Camellia oleifera abel hemicellulose membrane and preparation method thereof
By setting up the Hemicellulose polydehydroabietic acid copolymer on the Hemicellulose-Polyvinyl Alcohol blend film, the mechanical properties and processability problems of the hemicellulose film are solved, and transparency, flexibility and ultraviolet are achieved. Film preparation with absorption properties.
Patent Information
- Application Number
- CN202411050876.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-01
- Publication Date
- 2024-12-13
AI Technical Summary
The existing hemicellulose films have poor mechanical properties, film forming and hygroscopicity, and poor processability, making it difficult to meet the needs of high-performance films.
The blended film of oleifera hemicellulose-polyvinyl alcohol is used, and a polydehydroaberaic acid copolymer film of oleifera hemicellulose is provided thereon. It is made transparent, flexible and has Films with ultraviolet absorption properties.
The mechanical properties and thermal stability of the oleifera hemicellulose film are improved, its compatibility is enhanced, and good transparency and ultraviolet absorption properties are achieved.
Smart Images
Figure CN119119597A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of hemicellulose membranes, and in particular relates to a camellia oleifera hemicellulose membrane and a preparation method thereof. Background Art
[0002] Hemicellulose is one of the main components of plant fiber raw materials. It is a non-homogeneous polysaccharide composed of structural units such as D-xylose, L-arabinose, D-mannose, D-glucose, D-galactose and trace amounts of L-rhamnose. It is one of the most abundant renewable resources on earth. There are a large number of hydroxyl groups in its molecular structure, which gives it good chemical activity. At the same time, it has been widely studied and applied because of its advantages such as hydrophilicity, easy degradation, wide sources, good biocompatibility and renewability. In plant fiber raw materials, hemicellulose is connected to cellulose by hydrogen bonds and to lignin by covalent bonds such as ether bonds and ester bonds. Hemicellulose can be extracted from plant fiber raw materials by breaking these connections.
[0003] In recent years, polymer film materials derived from hemicellulose in biomass resources such as economic forest waste have gradually shown market prospects and commercial value. They are mainly used in food packaging films, edible coating films, etc., and can also be used as wound dressings. However, on the one hand, hemicellulose has a low molecular weight and strong hydrophilicity, and the resulting film has poor mechanical properties and film-forming properties and strong hygroscopicity; on the other hand, hemicellulose itself has strong hydrogen bonding, low solubility, and poor processability. It is usually necessary to modify the hemicellulose film to improve its comprehensive performance. Summary of the invention
[0004] The purpose of the present invention is to solve the above technical problems and provide a camellia oleifera hemicellulose film and a preparation method thereof, and to arrange a camellia oleifera hemicellulose polydehydroabietic acid copolymer film on a camellia oleifera hemicellulose-polyvinyl alcohol blend film, so as to finally obtain a film with good transparency, flexibility and ultraviolet absorption performance.
[0005] The camellia oleifera hemicellulose membrane in the technical solution of the present invention comprises a camellia oleifera hemicellulose-polyvinyl alcohol blended membrane and a camellia oleifera hemicellulose polydehydroabietic acid copolymer membrane arranged on the camellia oleifera hemicellulose-polyvinyl alcohol blended membrane.
[0006] Camellia oleifera hemicellulose contains a large number of hydroxyl functional groups, which can form intermolecular forces with a large number of oxygen elements on polyvinyl alcohol, making the Camellia oleifera hemicellulose-polyvinyl alcohol blend membrane and the Camellia oleifera hemicellulose polydehydroabietic acid copolymer have good compatibility, thereby enhancing the mechanical properties of the Camellia oleifera hemicellulose membrane.
[0007] Furthermore, the thickness of the Camellia oleifera hemicellulose-polyvinyl alcohol blended film is 300-800 μm.
[0008] Furthermore, the thickness of the Camellia oleifera hemicellulose polydehydroabietic acid copolymer film is 400-900 μm.
