A modified plant fiber impact-resistant material and preparation method thereof

Abstract

The present invention belongs to the technical field of impact-resistant materials, and relates to a modified plant fiber impact-resistant material and a preparation method thereof. The raw materials include: modified plant fiber, gel material, glass sand powder and alkali activator; the preparation steps are: uniformly mixing the gel material and glass sand powder to obtain a solid mixture; mixing the solid mixture with the alkali activator to obtain a geopolymer slurry; adding the modified plant fiber to the geopolymer slurry and mixing evenly, and then curing at room temperature to obtain the modified plant fiber impact-resistant material. Compared with conventional impact-resistant materials, the modified plant fiber impact-resistant material of the present invention, which is mainly made of AMIMCl modified straw fiber and KH‑560 modified sawdust fiber or mainly made of AMIMCl modified straw fiber, has higher strength and rigidity under the same quality conditions; good fire resistance, water resistance and air tightness; good thermal insulation performance; safe, fast and green preparation process; good economy and high cost performance.

Description

Technical Field

[0001] The invention relates to the technical field of impact-resistant materials, and in particular to a modified plant fiber impact-resistant material and a preparation method thereof. Background Art

[0002] Since the 1980s, many developing countries have actively explored the use of plant fibers as reinforcement materials for cement-based composites in order to reduce production costs. Although plant fibers have the limitations of relatively low elastic modulus and large strength fluctuations in their natural state, they have shown attractive potential as reinforcement materials due to their significant aspect ratio, lightweight characteristics, high specific strength, wide specific surface area and low cost. This trend is not limited to traditional wood and bamboo, but also includes hemp, coconut shells and various crop straws, all of which can effectively improve the performance of cement-based composites while promoting environmental protection and sustainable development practices.

[0003] However, with the growing market demand for high-performance new building materials, existing technologies have exposed some shortcomings in the application of plant fiber reinforced materials. The first is the problem of interfacial bonding between plant fibers and traditional substrates (such as cement), which directly affects the overall mechanical properties of composite materials, especially in terms of impact resistance. Secondly, natural fibers are easily degraded by environmental factors (such as moisture and microorganisms), which limits their service life and scope of application. In addition, although the awareness of the reuse of plant waste such as straw and sawdust has increased, there is a lack of efficient and environmentally friendly modification and composite technologies in the process of converting them into high-performance building materials, resulting in the finished products often being difficult to meet ideal standards in terms of fire resistance, waterproofness, air tightness and processing convenience.

[0004] Therefore, how to overcome the above challenges, that is, to ensure that plant fiber composites have sufficient strength and toughness while improving their weather resistance, processing efficiency and environmental protection properties, has become a key issue that needs to be solved urgently. Summary of the invention

[0005] The purpose of the present invention is to provide a modified plant fiber impact-resistant material and a preparation method thereof, so as to solve the problems existing in the above-mentioned prior art.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is to provide a modified plant fiber impact-resistant material, the raw materials of which include: modified plant fiber, gel material, glass sand powder and alkali activator;

[0008] The mass ratio of the modified plant fiber, gel material and glass sand powder is 30:40-70:60-30;

[0009] The mass / volume ratio of the sum of the mass of the modified plant fiber and the gel material to the alkali activator is 1 kg:500 mL.

[0010] Furthermore, the modified plant fiber includes AMIMCl modified straw fiber.

[0011] Preferably, the preparation steps of the AMIMCl modified straw fiber include:

[0012] S1, crushing the straw fiber into 20-40 meshes, pre-treating by steaming, blasting and boiling, then performing Soxhlet extraction with water and ethanol in sequence, and then drying to obtain a dry sample;

[0013] S2, adding the dry sample to the ionic liquid AMIMCl at a mass ratio of 1.5:20, stirring at 40-60° C. for 2-3 hours, separating the solid and the liquid, and using a water precipitation method to obtain a fiber sample from the obtained liquid portion;

[0014] S3, boiling the fiber sample in a 2% H2O2 aqueous solution at 50-60°C with stirring for 12 hours, blowing ozone into the sample, filtering the sample, and drying the obtained solid product at 103-107°C;

[0015] S4. Repeat step S3 at least once to obtain AMIMCl modified straw fiber.

