Ethylene and methyl methacrylate polymer and preparation thereof

Abstract

The invention discloses an ethylene and methyl methacrylate polymer. A unary sequence structure in a molecular chain of the ethylene and methyl methacrylate polymer comprises a group A introduced by methyl methacrylate, a group B introduced by ethylene and a group C which is introduced by ethylene and has an alkyl branched chain R, a binary sequence structure in a molecular chain of the ethylene and methyl methacrylate polymer comprises a group-A-B-and a group-A-C-and / or a group-A-A-; a ternary sequence structure in a molecular chain of the ethylene and methyl methacrylate polymer is a group-A-A-A-, and the-A-A-A-A-structure comprises an isotactic structure, a random structure and a simple structure. The ethylene and methyl methacrylate polymer provided by the invention is clearer and more ordered in structure, and can be better regulated as required; and the ester content in the polymer reaches 10-48 omega%, so that the polymer has a wider application prospect.

Description

Technical Field

[0001] The invention relates to a polymer of ethylene and methyl methacrylate and its preparation. Background Art

[0002] The existing commercial polymer products of ethylene and methyl methacrylate are produced by high-pressure free radical technology. Under high pressure and high temperature conditions, random ethylene and methyl methacrylate polymers are obtained, and the product structure cannot be precisely controlled as needed. In addition, the high-pressure method has harsh process conditions, large one-time investment, high device operation costs, and high safety requirements. Therefore, low-pressure coordination technology has become a research hotspot. In recent years, many novel coordination catalysts that can be used for the copolymerization of olefins (such as ethylene) and acrylate monomers (such as methyl acrylate) have been developed both at home and abroad. In theory, these catalysts that can catalyze the copolymerization of ethylene and monomers such as methyl acrylate can also catalyze the copolymerization of ethylene and methyl methacrylate. However, compared with methyl acrylate, methyl methacrylate has a larger spatial mobility steric hindrance, so its copolymerization activity is lower, the molecular weight of the copolymer is not high, and the insertion rate of methyl methacrylate in the copolymer is difficult to control. At present, the coordination copolymerization technology of ethylene and methyl methacrylate is mainly realized by using a single late transition metal catalyst, and the co-catalyst is an organoaluminum compound or a combination of an organoaluminum compound and an organoboron compound. Generally, under the condition that the molar ratio of the co-catalyst to the main catalyst is ≤1000:1, the copolymerization activity can reach 10 5 g / molcat, but the molecular weight of the obtained copolymer is only 10 4 In addition, there is also a method of using two different types of catalysts to mix. Currently, there is little research on the ethylene and methyl methacrylate polymer products obtained by coordination polymerization. Summary of the invention

[0003] In order to enable the product structure to be precisely controlled as required, an embodiment of the present invention provides an ethylene and methyl methacrylate polymer obtainable by a coordination copolymerization method, which has a microscopic chain structure similar to that of linear polyethylene and higher thermal stability, and is more suitable for mixing with various resins.

[0004] As a first aspect of the present invention, it relates to a polymer of ethylene and methyl methacrylate, wherein the monocyclic structure in the molecular chain of the polymer of ethylene and methyl methacrylate comprises: a group A introduced from methyl methacrylate, a group B introduced from ethylene, and a group C having an alkyl branch chain R introduced from ethylene,

[0005] Wherein, the structural formula of the group A is shown in formula (1):

[0006]

[0007] The structural formula of the group B is shown in formula (2):

[0008]

[0009] The structural formula of the group C is shown in formula (3):

[0010]

[0011] In formula (3), R is an alkyl group having 1 to 5 carbon atoms and / or an alkyl group having 6 to 40 carbon atoms, and R does not have a secondary branch;

[0012] The binary sequence structure in the molecular chain of the ethylene and methyl methacrylate polymer includes: a group -AB- and a group -AC- and / or a group -AA-,

[0013] Wherein, the structural formula of the group -AB- is shown in formula (4):

[0014]

[0015] The structural formula of the group -AA- is shown in formula (5):

[0016]

[0017] The structural formula of the group -AC- is shown in formula (6):

[0018]

[0019] In formula (6), R is an alkyl group having 1 to 5 carbon atoms and / or an alkyl group having 6 to 40 carbon atoms, and R does not have a secondary branch;

[0020] The ternary sequence structure in the molecular chain of the ethylene and methyl methacrylate polymer is a group -AAA-, and the structure of -AAA- includes isotactic, atactic and simple regular structures.

