Preparation method of tear-resistant reinforced modified PU composite plastic

Abstract

The invention discloses a preparation method of tear-resistant reinforced modified PU (polyurethane) composite plastic, belongs to the technical field of PU composite plastic processing, and is used for solving the technical problem that the tear resistance and wear resistance of polyurethane in the prior art need to be further improved. The preparation method comprises the following steps: under the protection of inert gas, adding acetone and dehydrated polyethylene glycol into a three-neck flask, stirring, raising the temperature of the three-neck flask to 40-50 DEG C, dropwise adding toluene diisocynate into the three-neck flask, reacting for 30-50 minutes after dropwise adding, raising the temperature of the three-neck flask to 70-80 DEG C, and keeping the temperature for 3-5 hours to obtain a polyurethane prepolymer; through modified polyurethane, HBP modified GO and modified epoxy resin, the tear resistance and tensile strength of polyurethane are improved, and the wear resistance of polyurethane is also retained.

Description

Technical Field

[0001] The invention relates to the technical field of PU composite plastic processing, and in particular to a method for preparing tear-resistant reinforced modified PU composite plastic. Background Art

[0002] Polyurethane is a polymer material produced by the reaction of isocyanate and polyol. It is widely used in foams, elastomers, coatings and other fields. It has the characteristics of good elasticity and wear resistance.

[0003] However, traditional polyurethane has poor tear resistance. In order to improve the tear resistance, early technologies were mainly achieved through physical blending or chemical modification. The strength was improved by adding fillers such as carbon black and silica. However, the fillers have poor dispersion, which can easily lead to a decrease in material homogeneity and increased processing difficulty. Although blending with plastics such as PVC can improve rigidity, it sacrifices the flexibility and resilience of PU, and the interface compatibility is poor. These have become key bottlenecks restricting the high-end application of polyurethane.

[0004] This defect is due to the characteristics of the molecular structure of polyurethane. Although the microphase separation structure of the hard segment and the soft segment gives the material elasticity, it is easy to produce stress concentration when subjected to external impact, resulting in rapid crack expansion and the formation of "silver streaks". This shortcoming directly limits the application of polyurethane in harsh environments. For example, automobile chassis seals need to withstand complex stresses and ultraviolet aging. Traditional polyurethanes are prone to cracking due to insufficient tear resistance. The improvement of polyurethane's tear resistance depends on multi-level innovations from molecular design to macro-composite technology. Although traditional modification methods have limitations, breakthroughs in composite materials, nanotechnology and greening have led the industry to turn to the development of polyurethane composite plastics. The introduction of a rigid phase to improve the toughness of the material while retaining its wear resistance is driving PU to be more widely used in high-end fields such as automobiles and aerospace. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a tear-resistant reinforced modified PU composite plastic, so as to solve the technical problems in the prior art that the tear resistance of polyurethane is poor and the wear resistance needs to be further improved.

[0006] The purpose of the present invention can be achieved by the following technical solution: A method for preparing a tear-resistant reinforced modified PU composite plastic, comprising the following steps:

[0007] S1. Under the protection of inert gas, add acetone and dehydrated polyethylene glycol into a three-necked flask and stir. The temperature of the three-necked flask is raised to 40-50° C., and toluene diisocyanate is dripped into the three-necked flask. After the addition is completed, react for 30-50 minutes. The temperature of the three-necked flask is raised to 70-80° C. and kept warm for 3-5 hours to obtain a polyurethane prepolymer;

[0008] The synthesis reaction mechanism of the polyurethane prepolymer is as follows:

[0009] The synthesis of the polyurethane prepolymer is achieved through a stepwise addition reaction of isocyanate and polyol. The core lies in controlling the -NCO / OH ratio reaction conditions to prepare a polyurethane prepolymer with highly active end groups.