[0016] More preferably, the steaming and boiling parameters are: pressure 2.5 MPa, material-liquid ratio 3:1, and time 25 min.

[0017] More preferably, the drying temperature is 103-107°C.

[0018] AMIMCl solution has a strong selective solubility for cellulose other than lignin, and can effectively separate cellulose from steam-exploded pretreated rice straw. Ozone blowing assisted hydrogen peroxide aqueous solution has a significant bleaching effect on crude cellulose, which is more environmentally friendly and efficient than the currently commonly used alkaline activated hydrogen peroxide. In the entire process, no volatile organic solvents are introduced, and the ionic liquid can be recovered by vacuum distillation to remove moisture, and no pollutants are discharged into the environment during the entire process.

[0019] Furthermore, the modified plant fiber also includes AMIMCl modified straw fiber and KH-560 modified sawdust fiber.

[0020] Preferably, the preparation steps of the KH-560 modified sawdust fiber include:

[0021] Sawdust fiber and 50% ethanol aqueous solution were mixed uniformly in a mass ratio of 1:10, the pH value was adjusted to 4, and then the silane coupling agent KH-560 was added. After stirring at 60° C. for 30 minutes, the mixture was allowed to stand for 3 hours, and then washed with water and dried to obtain the KH-560 modified sawdust fiber.

[0022] The purpose of washing with water is to remove excess coupling agent from the fiber surface.

[0023] More preferably, the amount of the silane coupling agent KH-560 added is such that the mass concentration of the silane coupling agent KH-560 added in the system is 1%.

[0024] More preferably, the drying temperature is 103-107°C.

[0025] Preferably, the mass ratio of the AMIMCl modified straw fiber to the KH-560 modified wood chip fiber is 0-30:0-30, and the amount of the AMIMCl modified straw fiber is not zero.

[0026] Furthermore, the gel material comprises, by mass percentage, 20-30% fly ash, 60-70% slag, and 5-10% silica fume.

[0027] Furthermore, the preparation step of the alkaline activator includes: mixing water glass and a NaOH solution with a concentration of 12 mol / L in a mass ratio of 4:6 and then standing for 24 hours to obtain the alkaline activator.

[0028] The second technical solution of the present invention is to provide a method for preparing the above-mentioned modified plant fiber impact-resistant material, the steps comprising:

[0029] Mixing the gel material and the glass sand powder uniformly to obtain a solid mixture;

[0030] mixing the solid mixture with an alkali activator to obtain a geopolymer slurry;

[0031] The modified plant fiber is added into the geopolymer slurry and mixed evenly, and then cured at room temperature to obtain the modified plant fiber impact-resistant material.

[0032] Furthermore, the normal temperature curing time is 28 days.

[0033] The third technical solution of the present invention is to provide an application of the above-mentioned modified plant fiber impact-resistant material in the exterior walls of buildings.

[0034] The fourth technical solution of the present invention is to provide an application of the above-mentioned modified plant fiber impact-resistant material in the interlayer of color steel plate.

[0035] The present invention discloses the following technical effects:

[0036] Compared with conventional impact-resistant materials, the modified plant fiber impact-resistant material with AMIMCl modified straw fiber and KH-560 modified sawdust fiber as main materials or AMIMCl modified straw fiber as main materials has higher strength and rigidity under the same quality conditions; good fire resistance, water resistance and air tightness; good thermal insulation performance; safe, fast and green preparation process; good economy and high cost performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0038] Figure 1 It is a process flow chart of the preparation method of the present invention. DETAILED DESCRIPTION

[0039] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0040] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0041] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0042] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0043] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0044] Unless otherwise specified, room temperature and normal temperature in the present invention refer to 20-30°C.