[0021] In one or some optional embodiments, taking the total molar number of the monocyclic structure group A, group B and group C as 100 mol%, the molar number of the group A accounts for 5-30 mol%, and the molar number of the group B and the group C accounts for 70-95 mol% in total; taking the total molar number of the group A and the group C as 100 mol%, the molar number of the group A accounts for 15-50 mol%, and the molar number of the group C accounts for 50-85 mol%.

[0022] In one or some preferred embodiments, taking the total molar number of the monocyclic structure group A, the group B and the group C as 100 mol%, the molar number of the group A accounts for 10-20 mol%, and the molar number of the group B and the group C accounts for 80-90 mol% in total; taking the total molar number of the group A and the group C as 100 mol%, the molar number of the group A accounts for 20-40 mol%, and the molar number of the group C accounts for 60-80 mol%.

[0023] In one or some optional embodiments, in the group C, based on the total molar number of the alkyl branch chain R as 100 mol%, methyl accounts for 50-85 mol%, and alkyl groups with 2-5 carbon atoms and / or alkyl groups with 6-40 carbon atoms account for 15-50 mol%; based on the total molar number of the alkyl groups with 2-5 carbon atoms and / or alkyl groups with 6-40 carbon atoms as 100 mol%, ethyl accounts for 0-45 mol%, propyl accounts for 0-15 mol%, butyl accounts for 0-15 mol%, pentyl accounts for 0-15 mol%, and alkyl groups with 6-40 carbon atoms account for 0-10 mol%.

[0024] In one or some preferred embodiments, in the group C, based on the total molar number of the alkyl branch chain R as 100 mol%, methyl groups account for 70-85 mol%, and alkyl groups with 2-5 carbon atoms and / or alkyl groups with 6-40 carbon atoms account for 15-30 mol%; based on the total molar number of the alkyl groups with 2-5 carbon atoms and / or alkyl groups with 6-40 carbon atoms as 100 mol%, ethyl groups account for 0-53 mol%, propyl groups account for 0-15 mol%, butyl groups account for 0-15 mol%, pentyl groups account for 0-15 mol%, and alkyl groups with 6-40 carbon atoms account for 0-2 mol%.

[0025] In one or some optional embodiments, taking the total molar number of the binary sequence structures -AB-, -AC- and -AA- as 100 mol%, -AC- accounts for 0 to 10 mol%, -AA- accounts for 0 to 30 mol%, and -AB- accounts for 60 to 100 mol%.

[0026] In one or some optional embodiments, based on the total molar number of the ternary sequence structure -AAA- as 100 mol%, the isotactic -AAA- accounts for 0 to 20 mol%, the irregular -AAA- accounts for 35 to 40 mol%, and the simple regular -AAA- accounts for 45 to 60 mol%.

[0027] In one or some optional embodiments, the weight average molecular weight of the ethylene and methyl methacrylate polymer is in the range of [1×10 4 g / mol, 1×10 6 g / mol), and the molecular weight distribution is 1 to 5.

[0028] In one or some preferred embodiments, the weight average molecular weight range of the ethylene and methyl methacrylate polymer is [1×10 5 g / mol, 1×10 6 g / mol), and the molecular weight distribution is 1 to 3.

[0029] In one or some optional embodiments, the total alkyl branching degree of the ethylene and methyl methacrylate polymer is 10 to 35 branches / 1000C.

[0030] In one or some preferred embodiments, the total alkyl branching degree of the ethylene and methyl methacrylate polymer is 10 to 20 branches / 1000C.

[0031] In one or some optional embodiments, the density of the ethylene and methyl methacrylate polymer is 0.925-0.950 kg / m 3 , ester content is 10-48ω%, melting point is 50-135°C, thermal decomposition temperature is ≥440°C, and water contact angle is ≤85°.

[0032] In one or some preferred embodiments, the density of the ethylene and methyl methacrylate polymer is 0.930-0.950 kg / m 3 , ester content is 18-30ω%, melting point is 100-135°C, thermal decomposition temperature is ≥450°C, and water contact angle is ≤80°.

[0033] As a second aspect of the present invention, it relates to a method for preparing the above-mentioned polymer of ethylene and methyl methacrylate, comprising:

[0034] Ethylene and methyl methacrylate are polymerized under catalyst conditions.

