Method for efficiently preparing plantain seed gum-ferulic acid green adhesive

Abstract

The invention discloses a method for efficiently preparing a plantain seed gum-ferulic acid green adhesive, and belongs to the technical field of plantain seed gum-ferulic acid green adhesive preparation processes, plantain seed gum and ferulic acid are used as raw materials, an efficient, simple and convenient grafting reaction can be achieved through the method, and after a sugar-phenol compound (5%) prepared through the method is fully dissolved, the plantain seed gum-ferulic acid green adhesive is obtained. The preparation of the green adhesive can be realized.

Description

Technical Field

[0001] The present invention relates to a preparation process of plantago seed gum-ferulic acid green adhesive, in particular to a method for efficiently preparing plantago seed gum-ferulic acid green adhesive, belonging to the technical field of plantago seed gum-ferulic acid green adhesive preparation process. Background Art

[0002] As a natural water-soluble dietary fiber extracted from the seeds of Plantago asiatica L., plantago seed gum has a unique chemical composition and excellent properties. It is mainly composed of polysaccharide substances such as arabinoxylan, galacturonic acid, rhamnose, galactose and glucose. These polysaccharides endow plantago seed gum with good water solubility, enabling it to disperse and dissolve rapidly in water. At the same time, it also has the characteristic of high viscosity and can form a stable colloidal system in solution, which has important applications in many fields.

[0003] For example, in the food industry, it is often used as a thickener and stabilizer, which can improve the texture and taste of food and extend the shelf life of food; in the pharmaceutical field, due to its good biocompatibility, it can be used to prepare drug sustained-release preparations, control the release rate of drugs, and improve the curative effect of drugs; in the cosmetics industry, it can increase the viscosity of products, improve the stability and user experience of products.

[0004] Ferulic acid is a natural phenolic acid widely present in the plant cell wall.

[0005] It not only has various biological activities such as antioxidant, anti-inflammatory and antibacterial, but also shows unique application value in the field of materials science. The phenolic hydroxyl group and double bond active groups in the molecular structure of ferulic acid enable it to participate in various chemical reactions, providing the possibility for its application in material modification.

[0006] However, there are many problems in the production and use of traditional adhesives at present.

[0007] On the one hand, many commercially available adhesives are based on synthetic materials. During the production process, they often consume a large amount of fossil energy and produce harmful chemical waste, causing serious pollution to the environment.

[0008] On the other hand, some traditional adhesives also have certain limitations in performance, such as insufficient viscosity, limited bonding range, poor water resistance, and it is difficult to meet the increasingly diverse industrial and living needs.

[0009] In the covalent modification technology of polysaccharides and polyphenols, although some studies have tried to combine natural polysaccharides and polyphenols to prepare new materials, the existing methods generally have problems such as harsh reaction conditions, complex operations and low reaction efficiency, and cannot achieve large-scale industrial production. Therefore, a method for efficiently preparing plantago seed gum-ferulic acid green adhesive is designed to solve the above problems. Summary of the Invention

[0010] The main object of the present invention is to provide a method for efficiently preparing a green binder of plantain gum-ferulic acid.

[0011] The object of the present invention can be achieved by adopting the following technical solutions:

[0012] A method for efficiently preparing a green binder of plantain gum-ferulic acid, comprising the following steps:

[0013] Step 1: Dissolve ferulic acid in N,N-dimethylformamide;

[0014] Step 2: Add an appropriate amount of N,N'-diisopropylcarbodiimide to the dissolved ferulic acid solution, wherein the molar ratio of ferulic acid to DIC is 1:1;

[0015] Step 3: After the reaction of the solution in Step 2 is completed, add an appropriate amount of 4-dimethylaminopyridine and react for 30 min, and the molar ratio of ferulic acid to DMAP is 6:5;

[0016] Step 4: Mix the dissolved plantain gum with the solution obtained in Step 3 and react overnight;

[0017] Step 5: After the reaction is completed, add anhydrous ethanol to terminate the reaction, and wash and filter with anhydrous ethanol;

[0018] Step 6: Dry the powder obtained by washing and filtering at low temperature to obtain a sugar-phenol complex;

[0019] Step 7: Dissolve the plantain gum-ferulic acid in deionized water with a mass fraction of 5% wt, stir and dissolve to obtain the green binder of plantain gum-ferulic acid.

[0020] Preferably, the dissolution temperature of ferulic acid in N,N-dimethylformamide in Step 1 is 20-30 °C;

[0021] The stirring speed is 200-300 r / min, and the dissolution time is 30-60 min.

