Poly (4-methyl-1-pentene) graft and preparation method thereof

Abstract

The invention discloses a poly (4-methyl-1-pentene) graft and a preparation method of the poly (4-methyl-1-pentene) graft. The graft is prepared by carrying out free radical polymerization on raw materials of poly (4-methyl-1-pentene) and a grafting monomer in a mass ratio of 100: (3-30) in a mixed solvent, the mixed solvent comprises a grafting solvent and an auxiliary solvent, the grafting solvent is an organic solvent without benzyl hydrogen, and the auxiliary solvent is selected from at least one of ethyl acetate, dichloromethane, trichloromethane, acetone, carbon tetrachloride and trichloroethylene; the graft monomer includes an unsaturated carboxylic acid monomer. According to the preparation method, the high-polarity poly 4-methyl-1-pentene graft with the grafting rate of more than 3.5% can be prepared, and the high-polarity poly 4-methyl-1-pentene graft is matched with modified TPX to be applied to the fields of high-adhesion composite films, flame-retardant cable sheaths and the like with strict requirements on interfacial compatibility and durability.

Description

Technical Field

[0001] The present application relates to the field of polyolefin compatibilizers, and in particular to a poly-4-methyl-1-pentene graft and a preparation method thereof. Background Art

[0002] Poly (4-methylpentene-1) (TPX), a high-performance polyolefin material, exhibits properties such as a high melting point (approximately 235°C), low density (0.83 g / cm³), excellent optical transparency, and a low dielectric constant due to its unique molecular structure. It is widely used in microporous filtration membranes, high-end medical consumables (such as syringes and culture dishes), high-temperature resistant packaging materials, electronic and electrical insulation coatings (such as heat-resistant wires), and precision physical and chemical laboratory equipment. However, the highly regular arrangement of methyl side chains in the TPX molecular chain results in extremely low surface energy and a lack of polar groups, which makes the material have obvious application limitations: on the one hand, its non-polar characteristics lead to poor interfacial compatibility with polar materials (such as inorganic fillers, flame retardants, and metal substrates), and problems such as delamination and peeling are prone to occur in scenarios such as composite films and flame-retardant cables; on the other hand, the presence of a large number of tertiary carbon sites in the TPX main chain makes it prone to free radical chain reactions under light or thermal oxidation conditions, causing molecular chain breakage or cross-linking, manifested as yellowing of the material, deterioration of mechanical properties and insufficient radiation resistance, which seriously restricts its application in long-term outdoor exposure environments or high-energy radiation scenarios (such as nuclear power plant cable sheaths).

[0003] To address these deficiencies, existing techniques typically employ polar monomer grafting modification to introduce polar functional groups, such as carboxylic acid groups, into the TPX molecular chain. For example, patent application CN116218466A discloses a method for preparing an environmentally friendly, odorless, edge-sealing hot-melt adhesive. This method involves grafting maleic anhydride onto poly-4-methyl-1-pentene, which is then used as a compatibilizer in a polyolefin composite system to enhance the hot-melt adhesive's interfacial bonding properties. However, this technical solution only briefly describes the preparation process of the grafted material. The grafting reaction system is susceptible to side reactions (such as monomer self-polymerization and backbone degradation) during free radical initiation, resulting in low grafting efficiency. This makes it difficult to meet the demanding requirements for high-performance composite materials. Summary of the Invention

[0004] In order to solve the problem that the current grafting rate of polar monomers in poly (4-methyl-1-pentene) grafts is low and cannot meet the application requirements of high adhesion, high compatibility, etc., this application provides a grafting modification method for preparing poly (4-methyl-1-pentene) grafts with a high grafting rate (greater than 3.5%).

[0005] In the first aspect, the present application provides a poly 4-methyl-1-pentene graft, which is prepared by free radical polymerization of poly 4-methyl-1-pentene and a grafting monomer in a mass ratio of 100:3 to 30 in a mixed solvent; the mixed solvent contains a grafting solvent and an auxiliary solvent, the grafting solvent is an organic solvent free of benzyl hydrogen, and the auxiliary solvent is selected from at least one of dichloromethane, acetone, methyl acetate, trichloroethylene, and ethyl acetate; the grafting monomer contains an unsaturated carboxylic acid monomer.