[0035] In one or some optional embodiments, the method specifically includes:

[0036] With ethylene and methyl methacrylate as copolymer monomers, the polymerization temperature is controlled at 30-100°C and the ethylene pressure is controlled at 1-10 MPa. The polymerization reaction is carried out for 1-8 hours under catalyst conditions to obtain ethylene and methyl methacrylate polymer.

[0037] In one or some optional embodiments, the catalyst is a salicylaldehyde imine type metal catalyst, and its general structural formula is shown in formula (7):

[0038]

[0039] In formula (7), R1 and R2 are H or a straight-chain alkyl group having 1 to 4 carbon atoms, R3 and R4 are large steric groups with electron-withdrawing substituents, and M is metal nickel or palladium.

[0040] In one or some preferred embodiments, the catalyst is a salicylaldehyde imine type nickel catalyst, and its structural formula is shown in formula (8) or formula (9):

[0041]

[0042] The ethylene and methyl methacrylate polymer provided by the present invention has a branched structure mainly based on linearity, and the proportion of branched carbon atoms of ≥6 C is ≤10 mol%, and there is no secondary or higher level branching. Compared with the ethylene and methyl methacrylate polymer obtained by the existing high-pressure free radical polymerization technology, the ethylene and methyl methacrylate polymer provided by the present invention has a clearer and more orderly structure, so that it can be better regulated on demand.

[0043] The ethylene and methyl methacrylate polymer provided by the present invention introduces a polar ester functional group into the vinyl main chain, thereby giving the vinyl polymer polarity. The ester content in the ethylene and methyl methacrylate polymer reaches 10-48ω%, and compared with post-functionalized vinyl polar polymers, the present invention has broader application prospects. DETAILED DESCRIPTION

[0044] The following is a detailed description of the embodiments of the present invention: The embodiments of the present invention are implemented on the premise of the technical solution of the present invention, and detailed implementation methods and processes are given, but the protection scope of the present invention is not limited to the following embodiments. The process parameters for which specific conditions are not specified in the following embodiments are generally based on conventional conditions.

[0045] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0046] The inventors implemented relevant technical solutions with reference to patents CN109021009A, CN101633707B, CN107868158A, CN107001524B, CN113773211A, CN109320558B, CN201610842249.6, and CN201611263064.6, and found that the properties such as the structure and polarity of the copolymers were not ideal. After further research and development, the inventors made the present invention.

[0047] Unless otherwise specified, the raw materials and equipment used for polymerizing ethylene and methyl methacrylate in the embodiments of the present invention are from:

[0048] Ethylene, polymerization grade, purity 99.9%, produced by Daqing Branch of China National Petroleum Corporation; methyl methacrylate, analytical grade, 99%, provided by Shanghai Aladdin Biochemical Technology Co., Ltd.; toluene, analytical grade, 99.5%, provided by Nanjing Chemical Reagent Co., Ltd.; hexane, 98%, produced by Fushun Branch of China National Petroleum Corporation; 250mL pressure reactor and 10L pressure reactor were manufactured by Yantai Keli Chemical Equipment Co., Ltd.

[0049] The equipment and method used for analyzing and testing the performance of ethylene and methyl methacrylate polymers in the embodiments of the present invention are:

[0050] The structural analysis of the polymer was performed using a Bruker-500 nuclear magnetic resonance spectrometer from Bruker, Switzerland. The 1H NMR test conditions were: frequency 300 Hz, 120°C, and CDCl3 as solvent. 13 C NMR test conditions: frequency 75 Hz, CDCl3 as solvent, tilt angle 74°, delay time 4 s, sampling time 1.5 s, determination method: proton decoupling method.

[0051] Polymer molecular weight and molecular weight distribution: CR-7 gel permeation chromatograph of PE Company, USA was used. Conditions: 135°C, 1,2,4-trichlorobenzene as eluent, flow rate 1.0 mL / min.

[0052] Melting point of polymer: Use Q2000 differential scanning calorimeter from TE Corporation of the United States. Raise the temperature to 170°C at a rate of 10°C / min, hold for 5 minutes, then cool down to 50°C at a rate of 10°C / min, and record the temperature drop and temperature rise curves.

[0053] Density of polymer: analyzed using the method in GB / T10332-2010, using a 6001 density meter from CEAST, Italy.

