Polyurethane composite and use thereof

Abstract

The application provides a polyurethane composite material and application thereof, and relates to the technical field of polyurethane materials. The polyurethane composite material is composed of component A and component B. Raw material components of component A include: 100 parts of polymeric diol, 1-8 parts of chain extender, 1-3 parts of catalyst, 0-5 parts of crosslinking agent, 0.1-2 parts of carbon-based material, 1-10 parts of anthraquinone compound and 0.5-2 parts of water. Component B is an isocyanate curing agent, and contains a prepolymer with multiple ester bonds and urea bonds. The polyurethane composite material has high mechanical strength and wear resistance and the like, and is suitable for treatment of nitrogen-containing sewage.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane materials technology, and relates to a polyurethane composite material and its applications. Background Technology

[0002] Anthraquinone compounds are redox mediators that can be used to treat nitrogenous wastewater, accelerating the denitrification process by microorganisms. To avoid the loss and secondary pollution caused by directly adding anthraquinone compounds to wastewater, they are typically immobilized on a carrier, such as on the surface of the carrier or dispersed within it. Polyurethane, a commonly used polymer material, is characterized by its ease of processing, high flexibility, high mechanical strength, good toughness, good wear resistance, and excellent foaming properties. It is a promising carrier for anthraquinone compounds, capable of supporting various fillers and meeting denitrification requirements. For example, Chinese patent CN119823342A discloses a highly hydrophilic nano-iron-rich polyurethane bio-enrichment filler, which is prepared from the following components in parts by weight: 50-70 parts of liquefied starch alcohol, component A, component B, and 0.2-0.3 parts of nano-iron powder; component A includes: 130-150 parts of polyether polyol, 8-10 parts of foaming agent, 0.7-0.9 parts of foam stabilizer, and 0.1-0.3 parts of gel catalyst; component B includes: 123-125 parts of isocyanate and 0.1-0.3 parts of catalyst.

[0003] For nitrogen removal treatment of nitrogen-containing wastewater, anthraquinone-containing packing materials are required not only to have good denitrification promotion effects but also to have good durability and sustained effectiveness. This places higher demands on the mechanical properties of the packing materials. Therefore, how to stably disperse anthraquinone compounds within polyurethane to better and more persistently exert their denitrification promotion effects remains a challenge. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a polyurethane composite material and its applications.

[0005] The technical solution of the present invention is as follows:

[0006] A polyurethane composite material, comprising component A and component B;

[0007] The raw material components of component A, by weight, include: 100 parts polymer diol, 1-8 parts chain extender, 1-3 parts catalyst, 0-5 parts crosslinking agent, 0.1-2 parts carbon-based material, 1-10 parts anthraquinone compound, and 0.5-2 parts water;

[0008] Component B is an isocyanate curing agent;

[0009] The isocyanate curing agent comprises a prepolymer with the structure shown in formula (1).

[0010] (1)

[0012] Wherein, X is selected from divalent organic groups with a molecular weight of 50-6000 that are reactive with NCO groups at 100℃, R1 and R2 are individually selected from C1-C4 alkyl groups, and R3 and R4 are individually selected from divalent organic groups with a molecular weight of 20-300 that are reactive with NCO groups at 100℃.

[0013] Preferably, the prepolymer accounts for not less than 20% by weight of component B.

[0014] Preferably, the isocyanate curing agent further comprises a diisocyanate monomer and its trimer.

[0015] Preferably, the isocyanate curing agent contains an average of not less than 2 NCO groups.

[0016] Preferably, the chain extender is selected from one or a combination of two or more of 1,2-ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol and 1,3-propanediol.

[0017] The catalyst is selected from dihydroxyalkylamine;

[0018] The crosslinking agent is selected from triethanolamine or triisopropanolamine.

[0019] Preferably, the carbon-based material is selected from one or a combination of two or more of graphene, graphene oxide, and carbon nanotubes.

