Epoxy silane coupling agent modified fly ash / polyurethane composite material and preparation method thereof

Abstract

The invention provides an epoxy silane coupling agent modified fly ash / polyurethane composite material and a preparation method thereof, and belongs to the technical field of polymer composite materials. Comprising the following steps: preparing an ethanol water solution, and adding an epoxy silane coupling agent to prepare an epoxy silane coupling agent solution; putting the fly ash into a high-speed stirrer, spraying the epoxy silane coupling agent solution to the surface of the fly ash in batches, stirring at a high speed, drying, and ball-milling to obtain epoxy group functionalized fly ash, namely modified fly ash; uniformly mixing polyether glycol, polyether triol and modified fly ash to obtain a component A, adding a catalyst into isocyanate, and uniformly mixing to obtain a component B; the modified fly ash / polyurethane composite material is obtained by mixing and uniformly stirring the two components, and standing and curing. According to the invention, a stable chemical bond is formed by an epoxy group and active hydrogen in polyurethane, so that the problem that the existing fly ash / polyurethane composite material is insufficient in adhesive property after being modified by a conventional silane coupling agent is solved.

Description

Technical Field

[0001] The invention relates to the technical field of polymer composite materials, in particular to an epoxy silane coupling agent modified fly ash / polyurethane composite material and a preparation method thereof. Background Art

[0002] At present, the treatment and recycling of fly ash has become an important issue in the field of environmental protection and renewable resource development. However, the comprehensive application of fly ash is still mainly concentrated in construction and road engineering, and its utilization rate is less than 50%. How to increase the utilization rate of fly ash and develop other application methods of fly ash, especially high value-added applications, has become a key issue that urgently needs to be broken through.

[0003] Polyurethane materials are widely used as coatings, adhesives, building materials, paving materials, etc. due to their diverse formulas, adjustable performance, non-toxicity, pollution-free, and durability. Adding inorganic powdered fillers to the polyurethane system can not only effectively reduce costs, but also greatly improve and enhance certain properties of the material. Fly ash has stable mechanical properties after high-temperature combustion, and its compatibility with high-molecular polymers is significantly improved after surface modification, so it can be added to polyurethane as a filler. For example, publication number CN108299619B discloses a method for preparing a single-component polyurethane coating by using coupling agent-modified fly ash. The fly ash modified by coupling agent KH570 is used to effectively improve the elongation at break, tensile strength, tear strength, stability, and film-forming properties of the single-molecule polyurethane coating. For example, publication number CN103012738B discloses a modified fly ash reinforced rigid polyurethane foam material and a preparation method thereof, wherein fly ash is modified with a composite silane coupling agent (two or more of titanate, aluminate, phosphate, and borate), thereby effectively improving the mechanical properties and heat resistance of the polyurethane foam material.

[0004] However, in the existing technical solutions, the application of fly ash in the polyurethane system mostly adopts conventional silane coupling agents (such as amino, mercaptosilane) or composite silane coupling agents, but the improvement of bonding performance is limited, especially it is difficult to meet the demand for high adhesion to multiple substrates in the fields of adhesives, structural reinforcement, etc. Summary of the invention

[0005] In order to overcome the shortcomings of the prior art, the purpose of the present invention is to provide an epoxy silane coupling agent modified fly ash / polyurethane composite material and a preparation method thereof, which forms a stable chemical bond between the epoxy group and the active hydrogen in the polyurethane, thereby solving the problem that the existing fly ash / polyurethane composite material has insufficient bonding performance after being modified with a conventional silane coupling agent. The bonding strength is improved by 10% to 30% compared with conventional silane modification, so that the obtained composite material has good adhesion to various substrates such as stone and glass, and the preparation method is simple, low in cost, and high in fly ash utilization, and is suitable for the fields of adhesives, building reinforcement, etc.

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

[0007] A preparation method of an epoxy silane coupling agent modified fly ash / polyurethane composite material, comprising the following steps:

[0008] S1. Prepare an ethanol aqueous solution, and add an epoxy silane coupling agent to the ethanol aqueous solution to prepare an epoxy silane coupling agent solution;

[0009] S2. Place fly ash in a high-speed mixer, and spray the epoxy silane coupling agent solution onto the surface of the fly ash in portions. After high-speed stirring, dry and ball mill to obtain epoxy-functionalized fly ash, that is, modified fly ash;

[0010] S3. Mix polyether diol, polyether triol and the modified fly ash uniformly to obtain component A, and add a catalyst to the isocyanate and mix uniformly to obtain component B;

[0011] S4. Mix and stir component A and component B uniformly, and stand for curing to obtain a modified fly ash / polyurethane composite material.