[0054] Melt flow index of polymer: analyzed by the method in GB / T 3682-2018, 6542 melt flow rate meter from CEAST, Italy, die diameter 2.095 cm, temperature 190°C, accuracy 0.1°C, load 2.16 kg.

[0055] Water contact angle of polymer: Tested using G-1 contact angle meter produced by Kyowa, Japan. Deionized water was dropped on the film surface for 1 min before testing. Three points with a distance of 5 mm were measured for each sample. A total of 6 readings were taken and the arithmetic average was taken. The drop volume was controlled at 1-5 μl.

[0056] The calculation of the ester content in the polymer refers to the method provided in patent CN107001542B.

[0057] The catalyst used in the embodiment of the present invention is a salicylaldehyde imine type metal catalyst, which has the following general structural formula:

[0058]

[0059] Among them, R1 and R2 are H or a straight-chain alkyl group with 1 to 4 carbon atoms, R3 and R4 are large steric groups with electron-withdrawing substituents, and M is metal nickel or palladium.

[0060] Considering the economic cost, salicylaldehyde imine type nickel catalyst is used in the embodiment of the present invention.

[0061] Examples 1 to 9

[0062] (1) Synthesis of salicylaldehyde imine type nickel catalyst

[0063] Synthesis of alkyl salicylaldehyde:

[0064] Under argon protection, 500 mL of dry toluene was added as a reaction solvent in a reactor with electromagnetic stirring and a condenser, and 1 mol of alkylphenol, 0.1 mol of anhydrous tin tetrachloride and 0.4 mol of tributylamine were added, stirred at room temperature for 20 minutes, 2.2 mol of paraformaldehyde was added, heated to 100 ° C, and the reaction was terminated after about 8 hours. After the reaction was completed, the reactant was cooled to room temperature and acidified with 2M hydrochloric acid until the pH value was equal to 2. After the acidification was completed, the reaction solution was poured into a separatory tank to separate the organic phase and the aqueous phase. After the aqueous phase was analyzed, it was reused as an acidifying agent, and the obtained organic phase was separated by a high-precision distillation device to obtain alkyl salicylaldehyde with a purity of about 95% and a yield of about 50%.

[0065] Synthesis of alkyl salicylaldehyde imine:

[0066] Under argon protection, 0.22 mol of alkyl salicylaldehyde and 240 mL of anhydrous ethanol were added in sequence to a reaction kettle equipped with electromagnetic stirring and a condenser, and 0.23 mol of 2,6-di(trifluoromethyl)aniline was added dropwise while stirring. After the addition, the temperature was raised to 80°C and the reaction was continued for 4 hours. The reaction solution was naturally cooled to room temperature, allowed to stand until no powder was precipitated, filtered, and the solid obtained after drying was recrystallized with anhydrous ethanol to obtain alkyl salicylaldehyde imine crystals with a yield of 80% and a purity of 95%.

[0067] Synthesis of nickel dialkyl salicylaldehyde imine:

[0068] In a reaction kettle equipped with a magnetic stirrer and a condenser, 0.172 mol of alkyl salicylaldehyde imine ligand and 400 mL of anhydrous ethanol were added in sequence, stirring was started, the temperature was raised to reflux, and 8.29% ethanol solution of nickel acetate tetrahydrate was slowly added dropwise. After the addition was completed, the reflux reaction was continued for 4 hours, and the mixture was naturally cooled to room temperature, allowed to stand, filtered, washed with anhydrous ethanol, and dried to obtain dialkyl salicylaldehyde imine nickel.

[0069] The structural formula of the dialkyl salicylaldehyde imine nickel prepared in this embodiment is:

[0070]