[0020] Preferably, the structure of the anthraquinone compound is shown in formula (2) below.

[0021] (2)

[0023] R5 and R7 are individually selected from one or more combinations of O, S and NH, while R6 and R8 are individually selected from C1-C6 alkylene groups.

[0024] More preferably, the anthraquinone compound is selected from one or a combination of two or more of 1,4-bis[(2-hydroxyethyl)amino]anthraquinone, 1-[(2-hydroxyethyl)amino]-4-[(3-hydroxypropyl)amino]anthraquinone, 1,4-bis[(3-hydroxypropyl)amino]anthraquinone, 2,5-bis[(3-hydroxypropyl)amino]anthraquinone, 1,8-bis[(3-hydroxypropyl)amino]anthraquinone, 2,5-bis[(2-hydroxyethyl)amino]anthraquinone, 2,6-bis[(2-hydroxyethyl)amino]anthraquinone and 2,6-bis[(3-hydroxypropyl)amino]anthraquinone.

[0025] Preferably, the molar ratio of active hydrogen in component A to NCO groups in component B is 1:1.08-1.2.

[0026] The application of a polyurethane composite material as described in any of the above embodiments for the treatment of nitrogen-containing wastewater.

[0027] The beneficial effects of this invention are:

[0028] (1) The isocyanate curing agent of the present invention contains a prepolymer with multiple ester bonds and urea bonds, which can form more hydrogen bonds, higher polarity and rigidity hard segments in the polyurethane structure, further improve the polarity of hard segments and the microphase separation of hard segments and soft segments, and improve the mechanical strength, wear resistance and other properties of polyurethane, and improve the durability of polyurethane as a filler.

[0029] (2) The hydroxyl groups of the anthraquinone compounds in this invention are not directly linked to the anthraquinone structure. The hydroxyl groups are highly active and can participate well in the reaction of polyurethane and be well dispersed in polyurethane through chemical bonding, thus playing a denitrification promoting role of redox mediator. Detailed Implementation

[0030] The technical solution of the present invention will be further explained and described below through specific embodiments.

[0031] On one hand, this invention proposes a polyurethane composite material in which a prepolymer with an aspartic ester structure is introduced into the isocyanate curing agent. The prepolymer contains multiple ester bonds and urea groups, increasing the hydrogen bonds and polarity of the polyurethane hard segments, thereby improving the microphase separation of the polyurethane soft and hard segments, and consequently enhancing the mechanical strength and wear resistance of the polyurethane. Specifically, the polyurethane composite material of this invention is composed of component A and component B;

[0032] The raw material components of component A, by weight, include: 100 parts polymer diol, 1-8 parts chain extender, 1-3 parts catalyst, 0-5 parts crosslinking agent, 0.1-2 parts carbon-based material, 1-10 parts anthraquinone compound, and 0.5-2 parts water;

[0033] Component B is an isocyanate curing agent;

[0034] The isocyanate curing agent comprises a prepolymer with the structure shown in formula (1) below.

[0035] (1)

[0037] Wherein, X is selected from divalent organic groups with a molecular weight of 50-6000 that are reactive with NCO groups at 100℃, R1 and R2 are individually selected from C1-C4 alkyl groups, and R3 and R4 are individually selected from divalent organic groups with a molecular weight of 20-300 that are reactive with NCO groups at 100℃.

[0038] The prepolymers mentioned above contain multiple ester bonds and urea groups, which increases the hydrogen bonds and polarity of the polyurethane hard segments, improves the rigidity of the polyurethane hard segments and the microphase separation between the soft and hard segments, thereby improving the mechanical strength and wear resistance of the polyurethane. For the X group in the above formula (1), it can be a divalent organic group containing cyclohexyl and the cyclohexyl is directly connected to the N on the urea bond -NCONH-. For example, X can be the divalent organic group remaining after removing two amino groups from diamine compounds containing cyclohexyl such as 4,4'-diaminodicyclohexylmethane, 3,3'-dimethyl-4,4'-diaminodicyclohexylmethane, 1,4-cyclohexyldiamine, 1,3-cyclohexyldiamine, and 2-methyl-1,4-cyclohexyldiamine. The rigidity of the cyclohexyl can further improve the rigidity of the polyurethane hard segments.