[0012] Preferably, in step S1, the volume ratio of the ethanol aqueous solution is 9:1, and the epoxy silane coupling agent is added to the ethanol aqueous solution to prepare an epoxy silane coupling agent solution with a concentration of 1 g / mL.

[0013] Preferably, in step S1, the epoxy silane coupling agent is one of 3-(2,3-epoxypropoxy)propyltrimethoxysilane KH560, 3-(2,3-epoxypropoxy)propyltriethoxysilane KH561, 3-(2,3-epoxypropoxy)propylmethyldimethoxysilane KH562 or 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane KH563.

[0014] Preferably, in step S2, the high-speed stirring time is 10 - 30 min, and the ball milling process is: ball milling in a ball mill at a rotation speed of 400 - 600 rpm for 0.5 - 1.5 h.

[0015] Preferably, in step S3, the mass ratio of the polyether diol, polyether triol and modified fly ash is 20:(30 - 35):(10 - 36); the mass ratio of the isocyanate to the catalyst is (45 - 68):0.15.

[0016] Preferably, in step S3, the polyether diol is one of PPG-2000 with a hydroxyl value of 55 ± 10 or PPG-1000 with a hydroxyl value of 110 ± 10, and the polyether triol is RT-305 with a hydroxyl value of 300 ± 70.

[0017] Preferably, in step S3, the isocyanate is one of polymethylene polyphenyl isocyanate, toluene diisocyanate or diphenylmethane diisocyanate.

[0018] Preferably, in step S3, the catalyst is an organotin catalyst, and the organotin catalyst is one or a combination of two of dibutyltin dilaurate or stannous octoate.

[0019] Preferably, in step S4, the mass ratio of component A to component B is (33 - 37):(13 - 17).

[0020] The present invention also provides a modified fly ash / polyurethane composite material prepared by the above preparation method.

[0021] According to the specific embodiments provided by the present invention, the following technical effects are disclosed:

[0022] The present invention modifies fly ash with a silane coupling agent containing glycidyloxy groups, and the epoxy groups form chemical bonds with the active hydrogens (-NH, -OH) in polyurethane. Compared with the prior art, the bonding strength is increased by 10% - 30%, significantly improving the bonding performance of the composite material.

[0023] (1) The present invention selects long-chain polyether diols with a molecular weight exceeding 1000 as the soft segment, and jointly prepares a polyurethane matrix with the crosslinking sites provided by polyether triols. The long-chain polyether diols endow polyurethane with flexibility due to their own long-chain structure; multiple hydroxyl groups in polyether triols form urethane bonds when reacting with isocyanates, constructing a stable three-dimensional network structure to provide strength for the material; while fly ash, as a reinforcing filler, has hard and brittle characteristics. When the two are combined, the flexible chain segments of long-chain polyether diols can buffer stress and reduce the internal stress concentration in the matrix caused by the hard and brittle nature of fly ash, thus generating a synergistic effect, enabling better combination of the matrix and the filler and making up for the deficiencies in the performance of fly ash itself.

[0024] (3) The composite material provided by the present invention has good adhesion to various different substrates such as stone and glass, expanding its applications in fields such as adhesives and reinforcement materials; moreover, the dry modification operation is simple, the utilization rate of fly ash is high, and it is easy to realize industrialization, meeting the requirements for the resource recovery of coal-based solid wastes. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0026] Figure 1 This is a flow chart of a preparation method of an epoxy silane coupling agent modified fly ash / polyurethane composite material of the present invention;

[0027] Figure 2 This is a comparison chart of the bonding strengths of fly ash / polyurethane composite materials modified with different silane coupling agents provided by an embodiment of the present invention; wherein, the abscissa represents different material systems, namely corresponding Comparative Example 1, Comparative Example 2, Comparative Example 3, Example 2, Example 4, Example 5, and Example 6; the ordinate is the bonding strength, with the unit of MPa. Detailed implementation manners

[0028] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0029] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific implementation manners.