[0045] In a specific embodiment of the present invention, the straw fiber used is rice straw fiber, with a moisture content of about 10%, dry matter of 91.77%, crude protein of 5.34%, crude fat of 4.73%, crude fiber of 43.56%, nitrogen-free extract of 35.73%, ash of 2.41%, calcium of 0.32%, total phosphorus of 0.12%, and a carbon-nitrogen ratio of 23:1; the sawdust used has a moisture content of about 13%, and crude protein>11%, crude fiber<11%, and crude ash<6%; Al2O3 and SiO2 account for more than 50wt% of the fly ash used, and the specific surface area is 600-800m 2 / kg, 45μm square hole sieve residue is less than 1%; the slag used has a moisture content of 1% and a specific surface area of ​​380-410m 2 / kg; the silica fume particle size is 0.1-0.3 μm, and the specific surface area is 15000-30000m 2 / kg; the specific gravity of the glass sand powder used is 2.42g / cm 3 , bulk density 15g / cm 3 , Mohs hardness 67 Mohs; the water glass Na2O·nSiO2 used has n selected from 1.5 to 3.5, a colorless, translucent glassy liquid with a transparency of ≥82%.

[0046] Figure 1 It is a process flow chart of the preparation method of the present invention.

[0047] The preparation steps of the alkaline activator used in the specific embodiment of the present invention include: dissolving NaOH flakes in water to obtain a 12 mol / L NaOH solution, then mixing water glass with the above NaOH solution in a mass ratio of 4:6, and standing for 24 hours to obtain the alkaline activator.

[0048] In a specific embodiment of the present invention, the preparation steps of the AMIMCl modified straw fiber used include:

[0049] S1, crushing straw fiber (rice straw fiber) to obtain crushed fiber with a particle size of 20 to 40 mesh;

[0050] S2. In an experimental device of a 10L reactor equipped with a quick-opening pneumatic butterfly valve, the crushed fiber was pretreated by steaming, explosion and boiling. The treatment parameters were: pressure 2.5MPa, solid-liquid ratio 3:1 (w / w), time 25min; the straw fiber particles were collected and Soxhlet extracted with water and ethanol in turn, and then dried in an oven at 105±2℃ for 6h to obtain a dry sample;

[0051] S3, adding the dried sample to the ionic liquid AMIMCl at a mass ratio of 1.5:20, stirring magnetically at 40-60°C for 2-3h, filtering out the solid part through a sieve (pore size: 38μm), and then adding sufficient water to precipitate the fiber to obtain a fiber sample;

[0052] S4. The fiber sample was placed in a three-necked flask containing a 2% H2O2 aqueous solution, and steamed at 50-60°C for 12 hours under magnetic stirring while blowing in ozone. After filtering, the straw fiber preparation was dried in an oven at 105±2°C for 12 days. This step was repeated once to obtain AMIMCl modified straw fiber.

[0053] The preparation steps of the KH-560 modified wood fiber used include:

[0054] The sawdust fiber and a 50% ethanol aqueous solution by mass fraction were mixed uniformly in a mass ratio of 1:10, the pH value was adjusted to 4, and then the silane coupling agent KH-560 was added until the mass concentration of the silane coupling agent KH-560 in the system was 1%, and the mixture was stirred at 60° C. for 30 minutes and then allowed to stand for 3 hours, and then the excess coupling agent on the fiber surface was removed by washing with water, and the KH-560 modified sawdust fiber was obtained after drying at 103-107° C.

[0055] Example 1

[0056] The preparation steps of the modified plant fiber impact-resistant material are as follows:

[0057] S1. Raw material preparation: preparing modified plant fiber (KH-560 modified sawdust fiber), gel material and glass sand powder in a mass ratio of 30:70:40, and preparing alkali activator in a mass / volume ratio of the sum of the mass of the modified plant fiber and the gel material to the alkali activator of 1kg:500mL; wherein the gel material is composed of 30% fly ash, 60% slag and 10% silica fume in terms of mass percentage;

[0058] S2, put the slag and fly ash into a mixer, stir at a speed of 200 rpm for 1 min, mix them evenly, then add silica ash and glass sand powder, dry mix and mix to obtain a solid mixture;

[0059] S3, adding an alkali activator to the solid mixture to prepare a geopolymer slurry;

[0060] S4, evenly adding modified plant fiber to the geopolymer slurry, stirring at a speed of 300 rpm for 2 minutes, fully mixing and maintaining the slump at 80 mm, to prepare a modified plant fiber impact-resistant material slurry;

[0061] S5. Inject the modified plant fiber impact-resistant material slurry into a mold, cover the surface with a plastic film, and cure it under normal temperature and humidity conditions for 28 days to obtain the modified plant fiber impact-resistant material.