[0071] (2) Polymerization of ethylene and methyl methacrylate

[0072] The polymerization reaction can be completed in a 250mL stainless steel pressure reactor with mechanical stirring. The reactor cover is equipped with a pressure-resistant liquid feeding tube. The reactor is replaced with 0.1MPa nitrogen three times to exhaust the air in the reactor; the reactor is heated to 150°C under a vacuum of -0.1MPa, kept at a constant temperature for 2h, and then cooled to room temperature; the reactor is replaced with 0.1MPa nitrogen three times again, and then the reactor is pressurized to 0.1MPa with 0.1MPa ethylene and replaced three times. Under ethylene atmosphere, at room temperature, 145 mL of toluene solution of dialkyl salicylaldehyde imine nickel is added to a reactor through a feeding tube, and then 5 mL of toluene solution of methyl methacrylate is added, and the total reaction volume is maintained at 150 mL; the temperature of the reactor is raised to the reaction temperature through an electric heater, and the reaction temperature is controlled by deionized water and the electric heater introduced into the reactor coil, and the temperature control accuracy is ±1°C through internal thermocouple monitoring; after the reaction temperature reaches 30-100°C, ethylene is charged, and the pressure of the reactor is kept constant at 1-10 MPa. After reacting for 1-8 hours, the ethylene pressure is released and 5% (v / v) acidic ethanol of 2 times the volume of the reaction solution is added to terminate the polymerization. The resulting precipitated polymer is collected, filtered, washed with ethanol several times, and then dried to constant weight under vacuum at 60°C.

[0073] Large-scale polymerization reactions can be completed in a 10L high-pressure reactor, and the reactor cover is equipped with a pressure-resistant liquid feeding pipe. The amount of ethylene and nitrogen can be measured by an online mass flow meter. The reaction temperature is uniformly raised by electrically heating the heat transfer oil in the outer jacket of the reactor. The outer jacket of the reactor is provided with a coil, and deionized water or other cooling medium for cooling can be passed into it. The reaction temperature is controlled to be constant within 30-100°C by adjusting the flow of cooling water online and heating the heat transfer oil through an electric heater. The temperature is monitored by a thermocouple inside the reactor and the signal required by the temperature controller is fed back. The temperature control accuracy is ±1°C. Similarly, the reactor is replaced with 0.1MPa nitrogen three times to exhaust the air in the reactor; the reactor is heated to 150°C at a vacuum of -0.1MPa, kept at a constant temperature for 2h, and then cooled to room temperature; the reactor is replaced with 0.1MPa nitrogen three times again, and then the reactor is pressurized to 0.1MPa with 0.1MPa ethylene, and replaced three times. At room temperature and in an ethylene atmosphere, 5.5 L of toluene solution of dialkyl salicylaldehyde imine nickel is added to the reactor through a feeding tube, and then 0.5 L of toluene solution of methyl methacrylate is added, and the total reaction volume is maintained at 6 L. The temperature of the reactor is raised to 30-100 ° C by an electric heater. After the reaction temperature is reached, ethylene is charged to keep the pressure of the reactor constant at 1-10 MPa. After reacting for 1-8 hours, 1 L of acidic methanol is added after the ethylene pressure is released to terminate the polymerization. The reactants are introduced into the separator from the discharge valve at the bottom of the reactor. The separator is a two-layer structure, with a stirring device suitable for solid-liquid systems on the upper part, and a filter screen is installed between the upper and lower layers. Start the stirring of the separator, and the liquid in the reactants will automatically fall into the lower part of the separator, and then be introduced into another closed container for recycling. A hot dry nitrogen or air flow is introduced into the lower part of the separator to dry the solid reactants remaining on the upper part of the separator screen. The gas is discharged from the top of the separator. The organic content in the gas is regularly tested. When the organic content is ≤100ppm, the solid reactants in the separator are collected, washed with ethanol, filtered, and dried several times, and finally dried to constant weight under vacuum at 60°C.

[0074] The experimental conditions and results of preparing ethylene and methyl methacrylate polymers in Examples 1 to 9 are shown in Table 1 below.

[0075] The ethylene and methyl methacrylate polymers in Examples 1 to 9 were analyzed and tested for performance, and the structural characterization results are shown in Table 2.

[0076] Embodiments 10 to 18

[0077] (1) Synthesis of salicylaldehyde imine type nickel catalyst

[0078] The synthesis method of the catalyst is similar to that of Example 1. The structural formula of the catalyst in this example is:

[0079]

[0080] (2) Polymerization of ethylene and methyl methacrylate

[0081] The same method as in Example 1 was used.

[0082] The experimental conditions and results of preparing the ethylene and methyl methacrylate polymers in Examples 10 to 18 are shown in Table 1. The ethylene and methyl methacrylate polymers in Examples 10 to 18 were analyzed and tested for performance, and the structural characterization results are shown in Table 2.

[0083] Comparative Example 1

[0084] (1) Synthesis of salicylaldehyde imine type nickel catalyst

[0085] The catalyst used in this comparative example is a catalyst with a tert-butyl group with large steric hindrance at the ortho position of O. The synthesis method thereof is similar to that of Example 1, and the structural formula thereof is:

[0086]

[0087] Wherein, tBu is tert-butyl.