[0009] The present invention also provides a method for preparing the above-mentioned Camellia oleifera hemicellulose film, comprising the following steps: mixing the Camellia oleifera hemicellulose solution and the polyvinyl alcohol solution, heating and concentrating the mixture, standing and degassing to prepare a casting liquid, casting the film and drying to obtain a Camellia oleifera hemicellulose-polyvinyl alcohol blended film, and then coating the Camellia oleifera hemicellulose polydehydroabietic acid copolymer.
[0010] Furthermore, the oil-tea camellia hemicellulose solution is obtained by dissolving the oil-tea camellia hemicellulose in water and performing rotary evaporation.
[0011] Furthermore, the concentration of the Camellia oleifera hemicellulose solution is 10-50 mg / ml.
[0012] Furthermore, the mass of the polyvinyl alcohol is 20-50% of the mass of the hemicellulose of Camellia oleifera.
[0013] Furthermore, the concentration of the polyvinyl alcohol solution is 5 to 15 mg / ml.
[0014] Furthermore, the polyvinyl alcohol solution is preheated at 80-100° C. for 10-30 minutes before being mixed with the tea oil hemicellulose solution.
[0015] Furthermore, the temperature for heating and concentrating is 80 to 120°C.
[0016] Furthermore, the standing degassing time is 10 to 30 minutes.
[0017] Preferably, the drying temperature is 50 to 80°C.
[0018] Furthermore, the preparation method of the polydehydroabietic acid copolymer of oil tea hemicellulose comprises the following steps: mixing dehydroabietic acid (2-methacryloyloxyhexyl) ester, oil tea hemicellulose-based initiator, pentamethyldiethylenetriamine and tetrahydrofuran, and then subjecting the mixture to multiple cycles of liquid nitrogen freezing-vacuuming-nitrogen pressurization, adding cuprous bromide, and then subjecting the mixture to liquid nitrogen freezing-vacuuming-nitrogen pressurization again, and reacting in an oil bath, and then precipitating and drying.
[0019] By introducing rosin groups through free radical polymerization, the rigidity of the Camellia oleifera hemicellulose-based graft copolymer was increased, and its thermal stability and mechanical properties were improved, ultimately obtaining a Camellia oleifera hemicellulose membrane with good transparency, flexibility and UV absorption function.
[0020] Furthermore, the molar mass of the tea oil hemicellulose-based initiator and pentamethyldiethylenetriamine are both 0.5-1.5% of the molar mass of dehydroabietic acid (2-methacryloyloxyhexyl) ester; and / or the molar mass of cuprous bromide is 0.5-1.5% of the molar mass of dehydroabietic acid (2-methacryloyloxyhexyl) ester.
[0021] Preferably, 1 to 5 mL of tetrahydrofuran is added to 1 g of dehydroabietic acid (2-methacryloyloxyhexyl) ester.
[0022] Furthermore, the temperature of the oil bath reaction is 40-80° C., and the time is 10-20 h.
[0023] Preferably, after the oil bath reaction, the reaction solution is passed through a neutral Al 2 O 3 The copper catalyst was removed by column, and then precipitation was performed several times using cold methanol as the precipitant.
[0024] Furthermore, the preparation method of dehydroabietic acid (2-methacryloyloxyhexyl) ester comprises the following steps:
[0025] (1) adding oxalyl chloride to a dehydroabietic acid solution, reacting at room temperature for 2 to 5 hours to obtain dehydroabietic acid chloride, adding a mixed solution of 4-dimethylaminopyridine and 1,6-hexanediol, reacting in an oil bath, filtering and precipitating, washing the filtrate and concentrating by rotary evaporation to obtain dehydroabietic acid hydroxyhexyl ester;
[0026] (2) After mixing hydroxyhexyl dehydroabietic acid, triethylamine, hydroquinone and tetrahydrofuran, adding methacryloyl chloride after stirring and dissolving, reacting at room temperature for 8 to 15 hours, filtering and precipitating, washing the filtrate and concentrating it by rotary evaporation; the reaction process is as follows:
[0027]
[0028] Furthermore, the dehydroabietic acid solution in step (1) is obtained by dissolving dehydroabietic acid in dichloromethane at a concentration of 0.03 to 0.10 g / mL.