[0010] S2. Under the protection of an inert gas, the polyurethane prepolymer, 2,2-dimethylolpropionic acid, and DMF are added to a three-necked flask and stirred. The temperature of the three-necked flask is raised to 50 - 60 °C, and the reaction is carried out for 4 - 6 h under insulation. After post-treatment, a modified polyurethane is obtained;

[0011] S3. The modified polyurethane, HBP-modified GO, and modified epoxy resin are added to a torque rheometer at a temperature of 50 - 60 °C and melt-mixed for 30 min to obtain a casting material;

[0012] S4. The casting material is injected into a mold, cooled and cured to obtain a PU composite plastic.

[0013] Furthermore, in step S1, the molar ratio of toluene diisocyanate to the hydroxyl groups in dehydrated polyethylene glycol is 0.525:1, and the dosage ratio of acetone to dehydrated polyethylene glycol is 3 g:10 g; in step S2, the molar ratio of the isocyanate groups in the polyurethane prepolymer to 2,2-dimethylolpropionic acid is 2:1; the dosage ratio of the polyurethane prepolymer to the DMF solvent is 10 g:3 g.

[0014] Furthermore, the preparation method of dehydrated polyethylene glycol is as follows: Polyethylene glycol is added to a three-necked flask. The temperature of the three-necked flask is raised to 110 - 120 °C, and the negative pressure is pumped to 0.1 MPa. Vacuum dehydration is carried out for 4 - 5 h to obtain dehydrated polyethylene glycol, where the polyethylene glycol is polyethylene glycol 400.

[0015] Furthermore, the modified epoxy resin is composed of epoxy resin, polyurethane prepolymer, diluent, and curing agent in a weight ratio of 100:16:25:20.

[0016] Furthermore, the epoxy resin is epoxy resin E-51, the diluent is butyl glycidyl ether, and the curing agent is m-xylenediamine.

[0017] Furthermore, the preparation method of HBP-modified GO is as follows: Graphene oxide, hydroxy phenylboronic acid, tetrabutylammonium bromide, and N,N-dimethylformamide are added to a three-necked flask and ultrasonically dispersed for 60 - 80 min. The temperature of the three-necked flask is raised to 110 - 120 °C, and the reaction is carried out for 20 - 24 h under insulation. After post-treatment, HBP-modified GO is obtained.

[0018] The synthesis reaction mechanism of HBP-modified GO is as follows:

[0019] The hydroxyl or epoxy oxygen atoms on the surface of graphene oxide act as nucleophiles, attacking the boron atom in the boronic acid group of HBP to form an intermediate. The intermediate dehydrates under mild acidic or neutral conditions to form a stable borate ester bond, releasing water molecules simultaneously, and HBP-modified GO is prepared.

[0020] Furthermore, the dosage ratio of the graphene oxide, hydroxyphenylboronic acid, tetrabutylammonium bromide, and N,N-dimethylformamide is 0.2 g:5 g:0.02 g:200 mL. The post-treatment includes: after the reaction is completed, the temperature of the three-necked flask is lowered to room temperature, and suction filtration is carried out. The filter cake is washed 3 times with acetone and then dried by suction. The filter cake is transferred to an oven at 60 - 80 °C and dried to a constant weight to obtain HBP-modified GO.

[0021] The present invention has the following beneficial effects:

[0022] 1. For the tear-resistant enhanced modified PU composite plastic of the present invention, the epoxy resin is modified by m-phenylenediamine. As an aliphatic primary amine, m-phenylenediamine reacts rapidly with the epoxy group to form a dense three-dimensional crosslinked network, significantly enhancing the hardness, rigidity, and creep resistance of the material. The crosslinked network inhibits the slippage of molecular chains, and the rigid crosslinked structure reduces surface plastic deformation, effectively improving the tensile strength and wear resistance. Moreover, m-phenylenediamine has high reaction activity and can be rapidly cured at room temperature or medium temperature, shortening the production cycle.

