A clove oil / ionic liquid material for toughening palm leaf warp and preparation and use method thereof

Abstract

The present invention relates to a clove oil / ionic liquid material for toughening the palm leaf sutra and a preparation and use method thereof. The present invention selects commercially available clove oil, utilizes the advantages of ionic liquid being "green", odorless, non-combustion-supporting and non-volatile, and introduces ionic liquid to modify the clove oil. The material has good stability, low volatility and low cost. In practical applications, it is found that the clove oil / ionic liquid material can effectively improve the flexibility of the simulated palm leaf sutra to 150-170% of the original (with elastic modulus as an indicator). More importantly, after the material is applied to the surface of the simulated palm leaf sutra, the toughening effect can be maintained for 5-7 months. The material has great commercial prospects and can be further promoted to the toughening protection of cultural relics such as paper cultural relics and textile cultural relics.

Description

Technical Field

[0001] The invention belongs to the research field of cultural relics protection materials and relates to a clove oil / ionic liquid material for toughening palm leaf scriptures and a preparation and use method thereof. Background Art

[0002] The palm leaf scripture is a scripture carried on palm leaves. It is known as the "Panda of Buddhism". It originated in India and is preserved in South Asia, Southeast Asia, Tibet, Yunnan and other places in my country. The palm leaf scripture is usually made of palm leaf leaves. After trimming, boiling, scrubbing, drying, and ventilation, it is bound and bundled into a palm leaf scripture box. The content is then engraved on it with an iron pen, and then pigment is applied to make the handwriting visible (Journal of University Libraries, 2020, 38, 91-96). The palm leaf scripture is an important carrier for studying Buddhist culture and Tibetan culture, and has important cultural and archaeological value. However, after a long history, the palm leaf scripture will inevitably become brittle, decayed and other diseases under the influence of environmental factors, and become extremely fragile. It is urgent to use appropriate materials to toughen it, restore its flexibility, and extend its life, so that researchers can conduct more in-depth research on it in the future.

[0003] Natural plant essential oils are compatible with palm leaf sutras and have few hidden dangers. They are often used as toughening materials for palm leaf sutras (Conservation of Cultural Property in India, 1989, 22, 120-127; Studies in Conservation, 2002, 47, 15-24). Clove oil has the advantages of being easy to absorb and having a good toughening effect for palm leaf sutras (Restaurator, 1992, 13, 37-46). In addition, clove oil has also been proven to have excellent insect repellent, antibacterial and antioxidant properties (Journal of Agricultural and Food Chemistry, 2006, 54, 6303-6307). However, clove oil is highly volatile and easily loses its toughening effect after volatilization. Summary of the invention

[0004] Technical issues to be solved

[0005] In order to avoid the shortcomings of the prior art, the present invention proposes a clove oil / ionic liquid material for toughening palm leaf warp and a preparation and use method thereof. First, an oil phase solution containing clove oil, ionic liquid, emulsifier, and organic solvent and an aqueous phase solution containing surfactant are prepared, and then the two solutions are mixed and micro-emulsified by ultrasonic oscillation using an ultrasonic crusher, and finally the organic solvent is carefully removed using a vacuum distillation device to obtain a clove oil / ionic liquid material.

[0006] Technical Solution

[0007] A clove oil / ionic liquid material for toughening palm leaf warp, characterized in that the clove oil is modified by using ionic liquid, wherein the mass ratio of the clove oil to the ionic liquid is 1:2 to 3:2.

[0008] The clove oil is commercially available.

[0009] The ionic liquid is 3-methyl-1-octylimidazolium hexafluorophosphate.

[0010] A clove oil / ionic liquid material for toughening palm leaf warp is characterized by the following steps: dissolving a surfactant in water to prepare an aqueous phase solution;

[0011] Step 1: adding an emulsifier to an organic solvent acetone and mixing, and adding an ionic liquid and clove oil in sequence while magnetically stirring to obtain an oil phase solution;

[0012] Add the surfactant sodium dodecyl sulfate into water and stir thoroughly to form an aqueous solution;

[0013] Step 2: Mixing the aqueous phase solution and the oil phase solution and ultrasonically oscillating to prepare an emulsion;

[0014] Step 3: The emulsion is distilled through a vacuum distillation device to evaporate the organic solvent to obtain the clove oil / ionic liquid material.