[0029] Furthermore, in step (1), the molar mass of oxalyl chloride is 1.5 to 2.0 times the molar mass of dehydroabietic acid.
[0030] Furthermore, in step (1), the molar masses of 4-dimethylaminopyridine and 1,6-hexanediol are both 8 to 15 times the molar mass of dehydroabietic acid.
[0031] Preferably, in step (1), the concentration of 4-dimethylaminopyridine in tetrahydrofuran is 0.1-0.5 g / mL.
[0032] Furthermore, in step (1), the temperature of the oil bath reaction is 40 to 80° C., and the time is 10 to 20 hours.
[0033] Preferably, the filtrate in step (1) is precipitated with petroleum ether, and after removing the precipitate, the filtrate is washed with a 5-10% dilute hydrochloric acid solution, and the upper layer of the liquid is repeatedly washed 3-5 times.
[0034] Furthermore, in step (2), the molar mass of triethylamine is 2.0 to 3.0 times the molar mass of hydroxyhexyl dehydroabietic acid; and / or the molar mass of hydroquinone is 0.3 to 0.6% of the molar mass of hydroxyhexyl dehydroabietic acid.
[0035] Preferably, in step (2), the concentration of hydroxyhexyl dehydroabietic acid in tetrahydrofuran is 0.01 to 0.05 g / mL.
[0036] Furthermore, in step (2), the molar amount of methacryloyl chloride is 1.0 to 2.0 times the molar mass of hydroxyhexyl dehydroabietic acid.
[0037] Preferably, the filtrate in step (2) is washed 3 to 5 times with a sodium hydroxide solution having a concentration of 5 to 10%.
[0038] Furthermore, the temperature of the rotary evaporation concentration is 50-90°C.
[0039] Furthermore, the preparation method of the oil-tea camellia hemicellulose-based initiator includes the following steps: firstly dissolving the oil-tea camellia hemicellulose and 4-dimethylaminopyridine in tetrahydrofuran and placing in an ice water bath at 0-5°C, then adding a mixed solution of 2-bromoisobutyryl bromide and tetrahydrofuran, stirring at room temperature for 20-30 hours, and then washing, filtering, and vacuum drying.
[0040] Furthermore, the molar mass ratio of Camellia oleifera hemicellulose and 4-dimethylaminopyridine is 1:2-5.
[0041] Preferably, the concentration of Camellia oleifera hemicellulose in tetrahydrofuran is 0.01-0.05 g / mL.
[0042] Furthermore, the concentration of 2-bromoisobutyryl bromide in the mixed solution of 2-bromoisobutyryl bromide and tetrahydrofuran is 0.5 to 1.0 g / mL.
[0043] Furthermore, the molar mass of 2-bromoisobutyryl bromide is 2 to 5 times the molar mass of Camellia oleifera hemicellulose.
[0044] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:
[0045] (1) a film of polydehydroabietic acid copolymer of hemicellulose of Camellia oleifera is arranged on a blended film of hemicellulose of Camellia oleifera and polyvinyl alcohol, thereby finally obtaining a film having good transparency, flexibility and ultraviolet absorption performance;
[0046] (2) Camellia oleifera hemicellulose contains a large number of hydroxyl functional groups, which can form intermolecular forces with a large number of oxygen elements on polyvinyl alcohol, making the Camellia oleifera hemicellulose-polyvinyl alcohol blend membrane and Camellia oleifera hemicellulose polydehydroabietic acid copolymer have good compatibility, thereby enhancing the mechanical properties of Camellia oleifera hemicellulose membrane;
[0047] (3) The introduction of rosin groups through free radical polymerization increased the rigidity of the Camellia oleifera hemicellulose-based graft copolymer and improved its thermal stability, thereby enhancing the mechanical properties of the Camellia oleifera hemicellulose membrane. BRIEF DESCRIPTION OF THE DRAWINGS
[0048] Figure 1 SEM images of the tea tree hemicellulose membrane obtained in Example 1: (a) surface image, (b) cross-sectional image;
[0049] Figure 2 This is a picture of the Camellia oleifera hemicellulose membrane obtained in Example 1;
[0050] Figure 3 The UV transmittance data of Example 1 are shown in the figure: (a) dehydroabietic acid, (b) oil-tea camellia hemicellulose, (c) dehydroabietic acid (2-methacryloyloxyhexyl) ester, and (d) oil-tea camellia hemicellulose polydehydroabietic acid copolymer;