[0006] In any of the above technical solutions, the grafting solvent is selected from one of decahydronaphthalene, cumene, tert-butylbenzene, dichlorobenzene, and trichlorobenzene.

[0007] This application significantly suppresses the ineffective consumption of free radicals in the solution grafting reaction by adopting a grafting solvent system that does not contain benzyl hydrogen. The presence of benzyl hydrogen in traditional solvents can lead to free radical chain transfer reactions, that is, free radicals capture benzyl hydrogen from solvent molecules to generate low-activity solvent radicals, thereby reducing the grafting efficiency. In this solution, the solvent that does not contain benzyl hydrogen cuts off this chain transfer path, forcing the free radicals to preferentially attack the tertiary carbon sites of the poly (4-methyl-1-pentene) (TPX) backbone, generating macromolecular free radicals (TPX·), which then combine with the double bonds of the unsaturated carboxylic acid monomers to form graft chains. This design concentrates the activity of the free radicals on the grafting reaction itself, effectively increasing the grafting rate to above 3.5%. At the same time, this application introduces an appropriate amount of auxiliary solvent to promote the diffusion and distribution of the monomer by adjusting the polarity and viscosity of the system. On the one hand, it avoids excessive free radical concentration in local areas that triggers self-polymerization side reactions of unsaturated carboxylic acid monomers, produces homopolymers, and reduces the grafting rate; on the other hand, the synergistic effect of the auxiliary solvent also compensates for the problem of excessive free radical attack on the main chain caused by the inertness of non-benzyl hydrogen solvents, shortens the residence time of large molecular free radicals (TPX·), ensures their rapid combination with monomers, and reduces the risk of β-scission of TPX caused by free radical retention, thereby maintaining the molecular weight stability of TPX and reducing its loss of mechanical properties.

[0008] In any of the above technical solutions, the amount of the grafting solvent is 600 to 1200% of the mass of the poly-4-methyl-1-pentene.

[0009] It is worth noting that the grafting solvent must have good solubility for TPX and be compatible with the reaction temperature of its free radical copolymerization, preferably with a boiling point greater than 100°C, to ensure reaction and dissolution efficiency. When the mass ratio of the grafting solvent to poly-4-methyl-1-pentene is less than 600%, TPX swells and cannot be completely dissolved to form a uniform solution.

[0010] In any of the above technical solutions, the amount of the auxiliary solvent is 5 to 25% of the mass of the poly-4-methyl-1-pentene.

[0011] In any of the above technical solutions, the unsaturated carboxylic acid monomer is selected from one or more of maleic acid, fumaric acid, itaconic acid, maleic anhydride, acrylic acid, methacrylic acid, methyl maleate, itaconic anhydride, and methylmaleic anhydride.

[0012] In any of the above technical solutions, the reaction temperature of the free radical polymerization is 100-140°C.

[0013] In any of the above technical solutions, during the free radical polymerization process, the amount of initiator used is 1 to 10% of the mass of the poly-4-methyl-1-pentene.

[0014] In any of the above technical solutions, during the free radical polymerization process, the addition rate of the initiator is 1.0 to 3.0 wt% / min.

[0015] This application achieves a dynamic balance of free radical concentration by precisely controlling the initiator dripping rate. Slow dripping avoids the explosive growth of free radicals caused by excessive initiator in a short period of time, thereby reducing the formation of homopolymers and uncontrollable attacks on the main chain. Combined with a 1-6 hour aging reaction time, it ensures that the generated macromolecular free radicals are fully combined with the monomers, reducing side reactions caused by residual unreacted free radicals. While improving the grafting rate, it ensures the molecular weight retention rate and mechanical property stability of the TPX graft.