[0015] The magnetic stirring in step 1 was performed at 30° C. for 1 h.

[0016] In step 2, ultrasonic oscillation is performed at a power of 200 to 400 W for 3 to 5 minutes using an ultrasonic crusher to prepare an emulsion from the aqueous phase / oil phase mixed solution.

[0017] In step 3, the organic solvent is evaporated by a vacuum distillation device, and the pressure in the device is reduced to 200-90 mbar within 30 minutes, and maintained for 10-20 minutes to allow the organic solvent to evaporate fully, thereby obtaining clove oil / ionic liquid material, and 10-15 mL can be prepared at a time.

[0018] In step 3, the vacuum distillation apparatus is used before heating and magnetic stirring at 30-35°C.

[0019] A method for using the clove oil / ionic liquid material for toughening the palm leaf sutra, characterized in that after being used on the surface of the palm leaf sutra, the flexibility of the palm leaf sutra is improved, and the improvement index is 150-170% of the original elastic modulus.

[0020] Used for toughening and protecting paper and textile cultural relics.

[0021] Beneficial Effects

[0022] The present invention proposes a clove oil / ionic liquid material for toughening of palm leaves and a preparation and use method. The present invention selects commercially available clove oil, utilizes the advantages of ionic liquid being "green", odorless, non-combustion-supporting and non-volatile, and introduces ionic liquid to modify the clove oil. Using microemulsification technology and solvent evaporation method, clove oil and ionic liquid 3-methyl-1-octylimidazole hexafluorophosphate are first mixed in a ratio of 1:2 to 3:2, and stirred evenly in an organic solvent acetone containing an emulsifier to prepare an oil phase solution; a surfactant is dissolved in water to prepare an aqueous phase solution; the two solutions are mixed and ultrasonically vibrated for 3 to 5 minutes to prepare an emulsion. The above emulsion is then subjected to a reduced pressure distillation device to evaporate the organic solvent to obtain a clove oil / ionic liquid material. The material has good stability, low volatility and low cost. In actual applications, it was found that the clove oil / ionic liquid material can effectively improve the flexibility of the simulated palm leaf scriptures to 150-170% of the original (with elastic modulus as an indicator). More importantly, after the material is applied to the surface of the simulated palm leaf scriptures, the toughening effect can be maintained for 5-7 months. This material has great commercial prospects and can be further promoted to the toughening and protection of cultural relics such as paper cultural relics and textile cultural relics.

[0023] Compared with commercially available clove oil, the clove oil / ionic liquid material provided by the present invention has good stability, low volatility and low cost. The material can be prepared in a single batch of 10 to 15 mL on a laboratory scale. Through applied research, it was found that the clove oil / ionic liquid material can effectively improve the flexibility of the simulated palm leaf sutra, which can be increased to 150 to 170% of the untoughened (with the elastic modulus as an indicator). In addition, the simulated palm leaf sutra samples after the material treatment were accelerated to age for 5 to 7 months in a constant temperature and humidity climate chamber. The simulated palm leaf sutra samples can still remain flexible, which is 140 to 160% of the untoughened ones. In contrast, the clove oil has volatilized and lost the toughening effect. DETAILED DESCRIPTION

[0024] The present invention will be further described with reference to the embodiments:

[0025] The present invention provides a clove oil / ionic liquid material and a preparation method thereof, which is mainly prepared by the following steps:

[0026] Step 1, preparing oil phase and water phase solutions: add 25-35 mg of emulsifier sorbitan monostearate (Span 60) to 25 mL of organic solvent acetone, add 0.2 g of ionic liquid 3-methyl-1-octylimidazole hexafluorophosphate and 0.1-0.3 g of clove oil (commercially available) in sequence while magnetically stirring, continue magnetic stirring at 30° C. for 1 hour to allow each component to fully dissolve to form a uniform oil phase solution; add 16-20 mg of surfactant sodium dodecyl sulfate to 50 mL of water, and stir fully to form a uniform water phase solution.