[0051] Figure 4 This is the infrared spectrum of the polydehydroabietic acid copolymer of Camellia oleifera hemicellulose in Example 1;
[0052] Figure 5 This is a thermodynamic performance diagram of Example 1, in which: (a) oil-tea camellia hemicellulose, (b) dehydroabietic acid (2-methacryloyloxyhexyl) ester, and (c) oil-tea camellia hemicellulose polydehydroabietic acid copolymer. DETAILED DESCRIPTION
[0053] The technical scheme of the present invention is further described below by specific examples and accompanying drawings. It should be understood that the specific examples described herein are only used to help understand the present invention and are not used for specific limitations of the present invention. The accompanying drawings used herein are only for better illustrating the disclosure of the present invention and do not have a limiting effect on the scope of protection. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used raw materials in the art, and the methods used in the embodiments are all conventional methods in the art.
[0054] Example 1
[0055] The method for preparing the hemicellulose film of Camellia oleifera in this embodiment comprises the following steps:
[0056] (1) 0.0066 mol of dehydroabietic acid was dissolved in 40 mL of dichloromethane to obtain a dehydroabietic acid solution, 0.011 mol of oxalyl chloride was added, and the mixture was reacted at room temperature for 3 h to obtain dehydroabietic acid chloride, 0.066 mol of 4-dimethylaminopyridine and 0.066 mol of 1,6-hexanediol were dissolved in 50 mL of tetrahydrofuran to form a mixed solution, and the mixture was reacted in an oil bath at 50° C. for 12 h, and the filtrate was dropped into petroleum ether for precipitation, and the obtained filtrate was washed three times with 10% dilute hydrochloric acid, and concentrated by rotary evaporation to obtain dehydroabietic acid hydroxyhexyl ester;
[0057] (2) 10 mmol of hydroxyhexyl dehydroabietic acid, 25 mmol of triethylamine, 0.0045 mmol of hydroquinone and 120 mL of tetrahydrofuran were mixed, 12 mmol of methacryloyl chloride was added under stirring to dissolve, and the mixture was reacted at room temperature for 10 h. After filtering, the filtrate was washed three times with 8% NaOH solution, and the solvent was removed by rotary evaporation at 65° C. to obtain the product dehydroabietic acid (2-methacryloyloxyhexyl) ester;
[0058] (3) 5 mmol of Camellia oleifera hemicellulose and 15 mmol of 4-dimethylaminopyridine were dissolved in 40 mL of tetrahydrofuran, placed in an ice-water bath at 0°C, and a mixed solution of 15 mmol of 2-bromoisobutyryl bromide and 5 mL of tetrahydrofuran was added, stirred at room temperature for 24 h, and the reaction solution was washed in water, filtered, and vacuum dried to obtain a Camellia oleifera hemicellulose-based initiator;
[0059] (4) 4.86 mmol of dehydroabietic acid (2-methacryloyloxyhexyl) ester, 0.0486 mmol of oil tea hemicellulose-based initiator, 0.0486 mmol of pentamethyldiethylenetriamine and 4 mL of tetrahydrofuran were mixed and subjected to three cycles of liquid nitrogen freezing-vacuuming-nitrogen pressurization. After adding 0.0486 mmol of cuprous bromide, liquid nitrogen freezing-vacuuming-nitrogen pressurization was performed again. The reaction was carried out in an oil bath at 55°C for 12 h. The reaction solution was passed through a neutral Al 2 O 3 The cuprous bromide was removed by column, cold methanol was used as a precipitant for precipitation, and after drying, a viscous polydehydroabietic acid copolymer of hemicellulose of Camellia oleifera was obtained;