[0016] In any of the above technical solutions, the initiator is at least one of azobisisobutyronitrile, azobisisoheptanenitrile, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl perbenzoate, dioctyl peroxydicarbonate, and percarbonate.

[0017] In a second aspect, the present application provides a method for preparing a poly-4-methyl-1-pentene graft, which comprises: Mixing a portion of the grafting solvent, the poly-4-methyl-1-pentene polymer, the polar monomer, and the grafting auxiliary solvent, stirring and mixing; stirring at a temperature of 100 to 140° C. to form a poly-4-methyl-1-pentene solution; The grafting solvent and the initiator are uniformly mixed to prepare an initiator solution, and the initiator solution is added dropwise to the poly (4-methyl-1-pentene) solution to carry out a polymerization reaction. After the dropwise addition is completed, the reaction is allowed to mature for 1 to 6 hours. After the reaction is completed, the temperature is lowered to below 60°C, and the reaction solution is poured into acetone. After being allowed to settle, the reaction solution is soaked and washed with anhydrous ethanol, and vacuum dried to obtain a grafted product of poly (4-methyl-1-pentene).

[0018] In summary, this application has the following beneficial effects: This application utilizes solvent system optimization, precise process parameter control, and the synergistic effect of auxiliary solvents to efficiently prepare poly-4-methyl-1-pentene grafts with high grafting yields (>3.5%) and low side reaction rates. The resulting product exhibits excellent polarity tunability, yellowing resistance, and radiation resistance, and is widely applicable in applications such as high-adhesion composite films and flame-retardant cable sheathing, where interfacial compatibility and durability are critical. This technology overcomes the bottlenecks of low efficiency and numerous side reactions associated with traditional grafting modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the infrared spectrum of the poly (4-methyl-1-pentene) graft in Example 3.

[0020] Figure 2 It is the infrared spectrum of poly-4-methyl-1-pentene in Example.

[0021] Figure 3 This is a comparison of the infrared spectra of the raw material poly 4-methyl-1-pentene and the poly 4-methyl-1-pentene graft. DETAILED DESCRIPTION

[0022] The brand of poly (4-methyl-1-pentene) in the following examples is TPX™ DX845 obtained from Mitsui Chemicals.

[0023] Example 1

[0024] A poly-4-methyl-1-pentene grafted product is prepared by the following steps: Place a 500 mL four-necked flask equipped with a stirrer, thermometer, and reflux condenser in an oil bath. Add 25.0 g of poly (4-methyl-1-pentene), 150.0 g of tert-butylbenzene, 1.6 g of itaconic acid, and 3.0 g of ethyl acetate. Adjust the stirring speed to 500 rpm / min and stir for 10 minutes. Then, turn on the oil bath heating device, set the temperature to 135°C, and stir at 300 rpm / min for 60 minutes to obtain a clear, transparent, and uniform poly (4-methyl-1-pentene) solution.

[0025] Mix 1.5g of benzoyl peroxide and 5.0g of tert-butylbenzene. Add the resulting mixture dropwise to the poly(4-methyl-1-pentene) solution using a syringe pump at a rate of 2.5wt% / min. After complete addition, allow the mixture to react for 4 hours and then cool naturally. Once the system temperature is below 60°C, pour the reaction solution into 800ml of acetone. Allow the mixture to settle, vacuum filter, and rinse three times with anhydrous ethanol. Dry under vacuum at 90°C for 24 hours to obtain the poly(4-methyl-1-pentene) grafted product.

[0026] 1.0-2.0 g of the dried grafted product was weighed, 150.0 ml of xylene was added, and the product was heated and stirred in an oil bath at 120°C for 2 h. The acid value of the grafted product was measured according to ASTM-D1386-15 (2022), which was converted into a grafting rate of 3.55%.