[0023] 2. For the tear-resistant enhanced modified PU composite plastic of the present invention, the carboxylic acid group is introduced by the reaction of the hydroxyl group with the isocyanate of the prepolymer, and ionic bonds may be formed after neutralization, improving the hydrophilicity and compatibility. The short-chain structure of 2,2-bis(hydroxymethyl)propionic acid can further promote the microphase separation of the hard segment and the soft segment, enhancing the tensile strength and wear resistance of the material while maintaining flexibility.

[0024] 3. For the tear-resistant enhanced modified PU composite plastic of the present invention, modified polyurethane, HBP-modified GO, and modified epoxy resin are mixed. During the mixing process, the active groups of HBP react with the functional groups of polyurethane or epoxy resin to form an interfacial bond. The heterocyclic structure of HBP and the aromatic ring of the modified epoxy resin produce π-π interactions, improving its thermal conductivity and electrical conductivity; the flexibility of polyurethane, the crack pinning effect of graphene oxide, and the high modulus of the modified epoxy resin greatly enhance the tear strength of the material, and the synergistic effect of polyurethane and graphene oxide reduces the friction coefficient of the material; during the interface optimization and processing improvement, HBP-modified GO is uniformly dispersed in polyurethane and epoxy resin, avoiding stress concentration caused by agglomeration, and the flexibility of polyurethane and the rigidity of epoxy resin achieve interfacial compatibility through HBP grafting. Detailed implementation mode

[0025] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] In this application, the epoxy resin is selected from Qingdao Baichen New Material Technology Co., Ltd., with the model of E-51, CAS number of 1675-54-3, viscosity of 11000-18000, and epoxy equivalent (g / mol) of 183-200.

[0027] Example 1

[0028] This example provides a method for preparing a tear-resistant enhanced modified PU composite plastic, which includes the following steps:

[0029] S1. Prepare dehydrated polyethylene glycol

[0030] Weigh: Add 20 g of polyethylene glycol to a three-necked flask. Raise the temperature of the three-necked flask to 110 °C, draw a negative pressure to a negative pressure of 0.1 MPa, and perform vacuum dehydration for 4 h to obtain dehydrated polyethylene glycol.

[0031] S2. Prepare polyurethane prepolymer

[0032] Weigh: Weigh 10 g of dehydrated polyethylene glycol and 3 g of acetone, add them to a three-necked flask protected by argon and stir. Raise the temperature of the three-necked flask to 40 °C. According to the molar ratio of toluene diisocyanate to hydroxyl groups in dehydrated polyethylene glycol of 0.525:1, drop the toluene diisocyanate solution into the three-necked flask. After the dropping is completed, react for 30 min, and distill off the low-boiling substances under reduced pressure to obtain the polyurethane prepolymer.

[0033] S3. Prepare modified polyurethane

[0034] Weigh: Weigh 10 g of polyurethane prepolymer and 3 g of DMF, add them to a three-necked flask protected by argon and stir. According to the molar ratio of isocyanate groups to 2,2-dimethylolpropionic acid of 2:1, add 2,2-dihydroxypropionic acid to the three-necked flask. Raise the temperature of the three-necked flask to 50 °C and keep the temperature for 4 h. After the reaction is completed, raise the temperature of the three-necked flask to 100 °C, draw a negative pressure to a negative pressure of 0.1 MPa, and distill off the low-boiling substances under reduced pressure to obtain the modified polyurethane.

[0035] S4. Prepare HBP-modified GO

[0036] Weigh: 2 g of graphene oxide, 50 g of hydroxyphenylboronic acid, 0.2 g of tetrabutylammonium bromide and 2000 mL of N,N-dimethylformamide and add them to a three-necked flask. Ultrasonically disperse for 60 min, raise the temperature of the three-necked flask to 110 °C, keep the temperature for reaction for 20 h. After the reaction is completed, lower the temperature of the three-necked flask to room temperature, perform suction filtration, wash the filter cake with acetone 3 times and then drain it. Transfer the filter cake to a drying oven at 60 °C and dry it to constant weight to obtain HBP-modified GO.