[0022] Preferably, after adding N,N'-diisopropylcarbodiimide in Step 2, the reaction temperature is controlled at 25-35 °C, and the reaction time is 2-3 h.

[0023] Preferably, the concentration of the dissolved plantain gum in Step 4 is 10-20% wt, and the stirring speed during the mixing reaction is 100-150 r / min.

[0024] Preferably, the number of times of washing with anhydrous ethanol in Step 5 is 3-5 times, and the washing time for each time is 10-15 min.

[0025] Preferably, the temperature for low-temperature drying in Step 6 is 40-60°C, and the drying time is 6-10h.

[0026] Preferably, when the adhesive is at 25°C and the shear rate is 10 (1 / s), the viscosity is not less than 5000 mPa·s.

[0027] Preferably, when the adhesive is subjected to a 180° peel adhesion test, at a peel rate of 10 mm / min, on a wood chip with a bonding surface size of 60 cm 2 the maximum tensile force is not less than 50 N, and the tensile endurance time is not less than 30 min.

[0028] Advantageous technical effects of the present invention:

[0029] A method for efficiently preparing a plantain gum-ferulic acid green adhesive provided by the present invention uses plantain gum, which is a natural water-soluble dietary fiber extracted from plantain seeds, and ferulic acid, which is a natural phenolic acid present in plant cell walls. The sources are natural, which makes the prepared adhesive have high safety and good biocompatibility, and can be widely used in fields with high safety requirements, such as food packaging and pharmaceutical product assembly, without harming the human body and the environment.

[0030] The preparation method is simple, efficient, the whole process steps are clear, the reaction conditions are mild, and it does not require complex equipment and harsh conditions, reducing the production cost and technical threshold. For example, in the grafting reaction, using common reagents and conventional reaction temperatures and times can complete the covalent grafting of ferulic acid to plantain gum in a short time, which is suitable for large-scale industrial production and provides a new feasible method for the covalent modification of polyphenols and polysaccharides.

[0031] The prepared sugar-phenol complex has excellent adhesive properties after dissolution. First, it has a high viscosity. In actual use, the high viscosity can ensure that the adhesive fits tightly with the adherend, forming a strong adhesion force to meet the adhesion requirements of various materials. Second, it has a wide adhesion range and can adhere well to materials such as wood chips and colored handmade paper, with rich applicable scenarios. Third, compared with commercially available children's adhesives, it has a small odor and has more advantages in application scenarios sensitive to odors. At the same time, it shows excellent performance in terms of maximum tensile force and tensile endurance time in the tensile test, and the strength and tensile resistance of the bonded wood chips are significantly enhanced, capable of withstanding greater external forces and ensuring the durability of the bonding effect. Description of the Drawings

[0032] Figure 1 is the structural characterization diagram of plantain gum-ferulic acid;

[0033] Figure 2 is the viscosity data diagram of the plantain gum-ferulic acid green adhesive;

[0034] Figure 3Tensile analysis diagram of the plantain gum-ferulic acid green binder;

[0035] Figure 4 Application display diagram of the plantain gum-ferulic acid green binder;

[0036] Figure 5 Odor comparison diagram of the plantain gum-ferulic acid green binder and commercially available binders. Specific implementation manners

[0037] To make the technical solutions of the present invention clearer and more definite to those skilled in the art, the present invention will be further described in detail below in conjunction with embodiments and drawings, but the implementation manners of the present invention are not limited thereto.

[0038] Example 1

[0039] Preparation of a plantain gum-ferulic acid green binder, the specific steps are as follows:

[0040] Prepare experimental equipment and reagents: Select a clean, dry and appropriately sized glass reaction vessel, such as a 500 ml round-bottom flask, and equip it with devices such as a magnetic stirrer, a thermometer, and a reflux condenser.

[0041] Weigh analytical pure ferulic acid, plantain gum, and reagents such as N,N-dimethylformamide (DMF), N,N'-diisopropylcarbodiimide (DIC), 4-dimethylaminopyridine (DMAP), and absolute ethanol.

[0042] Ensure that the experimental environment temperature is stable at about 25 °C and the relative humidity is maintained at 40-60%, so as to reduce the influence of environmental factors on the experiment.

[0043] Dissolution of ferulic acid (S1): Slowly add a precisely weighed amount of ferulic acid to a round-bottom flask containing an appropriate amount of N,N-dimethylformamide (DMF).

[0044] Turn on the magnetic stirrer and set the stirring speed to 250 r / min to fully dissolve the ferulic acid.

[0045] During the dissolution process, use a thermometer to monitor the solution temperature in real time to ensure that the temperature is maintained between 25-30 °C.

[0046] If the temperature is too high or too low, the stirring speed can be appropriately adjusted or cooling / heating measures can be taken.