[0039] The prepolymer can be obtained by reacting a corresponding polyaspartic ester resin with a diisocyanate monomer. The polyaspartic ester resin can be F420 resin or F520 resin from Feiyang Junyan Company, etc. The diisocyanate monomer can be IPDI, HDMI, HDI, etc. One method for preparing the prepolymer is as follows: Under nitrogen protection and at room temperature, 1 mol of polyaspartic ester resin (e.g., F420 resin) is added to a reaction vessel, and an excess (e.g., 2.2-2.5 mol) of diisocyanate monomer (e.g., IPDI, HDI, etc.) is added dropwise. The reaction temperature is controlled to not exceed 30°C. After the addition is complete, the reaction continues for 2-5 hours. Then, the temperature is raised to 100-120°C and the pressure is reduced to below 10 Pa to remove unreacted diisocyanate monomers, thus obtaining the prepolymer.

[0040] In this invention, there are no particular limitations on the polymer diol, which can be polyether diol, polyester diol, etc. Considering the hydrolysis resistance and elasticity of polyurethane, the polymer diol is preferably a polyether diol, such as polytetrahydrofuran ether diol or polypropylene glycol. Considering the mechanical strength of polyurethane, the polymer diol is preferably a polyester diol, such as polycarbonate diol or polycaprolactone diol. There are no particular limitations on the molecular weight of the polymer diol, and the number average molecular weight can be 500-2000. Since the prepolymer used in this invention can improve the mechanical strength and abrasion resistance of polyurethane, the polymer diol in component A is preferably a polyether diol. The polymer diol can be obtained directly from the market.

[0041] In some embodiments, the prepolymer accounts for at least 20% of the weight of component B. If the weight percentage of the prepolymer in component B is insufficient, the prepolymer cannot effectively perform its function. For example, the weight percentage of the prepolymer in component B can be any value or any value between 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, and 85%, without any particular limitation.

[0042] In some embodiments, the isocyanate curing agent further comprises a diisocyanate monomer and its trimer, for example, IPDI, HMDI, HDI, HDI trimer, IPDI trimer, etc.

[0043] In some embodiments, the average number of NCO groups in the isocyanate curing agent is not less than 2, and can be 2-3, such as 2.1, 2.3, 2.4, 2.5, 2.7, 3, etc. Generally, as the average number of NCO groups in the isocyanate curing agent increases, the crosslinking density of the polyurethane increases. At a suitable crosslinking density, polyurethane exhibits good mechanical strength, abrasion resistance, and other properties. Therefore, the isocyanate curing agent can contain a trimer of diisocyanate monomers, such as IPDI trimer and / or HDI trimer. The weight percentage of the diisocyanate monomer trimer in the isocyanate curing agent can be 10-50%, or further, 10-30% by weight.

[0044] In some embodiments, the chain extender is selected from one or a combination of two or more of 1,2-ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol and 1,3-propanediol; the weight parts of the chain extender may be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, etc.

[0045] The catalyst is selected from dihydroxyalkylamine; the weight parts of the catalyst can be 1 part, 1.5 parts, 2 parts, 2.5 parts, 3 parts, etc.; for example, the catalyst can be dihydroxyethylamine, dihydroxypropylamine, dihydroxybutylamine, etc.

[0046] The crosslinking agent is selected from triethanolamine or triisopropanolamine; the weight parts of the crosslinking agent can be 0 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, etc.