[0037] S5. Prepare modified epoxy resin

[0038] Add 100 g of epoxy resin to a dry three-necked flask, set the temperature of the drying oven to 100 °C, and perform vacuum dehydration for 60 min. Add 20 g of butyl glycidyl ether, 25 g of m-xylenediamine and 16 g of the above-prepared polyurethane prepolymer to the dehydrated epoxy resin under argon protection and stir. Set the temperature of the constant-temperature water bath to 120 °C, place the mixture in this water bath for 60 min. After the reaction is completed, wait for the colloid to cool to room temperature to obtain modified epoxy resin.

[0039] S6. Prepare casting material

[0040] Weigh: 700 g of modified polyurethane, 150 g of HBP-modified GO and 150 g of modified epoxy resin and add them to a torque rheometer at 120 °C, and perform melt mixing for 30 min to obtain casting material;

[0041] Inject the casting material into a mold, cool and cure to obtain PU composite plastic.

[0042] Example 2

[0043] This example provides a method for preparing a tear-resistant enhanced modified PU composite plastic,

[0044] S1. Prepare dehydrated polyethylene glycol

[0045] Weigh: Add 20 g of polyethylene glycol to a three-necked flask, raise the temperature of the three-necked flask to 115 °C, draw a negative pressure to a negative pressure of 0.1 MPa, and perform vacuum dehydration for 4.5 h to obtain dehydrated polyethylene glycol.

[0046] S2. Prepare polyurethane prepolymer

[0047] Weigh: Weigh 10 g of dehydrated polyethylene glycol and 3 g of acetone, add them to a three-necked flask under argon protection and stir. Raise the temperature of the three-necked flask to 45 °C, and dropwise add a toluene diisocyanate solution to the three-necked flask according to the molar ratio of toluene diisocyanate to the hydroxyl group in dehydrated polyethylene glycol of 0.525:1. After the dropping is completed, react for 30 min, and distill off the low-boiling substances under reduced pressure to obtain polyurethane prepolymer.

[0048] S3. Prepare modified polyurethane

[0049] Weigh: 10 g of polyurethane prepolymer and 3 g of DMF, add them to a three-necked flask under argon protection and stir. According to the molar ratio of isocyanate group to 2,2-dimethylolpropionic acid being 2:1, add 2,2-dimethylolpropionic acid to the three-necked flask. Raise the temperature of the three-necked flask to 55 °C and keep the temperature for 4.5 h. After the reaction is completed, raise the temperature of the three-necked flask to 100 °C, evacuate to a negative pressure of 0.1 MPa, and distill off low-boiling substances under reduced pressure to obtain modified polyurethane.

[0050] S4. Prepare HBP-modified GO

[0051] Weigh: 2 g of graphene oxide, 50 g of hydroxyphenylboronic acid, 0.2 g of tetrabutylammonium bromide and 2000 mL of N,N-dimethylformamide, add them to a three-necked flask, ultrasonically disperse for 60 min, raise the temperature of the three-necked flask to 115 °C, keep the temperature for 25 h. After the reaction is completed, lower the temperature of the three-necked flask to room temperature, filter by suction, wash the filter cake with acetone 3 times and then dry by suction. Transfer the filter cake to an oven at 65 °C and dry to constant weight to obtain HBP-modified GO.

[0052] S5. Prepare modified epoxy resin

[0053] Add 100 g of epoxy resin to a dry three-necked flask, set the temperature of the drying oven to 100 °C, and dehydrate under reduced pressure for 60 min. Add 20 g of butyl glycidyl ether, 25 g of m-xylenediamine and 16 g of the above-prepared polyurethane prepolymer to the dehydrated epoxy resin under argon protection and stir. Set the temperature of the constant-temperature water bath to 125 °C, place the mixture in this water bath for 60 min. After the reaction is completed, wait for the colloid to cool to room temperature to obtain modified epoxy resin.