[0047] Continue stirring for 45 min until the ferulic acid is completely dissolved to form a clear and transparent solution.

[0048] Adding DIC (S2): After the ferulic acid is completely dissolved, accurately measure an appropriate amount of DIC with a pipette according to a molar ratio of ferulic acid to DIC of 1:1, and slowly add it dropwise to the DMF solution of ferulic acid.

[0049] During the dropwise addition, the stirring state was maintained to allow DIC to be fully mixed with the solution. After the dropwise addition was completed, the reaction vessel was placed in an oil bath pot, the oil bath temperature was set to 30°C, and the reaction was continued for 2.5 hours.

[0050] During the reaction, closely observe the changes in color and state of the solution and record any phenomena that may occur.

[0051] Add DMAP and react (S3): When the solution in S2 has completed the reaction (the progress of the reaction can be determined by thin layer chromatography or other suitable analytical methods), accurately weigh an appropriate amount of 4-dimethylaminopyridine (DMAP) according to a molar ratio of ferulic acid to DMAP of 6:5, and add it to the reaction solution.

[0052] The reaction was continued with stirring for 30 min, and the reaction temperature was still maintained at 30°C.

[0053] To ensure sufficient reaction, the stirring speed can be appropriately adjusted to 300r / min.

[0054] Mixing reaction with psyllium gum (S4): In another clean container, psyllium gum is dissolved in an appropriate amount of deionized water to prepare a psyllium gum solution with a concentration of 15%wt.

[0055] After the reaction of S3 is completed, the dissolved psyllium gum solution is slowly poured into the round-bottom flask containing the ferulic acid reaction product and mixed evenly. The reaction vessel is sealed and placed at room temperature to react overnight (about 12 hours). During the reaction process, the reaction vessel is gently shaken at intervals to ensure that the reactants are fully in contact.

[0056] Termination of reaction and washing and filtration (S5): After the reaction is allowed to proceed overnight, an excess of anhydrous ethanol is added to the reaction solution to terminate the reaction.

[0057] At this point, a precipitate will appear in the solution.

[0058] The reaction mixture was transferred to a Buchner funnel and filtered. The precipitate was washed with anhydrous ethanol, using about 50 ml of anhydrous ethanol each time, for a total of 3 washes.

[0059] After each wash, continue to filter until the filtrate is clear.

[0060] Low-temperature drying and product collection (S6): The powder obtained by washing and filtration is transferred to a watch glass, and placed in a vacuum drying oven for low-temperature drying.

[0061] Set the drying oven temperature to 50 °C, the vacuum degree to 0.08 MPa, and the drying time to 8 h.

[0062] After drying is completed, take out the petri dish and wait for the powder to cool to room temperature to obtain the sugar-phenol complex.

[0063] Collect the sugar-phenol complex in a dry and clean sample bottle, label it, and indicate information such as the preparation date and batch number.

[0064] Prepare the green binder (S7): Weigh a certain amount of the sugar-phenol complex and dissolve it in deionized water to prepare a solution with a mass fraction of 5% wt.

[0065] During the dissolution process, use a magnetic stirrer to stir at a stirring speed of 300 r / min until the sugar-phenol complex is completely dissolved to form a uniform and stable psyllium gum-ferulic acid green binder solution.

[0066] Perform FT-IR structural characterization on the prepared sugar-phenol complex, as Figure 1 shown.

[0067] Figure 1 The results show that ferulic acid was successfully grafted onto psyllium gum by this method within a short time, and the amount of grafted ferulic acid is related to the reaction time.

[0068] Example 2

[0069] This example is used to determine the viscosity characteristics of the sugar-phenol complex prepared in S6 of Example 1.

[0070] Experimental instrument preparation: Select a TA DHR-2 rheometer equipped with a stainless steel parallel plate (diameter 25 mm) to ensure that the instrument is calibrated and in normal working condition.

[0071] Before the experiment, set the temperature control system of the rheometer to 25 °C and stabilize it for 30 min to ensure the accuracy of the test environment temperature.

[0072] Sample preparation: Take an appropriate amount of the sugar-phenol complex prepared in Example 1 and prepare a 5% wt green binder solution according to the method of S7 in Example 1. Carefully transfer the solution to the sample stage of the rheometer to ensure that the sample is evenly distributed and there are no bubbles.

[0073] Oscillation sweep measurement: Use the Viscosity Curve mode of the rheometer to perform oscillation sweep measurement in the range of 0.1 to 100 (1 / s).

[0074] During the measurement process, the instrument automatically records the viscosity data of the binder at different shear rates.