[0030] As Figure 1 shown, the present invention provides a preparation method of an epoxy silane coupling agent modified fly ash / polyurethane composite material, including the following steps:

[0031] S1. Prepare an ethanol aqueous solution, and add an epoxy silane coupling agent to the ethanol aqueous solution to prepare an epoxy silane coupling agent solution;

[0032] S2. Place fly ash in a high-speed mixer, and spray the epoxy silane coupling agent solution onto the surface of the fly ash in portions. After high-speed stirring, dry and ball mill to obtain epoxy-functionalized fly ash, that is, modified fly ash;

[0033] S3. Mix polyether diol, polyether triol with the modified fly ash evenly to obtain Component A, and add a catalyst to the isocyanate and mix evenly to obtain Component B;

[0034] S4. Mix Component A and Component B and stir evenly, and let it stand for curing to obtain a modified fly ash / polyurethane composite material.

[0035] Among them, in step S1, the preparation volume ratio of the ethanol aqueous solution is 9:1. The epoxy silane coupling agent is added to the ethanol aqueous solution to prepare an epoxy silane coupling agent solution with a concentration of 1 g / mL. The epoxy silane coupling agent is one of 3-(2,3-epoxypropoxy)propyltrimethoxysilane KH560, 3-(2,3-epoxypropoxy)propyltriethoxysilane KH561, 3-(2,3-epoxypropoxy)propylmethyldimethoxysilane KH562, or 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane KH563.

[0036] In step S2, the high-speed stirring time is 10 - 30 min. The ball milling process is as follows: ball milling in a ball mill at a rotation speed of 400 - 600 rpm for 0.5 - 1.5 h.

[0037] In step S3, the mass ratio of the polyether diol, polyether triol, and modified fly ash is 20:(30 - 35):(10 - 36); the mass ratio of the isocyanate to the catalyst is (45 - 68):0.15. The polyether diol is one of PPG-2000 with a hydroxyl value of 55 ± 10 or PPG-1000 with a hydroxyl value of 110 ± 10. The polyether triol is RT-305 with a hydroxyl value of 300 ± 70. The isocyanate is one of polymethylene polyphenyl isocyanate, toluene diisocyanate, or diphenylmethane diisocyanate. The catalyst is an organotin catalyst, and the organotin catalyst is one or a combination of two of dibutyltin dilaurate or stannous octoate.

[0038] In step S4, the mass ratio of component A to component B is (33 - 37):(13 - 17).

[0039] In addition, in the above content, first, the ethanol aqueous solution is used as a solvent, which helps to disperse the epoxy silane coupling agent so that it can act on the fly ash uniformly. After spraying this solution onto the fly ash surface in portions and then performing high-speed stirring, it can promote the full contact between the epoxy silane coupling agent and the fly ash surface. In the presence of water, the siloxane groups in the epoxy silane coupling agent molecules will undergo hydrolysis reactions to generate silanol groups. These silanol groups can undergo condensation reactions with the hydroxyl groups on the fly ash surface to form stable siloxane bonds, thereby chemically bonding the epoxy silane coupling agent to the fly ash surface. Second, the polyether diol provides flexible segments, endowing the polyurethane with good flexibility; the polyether triol provides crosslinking sites, enabling the polyurethane to form a three-dimensional network structure and enhancing the strength and stability of the material. The modified fly ash is added as a filler, which can not only reduce costs but also utilize the epoxy groups on its surface to undergo chemical reactions with the active hydrogens in the polyurethane, enhancing the interfacial bonding force. Third, the organotin catalyst can significantly accelerate the reaction rate between the isocyanate and the hydroxyl group. When component A and component B are mixed, the isocyanate groups will undergo stepwise addition polymerization reactions with the hydroxyl groups in the polyether diol and polyether triol to form urethane bonds, constructing the macromolecular network structure of the polyurethane. At the same time, the epoxy groups on the surface of the modified fly ash will undergo ring-opening reactions with the active hydrogens in the polyurethane to form chemical bond connections, binding the fly ash in the polyurethane matrix. Finally, during the static curing process, the reaction continues, further improving the polyurethane network, and ultimately obtaining a modified fly ash / polyurethane composite material with excellent properties.

[0040] The following further elaborates on the present invention through specific embodiments.

[0041] Example 1

[0042] In this example, the preparation method of the epoxy silane coupling agent-modified fly ash / polyurethane composite material includes the following steps:

[0043] (1) Surface modification of fly ash: Prepare an ethanol aqueous solution with a volume ratio of 9:1, and then add the epoxy silane coupling agent KH560 to the ethanol aqueous solution to prepare an epoxy silane coupling agent solution with a concentration of 1 g / mL. Place the fly ash in a high-speed mixer, spray the epoxy silane coupling agent solution onto the fly ash surface in portions, dry the modified fly ash after high-speed stirring for 10 min, and ball-mill it at 400 rpm in a ball mill for 0.5 h to obtain dry-modified fly ash.