[0060] (5) dissolving the camellia oleifera hemicellulose in water to prepare a camellia oleifera hemicellulose solution with a concentration of 20 mg / ml, stirring and preheating at 90° C. for 20 min, dissolving polyvinyl alcohol in water to prepare a polyvinyl alcohol solution with a concentration of 10 mg / ml, stirring and preheating at 95° C. for 20 min; mixing the camellia oleifera hemicellulose solution and the polyvinyl alcohol solution, wherein the mass of the polyvinyl alcohol is 30% of the mass of the camellia oleifera hemicellulose, heating and concentrating at 90° C., stopping heating after the solution becomes a viscous liquid, standing and degassing at room temperature for 20 min to prepare a casting solution, casting a camellia oleifera hemicellulose-polyvinyl alcohol blend film with a thickness of 500 μm, drying at 60° C., and then coating a camellia oleifera hemicellulose polydehydroabietic acid copolymer with a thickness of 500 μm;
[0061] Example 2
[0062] The difference between this embodiment and embodiment 1 is that in step (1), 0.0066 mol of dehydroabietic acid is dissolved in 40 mL of dichloromethane to obtain a dehydroabietic acid solution, 0.012 mol of oxalyl chloride is added, and the mixture is reacted at room temperature for 3 h to obtain dehydroabietic acid chloride, 0.072 mol of 4-dimethylaminopyridine and 0.075 mol of 1,6-hexanediol are dissolved in 50 mL of tetrahydrofuran to form a mixed solution, the mixture is reacted in an oil bath at 60° C. for 12 h, the filtrate is dropped into petroleum ether for precipitation, the obtained filtrate is washed three times with 10% dilute hydrochloric acid, and concentrated by rotary evaporation to obtain dehydroabietic acid hydroxyhexyl ester.
[0063] Example 3
[0064] The difference between this embodiment and embodiment 1 is that in step (2), 10 mmol of hydroxyhexyl dehydroabietic acid ester, 28 mmol of triethylamine, 0.005 mmol of hydroquinone and 120 mL of tetrahydrofuran are mixed, 15 mmol of methacryloyl chloride is added under stirring to dissolve, the mixture is reacted at room temperature for 12 h, the filtrate is filtered, washed three times with 8% NaOH solution, and the solvent is removed by rotary evaporation at 65° C. to obtain the product, dehydroabietic acid (2-methacryloyloxyhexyl) ester.
[0065] Example 4
[0066] The difference between this embodiment and embodiment 1 is that in step (4), 4.86 mmol of dehydroabietic acid (2-methacryloyloxyhexyl) ester, 0.052 mmol of oil tea hemicellulose-based initiator, 0.06 mmol of pentamethyldiethylenetriamine and 4 mL of tetrahydrofuran are mixed and then subjected to three cycles of liquid nitrogen freezing-vacuuming-nitrogen pressurization, 0.05 mmol of cuprous bromide is added and then subjected to liquid nitrogen freezing-vacuuming-nitrogen pressurization again, and the reaction is carried out in an oil bath at 65° C. for 12 h. The reaction solution is passed through a neutral Al 2 O 3 The cuprous bromide was removed from the column, cold methanol was used as a precipitant for precipitation, and a viscous polydehydroabietic acid copolymer of Camellia oleifera hemicellulose was obtained after drying.
[0067] Example 5
[0068] The difference between this embodiment and embodiment 1 is that in step (5), the camellia oleifera hemicellulose is dissolved in water to prepare a camellia oleifera hemicellulose solution with a concentration of 20 mg / ml, and the solution is preheated at 90°C with stirring for 20 min; polyvinyl alcohol is dissolved in water to prepare a polyvinyl alcohol solution with a concentration of 10 mg / ml, and the solution is preheated at 95°C with stirring for 20 min; the camellia oleifera hemicellulose solution and the polyvinyl alcohol solution are mixed, the mass of the polyvinyl alcohol being 35% of the mass of the camellia oleifera hemicellulose, and the mixture is heated and concentrated at 90°C until it becomes a viscous liquid, and the heating is stopped after the mixture is allowed to stand at room temperature for 20 min to degas. The mixture is cast into a camellia oleifera hemicellulose-polyvinyl alcohol blend film with a thickness of 600 μm, and after drying at 60°C, a camellia oleifera hemicellulose polydehydroabietic acid copolymer with a thickness of 500 μm is coated.