[0075] Measure each measurement point stably three times and take the average value as the viscosity value of that point to reduce experimental error.

[0076] Result analysis: The results Figure 2 show that ferulic acid-modified and grafted plantago seed gum can effectively improve the viscosity of plantago seed gum, and the viscosity of the sugar-phenol complex grafted for 10 hours is relatively high.

[0077] It can be seen from the data curve that as the shear rate increases, the viscosity of the adhesive shows a trend of first decreasing and then stabilizing.

[0078] This indicates that the adhesive has certain shear-thinning properties. At low shear rates, the intermolecular interactions are strong and the viscosity is high; while at high shear rates, the molecular chains are stretched and oriented, and the intermolecular forces are weakened, resulting in a decrease in viscosity.

[0079] The viscosity of the sugar-phenol complex grafted for 10 hours is always higher than that of samples with other grafting times throughout the measurement range, which indicates that its molecular structure is more reasonable, forming a more stable network structure, and thus having better adhesive properties.

[0080] Example 3

[0081] This example is used to evaluate the tensile properties of the green adhesive prepared in S7 of Example 1 at a mass fraction of 5% (wt).

[0082] Experimental material preparation: Select wooden chips with uniform texture and flat surface as the base material, cut the wooden chips into a size of 16 cm × 4 cm, ensure that the surface area of each wooden chip is the same, which is 60 cm 2 .

[0083] Slightly polish the surface of the wooden chips with sandpaper to increase the adhesion between the adhesive and the wooden chips. Prepare the green adhesive prepared in Example 1 and a tensile testing machine with an accuracy of 0.1 N.

[0084] Sample preparation: Take an equal amount of the prepared green adhesive and evenly apply it on the bonding surface of the wooden chips using a glass rod, ensuring that the adhesive is evenly distributed and has a uniform thickness.

[0085] After application, press the bonding surfaces of the two wooden chips coated with the adhesive against each other and apply a certain pressure (about 1 kg / cm 2 ) to make the two wooden chips tightly bonded. Place the bonded wooden chips at room temperature and let them stand for 24 h to allow the adhesive to fully cure.

[0086] Tensile test: Install the wooden chip with the green adhesive backing layer on the tensile testing machine and adjust the position of the wooden chip so that its peeling angle relative to the base material is 180°.

[0087] Set the peeling rate of the tensile testing machine to 10 mm / min, start the tensile testing machine to conduct a 180° peeling adhesion test. During the test, the tensile testing machine records the tensile data in real time until the wood chips are completely separated.

[0088] Each sample was tested 5 times, and the average value was taken as the maximum tensile force and tensile endurance time of the sample.

[0089] Result analysis: The results Figure 3 showed that the maximum tensile force and tensile endurance time of the green binder of plantain gum-ferulic acid prepared by this method were significantly better than those of the original sugar, and the strength and tensile resistance of the plantain gum for bonding wood chips were significantly enhanced. Compared with the original sugar, the maximum tensile force of this green binder increased by 300 N, and the tensile endurance time was extended by about 3 / 1 times.

[0090] This indicates that the graft modification of ferulic acid significantly enhanced the adhesion performance of plantain gum, enabling it to withstand greater tensile forces in practical applications and having better usage effects.

[0091] Example 4

[0092] This example is used to evaluate the adhesion comparison between the green binder prepared by S7 in Example 1 and commercially available children's binders.

[0093] Experimental material preparation: Select a variety of commercially available children's binders and colored handmade paper with the same specifications as in Example 3.

[0094] Prepare experimental tools such as scissors and tweezers.

[0095] Sample preparation: Take appropriate amounts of the green binder prepared in Example 1 and various commercially available children's binders respectively, and apply them evenly at the same position on the colored handmade paper, trying to keep the application area and thickness as consistent as possible. 3 samples were prepared for each binder.

[0096] Adhesion test: Press the colored handmade papers coated with the binder together in pairs and gently press to make them adhere tightly.

[0097] Leave the adhered handmade paper at room temperature for 24 h to allow the binder to fully cure.

[0098] Result observation and analysis: The results are as Figure 4 shown. In the application of colored handmade paper, the green binder prepared by this method adhered more tightly.

[0099] It was found through observation that for the handmade paper adhered with the green binder of the present invention, after slight tearing, the paper did not separate, and some of the paper fibers at the adhesion part were intertwined with each other; while for the handmade paper adhered with some commercially available children's binders, it was easy to separate during tearing, and the paper fibers at the adhesion part were not tightly combined.

[0100] This indicates that the green adhesive of the present invention has better adhesion effect in the adhesion application of colored handmade paper and can meet the requirements of higher adhesion strength.

