sample is neutral, and drying the sample to obtain the embrittled sample. The method has the advantages that the fibers of the beetle are controllably degraded through the sulfuric acid solution, that is, natural embrittlement of the beetle is simulated through chemical treatment, the embrittlement state of the beetle can be quickly simulated, a standardized sample is provided for protection and repair research, and the method can be used for cultural relic protection material testing, repair technology verification and aging mechanism research.

Description

Technical Field

[0001] This invention relates to the field of cultural relic restoration and protection technology, and in particular to a sample of brittle palm leaf and its preparation method. Background Technology

[0002] Current Status of Palm-Leaf Manuscripts: Palm-leaf manuscripts are precious ancient document carriers. Due to long-term storage, they are prone to oxidation, hydrolysis, and other embrittlement phenomena, leading to a decrease in mechanical strength. Studying their embrittlement mechanism requires not only artifact samples but also controllable simulated samples to verify the degradation mechanism and evaluate the protective effect. However, artifact samples are quite precious, and their natural aging cycle is too long.

[0003] Existing technological limitations: Current conventional methods for simulating the aging of organic artifacts (such as damp heat aging and ultraviolet irradiation) are time-consuming and cannot accurately simulate the embrittlement characteristics caused by acidic hydrolysis of cellulose. Currently, there are no patents for methods to prepare simulated aging samples of palm-leaf manuscripts. Similar methods for preparing simulated wooden artifact samples include CN115753296B, which uses alkali treatment, sulfates, and oxidants to prepare simulated marine-exposed wooden artifacts; CN115476416B, which uses iron ions, hydrochloric acid, and sodium hydroxide in a hydrothermal method to prepare simulated waterlogged archaeological wood; and CN113829459B, which uses sodium hydroxide vacuum impregnation and a hydrothermal method to prepare artificially degraded waterlogged wood. All of these methods use sodium hydroxide alkali treatment, which differs significantly from the acidification process that occurs during the long-term preservation of palm-leaf manuscripts, leading to the degradation of hemicellulose and cellulose. Furthermore, the acid concentrations used in some of these patents are too low to cause significant cellulose degradation, thus failing to effectively prepare simulated embrittled palm-leaf manuscript samples.

[0004] In addition, the material used in the palm leaf sutra is the leaf of the palm tree, which has a rich waxy layer on its surface. It is difficult to fully expel the air bubbles in the internal pores using conventional methods, making it difficult to guarantee the uniformity and effectiveness of the simulated acid hydrolysis. Summary of the Invention

[0005] To address the above problems, this invention provides a brittle palm fiber sample and its preparation method. The palm fiber is controlled to degrade with sulfuric acid solution, i.e., the natural brittleness of palm fiber is simulated by chemical treatment. This method can quickly simulate the brittle state of palm fiber, providing a standardized sample for conservation and restoration research. It can be used for testing cultural relic conservation materials, verifying restoration techniques, and studying aging mechanisms.

[0006] Specifically, according to a first aspect of the present invention, a method for preparing a brittle shell leaf sample is provided, comprising: Step 1: Select palm leaves, cut them to obtain palm leaf samples, soak them in water and heat them to remove surface impurities and internal soluble substances, and make the palm leaf samples saturated with water; Step 2: Prepare a sulfuric acid solution, and immerse the pretreated betel leaves in the sulfuric acid solution to achieve different degrees of cellulose degradation and embrittlement. Step 3: Rinse with deionized water, repeatedly soak the betel leaf sample treated in Step 2 until neutral, and dry to obtain a brittle betel leaf sample.

[0007] Furthermore, in step 1, the palm plant is the palm palm.

[0008] Furthermore, in step 1, the palm leaves are cut into standard sizes, namely 5cm × 1cm.

[0009] Furthermore, in step 1, the palm leaves are heated to 100°C for 0.5-2 hours.

[0010] Preferably, the palm leaves are heated to 100°C for 1 hour.

[0011] Furthermore, in step 2, the concentration of the sulfuric acid solution is 10% to 30%.

[0012] Preferably, the concentration of the sulfuric acid solution is 20%.

[0013] Further, in step 2, the pretreatment operation is as follows: vacuum or depressurization pretreatment of the beech leaf sample, using a vacuum pump to depressurize to 0.1-0.01 atm, and processing time is 0.5-2 hours.

[0014] Preferably, the pretreatment operation is as follows: vacuum or reduced pressure pretreatment of the beech leaf sample, using a vacuum pump to reduce the pressure to 0.01 atm, and the treatment time is 1 hour.

[0015] Furthermore, in step 2, the fern leaves are soaked in a sulfuric acid solution at a temperature of 60-80°C for 0.5-6 hours.

[0016] Preferably, the fern leaves are soaked in a sulfuric acid solution at a controlled temperature of 60°C for 2 hours.