[0069] Example 6
[0070] The difference between this embodiment and embodiment 1 is that in step (5), the camellia oleifera hemicellulose is dissolved in water to prepare a camellia oleifera hemicellulose solution with a concentration of 20 mg / ml, and the solution is preheated at 90°C with stirring for 20 min; polyvinyl alcohol is dissolved in water to prepare a polyvinyl alcohol solution with a concentration of 10 mg / ml, and the solution is preheated at 95°C with stirring for 20 min; the camellia oleifera hemicellulose solution and the polyvinyl alcohol solution are mixed, the mass of the polyvinyl alcohol being 40% of the mass of the camellia oleifera hemicellulose, the mixture is heated and concentrated at 90°C, the heating is stopped after the mixture becomes a viscous liquid, the mixture is allowed to stand at room temperature for 20 min to degas, a casting solution is prepared, the film is cast into a camellia oleifera hemicellulose-polyvinyl alcohol blend film with a thickness of 500 μm, and after drying at 60°C, a camellia oleifera hemicellulose polydehydroabietic acid copolymer with a thickness of 600 μm is coated.
[0071] Example 7
[0072] The difference between this embodiment and embodiment 1 is that in step (5), the camellia oleifera hemicellulose is dissolved in water to prepare a camellia oleifera hemicellulose solution with a concentration of 20 mg / ml, and the solution is stirred and preheated at 90°C for 20 min; polyvinyl alcohol is dissolved in water to prepare a polyvinyl alcohol solution with a concentration of 10 mg / ml, and the solution is stirred and preheated at 95°C for 20 min; the camellia oleifera hemicellulose solution and the polyvinyl alcohol solution are mixed, the mass of the polyvinyl alcohol is 30% of the mass of the camellia oleifera hemicellulose, the mixture is heated and concentrated at 90°C, the heating is stopped after the mixture becomes a viscous liquid, the mixture is allowed to stand at room temperature for 20 min to degas, a casting solution is prepared, the film is cast into a camellia oleifera hemicellulose-polyvinyl alcohol blend film with a thickness of 500 μm, and after drying at 60°C, a camellia oleifera hemicellulose polydehydroabietic acid copolymer with a thickness of 300 μm is coated.
[0073] Example 8
[0074] The difference between this embodiment and embodiment 1 is that in step (5), the camellia oleifera hemicellulose is dissolved in water to prepare a camellia oleifera hemicellulose solution with a concentration of 20 mg / ml, and the solution is stirred and preheated at 90°C for 20 min; polyvinyl alcohol is dissolved in water to prepare a polyvinyl alcohol solution with a concentration of 10 mg / ml, and the solution is stirred and preheated at 95°C for 20 min; the camellia oleifera hemicellulose solution and the polyvinyl alcohol solution are mixed, the mass of the polyvinyl alcohol is 30% of the mass of the camellia oleifera hemicellulose, the mixture is heated and concentrated at 90°C, the heating is stopped after the mixture becomes a viscous liquid, the mixture is allowed to stand at room temperature for 20 min to degas, a casting solution is prepared, the film is cast into a camellia oleifera hemicellulose-polyvinyl alcohol blend film with a thickness of 500 μm, and after drying at 60°C, a camellia oleifera hemicellulose polydehydroabietic acid copolymer with a thickness of 1000 μm is coated.
[0075] Comparative Example 1
[0076] The difference between this comparative example and Example 1 is that step (5) is to dissolve the camellia oleifera hemicellulose in water to prepare a camellia oleifera hemicellulose solution with a concentration of 20 mg / ml, and preheat the solution with stirring at 90°C for 20 min; polyvinyl alcohol is dissolved in water to prepare a polyvinyl alcohol solution with a concentration of 10 mg / ml, and preheat the solution with stirring at 95°C for 20 min; the camellia oleifera hemicellulose solution and the polyvinyl alcohol solution are mixed, the mass of the polyvinyl alcohol being 30% of the mass of the camellia oleifera hemicellulose, and the mixture is heated and concentrated at 90°C until it becomes a viscous liquid, and the heating is stopped after the mixture is allowed to stand at room temperature for 20 min to degas. The mixture is cast into a camellia oleifera hemicellulose-polyvinyl alcohol blend film with a thickness of 500 μm, and then dried at 60°C.