[0101] Example 5

[0102] This example is used to evaluate the odor comparison between the green adhesive prepared from S7 in Example 1 and commercially available children's adhesives.

[0103] Experimental preparation: Prepare multiple transparent sealed containers of the same specification, and place the green adhesive prepared in Example 1 and various commercially available children's adhesives into different containers respectively, with 3 portions of each adhesive placed to ensure the same sample amount.

[0104] After sealing the containers, place them in an environment with good ventilation and a temperature of 25 °C.

[0105] Odor evaluation: Invite 10 volunteers with normal olfaction to participate in the odor evaluation experiment.

[0106] Before the evaluation, the volunteers need to rinse their mouths with clean water to reduce the influence of oral odor on olfaction.

[0107] Each time, open one container and let the volunteers smell its odor, and score according to the intensity and irritation of the odor. The scoring standard is 1 - 5 points, with 1 point indicating extremely faint odor and no irritation, and 5 points indicating strong and pungent odor.

[0108] Each sample is scored by 10 volunteers respectively, and the average value is taken as the odor score of the sample.

[0109] Result analysis: The results are as Figure 5 shown. In terms of odor, the green adhesive prepared by this method has a very small odor.

[0110] The experimental data shows that the average odor score of the green adhesive of the present invention is about 1.5 points, while the average odor scores of most commercially available children's adhesives are between 3 - 4 points. This indicates that the green adhesive of the present invention has obvious advantages in terms of odor, is more environmentally friendly and healthy, and is more suitable for application scenarios with high odor requirements, such as children's handicrafts, food packaging and other fields.

[0111] The above are only further embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the scope disclosed by the present invention, according to the technical solution and its concept of the present invention, makes equivalent substitutions or changes, all belong to the protection scope of the present invention.

Claims

1. A method for efficiently preparing psyllium gum-ferulic acid green adhesive, characterized in that: The steps include: Step 1: dissolving ferulic acid in N,N-dimethylformamide; Step 2: adding an appropriate amount of N,N'-diisopropylcarbodiimide to the dissolved ferulic acid solution, wherein the molar ratio of ferulic acid to DIC is 1:1; Step 3: After the solution reaction in step 2 is completed, add an appropriate amount of 4-dimethylaminopyridine and react for 30 minutes. The molar ratio of ferulic acid to DMAP is 6:5; Step 4: Mix the dissolved psyllium gum with the solution obtained in step 3 and react overnight; Step 5: After the reaction is completed, add anhydrous ethanol to terminate the reaction, and wash and filter with anhydrous ethanol; Step 6: drying the powder obtained by washing and filtering at low temperature to obtain a sugar-phenol complex; Step 7: dissolving psyllium gum-ferulic acid in deionized water with a mass fraction of 5%wt, stirring and dissolving, thereby obtaining psyllium gum-ferulic acid green adhesive.

2. The method for efficiently preparing the psyllium gum-ferulic acid green adhesive according to claim 1, characterized in that: In the step 1, the dissolution temperature of ferulic acid in N,N-dimethylformamide is 20-30°C; The stirring speed is 200-300r / min and the dissolution time is 30-60min.

3. The method for efficiently preparing the psyllium gum-ferulic acid green adhesive according to claim 2, characterized in that: After adding N,N'-diisopropylcarbodiimide in step 2, the reaction temperature is controlled at 25-35°C and the reaction time is 2-3h.

4. The method for efficiently preparing psyllium gum-ferulic acid green adhesive according to claim 3, characterized in that: The concentration of the dissolved psyllium gum in step 4 is 10-20%wt, and the stirring speed during the mixing reaction is 100-150r / min.

5. The method for efficiently preparing psyllium gum-ferulic acid green adhesive according to claim 4, characterized in that: The number of times of washing with anhydrous ethanol in step 5 is 3-5 times, and the time of each washing is 5-15 minutes.

6. The method for efficiently preparing psyllium gum-ferulic acid green adhesive according to claim 5, characterized in that: The temperature of low temperature drying in step 6 is 40-60° C., and the drying time is 6-10 hours.

7. The method for efficiently preparing psyllium gum-ferulic acid green adhesive according to claim 6, characterized in that: The adhesive has a viscosity of not less than 5000 mPa·s at 25° C. and a shear rate of 10 (1 / s).

8. The method for efficiently preparing psyllium gum-ferulic acid green adhesive according to claim 7, characterized in that: The adhesive was tested for 180° peeling at a rate of 10 mm / min on a bonded surface of 60 cm. 2 On the wood chips, the maximum tensile force is not less than 50N and the tensile time is not less than 30min.

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