[0027] Example 2

[0028] A poly-4-methyl-1-pentene grafted product is prepared by the following steps: Place a 2000 mL four-necked flask equipped with a stirrer, thermometer, and reflux condenser in an oil bath. Add 125.0 g of poly (4-methyl-1-pentene), 935.0 g of dichlorobenzene, 13.0 g of itaconic anhydride, and 18.8 g of methyl acetate. Adjust the stirring speed to 500 rpm / min and stir for 10 minutes. Then, turn on the oil bath heating device, set the temperature to 125°C, and stir at 350 rpm / min for 30 minutes to obtain a clear, transparent, and uniform poly (4-methyl-1-pentene) solution.

[0029] Mix 12.5g of dicumyl peroxide and 25.0g of dichlorobenzene. Add the resulting mixture dropwise to the poly(4-methyl-1-pentene) solution using a syringe pump at a rate of 3.0wt% / min. After complete addition, allow the mixture to react for 4.5 hours and then cool naturally. Once the system temperature is below 60°C, pour the reaction solution into 1800ml of acetone. Allow the mixture to settle, vacuum filter, and rinse three times with anhydrous ethanol. Dry under vacuum at 90°C for 18 hours to obtain the poly(4-methyl-1-pentene) grafted product.

[0030] 1.0-2.0 g of the dried grafted product was weighed, 150.0 ml of xylene was added, and the product was heated and stirred in an oil bath at 120°C for 2 h. The acid value of the grafted product was measured according to ASTM-D1386-15 (2022), which was converted into a grafting rate of 4.53%.

[0031] Example 3

[0032] A poly-4-methyl-1-pentene grafted product is prepared by the following steps: Place a 500 mL four-necked flask equipped with a stirrer, thermometer, and reflux condenser in an oil bath. Add 10.5 g of poly (4-methyl-1-pentene), 90.0 g of cumene, 2.0 g of maleic acid, and 2.6 g of dichloromethane. Adjust the stirring speed to 400 rpm / min and stir for 20 minutes. Then, turn on the oil bath heating device, set the temperature to 125°C, and stir at 400 rpm / min for 50 minutes to obtain a clear, transparent, and uniform poly (4-methyl-1-pentene) solution.

[0033] Mix 1.0g of tert-butyl peroxybenzoate and 6.0g of cumene. Add the mixed solution dropwise to the poly (4-methyl-1-pentene) solution using a syringe pump at a rate of 1.6wt% / min. After the mixed solution is added dropwise, allow to react for 5.0h and then cool naturally. When the system temperature is below 60°C, pour the reaction solution into 500ml of acetone. Allow to settle, vacuum filter, and rinse three times with anhydrous ethanol. Dry under vacuum at 90°C for 16h to obtain the poly (4-methyl-1-pentene) (TPX) grafted product. Figure 3 From the infrared spectrum, it can be seen that there is no characteristic peak near 1780cm-1 before grafting modification; there is an obvious characteristic peak near 1780cm-1 after grafting modification, indicating that maleic acid is successfully grafted onto the poly (4-methyl-1-pentene) molecular chain.

[0034] 1.0-2.0 g of the dried grafted product was weighed, 150.0 ml of xylene was added, and the product was heated and stirred in an oil bath at 120°C for 2 h. The acid value of the grafted product was measured according to ASTM-D1386-15 (2022), which was converted into a grafting rate of 5.83%.

[0035] Example 4

[0036] A poly-4-methyl-1-pentene grafted product is prepared by the following steps: Place a 500 mL four-necked flask equipped with a stirrer, thermometer, and reflux condenser in an oil bath. Add 18.0 g of poly (4-methyl-1-pentene), 180.0 g of decahydronaphthalene, 2.0 g of maleic anhydride, and 3.6 g of trichloroethylene. Adjust the stirring speed to 500 rpm / min and stir for 20 minutes. Then, turn on the oil bath heating device, set the temperature to 131°C, and stir at 350 rpm / min for 60 minutes to obtain a clear, transparent, and homogeneous poly (4-methyl-1-pentene) solution.