[0054] S6. Prepare casting material

[0055] Weigh: 700 g of modified polyurethane, 150 g of HBP-modified GO and 150 g of modified epoxy resin, add them to a torque rheometer at 50 °C, and melt and mix for 30 min to obtain casting material;

[0056] Inject the casting material into a mold, cool and cure to obtain PU composite plastic.

[0057] Example 3

[0058] This example provides a method for preparing a tear-resistant enhanced modified PU composite plastic.

[0059] S1. Prepare dehydrated polyethylene glycol

[0060] Weigh: Add 20 g of polyethylene glycol into a three-necked flask. Raise the temperature of the three-necked flask to 120 °C, evacuate to a negative pressure of 0.1 MPa, and carry out vacuum dehydration for 5 h to obtain dehydrated polyethylene glycol.

[0061] S2. Prepare polyurethane prepolymer

[0062] Weigh: Weigh 10 g of dehydrated polyethylene glycol and 240 mL of acetone. Under the protection of inert gas, add them into a three-necked flask and stir. Raise the temperature of the three-necked flask to 50 °C. According to the molar ratio of toluene diisocyanate to hydroxyl groups in dehydrated polyethylene glycol being 0.525:1, dropwise add toluene diisocyanate into the three-necked flask. After the addition is completed, react for 30 min, and distill off low-boiling substances under reduced pressure to obtain a polyurethane prepolymer.

[0063] S3. Prepare modified polyurethane

[0064] Weigh: Weigh 10 g of polyurethane prepolymer and 3 g of DMF. Add them into a three-necked flask protected by argon and stir. According to the molar ratio of isocyanate groups to 2,2-dimethylolpropionic acid being 2:1, add 2,2-dimethylolpropionic acid into the three-necked flask. Raise the temperature of the three-necked flask to 60 °C and keep the temperature for 5 h. After the reaction is completed, raise the temperature of the three-necked flask to 100 °C, evacuate to a negative pressure of 0.1 MPa, and distill off low-boiling substances under reduced pressure to obtain modified polyurethane.

[0065] S4. Prepare HBP-modified GO

[0066] Weigh: Add 2 g of graphene oxide, 50 g of hydroxyphenylboronic acid, 0.2 g of tetrabutylammonium bromide, and 2000 mL of N,N-dimethylformamide into a three-necked flask, ultrasonically disperse for 60 min, raise the temperature of the three-necked flask to 120 °C, and keep the temperature for 30 h. After the reaction is completed, lower the temperature of the three-necked flask to room temperature, carry out suction filtration, wash the filter cake with acetone three times and then dry it by suction. Transfer the filter cake to a drying oven at 60 °C and dry to constant weight to obtain HBP-modified GO.

[0067] S5. Prepare modified epoxy resin

[0068] Add 100 g of epoxy resin into a dry three-necked flask, set the temperature of the drying oven to 100 °C, and carry out dehydration under reduced pressure for 60 min. Add 20 g of butyl glycidyl ether, 25 g of m-phenylenediamine, and 16 g of the above-prepared polyurethane prepolymer into the dehydrated epoxy resin protected by argon and stir. Set the temperature of the constant-temperature water bath to 130 °C, place the mixture in this water bath for 60 min. After the reaction is completed, wait for the colloid to cool to room temperature to obtain modified epoxy resin.

[0069] S6. Prepare casting material

[0070] Weigh: 700 g of modified polyurethane, 150 g of HBP-modified GO, and 150 g of modified epoxy resin are added to a torque rheometer at a temperature of 50 °C and melt-mixed for 30 min to obtain a casting material;

[0071] Inject the casting material into a mold, cool and cure to obtain a PU composite plastic.