[0088] (2) Polymerization of ethylene and methyl methacrylate

[0089] The same method as in Example 1 was used.

[0090] The experimental conditions and results of preparing the polymer of ethylene and methyl methacrylate in this comparative example are shown in Table 1 below.

[0091] The ethylene and methyl methacrylate polymer in this comparative example was analyzed and tested for performance, and the structural characterization results are shown in Table 2.

[0092] Table 1 Experimental results of preparation of ethylene and methyl methacrylate polymers

[0093]

[0094] Table 2 Analysis results of ethylene and methyl methacrylate polymers

[0095]

[0096] Note: ①A is an ester group, ②C is an alkyl side chain, ③A-C is a sequence unit in which the ester group and the alkyl side chain are directly adjacent, ④A-A is a continuous ester sequence unit, and ⑤ a ternary sequence refers to an alkyl chain segment.

[0097] From the analysis of Table 1 and Table 2, it can be seen that under the same process conditions, the embodiments of the present invention achieve the introduction of methyl methacrylate functional groups into the vinyl polymer. Compared with the comparative example, the ethylene and methyl methacrylate polymer provided by the embodiments of the present invention has a higher ester content, which can reach 10-48 ω%, and a higher weight average molecular weight, which can reach [1×10 5 g / mol, 1×10 6 g / mol).

[0098] Although the specific embodiments of the present invention have been described in detail, it will be understood by those skilled in the art. According to all the teachings disclosed, various modifications and replacements can be made to those details, and these changes are all within the protection scope of the present invention. The full scope of the present invention is given by the attached claims and any equivalents thereof.

Claims

1. A polymer of ethylene and methyl methacrylate, characterized in that: The monocyclic structure in the molecular chain of the ethylene and methyl methacrylate polymer includes: a group A introduced from methyl methacrylate, a group B introduced from ethylene, and a group C having an alkyl branch chain R introduced from ethylene, Wherein, the structural formula of the group A is shown in formula (1): The structural formula of the group B is shown in formula (2): The structural formula of the group C is shown in formula (3): In formula (3), R is an alkyl group having 1 to 5 carbon atoms and / or an alkyl group having 6 to 40 carbon atoms, and R does not have a secondary branch; The binary sequence structure in the molecular chain of the ethylene and methyl methacrylate polymer includes: a group -AB- and a group -AC- and / or a group -AA-, Wherein, the structural formula of the group -AB- is shown in formula (4): The structural formula of the group -AA- is shown in formula (5): The structural formula of the group -AC- is shown in formula (6): In formula (6), R is an alkyl group having 1 to 5 carbon atoms and / or an alkyl group having 6 to 40 carbon atoms, and R does not have a secondary branch; The ternary sequence structure in the molecular chain of the ethylene and methyl methacrylate polymer is a group -AAA-, and the structure of -AAA- includes isotactic, atactic and simple regular structures.

2. The polymer of ethylene and methyl methacrylate according to claim 1, characterized in that Taking the total molar number of the monocyclic structure group A, group B and group C as 100 mol%, the molar number of the group A accounts for 5 to 30 mol%, and the molar number of the group B and the group C accounts for 70 to 95 mol% in total; taking the total molar number of the group A and the group C as 100 mol%, the molar number of the group A accounts for 15 to 50 mol%, and the molar number of the group C accounts for 50 to 85 mol%.

3. The polymer of ethylene and methyl methacrylate according to claim 2, characterized in that Taking the total molar number of the monocyclic structure group A, group B and group C as 100 mol%, the molar number of the group A accounts for 10-20 mol%, and the molar number of the group B and the group C accounts for 80-90 mol% in total; taking the total molar number of the group A and the group C as 100 mol%, the molar number of the group A accounts for 20-40 mol%, and the molar number of the group C accounts for 60-80 mol%.

4. The polymer of ethylene and methyl methacrylate according to claim 1, characterized in that In the group C, taking the total molar number of the alkyl branch chain R as 100 mol%, the methyl group accounts for 50-85 mol%, and the alkyl group with 2-5 carbon atoms and / or the alkyl group with 6-40 carbon atoms accounts for 15-50 mol%; taking the total molar number of the alkyl group with 2-5 carbon atoms and / or the alkyl group with 6-40 carbon atoms as 100 mol%, the ethyl group accounts for 0-45 mol%, the propyl group accounts for 0-15 mol%, the butyl group accounts for 0-15 mol%, the pentyl group accounts for 0-15 mol%, and the alkyl group with 6-40 carbon atoms accounts for 0-10 mol%.