[0044] (2) Mix polyether diol PPG1000, polyether triol RT305 and the modified fly ash evenly according to a mass ratio of 4:7:2 to obtain Component A; add stannous octoate as a catalyst to toluene diisocyanate, and mix evenly to obtain Component B, where the mass ratio of the isocyanate to the catalyst is 34:0.15; stir and mix Component A and Component B evenly according to a mass ratio of 33:17, and then let it stand and cure to obtain the modified fly ash / polyurethane composite material.

[0045] Example 2

[0046] In this example, the preparation method of the epoxy silane coupling agent modified fly ash / polyurethane composite material includes the following steps:

[0047] (1) Surface modification of fly ash: Prepare an ethanol aqueous solution with a volume ratio of 9:1, and then add epoxy silane coupling agent KH560 to the ethanol aqueous solution to prepare an epoxy silane coupling agent solution with a concentration of 1 g / mL. Place the fly ash in a high-speed mixer, spray the epoxy silane coupling agent solution onto the surface of the fly ash in portions, dry the modified fly ash after high-speed stirring for 20 min, and mill it in a ball mill at 400 rpm for 1 h to obtain dry-modified fly ash.

[0048] (2) Mix polyether diol PPG2000, polyether triol RT305 and the modified fly ash evenly according to a mass ratio of 19:31:20 to obtain Component A; add stannous octoate as a catalyst to toluene diisocyanate, and mix evenly to obtain Component B, where the mass ratio of the isocyanate to the catalyst is 34:0.15; stir and mix Component A and Component B evenly according to a mass ratio of 7:3, and then let it stand and cure to obtain the modified fly ash / polyurethane composite material.

[0049] Example 3

[0050] In this example, the preparation method of the epoxy silane coupling agent modified fly ash / polyurethane composite material includes the following steps:

[0051] (1) Surface modification of fly ash: Prepare an ethanol aqueous solution with a volume ratio of 9:1, and then add epoxy silane coupling agent KH560 to the ethanol aqueous solution to prepare an epoxy silane coupling agent solution with a concentration of 1 g / mL. Place the fly ash in a high-speed mixer, spray the epoxy silane coupling agent solution onto the surface of the fly ash in portions, dry the modified fly ash after high-speed stirring for 30 min, and mill it in a ball mill at 600 rpm for 1.5 h to obtain dry-modified fly ash.

[0052] (2) Mix polyether diol PPG2000, polyether triol RT305 and the modified fly ash evenly according to a mass ratio of 17:27:30 to obtain Component A; add a compound catalyst to toluene diisocyanate, where the mass ratio of dibutyltin dilaurate to stannous octoate is 1:1, and after mixing evenly, obtain Component B. The mass ratio of the isocyanate to the catalyst is 26:0.15; stir and mix Component A and Component B evenly according to a mass ratio of 37:13, and then stand for curing to obtain a modified fly ash / polyurethane composite material.

[0053] Example 4

[0054] In this example, the difference from Example 2 is that the epoxy silane coupling agent is replaced by KH561, and the remaining steps are the same as those in Example 2.

[0055] Example 5

[0056] In this example, the difference from Example 2 is that the epoxy silane coupling agent is replaced by KH562, and the remaining steps are the same as those in Example 2.

[0057] Example 6

[0058] In this example, the difference from Example 2 is that the epoxy silane coupling agent is replaced by KH563, and the remaining steps are the same as those in Example 2.

[0059] Comparative Example 1

[0060] In this comparative example, no fly ash is added during the preparation process. Only mix polyether diol PPG2000 and polyether triol RT305 evenly according to a mass ratio of 12:19 to obtain Component A; add the catalyst dibutyltin dilaurate to polymethylene polyphenyl isocyanate, and after mixing evenly, obtain Component B. The mass ratio of the isocyanate to the catalyst is 38:0.15; stir and mix Component A and Component B evenly according to a mass ratio of 31:19, and then stand for curing to obtain a pure polyurethane material.

[0061] Comparative Example 2

[0062] In this comparative example, the difference from Example 2 is that the KH560-modified fly ash is replaced by unmodified fly ash, and the remaining preparation steps are the same as those in Example 2.