[0072] Comparative Example 1

[0073] The difference between this comparative example and Example 3 is that step S5 is cancelled, and the epoxy resin in step S5 is used to replace the modified epoxy resin in step S6.

[0074] Comparative Example 2

[0075] The difference between this comparative example and Example 3 is that step S4 is cancelled, and the graphene oxide in step S4 is used to replace the HBP-modified GO in step S6.

[0076] Comparative Example 3

[0077] The difference between this comparative example and Example 3 is that no polyurethane prepolymer is added in step S5.

[0078] Comparative Example 4

[0079] The difference between this comparative example and Example 3 is that no m-xylenediamine is added in step S5.

[0080] Performance test:

[0081] Refer to the standard GB / T 12833-2006 "Rubber and Plastics - Tear Strength and Cohesive Strength - Analysis of Multimodal Curves in Determination" to determine the tear strength and tensile strength of the PU composite plastics prepared in Examples 1-3 and Comparative Examples 1-4;

[0082] Refer to the standard GB / T 529-2008 "Determination of Tear Strength of Vulcanized Rubber or Thermoplastic Rubber (Pant, Right Angle and Crescent Specimens)" to determine the tear strength of the PU composite plastics prepared in Examples 1-3 and Comparative Examples 1-4;

[0083] Refer to the standard GB / T 1451-2005 "Test Method for Simply Supported Beam Impact Toughness of Fiber Reinforced Plastics" to determine the tensile strength and impact strength of the PU composite plastics prepared in Examples 1-3 and Comparative Examples 1-4;

[0084] Refer to the standard GB / T 19089-2012 "Determination of Abrasion Resistance of Rubber or Plastic Coated Fabrics - Martindale Method" to determine the abrasion resistance of the PU composite plastics prepared in Examples 1-3 and Comparative Examples 1-4. The specific test results are shown in Table 1 below:

[0085] Table 1 - Performance Detection Data Table of Specimens

[0086]

[0087] Data analysis:

[0088] By comparing and analyzing the data in Table 1 above, the tear strength of the polyurethane composite plastic prepared by the present invention reaches 68.2 kN / m, the tensile strength reaches 65.3 MPa, the elongation at break reaches 15.3%, and the impact strength reaches 40.2 kJ / m 2 , and all performance parameters are higher than those of the comparative examples. The present invention combines the preparation of modified polyurethane, modified epoxy resin, and HBP-modified GO. The prepared polyurethane composite plastic not only improves the tear resistance of the material but also effectively improves the tensile strength, elongation at break, and impact strength of the material.

[0089] Compared with the example, the unmodified epoxy resin in the comparative example 1 cannot form a dense three-dimensional crosslinked network in the material, and its effects on tear resistance, tensile strength, and wear resistance are significantly lower than those of the modified epoxy resin.

[0090] Compared with the example, the replacement of HBP-modified GO with graphene oxide in the comparative example 2 cannot inhibit the degradation of graphene oxide in an oxidative environment, reducing the tear strength and tensile strength of the material.

[0091] Compared with the example, an appropriate amount of polyurethane prepolymer in the modified epoxy resin in the comparative example 3 can improve the wear resistance of the material, and both the friction coefficient and the wear amount are effectively improved in the data analysis.

[0092] Compared with the example, m-xylenediamine plays an important role in the modified epoxy resin. As an aliphatic primary amine, m-xylenediamine reacts quickly with epoxy groups to form a dense three-dimensional crosslinked network. The crosslinked network inhibits the slippage of molecular chains, and the hard crosslinked structure reduces surface plastic deformation, effectively improving the tensile strength and wear resistance.

[0093] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only the specific embodiments. Obviously, many modifications and variations can be made according to the content of this specification. These embodiments are selected and specifically described in this specification to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and utilize the present invention well. The present invention is only limited by the claims and their full scope and equivalents.