[0037] Mix 1.8g of dioctyl peroxydicarbonate and 15.0g of decahydronaphthalene. Add the resulting mixture dropwise to the poly(4-methyl-1-pentene) solution using a syringe pump at a rate of 2.6wt% / min. After complete addition, allow the mixture to react for 4.5 hours and then cool naturally. Once the system temperature is below 60°C, pour the reaction solution into 250.0ml of acetone. Allow the mixture to settle, vacuum filter, and rinse three times with methanol. Dry under vacuum at 90°C for 20 hours to obtain the poly(4-methyl-1-pentene) (TPX) grafted product.

[0038] 1.0-2.0 g of the dried grafted product was weighed, 150.0 ml of xylene was added, and the product was heated in an oil bath at 120°C with stirring for 2 h. The acid value of the grafted product was measured according to ASTM-D1386-15 (2022), which was converted into a grafting rate of 3.93%.

[0039] Example 5

[0040] A poly-4-methyl-1-pentene grafted product is prepared by the following steps: Place a 1500 mL four-necked flask equipped with a stirrer, thermometer, and reflux condenser in an oil bath. Add 45.0 g of poly (4-methyl-1-pentene), 495.0 g of trichlorobenzene, 4.2 g of methacrylic acid, and 2.5 g of acetone. Adjust the stirring speed to 250 rpm / min and stir for 15 minutes. Then, turn on the oil bath heating device, set the temperature to 120°C, and stir at 300 rpm / min for 40 minutes to obtain a clear, transparent, and uniform poly (4-methyl-1-pentene) solution.

[0041] Mix 3.0 g of tert-butyl hydroperoxide and 8.0 g of trichlorobenzene. Add the resulting mixture dropwise to the poly (4-methyl-1-pentene) solution using a syringe pump at a rate of 1.0 wt% / min. After complete addition, allow the mixture to react for 5.5 hours, then cool naturally. Once the system temperature is below 60°C, pour the reaction solution into 250.0 ml of acetone. Allow the mixture to settle, vacuum filter, and rinse three times with methanol. Dry under vacuum at 80°C for 18 hours to obtain the poly (4-methyl-1-pentene) (TPX) grafted product.

[0042] 1.0-2.0 g of the dried grafted product was weighed, 150.0 ml of xylene was added, and the product was heated and stirred in an oil bath at 120°C for 2 h. The acid value of the grafted product was measured according to ASTM-D1386-15 (2022), which was converted into a grafting rate of 4.70%.

[0043] Example 6

[0044] A poly-4-methyl-1-pentene graft compound, which differs from Example 3 in that the dropping rate of the mixed solution (initiator solution) is set to 0.5 wt% / min.

[0045] Example 7

[0046] A poly-4-methyl-1-pentene graft compound, which differs from Example 3 in that the dropping rate of the mixed solution (initiator solution) is set to 5.0 wt% / min.

[0047] Comparative Example 1 A poly-4-methyl-1-pentene graft product is different from Example 3 in that ethyl acetate is replaced by an equal mass of cumene in each preparation step.

[0048] Comparative Example 2 A poly-4-methyl-1-pentene graft product is different from Example 3 in that cumene is replaced by toluene of equal mass in each preparation step.

[0049] Comparative Example 3 A poly-4-methyl-1-pentene graft product is prepared, which differs from Example 3 in that cumene and ethyl acetate are replaced by toluene in equal mass in each preparation step, as follows: Place a 500 mL four-necked flask equipped with a stirrer, thermometer, and reflux condenser in an oil bath. Add 10.5 g of poly (4-methyl-1-pentene), 92.6 g of toluene, and 2.0 g of maleic acid. Adjust the stirring speed to 400 rpm / min and stir for 20 minutes. Then, turn on the oil bath heating device, set the temperature to 125°C, and stir at 400 rpm / min for 50 minutes to obtain a clear, transparent, and uniform poly (4-methyl-1-pentene) solution.