[0063] Comparative Example 3

[0064] In this comparative example, the difference from Example 2 is that the epoxy group-containing silane coupling agent KH560 is replaced by the epoxy group-free silane coupling agent 3-aminopropyltriethoxysilane KH550, and the remaining preparation steps are the same as those in Example 2.

[0065] According to the above, the prepared composite materials were tested for their tensile strength, compressive strength, and bond strength in accordance with the standards GB / T7124—2008 and GB / T528—2009. The mechanical property data obtained are shown in Table 1 as follows:

[0066] Table 1 Mechanical Property Data of Materials

[0067] Tensile strength / MPa Compressive strength / MPa Bonding strength / MPa Example 1 15 90 8 Example 2 23 137 13 Example 3 18 119 10 Example 4 22 135 12 Example 5 20 125 11 Example 6 19 123 11 Comparative example 1 13 64 8 Comparative example 2 16 94 9 Comparative example 3 22 135 10

[0068] As can be seen from Table 1, the epoxy silane coupling agent-modified fly ash / polyurethane composite materials prepared by the present invention have significant advantages in mechanical properties. The tensile strength of Examples 1 to 6 ranges from 15 to 23 MPa, the compressive strength ranges from 90 to 137 MPa, and the bond strength ranges from 8 to 13 MPa. For Comparative Example 1, the tensile strength is only 13 MPa, the compressive strength is 64 MPa, and the bond strength is 8 MPa. Comparative Examples 2 and 3 are also lower than most of the examples in terms of various mechanical property indexes. This indicates that the composite materials prepared by modifying fly ash with epoxy silane coupling agent have a significant improvement in strength compared with the polyurethane materials without adding modified fly ash and the composite materials without using the modification method of the present invention, further proving that the technical solution of the present invention can effectively enhance the mechanical properties of the materials.

[0069] In addition, the present invention also carried out adhesion tests on the composite materials prepared in Example 2, Examples 4 to 6, and Comparative Examples 1 to 3 on different substrates. The test data obtained are shown in Table 2 as follows:

[0070] Table 2 Adhesion Test Data

[0071]

[0072] Based on Table 2, it can be seen that, represented by Example 2, Example 4, Example 5, and Example 6, the composite materials have good adhesion to various substrates such as glass, pine wood, granite, stainless steel, polytetrafluoroethylene, and polypropylene. For example, the adhesion of Example 2 to glass reaches 4.93 MPa, and to granite is 5.68 MPa. While the adhesion of Comparative Examples 1 to 3 to each substrate is generally low. For example, the adhesion of Comparative Example 2 to glass is only 2.78 MPa. This fully shows that the composite materials of the present invention far exceed the comparative materials in terms of multi-substrate adhesion performance and can meet the requirements of high adhesion to multi-substrates in fields such as adhesives and building reinforcement.

[0073] At the same time, referring to Figure 2, Comparative Example 1 is a polyurethane material without added modified fly ash, and its bonding strength is 8 MPa. For Examples 2, 4, 5, and 6 prepared by modifying fly ash with epoxy silane coupling agent, the bonding strengths are 13 MPa, 12 MPa, 11 MPa, and 11 MPa respectively, which are significantly higher than that of Comparative Example 1. Furthermore, it shows that for the polyurethane composite material prepared by modifying fly ash with epoxy silane coupling agent in the present invention, compared with the polyurethane material without added modified fly ash, the bonding strength is significantly improved, verifying the effectiveness of this modification method in enhancing the bonding performance. In addition, Comparative Example 2 and Comparative Example 3 respectively represent materials that do not adopt the specific modification method of the present invention, and their bonding strengths are 9 MPa and 10 MPa respectively, still lower than those of Examples 2-6. It further illustrates that the scheme of modifying with epoxy silane coupling agent in the present invention is superior to other materials that do not adopt this specific modification method in terms of improving the bonding strength. At the same time, Examples 2, 4, 5, and 6 respectively use different epoxy silane coupling agents to modify fly ash, and there are differences in their bonding strengths, which also indicates that even if all use epoxy silane coupling agent for modification, due to the differences in the chemical structures and activity characteristics of different coupling agents, the interaction modes and degrees with fly ash and polyurethane matrix are also different, and thus have different degrees of influence on the final bonding performance of the composite material.