[0017] Furthermore, in step 3, the beech leaf sample is dried at 10-25℃ and 60-80% RH.

[0018] Preferably, the clams are dried at 20°C and 70% RH.

[0019] According to a second aspect of the present invention, a brittle shell leaf sample is provided, which is prepared by the preparation method described in any of the above aspects.

[0020] The beneficial effects of this invention are: Using an appropriate concentration of sulfuric acid as the degradation factor solves the problem of limited degradation capacity of low-concentration sulfuric acid on cellulose crystalline regions, while avoiding carbonization or over-degradation of the sample due to excessively high concentrations. Combined with pretreatment using vacuum or reduced pressure, this allows for the full removal of air bubbles from the internal pores of the betel leaves, ensuring sufficient contact of the sulfuric acid solution with the cellulose surface, resulting in a more uniform and effective degradation process. This method effectively simulates the acidic degradation of hemicellulose and cellulose and the destruction of the fiber microstructure caused by acidification during natural storage of betel leaves.

[0021] The prepared simulated samples exhibit significant embrittlement characteristics, with bending strength decreasing by approximately 0-70% and deflection decreasing by approximately 0-60%. Attached Figure Description

[0022] Figure 1 This is a flowchart of the method for preparing simulated brittle shell leaf samples according to the present invention; Figure 2 Infrared spectra of treated and undegraded bay leaves according to Embodiments 1 to 2 of the present invention; Figure 3 This is a comparison of the cross-sectional micromorphology of the vascular bundles of treated and undegraded betel leaves according to Embodiments 1 and 2 of the present invention; Figure 4 The bending strength of the treated and undegraded bay leaves according to Embodiments 1 to 2 of the present invention; Figure 5 The fracture deflection of the shell leaf and the undegraded shell leaf are determined according to Embodiments 1 to 2 of the present invention. Detailed Implementation

[0023] The following specific implementation examples further illustrate the embodiments of the present invention. These implementation examples are merely illustrative and not intended to limit the scope of the invention. Furthermore, various equivalent modifications made to the present invention by those skilled in the art after reading the teachings of this invention also fall within the scope claimed in the claims of this application.

[0024] This invention provides a brittle palm leaf sample and its preparation method. The method involves immersing the palm leaf sample in water and heating it to 100°C for 1 hour to remove surface impurities and internal soluble substances, thus saturating the sample with water. A 20% sulfuric acid solution is prepared, and the sample is immersed in the solution at a controlled temperature of 60-80°C for 0.5-6 hours. Different temperatures and times are selected according to experimental requirements; higher temperatures and longer treatment times result in a higher degree of brittleness in the simulated sample. The sample is then rinsed with deionized water, repeatedly immersed until neutral, and dried at 20°C and 70% RH to obtain simulated palm leaf samples with varying degrees of brittleness.

[0025] Specifically, the technical solution of the present invention first provides a method for preparing a sample of brittle shell leaves, such as... Figure 1 As shown, the method includes: S101: Substrate selection: Select palm leaves (such as palm palm leaves) that are consistent with the material of palm leaves, cut them into standard sizes (such as 5cm×1cm), soak them in water and heat them to 100℃ for 0.5-2 hours to remove surface impurities and internal soluble substances, and make the palm leaf sample saturated with water.

[0026] S102: Sulfuric acid treatment involves preparing a 10%~30% sulfuric acid solution, immersing the sample in the solution, and controlling the temperature (60~80℃) and time (0.5~6 hours) to achieve different degrees of cellulose degradation and embrittlement.

[0027] S103: Neutralize and clean by rinsing with deionized water, repeatedly soaking until neutral, and drying at 10-25℃ and 60-80%RH.

[0028] The present invention also provides a brittle shell leaf sample, which is prepared by the preparation method described above.

[0029] Example 1 The palm leaf samples were soaked in water and heated to 100℃ for 1 hour to remove surface impurities and internal soluble substances, ensuring the samples were saturated with water. The pretreatment of the palm leaf samples involved reducing the pressure to 0.01 atm using a vacuum pump for 1 hour. A 20% sulfuric acid solution was prepared, and the samples were soaked in the solution at 60℃ for 2 hours. The samples were rinsed with deionized water and repeatedly soaked until neutral. They were then dried at 20℃ and 70% RH to obtain moderately brittle simulated palm leaf samples. Infrared spectroscopy analysis of the samples was performed using attenuated total reflectance Fourier transform infrared spectroscopy (Thermo Fisher Nicolet Summit). The results (e.g.) Figure 2 This indicates that it is located at 1733cm. -1 The absorption peaks of the C=O stretching vibration from hemicellulose in the vicinity are significantly reduced, located at 2921, 2852, and 1376 cm⁻¹. -1 The absorption peaks of CH stretching and bending vibrations from hemicellulose and cellulose in the vicinity were significantly reduced, indicating that hemicellulose and cellulose underwent significant degradation. The sample cross-section was observed using a scanning electron microscope (HITACHITM4000PLUS). Figure 3 As shown in the figure, the cell walls of the fibers in the vascular bundles are significantly thinned and the porosity is increased, indicating that the fibers are destroyed due to cellulose degradation. The flexural strength and fracture deflection were tested using a HITACHITMA 7100 static thermomechanical analyzer, and the results are as follows. Figure 4 , Figure 5As shown, the flexural strength of the moderately degraded sample obtained under these conditions decreased from 45.4±10.0MPa to 28.6±4.5MPa, and the deflection decreased from 0.050±0.012 to 0.029±0.005, indicating that the mechanical strength and flexibility of the prepared simulated sample decreased, i.e., embrittlement occurred.