[0077] Example 1 The hemicellulose membrane obtained from the oil tea tree is as follows Figure 2 As shown in the figure, the surface is smooth and flat, with good film-forming property and transparency; SEM pictures are shown in Figure 1 As shown in (a), after magnification 1000 times, the surface of the Camellia oleifera hemicellulose membrane is still flat, uniform and continuous. Figure 1 As shown in (b), it can be seen that at the fracture site of the membrane, certain deformations such as folding, stretching, and wrinkling will occur, and there is no direct breakage phenomenon, indicating that the oil tea hemicellulose membrane has certain flexibility and ductility;
[0078] Figure 3 It can be seen that the ultraviolet transmittance of the oil-tea hemicellulose film obtained in Example 1 is always higher than that of dehydroabietic acid (2-methacryloyloxyhexyl) ester, which shows that the introduction of the rosin-based polymer gives the oil-tea hemicellulose polydehydroabietic acid copolymer film good ultraviolet absorption performance; the transmittance is higher than that of oil-tea hemicellulose and dehydroabietic acid hydroxyhexyl ester, which shows that the oil-tea hemicellulose film has certain barrier properties in the ultraviolet light region of 320-400nm;
[0079] Figure 4It can be seen that the polydehydroabietic acid copolymer of Camellia oleifera hemicellulose has a peak at 1725 cm -1 and 1248cm -1 They all have the same absorption peaks, corresponding to C=O and COC in the ester group, and are at 1170-1000cm -1 There is a similar absorption band to xylan, indicating that the dehydroabietic acid copolymer was successfully grafted onto the hemicellulose of Camellia oleifera.
[0080] Figure 5 It can be seen that the T d,5 and T d,max The temperature of the 2-methacryloyloxyhexyl dehydroabietic acid ester was 221℃ and 304℃ respectively. The temperature of the 2-methacryloyloxyhexyl dehydroabietic acid ester was significantly reduced. d,5 (61.5℃) and T d,max (284.1℃) value, and after grafting with polydehydroabietic acid side chain, the polydehydroabietic acid copolymer of tea oil hemicellulose (T d,5 =310.7℃, T d,max =422.5℃) d,5 and T d,max The values increased significantly, indicating that the introduction of dehydroabietic acid monomers significantly improved the thermal stability of Camellia oleifera hemicellulose;
[0081] The camellia oleifera hemicellulose films obtained in Examples 1-6 all have good transparency, thermodynamic stability and ultraviolet absorption performance; the camellia oleifera hemicellulose polydehydroabietic acid copolymer film in Example 7 is relatively thin, and the stability and ultraviolet absorption performance of the obtained camellia oleifera hemicellulose film are deteriorated; the camellia oleifera hemicellulose polydehydroabietic acid copolymer film in Example 8 is relatively thick, and its compatibility with the camellia oleifera hemicellulose-polyvinyl alcohol blended film is deteriorated, and the stability and mechanical properties of the obtained camellia oleifera hemicellulose film are reduced; Comparative Example 1 only uses the camellia oleifera hemicellulose-polyvinyl alcohol blended membrane, and the blended membrane is brittle, easy to break, and has poor mechanical properties.
[0082] Finally, it should be noted that the specific embodiments described herein are merely examples of the spirit of the present invention, and are not intended to limit the implementation methods of the present invention. Those skilled in the art of the present invention may make various modifications or supplements to the described embodiments or replace them in similar ways. It is not necessary and impossible to provide all examples of all implementation methods here. However, these obvious changes or modifications derived from the essential spirit of the present invention still fall within the scope of protection of the present invention, and interpreting them as any additional limitation is contrary to the spirit of the present invention.