[0027] Step 2, microemulsification: add the aqueous phase solution to the oil phase solution, and use an ultrasonic crusher to perform ultrasonic oscillation at a power of 200 to 400 W for 3 to 5 minutes to prepare the aqueous phase / oil phase mixed solution into an emulsion.

[0028] Step 3, evaporation of the organic solvent: heat the above emulsion at 30-35°C with magnetic stirring, use a vacuum distillation apparatus, reduce the pressure in the apparatus to 200-90 mbar within 30 minutes, and maintain it for 10-20 minutes to allow the organic solvent to fully evaporate to obtain clove oil / ionic liquid material. 10-15 mL can be prepared at a time.

[0029] Embodiment 1:

[0030] 0.1g of commercially available clove oil, 0.2g of ionic liquid, and 25mg of emulsifier Span 60 were mixed uniformly in 25mL of organic solvent acetone at 30°C for 1h under magnetic stirring to prepare an oil phase solution; 16mg of surfactant sodium dodecyl sulfate was fully dissolved in 50mL of water to prepare an aqueous phase solution. The aqueous phase solution was injected into the oil phase solution while magnetically stirring, and the mixed solution was ultrasonically oscillated for 3min at 400W using an ultrasonic crusher to prepare an emulsion. The emulsion was then heated and magnetically stirred at 30°C, and a vacuum distillation device was used to reduce the pressure in the device to 90mbar within 30min, and maintained for 20min to allow the organic solvent to fully evaporate to obtain a clove oil / ionic liquid material. 10mL of emulsion can be prepared at a single time, in which the content of clove oil is 85%.

[0031] The clove oil / ionic liquid material emulsion was applied to the surface of the simulated palm leaf sutra sample, and after it was fully absorbed, the residual emulsion on the surface was wiped off with absorbent cotton. The simulated palm leaf sutra sample treated with pure clove oil was used as a comparison.

[0032] Test results: The elastic modulus of the simulated palm leaf scriptures treated with clove oil / ionic liquid material and clove oil increased to 150% and 145% of the untoughened samples. The simulated palm leaf scriptures samples after toughening were subjected to artificial accelerated aging treatment. After 5 months, the elastic modulus of the simulated palm leaf scriptures treated with clove oil / ionic liquid material was still 140% of the untoughened samples, while clove oil had lost its toughening effect.

[0033] Embodiment 2:

[0034] 0.2g of commercially available clove oil, 0.2g of ionic liquid, and 30mg of emulsifier Span 60 were mixed uniformly in 25mL of organic solvent acetone at 30°C for 1h under magnetic stirring to prepare an oil phase solution; 18mg of surfactant sodium dodecyl sulfate was fully dissolved in 50mL of water to prepare an aqueous phase solution. The aqueous phase solution was injected into the oil phase solution while magnetic stirring, and the mixed solution was ultrasonically oscillated for 4min at 300W using an ultrasonic crusher to prepare an emulsion. The emulsion was then heated and magnetically stirred at 35°C, and a vacuum distillation device was used to reduce the pressure in the device to 200mbar within 30min, and maintained for 15min to allow the organic solvent to fully evaporate to obtain a clove oil / ionic liquid material. 12mL of emulsion can be prepared at a single time, in which the content of clove oil is 88%.

[0035] The clove oil / ionic liquid material emulsion was applied to the surface of the simulated palm leaf sutra sample, and after it was fully absorbed, the residual emulsion on the surface was wiped off with absorbent cotton. The simulated palm leaf sutra sample treated with pure clove oil was used as a comparison.

[0036] Test results: The elastic modulus of the simulated palm leaf scriptures treated with clove oil / ionic liquid material and clove oil increased to 160% and 148% of the untoughened samples. The simulated palm leaf scriptures samples after toughening were subjected to artificial accelerated aging treatment. After 6 months, the elastic modulus of the simulated palm leaf scriptures treated with clove oil / ionic liquid material was still 152% of the untoughened samples, while clove oil had lost its toughening effect.