[0047] In some embodiments, the carbon-based material is selected from one or a combination of two or more of graphene, graphene oxide, and carbon nanotubes. The carbon-based material exhibits good electrical conductivity, which is beneficial for electron conduction within the polyurethane, further enhancing the performance of anthraquinone as a redox mediator and further improving its denitrification effect on nitrogen-containing wastewater. The weight percentage of the carbon-based material can be 0.1 parts, 0.2 parts, 0.3 parts, 0.5 parts, 0.8 parts, 1 part, 1.5 parts, 2 parts, etc. Further, the weight percentage of the carbon-based material can be 0.1-1 parts.

[0048] In some embodiments, the structure of the anthraquinone compound is shown in formula (2).

[0049] (2)

[0051] In this composition, R5 and R7 are individually selected from one or more combinations of O, S, and NH, while R6 and R8 are individually selected from C1-C6 alkylene groups. For example, the weight parts of the anthraquinone compound can be 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, 10 parts, etc. Further, the weight parts of the anthraquinone compound can be 2-8 parts.

[0052] Conventional anthraquinone compounds containing active hydrogen, such as 1,5-diaminoanthraquinone, 2,6-diaminoanthraquinone, and 1,8-dihydroxyanthraquinone, have amino or hydroxyl groups directly linked to the anthraquinone structure. Due to the steric hindrance and electron-withdrawing effect of the anthraquinone structure, the amino or hydroxyl groups have low reactivity. This leads to the NCO groups preferentially reacting with other active hydrogen groups after the mixture of components A and B, resulting in low reaction efficiency and poor effect of the anthraquinone compounds, which cannot be well chemically bonded to the polyurethane structure. In this invention, anthraquinone compounds with the structure of the above formula (2) are used. There are intermediate structures -R5R6- and / or -R7R8- between the two terminal hydroxyl groups and the anthraquinone structure. Therefore, the terminal hydroxyl groups are less affected by the steric hindrance and electron-withdrawing effect of the anthraquinone structure, and the terminal hydroxyl groups have higher reactivity. The anthraquinone compounds can participate in the reaction of polyurethane more fully and uniformly. Therefore, using the anthraquinone compounds shown in the above formula (2) can improve the dispersibility and dispersion stability of anthraquinone compounds in polyurethane and effectively prolong the duration of the denitrification promoting effect of foamed polyurethane.

[0053] In some embodiments, the anthraquinone compound is selected from one or a combination of two or more of 1,4-bis[(2-hydroxyethyl)amino]anthraquinone, 1-[(2-hydroxyethyl)amino]-4-[(3-hydroxypropyl)amino]anthraquinone, 1,4-bis[(3-hydroxypropyl)amino]anthraquinone, 2,5-bis[(3-hydroxypropyl)amino]anthraquinone, 1,8-bis[(3-hydroxypropyl)amino]anthraquinone, 2,5-bis[(2-hydroxyethyl)amino]anthraquinone, 2,6-bis[(hydroxyethyl)amino]anthraquinone, and 2,6-bis[(3-hydroxypropyl)amino]anthraquinone. The above anthraquinone compounds contain four active hydrogen atoms. The two active hydrogen atoms on the secondary amino group are subject to greater steric hindrance and stronger electron-withdrawing effects due to the anthraquinone structure, resulting in lower reactivity. The two active hydrogen atoms on the hydroxyl group are subject to less steric hindrance and weaker electron-withdrawing effects due to the anthraquinone structure, resulting in higher reactivity. Therefore, the anthraquinone compound shown in formula (2) contains two highly active terminal hydroxyl groups, which can react quickly with the isocyanate curing agent, thus avoiding different reaction results of different raw material components due to the different activity of active hydrogen in the raw material components of component A.

[0054] In some embodiments, the molar ratio of active hydrogen in component A to NCO groups in component B is 1:1.08-1.2. For example, the molar ratio can be any value or any value between 1:1.08, 1:1.1, 1:1.12, 1:1.15, 1:1.17, 1:1.2, etc., without any particular limitation.