Claims

1. A method for preparing a tear-resistant reinforced modified PU composite plastic, characterized in that: The following steps are involved: S1. Under the protection of inert gas, add acetone and dehydrated polyethylene glycol into a three-necked flask and stir. The temperature of the three-necked flask is raised to 40-50° C., and toluene diisocyanate is dripped into the three-necked flask. After the addition is completed, react for 30-50 minutes. The temperature of the three-necked flask is raised to 70-80° C. and kept warm for 3-5 hours to obtain a polyurethane prepolymer; S2. Under the protection of inert gas, add polyurethane prepolymer, 2,2-dimethylol propionic acid and DMF into a three-necked flask and stir, raise the temperature of the three-necked flask to 50-60° C., keep the temperature for 4-6 hours, and post-treat to obtain modified polyurethane; S3, adding the modified polyurethane, HBP-modified GO and modified epoxy resin into a torque rheometer at a temperature of 50-60° C., and melt-mixing for 30 minutes to obtain a casting material; S4, injecting the casting material into the mold, cooling and solidifying it to obtain PU composite plastic.

2. The method for preparing a tear-resistant reinforced modified PU composite plastic according to claim 1, characterized in that: In step S1, the molar ratio of toluene diisocyanate to hydroxyl group in dehydrated polyethylene glycol is 0.525:1, and the usage ratio of acetone to dehydrated polyethylene glycol is 3g:10g; in step S2, the molar ratio of isocyanate group to 2,2-dihydroxymethylpropionic acid in the polyurethane prepolymer is 2:1; and the usage ratio of the polyurethane prepolymer to DMF is 10g:3g.

3. The method for preparing a tear-resistant reinforced modified PU composite plastic according to claim 1, characterized in that: In step S2, the post-treatment step is: after the reaction is completed, the temperature of the three-necked flask is increased to 70-80°C, and the negative pressure is reduced to 0.1 MPa for 2-3 hours to obtain a modified polyurethane.

4. The method for preparing a tear-resistant reinforced modified PU composite plastic according to claim 1, characterized in that: The preparation method of dehydrated polyethylene glycol is as follows: adding polyethylene glycol into a three-necked flask, raising the temperature of the three-necked flask to 110-120° C., evacuating the negative pressure to 0.1 MPa, and vacuum dehydrating for 4-5 hours to obtain dehydrated polyethylene glycol, wherein the polyethylene glycol is polyethylene glycol 400.

5. The method for preparing a tear-resistant reinforced modified PU composite plastic according to claim 1, characterized in that: The modified epoxy resin is composed of epoxy resin, polyurethane prepolymer, diluent and curing agent in a weight ratio of 100:16:25:

20.

6. The method for preparing a tear-resistant reinforced modified PU composite plastic according to claim 5, characterized in that: The epoxy resin is epoxy resin E-51, the diluent is butyl glycidyl ether, and the curing agent is meta-xylylenediamine.

7. The method for preparing a tear-resistant reinforced modified PU composite plastic according to claim 1, characterized in that: The preparation method of HBP-modified GO is as follows: graphene oxide, hydroxyphenylboric acid, tetrabutylammonium bromide and N,N-dimethylformamide are added to a three-necked flask, ultrasonically dispersed for 60-80 minutes, the temperature of the three-necked flask is increased to 110-120° C., the reaction is kept warm for 20-24 hours, and post-treated to obtain HBP-modified GO.

8. The method for preparing a tear-resistant reinforced modified PU composite plastic according to claim 7, characterized in that: The amount ratio of the graphene oxide, hydroxyphenylboric acid, tetrabutylammonium bromide and N,N-dimethylformamide is 0.2g:5g:0.02g:200mL. The post-treatment includes: after the reaction is completed, the temperature of the three-necked flask is lowered to room temperature, filtered, the filter cake is washed with acetone for 3 times and then dried, and the filter cake is transferred to a drying oven with a temperature of 60-80°C and dried to constant weight to obtain HBP-modified GO.

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