[0062] Example 2

[0063] Compared with Example 1, the only difference is that the modified plant fiber consists of AMIMCl modified straw fiber and KH-560 modified wood chip fiber in a mass ratio of 7.5:22.5.

[0064] Example 3

[0065] Compared with Example 1, the only difference is that the modified plant fiber consists of AMIMCl modified straw fiber and KH-560 modified sawdust fiber in a mass ratio of 1:1.

[0066] Example 4

[0067] Compared with Example 1, the only difference is that the modified plant fiber consists of AMIMCl modified straw fiber and KH-560 modified wood chip fiber in a mass ratio of 22.5:7.5.

[0068] Example 5

[0069] Compared with Example 1, the only difference is that the modified plant fiber is AMIMCl modified straw fiber.

[0070] Comparative Example 1

[0071] Compared with Example 1, the only difference is that the modified plant fiber is unmodified straw fiber of the same mass.

[0072] Comparative Example 2

[0073] Compared with Example 1, the only difference is that the modified plant fiber is unmodified wood chip fiber of the same mass.

[0074] Comparative Example 3

[0075] Compared with Example 1, the only difference is that no modified plant fiber is added.

[0076] Comparative Example 4

[0077] Compared with Example 1, the only difference is that the modified plant fiber is changed from a single modified sawdust fiber to bamboo fiber of the same mass.

[0078] Comparative Example 5

[0079] Compared with Example 4, the only difference is that unmodified sawdust fibers are used to replace KH-560 modified sawdust fibers, that is, AMIMCl modified straw fibers and unmodified sawdust fibers are used in a mass ratio of 22.5:7.5.

[0080] Test example

[0081] The test blocks with a size of 70.7 mm × 70.7 mm × 70.7 mm were prepared by the preparation methods of Examples 1 to 5 and Comparative Examples 1 to 4. The test blocks were subjected to drop hammer impact according to the drop hammer impact test method recommended by ACI544. The results are shown in Table 1, where N1 is the number of initial cracks; W1 is the impact energy at the initial crack; K1 is the average crack width at the initial crack; N2 is the number of final cracks; W2 is the impact energy at the final crack; and K2 is the average crack width at the final crack.

[0082] Table 1

[0083]

[0084] It can be seen from the experimental results in Table 1 that in Examples 1 to 5, with the increase of modified straw fiber, the number of initial cracks, final cracks, and impact energy consumption of the composite material all increase successively. The impact energy consumption of the composite material shows a trend of first increasing and then decreasing with the increase of the modified straw fiber content. When the modified straw fiber content reaches 22.5 parts, the average number of initial cracks and final cracks of the composite material is the largest, the impact energy consumption is the largest, and the impact resistance is the best. As the modified straw fiber content reaches 30 parts, the impact resistance of the composite material shows a decreasing trend.

[0085] The addition of modified straw fiber plays a bridging role inside the matrix, allowing the fiber and the geopolymer matrix to bear deformation energy together. The addition of modified plant fiber makes up for the internal defects of fine holes produced during the condensation and shrinkage process of the geopolymer matrix. When subjected to external impact, each modified straw fiber is equivalent to a small energy-consuming body, and the modified straw fiber itself has a certain tensile strength and elastic modulus, which will improve the impact resistance of the composite test block; when the matrix cracks, the modified straw fiber plays a crack-blocking effect, the cracks develop slowly, the number of impacts increases, and the impact toughness of the composite material is greatly improved; when the modified straw fiber content exceeds a certain range, there are too many fibers, and the weak layers of the fiber-matrix bonding interface are more, which is not conducive to improving the impact resistance of the composite material.