[0055] On the other hand, the present invention also proposes an application of the polyurethane composite material described in any of the above embodiments for the treatment of nitrogen-containing wastewater. Nitrogen pollutants in nitrogen-containing wastewater include nitrates, nitrites, organic dyes, etc.

[0056] The technical solution of the present invention will be further described and illustrated below with reference to various embodiments. Unless otherwise specified, the parts mentioned in the following embodiments are parts by weight.

[0057] Example 1

[0058] The raw material components of component A include: 100 parts polytetrahydrofuran ether diol (number average molecular weight 1200), 3 parts 1,4-butanediol, 1.5 parts dihydroxyethylamine, 0.3 parts single-walled carbon nanotubes (SWNT), 4 parts 2-methylanthraquinone, and 1 part water.

[0059] Component B is an isocyanate curing agent, composed of prepolymer, HDI, and HDI trimer in a weight ratio of 2:6:2.

[0060] The structure of the prepolymer is shown in formula (1) above. It is prepared by mixing F420 resin and HDI in a molar ratio of 1:2.3 according to the aforementioned method for preparing the prepolymer.

[0061] The molar ratio of active hydrogen in component A to NCO groups in component B is 1:1.1.

[0062] The raw material components of component A are mixed and dispersed uniformly at high speed to obtain component A. Component A and component B are then mixed uniformly to obtain the polyurethane composite material.

[0063] Comparative Example 1

[0064] The difference between this comparative example and Example 1 is that in Example 1, the prepolymer was replaced with an equal weight of HDI. The remaining steps remain unchanged.

[0065] Comparative Example 2

[0066] The difference between this comparative example and Example 1 is that in Example 1, the prepolymer was replaced with an equal weight of HDI trimer. The remaining steps remained unchanged.

[0067] Example 2

[0068] The difference between this embodiment and Example 1 is that in Example 1, 2-methylanthraquinone was replaced with an equal weight of 2,6-diaminoanthraquinone. The remaining steps remain unchanged.

[0069] Example 3

[0070] The difference between this embodiment and Example 1 is that in Example 1, 2-methylanthraquinone was replaced with an equal weight of 1,4-bis[(2-hydroxyethyl)amino]anthraquinone. The remaining steps remained unchanged.

[0071] Example 4

[0072] The difference between this embodiment and Example 3 is that in Example 3, the amount of 1,4-bis[(2-hydroxyethyl)amino]anthraquinone was increased from 2 parts to 8 parts. The remaining steps remained unchanged.

[0073] Example 5

[0074] The raw material components of component A include: 100 parts polytetrahydrofuran ether diol (number average molecular weight 1000), 4 parts ethylene glycol, 2 parts dihydroxyethylamine, 1 part triethanolamine, 0.5 parts single-walled carbon nanotubes (SWNT), 5 parts 1,4-bis[(2-hydroxyethyl)amino]anthraquinone, and 1.2 parts water.

[0075] Component B is an isocyanate curing agent, composed of prepolymer, HDI, and HDI trimer in a weight ratio of 5:3:2.

[0076] The structure of the prepolymer is shown in formula (1) above. It is prepared by mixing F520 resin and IPDI in a molar ratio of 1:2.2 according to the aforementioned method for preparing the prepolymer.

[0077] The molar ratio of active hydrogen in component A to NCO groups in component B is 1:1.15.

[0078] The raw material components of component A are mixed and dispersed uniformly at high speed to obtain component A. Component A and component B are then mixed uniformly to obtain the polyurethane composite material.

[0079] Example 6

[0080] The raw material components of component A include: 100 parts polytetrahydrofuran ether diol (number average molecular weight 1000), 4 parts ethylene glycol, 2 parts dihydroxyethylamine, 1 part triethanolamine, 0.5 parts single-walled carbon nanotubes (SWNT), 5 parts 1,4-bis[(2-hydroxyethyl)amino]anthraquinone, and 1.2 parts water.