[0037] Embodiment three:

[0038] 0.3g of commercially available clove oil, 0.2g of ionic liquid, and 35mg of emulsifier Span 60 were mixed uniformly in 25mL of organic solvent acetone at 30°C for 1h under magnetic stirring to prepare an oil phase solution; 20mg of surfactant sodium dodecyl sulfate was fully dissolved in 50mL of water to prepare an aqueous phase solution. The aqueous phase solution was injected into the oil phase solution while magnetic stirring, and the mixed solution was ultrasonically oscillated for 5min at 200W using an ultrasonic crusher to prepare an emulsion. The emulsion was then heated and magnetically stirred at 32°C, and a vacuum distillation device was used to reduce the pressure in the device to 100mbar within 30min, and maintained for 10min to allow the organic solvent to fully evaporate to obtain a clove oil / ionic liquid material. 15mL of emulsion can be prepared at a single time, in which the content of clove oil is 90%.

[0039] The clove oil / ionic liquid material emulsion was applied to the surface of the simulated palm leaf sutra sample, and after it was fully absorbed, the residual emulsion on the surface was wiped off with absorbent cotton. The simulated palm leaf sutra sample treated with pure clove oil was used as a comparison.

[0040] Test results: The elastic modulus of the simulated palm leaf scriptures samples treated with clove oil / ionic liquid materials and clove oil increased to 170% and 147% of the untoughened samples. The simulated palm leaf scriptures samples after toughening were subjected to artificial accelerated aging treatment. After 7 months, the elastic modulus of the simulated palm leaf scriptures samples treated with clove oil / ionic liquid materials was still 160% of the untoughened samples, while clove oil had lost its toughening effect.

[0041] Although the content of the present invention has been described in detail through the above preferred embodiments, it should be appreciated that the above description should not be considered as a limitation of the present invention. After reading the above content, it will be apparent to those skilled in the art that various modifications and substitutions of the present invention will occur. Therefore, the protection scope of the present invention should be limited by the appended claims.

Claims

1. A method for preparing clove oil / ionic liquid material for toughening palm leaf warp, characterized in that The steps are as follows: dissolving the surfactant in water to prepare an aqueous phase solution; Step 1: adding an emulsifier to an organic solvent acetone and mixing, and sequentially adding an ionic liquid and clove oil while magnetically stirring to obtain an oil phase solution; the ionic liquid is 3-methyl-1-octylimidazole hexafluorophosphate; Add the surfactant sodium dodecyl sulfate into water and stir thoroughly to form an aqueous solution; Step 2: Mixing the aqueous phase solution and the oil phase solution and ultrasonically oscillating to prepare an emulsion; Step 3: The emulsion is distilled through a vacuum distillation device to evaporate the organic solvent to obtain the clove oil / ionic liquid material.

2. The method according to claim 1, characterized in that: The magnetic stirring in step 1 was performed at 30° C. for 1 h.

3. The method according to claim 1, characterized in that: In step 2, ultrasonic oscillation is performed at a power of 200 to 400 W for 3 to 5 minutes using an ultrasonic crusher to prepare an emulsion from the aqueous phase / oil phase mixed solution.

4. The method according to claim 1, characterized in that: In step 3, the organic solvent is evaporated by a vacuum distillation device, and the pressure in the device is reduced to 200-90 mbar within 30 minutes, and maintained for 10-20 minutes to allow the organic solvent to evaporate fully, thereby obtaining clove oil / ionic liquid material, and 10-15 mL can be prepared at a time.

5. The method according to claim 1, characterized in that: In step 3, the vacuum distillation apparatus is used before heating and magnetic stirring at 30-35°C.

6. A clove oil / ionic liquid material for toughening palm leaf warp prepared by the method according to any one of claims 1 to 5, characterized in that The clove oil is modified by using ionic liquid, wherein the mass ratio of the clove oil to the ionic liquid is 1:2 to 3:

2.

7. The clove oil / ionic liquid material for toughening palm leaf warp according to claim 6, characterized in that: The clove oil is commercially available.

8. A method for using the clove oil / ionic liquid material for toughening palm leaf warp according to claim 6 or 7, characterized in that: After being applied to the surface of the palm leaf sutra, the flexibility of the palm leaf sutra can be improved, with the improvement index reaching 150-170% of the original elastic modulus.

9. The method of use according to claim 8, characterized in that: Used for toughening and protecting paper and textile cultural relics.