[0050] Mix 1.8g of tert-butyl peroxybenzoate and 6.0g of toluene. Add the resulting mixture dropwise to the poly(4-methyl-1-pentene) solution using a syringe pump at a rate of 1.6wt% / min. After complete addition, allow the mixture to react for 5.0h before naturally cooling. Once the system temperature falls below 60°C, pour the reaction solution into 500ml of acetone. Allow the mixture to settle, vacuum filter, and rinse three times with anhydrous ethanol. Dry under vacuum at 90°C for 16h to obtain the poly(4-methyl-1-pentene) (TPX) grafted product.

[0051] 1.0-2.0 g of the dried grafted product was weighed, 150.0 ml of xylene was added, and the product was heated and stirred in an oil bath at 120°C for 2 h. The acid value of the grafted product was measured according to ASTM-D1386-15 (2022), which was converted into a grafting rate of 5.83%.

[0052] Comparative Example 4 A poly-4-methyl-1-pentene grafted product is prepared by the following steps: Place a 2000 mL four-necked flask equipped with a stirrer, thermometer, and reflux condenser in an oil bath. Add 125.0 g of poly (4-methyl-1-pentene), 935.0 g of xylene, 13.0 g of itaconic anhydride, and 18.8 g of methyl acetate. Adjust the stirring speed to 500 rpm / min and stir for 10 minutes. Then, turn on the oil bath heating device, set the temperature to 125°C, and stir at 350 rpm / min for 30 minutes to obtain a clear, transparent, and uniform poly (4-methyl-1-pentene) solution.

[0053] Mix 12.5g of dicumyl peroxide and 25.0g of xylene. Add the resulting mixture dropwise to the poly (4-methyl-1-pentene) solution using a syringe pump for 0.5h. After complete addition, allow the mixture to react for 4.5h before cooling naturally. Once the system temperature is below 60°C, pour the reaction solution into 1800ml of acetone. Allow the mixture to settle, vacuum filter, and rinse three times with anhydrous ethanol. Dry under vacuum at 90°C for 18h to obtain the poly (4-methyl-1-pentene) (TPX) grafted product.

[0054] 1.0-2.0 g of the dried grafted product was weighed, 150.0 ml of xylene was added, and the product was heated and stirred in an oil bath at 120°C for 2 h. The acid value of the grafted product was measured according to ASTM-D1386-15 (2022), which was converted into a grafting rate of 0.90%. Performance testing

[0055] Test 1: Grafting rate test Sample preparation: 1.0-2.0 g of the grafted product obtained in each embodiment and comparative example.

[0056] Test method: Refer to ASTM-D1386-15 (2022) for testing. Weigh 1.0 g to 2.0 g of sample (recorded as m1) to the nearest 0.0001 g, transfer to a 500 ml flask, add 150.0 ml of xylene, and heat in a 120 ° C oil bath with stirring for 2.0 h until the solution becomes clear and transparent.

[0057] While stirring, add 5–8 drops of phenolphthalein indicator and titrate the hot solution with a standard ethanolic potassium hydroxide solution (concentration: cm⁻¹) until the solution first displays a pink color. The endpoint is determined when the pink color persists for at least 10 seconds. Record the volume of standard solution consumed as V1.

[0058] Without adding sample, repeat the above steps to determine the blank titration value and record the volume of standard solution consumed as V0.

[0059] The acid value of the grafted product was calculated according to the following formula: The conversion to grafting rate is: G%=AN×98.06 / (2×561).

[0060] Test 2: Mechanical properties test Specimen Preparation: Using a flatbed vulcanizer, place the dried grafted particles in a mold (mold dimensions refer to the standard 1A dumbbell specimen in ISO 527-2-2012) at a temperature of 220-235°C and a pressure of 10-15 MPa. Use a standard dumbbell-shaped cutter (dimensions: total length ≥ 75 mm, gauge length 25 mm, width 5 mm, thickness 2 mm) to cut the specimens, ensuring there are no gaps, bubbles, or impurities. Prepare five specimens per group.