[0081] Component B is an isocyanate curing agent, composed of prepolymer, HDI, and HDI trimer in a weight ratio of 5:3:2.

[0082] The structure of the prepolymer is shown in formula (1) above, where X is the divalent organic group remaining after removing two amino groups from p-phenylenediamine. It is prepared by the corresponding polyaspartic acid ester resin and IPDI in a molar ratio of 1:2.2 according to the aforementioned prepolymer preparation method.

[0083] The molar ratio of active hydrogen in component A to NCO groups in component B is 1:1.15.

[0084] The raw material components of component A are mixed and dispersed uniformly at high speed to obtain component A. Component A and component B are then mixed uniformly to obtain the polyurethane composite material.

[0085] Example 7

[0086] The raw material components of component A include: 100 parts polytetrahydrofuran ether diol (number average molecular weight 1000), 4 parts ethylene glycol, 2 parts dihydroxyethylamine, 1 part triethanolamine, 0.5 parts single-walled carbon nanotubes (SWNT), 5 parts 1,4-bis[(2-hydroxyethyl)amino]anthraquinone, and 1.2 parts water.

[0087] Component B is an isocyanate curing agent, composed of prepolymer, HDI, and HDI trimer in a weight ratio of 5:3:2.

[0088] The structure of the prepolymer is shown in formula (1) above, where X is the divalent organic group remaining after removing two amino groups from 1,4-butanediamine, and is prepared by the corresponding polyaspartic acid ester resin and IPDI in a molar ratio of 1:2.2 according to the aforementioned prepolymer preparation method.

[0089] The molar ratio of active hydrogen in component A to NCO groups in component B is 1:1.15.

[0090] The raw material components of component A are mixed and dispersed uniformly at high speed to obtain component A. Component A and component B are then mixed uniformly to obtain the polyurethane composite material.

[0091] Performance testing

[0092] 1. Mechanical property testing

[0093] Test samples were prepared according to GB / T 1041-2008, with sample dimensions of 20 mm × 20 mm × 20 mm. Displacement control was used, with a loading rate of 10 mm / min and an inlet force of 0.01 N. Stress-strain curves were tested. Higher stress at the same strain indicates better compressibility, higher mechanical strength, and better stability.

[0094] The results are shown in Table 1 below.

[0095] Table 1 Stress-strain results

[0096]

[0097] Therefore, by adding a prepolymer containing multiple ester and urea bonds to the isocyanate composition, the present invention can significantly improve the compressibility of foamed polyurethane, which is beneficial to maintaining the performance stability and prolonging the effect of foamed polyurethane during use.

[0098] Nitrogen removal performance test: 500 ml of denitrification medium with an initial concentration of 50 mg / L (initial nitrate concentration of 50 mg / L) was prepared and inoculated with 3% microorganisms activated and cultured in LB medium. The inoculated denitrification medium was placed in a constant temperature shaker at 36℃ and 120 r / min to ensure that 10 g of the tested polyurethane foam (of the same size) was in a good fluidized state. Samples were taken every 5 h. After centrifuging at 3000 rpm for 10 min, the supernatant of the sample was quantitatively diluted, and the absorbance was measured by UV spectrophotometer to calculate the corresponding concentration and the nitrogen removal rate. The nitrogen removal rate at time t = (C0 - C t ) / C0×100%, where C0 is the initial concentration of nitrate, C t Let t represent the nitrate concentration at time t. Each sample was measured three times, and the average of the three results was taken. The denitrification rate was compared after 15 hours of denitrification.

[0099] Durability: The polyurethane foam samples (of the same size) were immersed in water for 96 hours, then air-dried at room temperature for 24 hours. The denitrification performance was then tested according to the above method, and the denitrification rate retention rate after 15 hours of denitrification was measured. Denitrification rate retention rate = (Denitrification rate after immersion / Denitrification rate before immersion) × 100%. A higher denitrification rate retention rate indicates better stability and durability of the denitrification performance of the polyurethane foam.