5. The polymer of ethylene and methyl methacrylate according to claim 4, characterized in that In the group C, taking the total molar number of the alkyl branch chain R as 100 mol%, the methyl group accounts for 70-85 mol%, and the alkyl group with 2-5 carbon atoms and / or the alkyl group with 6-40 carbon atoms accounts for 15-30 mol%; taking the total molar number of the alkyl group with 2-5 carbon atoms and / or the alkyl group with 6-40 carbon atoms as 100 mol%, the ethyl group accounts for 0-53 mol%, the propyl group accounts for 0-15 mol%, the butyl group accounts for 0-15 mol%, the pentyl group accounts for 0-15 mol%, and the alkyl group with 6-40 carbon atoms accounts for 0-2 mol%.

6. The polymer of ethylene and methyl methacrylate according to claim 1, characterized in that Taking the total molar number of the binary sequence structures -AB-, -AC- and -AA- as 100 mol%, -AC- accounts for 0 to 10 mol%, -AA- accounts for 0 to 30 mol%, and -AB- accounts for 60 to 100 mol%.

7. The polymer of ethylene and methyl methacrylate according to claim 1, characterized in that Taking the total molar number of the ternary sequence structure -AAA- as 100 mol%, the isotactic -AAA- accounts for 0-20 mol%, the irregular -AAA- accounts for 35-40 mol%, and the simple regular -AAA- accounts for 45-60 mol%.

8. The polymer of ethylene and methyl methacrylate according to claim 1, characterized in that The weight average molecular weight range of the ethylene and methyl methacrylate polymer is [1×10 4 g / mol, 1×10 6 g / mol), and the molecular weight distribution is 1 to 5.

9. The polymer of ethylene and methyl methacrylate according to claim 8, characterized in that The weight average molecular weight range of the ethylene and methyl methacrylate polymer is [1×10 5 g / mol, 1×10 6 g / mol), and the molecular weight distribution is 1 to 3.

10. The polymer of ethylene and methyl methacrylate according to claim 1, characterized in that The total alkyl branching degree of the ethylene and methyl methacrylate polymer is 10 to 35 branches / 1000C.

11. The polymer of ethylene and methyl methacrylate according to claim 1, characterized in that The total alkyl branching degree of the ethylene and methyl methacrylate polymer is 10 to 20 branches / 1000C.

12. The polymer of ethylene and methyl methacrylate according to claim 1, characterized in that The density of the ethylene and methyl methacrylate polymer is 0.925-0.950 kg / m 3 , ester content is 10-48ω%, melting point is 50-135°C, thermal decomposition temperature is ≥440°C, and water contact angle is ≤85°.

13. The polymer of ethylene and methyl methacrylate according to claim 12, characterized in that The density of the ethylene and methyl methacrylate polymer is 0.930-0.950 kg / m 3 , ester content is 18-30ω%, melting point is 100-135°C, thermal decomposition temperature is ≥450°C, and water contact angle is ≤80°.

14. A method for preparing a polymer of ethylene and methyl methacrylate according to any one of claims 1 to 13, characterized in that: include: Ethylene and methyl methacrylate are polymerized under catalyst conditions.

15. The method according to claim 14, characterized in that The method specifically comprises: With ethylene and methyl methacrylate as copolymer monomers, the polymerization temperature is controlled at 30-100°C and the ethylene pressure is controlled at 1-10 MPa. The polymerization reaction is carried out for 1-8 hours under catalyst conditions to obtain ethylene and methyl methacrylate polymer.

16. The method according to claim 15, characterized in that The catalyst is a salicylaldehyde imine type metal catalyst, and its general structural formula is shown in formula (7): In formula (7), R1 and R2 are H or a straight-chain alkyl group having 1 to 4 carbon atoms, R3 and R4 are large steric groups with electron-withdrawing substituents, and M is metal nickel or palladium.

17. The method according to claim 16, characterized in that The catalyst is a salicylaldehyde imine type nickel catalyst, and its structural formula is shown in formula (8) or formula (9):

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