[0061] Test Method: Tests were conducted in accordance with ASTM D638-2014, Standard Test Method for Tensile Properties of Plastics. A universal testing machine (Instron 5567) was used at a tensile speed of 50 mm / min, an ambient temperature of 23 ± 2°C, and a humidity of 50 ± 5%. The breaking strength (MPa) was recorded.

[0062] Table 1. Performance test results

[0063] Table 1 shows that compared to Examples 1-7, Comparative Example 1 (no auxiliary solvent added), Comparative Example 2 (using an organic solvent containing benzyl hydrogen as the grafting solvent), Comparative Example 3 (no auxiliary solvent added and using an organic solvent containing benzyl hydrogen as the grafting solvent), and Comparative Example 4 (using an organic solvent containing benzyl hydrogen as the grafting solvent) all showed significant decreases in grafting rate and mechanical properties. This demonstrates the positive effect of organic solvents and auxiliary solvents that do not contain benzyl hydrogen on improving the grafting rate of TPX.

[0064] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A poly-4-methyl-1-pentene graft, characterized in that: The invention is prepared by free radical polymerization of poly-4-methyl-1-pentene and a grafting monomer in a mass ratio of 100:3 to 30 in a mixed solvent; the mixed solvent comprises a grafting solvent and an auxiliary solvent, the grafting solvent is an organic solvent free of benzyl hydrogen, and the auxiliary solvent is selected from at least one of dichloromethane, acetone, methyl acetate, trichloroethylene, and ethyl acetate; the grafting monomer comprises an unsaturated carboxylic acid monomer.

2. The poly-4-methyl-1-pentene graft according to claim 1, characterized in that The grafting solvent is selected from one of decahydronaphthalene, cumene, tert-butylbenzene, dichlorobenzene and trichlorobenzene.

3. The poly-4-methyl-1-pentene graft according to claim 1, characterized in that The amount of the grafting solvent is 600-1200% of the mass of the poly-4-methyl-1-pentene.

4. The poly-4-methyl-1-pentene graft according to claim 1, characterized in that The amount of the auxiliary solvent used is 5 to 25% of the mass of the poly-4-methyl-1-pentene.

5. The poly-4-methyl-1-pentene graft according to claim 1, characterized in that The unsaturated carboxylic acid monomer is selected from one or more of maleic acid, fumaric acid, itaconic acid, maleic anhydride, acrylic acid, methacrylic acid, methyl maleate, itaconic anhydride, and methylmaleic anhydride.

6. The poly-4-methyl-1-pentene graft according to claim 1, characterized in that The reaction temperature of the free radical polymerization is 100-140°C.

7. The poly-4-methyl-1-pentene graft according to claim 1, characterized in that In the free radical polymerization process, the amount of initiator used is 1 to 10% of the mass of the poly-4-methyl-1-pentene.

8. The poly-4-methyl-1-pentene graft according to claim 1, characterized in that During the free radical polymerization process, the initiator is added at a rate of 1.0 to 3.0 wt% / min.

9. The poly-4-methyl-1-pentene graft according to claim 7, characterized in that: The initiator is at least one of azobisisobutyronitrile, azobisisoheptanenitrile, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl perbenzoate, dioctyl peroxydicarbonate, and percarbonate.

10. A method for preparing a poly-4-methyl-1-pentene graft, characterized in that: include: Mixing a portion of the grafting solvent, the poly-4-methyl-1-pentene polymer, the polar monomer, and the grafting auxiliary solvent, stirring and mixing; stirring at a temperature of 80 to 140° C. to form a poly-4-methyl-1-pentene solution; The grafting solvent and the initiator are uniformly mixed to prepare an initiator solution, and the initiator solution is added dropwise to the poly (4-methyl-1-pentene) solution to carry out a polymerization reaction. After the dropwise addition is completed, the reaction is allowed to mature for 1 to 6 hours. After the reaction is completed, the temperature is lowered to below 60°C, and the reaction solution is poured into acetone. After being allowed to settle, the reaction solution is soaked and washed with anhydrous ethanol, and vacuum dried to obtain a grafted product of poly (4-methyl-1-pentene).

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