[0074] Therefore, by using the above method for preparing a polyurethane composite material modified with an epoxy silane coupling agent and fly ash, stable chemical bonds are formed between the epoxy groups and the active hydrogen in the polyurethane, solving the problem of insufficient bonding performance of the existing fly ash / polyurethane composite material after being modified with a conventional silane coupling agent. The bonding strength is increased by 10% - 30% compared with that of the conventional silane modification, enabling the obtained composite material to have good adhesion to various substrates such as stone and glass. Moreover, the preparation method is simple, the cost is low, and the utilization rate of fly ash is high, which is applicable to fields such as adhesives and building reinforcement.

[0075] In this specification, each example is described in a progressive manner. The key point of each example is to illustrate the differences from other examples. The same or similar parts among the examples can be referred to each other.

[0076] Specific examples are used in this article to elaborate on the principles and implementation manners of the present invention. The descriptions of the above examples are only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A method for preparing an epoxy silane coupling agent modified fly ash / polyurethane composite material, characterized in that: The following steps are involved: S1, preparing an ethanol aqueous solution, and adding an epoxy silane coupling agent to the ethanol aqueous solution to prepare an epoxy silane coupling agent solution; S2, placing fly ash in a high-speed mixer, and spraying the epoxy silane coupling agent solution onto the surface of the fly ash in batches, and drying and ball milling after high-speed stirring to obtain epoxy functionalized fly ash, i.e., modified fly ash; S3, uniformly mixing the polyether diol, the polyether triol and the modified fly ash to obtain component A, and adding a catalyst to the isocyanate and mixing them uniformly to obtain component B; S4, mixing the component A and the component B, stirring them evenly, and standing them to solidify to obtain a modified fly ash / polyurethane composite material.

2. The method for preparing the epoxy silane coupling agent modified fly ash / polyurethane composite material according to claim 1, characterized in that: In step S1, the volume ratio of the ethanol-water solution is 9:1, and the epoxy silane coupling agent is added to the ethanol-water solution to prepare an epoxy silane coupling agent solution with a concentration of 1 g / mL.

3. The method for preparing the epoxy silane coupling agent modified fly ash / polyurethane composite material according to claim 1, characterized in that: In step S1, the epoxy silane coupling agent is one of 3-(2,3-epoxypropoxy)propyltrimethoxysilane KH560, 3-(2,3-epoxypropoxy)propyltriethoxysilane KH561, 3-(2,3-epoxypropoxy)propylmethyldimethoxysilane KH562 or 3-(2,3-epoxypropoxy)propylmethyldiethoxysilane KH563.

4. The method for preparing the epoxy silane coupling agent modified fly ash / polyurethane composite material according to claim 1, characterized in that: In step S2, the high-speed stirring time is 10 to 30 minutes, and the ball milling process is: ball milling in a ball mill at a rotation speed of 400 to 600 rpm for 0.5 to 1.5 hours.

5. The method for preparing the epoxy silane coupling agent modified fly ash / polyurethane composite material according to claim 1, characterized in that: In step S3, the mass ratio of the polyether diol, polyether triol and modified fly ash is 20:(30-35):(10-36); the mass ratio of the isocyanate and the catalyst is (45-68):0.

15.

6. The method for preparing the epoxy silane coupling agent modified fly ash / polyurethane composite material according to claim 5, characterized in that: In step S3, the polyether diol is one of PPG-2000 with a hydroxyl value of 55±10 or PPG-1000 with a hydroxyl value of 110±10, and the polyether triol is RT-305 with a hydroxyl value of 300±70.

7. The method for preparing the epoxy silane coupling agent modified fly ash / polyurethane composite material according to claim 5, characterized in that: In step S3, the isocyanate is one of polymethylene phenyl isocyanate, toluene diisocyanate or diphenylmethane diisocyanate.

8. The method for preparing the epoxy silane coupling agent modified fly ash / polyurethane composite material according to claim 5, characterized in that: In step S3, the catalyst is an organotin catalyst, and the organotin catalyst is one or a combination of dibutyltin dilaurate or stannous octoate.

9. The method for preparing the epoxy silane coupling agent modified fly ash / polyurethane composite material according to claim 1, characterized in that: In step S4, the mass ratio of component A to component B is (33-37):(13-17).

10. A modified fly ash / polyurethane composite material prepared by the method for preparing a fly ash / polyurethane composite material modified by an epoxy silane coupling agent as claimed in any one of claims 1 to 9.

Images