[0086] Comparative Example 5 uses AMIMCl modified straw fiber and unmodified sawdust fiber in a mass ratio of 22.5:7.5, and Example 4 uses AMIMCl modified straw fiber and KH-560 modified sawdust fiber in a mass ratio of 22.5:7.5. However, it can be seen from the data in Table 1 that when the KH-560 modified sawdust fiber is replaced with the unmodified sawdust fiber, the performance of the impact-resistant material prepared is significantly lower than that of Example 4. It can be seen that the AMIMCl modified straw fiber and the KH-560 modified sawdust fiber in the present application have a synergistic effect on the performance of the impact-resistant material.

[0087] The embodiments described above are only descriptions of the preferred modes of the present invention, and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary technicians in this field should all fall within the protection scope determined by the claims of the present invention.

Claims

1. A modified plant fiber impact-resistant material, characterized in that: The raw materials include: modified plant fiber, gel material, glass sand powder and alkali activator; The mass ratio of the modified plant fiber, gel material and glass sand powder is 30:40~70:60~30; The mass / volume ratio of the sum of the mass of the modified plant fiber and the gel material to the alkali activator is 1kg:500mL; The gel material comprises, by mass percentage, 20-30% fly ash, 60-70% slag, and 5-10% silica ash; The preparation step of the alkaline activator comprises: mixing water glass and a NaOH solution with a concentration of 12 mol / L in a mass ratio of 4:6 and standing for 24 hours to obtain the alkaline activator; The modified plant fibers are AMIMCl modified straw fibers and KH-560 modified sawdust fibers; The mass ratio of AMIMCl modified straw fiber to KH-560 modified sawdust fiber in the modified plant fiber is 0-30:0-30, and the amount of AMIMCl modified straw fiber is not 0; The preparation steps of the AMIMCl modified straw fiber include: S1. The straw fiber is crushed into 20-40 meshes, pre-treated by steaming and boiling, and then Soxhlet extraction is performed with water and ethanol in sequence, and then dried to obtain a dry sample; the steaming and boiling parameters are: pressure 2.5MPa, material-liquid ratio 3:1, time 25min; the drying temperature is 103-107°C; S2, adding the dry sample to the ionic liquid AMIMCl at a mass ratio of 1.5:20, stirring at 40-60° C. for 2-3 hours, separating the solid and the liquid, and using a water precipitation method to obtain a fiber sample from the obtained liquid portion; S3, boiling the fiber sample in a 2% H2O2 aqueous solution at 50-60°C with stirring for 12 hours, blowing ozone into the sample, filtering the sample, and drying the obtained solid product at 103-107°C; S4, repeating step S3 at least once to obtain AMIMCl modified straw fiber; The preparation steps of the modified sawdust fiber include: uniformly mixing sawdust fiber and 50% ethanol aqueous solution at a mass ratio of 1:10, adjusting the pH value to 4, then adding silane coupling agent KH-560, stirring at 60°C for 30 minutes and then standing for 3 hours, then washing with water, and drying to obtain the KH-560 modified sawdust fiber; the amount of the silane coupling agent KH-560 added is such that the mass concentration of the silane coupling agent KH-560 added to the system is 1%; and the drying temperature is 103-107°C.

2. A method for preparing the modified plant fiber impact-resistant material according to claim 1, characterized in that the steps include: Mixing the gel material and the glass sand powder uniformly to obtain a solid mixture; mixing the solid mixture with an alkali activator to obtain a geopolymer slurry; The modified plant fiber is added into the geopolymer slurry and mixed evenly, and then cured at room temperature to obtain the modified plant fiber impact-resistant material.

3. The preparation method according to claim 2, characterized in that: The normal temperature curing time is 28 days.

4. Use of the modified plant fiber impact-resistant material as claimed in claim 1 in building exterior walls.

5. An application of the modified plant fiber impact-resistant material as claimed in claim 1 in the interlayer of color steel plates.

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