[0100] The results are shown in Table 2 below.

[0101] Table 2

[0102]

[0103] As shown in Table 2 above, the anthraquinone compound with the structure shown in formula (2) exhibits higher denitrification persistence and a high denitrification retention rate, which can basically reach over 95%. This indicates that the anthraquinone compound can be chemically bonded to the polyurethane foam and has good stability. In contrast to Examples 1-3 and Comparative Examples 1-2, the anthraquinone compound cannot be chemically bonded to the polyurethane foam, or the chemical bonding efficiency is low and the effect is poor, which leads to a lower denitrification retention rate.

[0104] As described above, the basic principles, main features, and advantages of the present invention have been shown and described. Those skilled in the art should understand that the present invention is not limited to the above embodiments, which are merely preferred embodiments and should not be construed as limiting the scope of the invention. All equivalent changes and modifications made in accordance with the scope of the patent and the description should still fall within the scope of the present invention. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A polyurethane composite material, characterized in that, It consists of component A and component B; The raw material components of component A, by weight, include: 100 parts polymer diol, 1-8 parts chain extender, 1-3 parts catalyst, 0-5 parts crosslinking agent, 0.1-2 parts carbon-based material, 1-10 parts anthraquinone compound, and 0.5-2 parts water; Component B is an isocyanate curing agent; The isocyanate curing agent comprises a prepolymer with the structure shown in formula (1). （1） Wherein, X is selected from divalent organic groups with a molecular weight of 50-6000 that are reactive with NCO groups at 100℃, R1 and R2 are individually selected from C1-C4 alkyl groups, and R3 and R4 are individually selected from divalent organic groups with a molecular weight of 20-300 that are reactive with NCO groups at 100℃. The prepolymer accounts for no less than 20% of the weight of component B.

2. The polyurethane composite material according to claim 1, characterized in that, The isocyanate curing agent also includes diisocyanate monomers and their trimers.

3. The polyurethane composite material according to claim 1, characterized in that, The isocyanate curing agent contains an average of no less than 2 NCO groups.

4. The polyurethane composite material according to claim 1, characterized in that, The chain extender is selected from one or a combination of two or more of 1,2-ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,8-octanediol and 1,3-propanediol. The catalyst is selected from dihydroxyalkylamine; The crosslinking agent is selected from triethanolamine or triisopropanolamine.

5. The polyurethane composite material according to claim 1, characterized in that, The carbon-based material is selected from one or a combination of two or more of graphene, graphene oxide, and carbon nanotubes.

6. The polyurethane composite material according to claim 1, characterized in that, The structure of the anthraquinone compound is shown in formula (2) below. （2） R5 and R7 are individually selected from one or more combinations of O, S and NH, while R6 and R8 are individually selected from C1-C6 alkylene groups.

7. The polyurethane composite material according to claim 6, characterized in that, The anthraquinone compound is selected from one or a combination of two or more of 1,4-bis[(2-hydroxyethyl)amino]anthraquinone, 1-[(2-hydroxyethyl)amino]-4-[(3-hydroxypropyl)amino]anthraquinone, 1,4-bis[(3-hydroxypropyl)amino]anthraquinone, 2,5-bis[(3-hydroxypropyl)amino]anthraquinone, 1,8-bis[(3-hydroxypropyl)amino]anthraquinone, 2,5-bis[(2-hydroxyethyl)amino]anthraquinone, 2,6-bis[(2-hydroxyethyl)amino]anthraquinone and 2,6-bis[(3-hydroxypropyl)amino]anthraquinone.

8. The polyurethane composite material according to claim 1, characterized in that, The molar ratio of active hydrogen in component A to NCO groups in component B is 1:1.08-1.

2.

9. An application of the polyurethane composite material according to any one of claims 1-8, characterized in that, Used for the treatment of nitrogen-containing wastewater.

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