[0030] Example 2 The palm leaf samples were soaked in water and heated to 100℃ for 1 hour to remove surface impurities and internal soluble substances, ensuring the samples were saturated with water. The pretreatment of the palm leaf samples involved reducing the pressure to 0.01 atm using a vacuum pump for 1 hour. A 20% sulfuric acid solution was prepared, and the samples were soaked in the solution at 80℃ for 1 hour. The samples were rinsed with deionized water and repeatedly soaked until neutral. They were then dried at 20℃ and 70% RH to obtain severely brittle simulated palm leaf samples. Infrared spectroscopy analysis of the samples was performed using attenuated total reflectance Fourier transform infrared spectroscopy (Thermo Fisher Nicolet Summit). The results (e.g.) Figure 2 This indicates that it is located at 1733cm. -1 The absorption peaks of the C=O stretching vibration from hemicellulose in the vicinity have largely disappeared, and are located at 2921, 2852, and 1376 cm⁻¹. -1 The absorption peaks of CH stretching and bending vibrations from hemicellulose and cellulose in the vicinity decreased significantly, indicating that hemicellulose was nearly completely degraded and cellulose underwent significant degradation. The sample cross-section was observed using a scanning electron microscope (HITACHI TM4000PLUS) (e.g., ...). Figure 3 As shown in the figure, the cell walls of the fibers in the vascular bundles are significantly thinned and the porosity is significantly increased, indicating that the fibers are significantly damaged due to cellulose degradation. The flexural strength and fracture deflection of the HITACHI TMA7100 were tested using a static thermomechanical analyzer, and the results are as follows: Figure 4 , Figure 5 As shown, the bending strength of the heavily degraded sample obtained under these conditions decreased from 45.4±10.0MPa to 14.7±2.7MPa, and the deflection decreased from 0.050±0.012 to 0.019±0.005, indicating that the mechanical strength and flexibility of the prepared simulated sample decreased, which is a relatively serious form of embrittlement.

[0031] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a sample of brittle shell leaves, characterized in that, Includes the following steps: Step 1: Select palm leaves, cut them to obtain palm leaf samples, soak them in water and heat them to remove surface impurities and internal soluble substances, and make the palm leaf samples saturated with water; Step 2: Prepare a sulfuric acid solution, and immerse the pretreated betel leaves in the sulfuric acid solution to achieve different degrees of cellulose degradation and embrittlement. Step 3: Rinse with deionized water, repeatedly soak the betel leaf sample treated in Step 2 until neutral, and dry to obtain a brittle betel leaf sample.

2. The preparation method according to claim 1, characterized in that, In step 1, the palm plant is the palm palm.

3. The preparation method according to claim 1, characterized in that, In step 1, the palm leaves are cut into standard sizes of 5cm × 1cm.

4. The preparation method according to claim 1, characterized in that, In step 1, the palm leaves are heated to 100°C for 0.5-2 hours.

5. The preparation method according to claim 1, characterized in that, In step 2, the concentration of the sulfuric acid solution is 10% to 30%.

6. The preparation method according to claim 1, characterized in that, In step 2, the pretreatment operation is as follows: vacuum or depressurization pretreatment of the beech leaf sample, using a vacuum pump to depressurize to 0.1-0.01 atm, and the treatment time is 0.5-2 hours.

7. The preparation method according to claim 6, characterized in that, The pretreatment operation is as follows: vacuum or depressurization pretreatment of the beech leaf sample, using a vacuum pump to depressurize to 0.01 atm, and the treatment time is 1 hour.

8. The preparation method according to claim 1, characterized in that, In step 2, the fern leaves are soaked in a sulfuric acid solution at a temperature of 60-80°C for 0.5-6 hours.

9. The preparation method according to claim 1, characterized in that, In step 3, the beech leaf sample is dried at 10-25℃ and 60-80% RH.

10. A sample of brittle shell leaves, characterized in that, The brittle shell leaf sample was prepared using the preparation method according to any one of claims 1 to 9.

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