Claims
1. A tea tree hemicellulose film, characterized in that The invention comprises a camellia oleifera hemicellulose-polyvinyl alcohol blended membrane and a camellia oleifera hemicellulose polydehydroabietic acid copolymer membrane arranged on the camellia oleifera hemicellulose-polyvinyl alcohol blended membrane.
2. The tea oil hemicellulose film according to claim 1, characterized in that The thickness of the Camellia oleifera hemicellulose-polyvinyl alcohol blended film is 300-800 μm.
3. The tea oil hemicellulose film according to claim 1, characterized in that The thickness of the Camellia oleifera hemicellulose polydehydroabietic acid copolymer film is 400-900 μm.
4. A method for preparing the tea oil hemicellulose film according to claim 1, characterized in that: The following steps are involved: The hemicellulose solution of Camellia oleifera and the polyvinyl alcohol solution are mixed and heated to concentrate, and then allowed to stand for degassing to prepare a casting solution, which is then cast into a film and dried to obtain a Camellia oleifera hemicellulose-polyvinyl alcohol blended film, which is then coated with a Camellia oleifera hemicellulose polydehydroabietic acid copolymer.
5. The preparation method according to claim 4, characterized in that: The mass of polyvinyl alcohol is 20-50% of the mass of hemicellulose of Camellia oleifera.
6. The preparation method according to claim 4, characterized in that: The preparation method of the polydehydroabietic acid copolymer of oil tea hemicellulose comprises the following steps: mixing dehydroabietic acid (2-methacryloyloxyhexyl) ester, oil tea hemicellulose-based initiator, pentamethyldiethylenetriamine and tetrahydrofuran, and then subjecting the mixture to multiple cycles of liquid nitrogen freezing-vacuuming-nitrogen pressurization; adding cuprous bromide, subjecting the mixture to liquid nitrogen freezing-vacuuming-nitrogen pressurization again; and reacting in an oil bath, precipitating and drying.
7. The preparation method according to claim 6, characterized in that: The molar mass of the hemicellulose-based initiator of Camellia oleifera and pentamethyldiethylenetriamine is 0.5-1.5% of the molar mass of dehydroabietic acid (2-methacryloyloxyhexyl) ester; and / or the molar mass of cuprous bromide is 0.5-1.5% of the molar mass of dehydroabietic acid (2-methacryloyloxyhexyl) ester.
8. The preparation method according to claim 6, characterized in that: The preparation method of dehydroabietic acid (2-methacryloyloxyhexyl) ester comprises the following steps: (1) adding oxalyl chloride to a dehydroabietic acid solution, reacting at room temperature for 2 to 5 hours to obtain dehydroabietic acid chloride, adding a mixed solution of 4-dimethylaminopyridine and 1,6-hexanediol, reacting in an oil bath, filtering and precipitating, washing the filtrate and concentrating by rotary evaporation to obtain dehydroabietic acid hydroxyhexyl ester; (2) After mixing hydroxyhexyl dehydroabietic acid, triethylamine, hydroquinone and tetrahydrofuran, add methacryloyl chloride after stirring to dissolve, react at room temperature for 8 to 15 hours, filter and precipitate, wash the filtrate and concentrate it by rotary evaporation.
9. The preparation method according to claim 8, characterized in that: In step (2), the molar mass of triethylamine is 2.0 to 3.0 times the molar mass of hydroxyhexyl dehydroabietic acid; and / or the molar mass of hydroquinone is 0.3 to 0.6% of the molar mass of hydroxyhexyl dehydroabietic acid.
10. The preparation method according to claim 6, characterized in that: The preparation method of a hemicellulose-based initiator of Camellia oleifera comprises the following steps: firstly dissolving Camellia oleifera hemicellulose and 4-dimethylaminopyridine in tetrahydrofuran and placing in an ice water bath at 0-5°C, then adding a mixed solution of 2-bromoisobutyryl bromide and tetrahydrofuran, stirring at room temperature for reaction for 20-30 hours, then washing, filtering and vacuum drying.