A method for preparing POE-grafted MAH with high grafting rate and low crosslinking degree

Abstract

This invention discloses a method for preparing POE-grafted MAH with high grafting rate and low crosslinking degree. The method includes the following steps: blending POE elastomer with MAH, an initiator, and optionally an auxiliary agent; performing a melt grafting reaction in a screw extruder; extruding; and granulating to obtain the POE-grafted MAH; wherein the POE elastomer has a relative active site content (RAS) of 0.15 or greater and a crosslinking grafting ratio (CRG) of 0.06 or lower at a reaction temperature T. This invention can prepare POE-grafted MAH with high grafting rate and low crosslinking degree.

Description

Technical Field

[0001] This invention belongs to the field of modified polymer materials technology, specifically relating to a method for preparing POE grafted with MAH with high grafting rate and low crosslinking degree. Background Technology

[0002] POE is a thermoplastic elastomer material obtained by copolymerizing ethylene and α-olefins. It possesses not only the plasticity of plastics but also the high elasticity and toughness of rubber, and is therefore often used as a toughening modifier for rigid plastics. However, as a typical non-polar material, POE has poor compatibility with polar polymers, making it difficult to provide good toughening effects. Grafting POE with MAH (maleic anhydride) can effectively improve the compatibility problem with polar plastics. After blending with polar plastics, it forms an "island structure," significantly improving the material's toughness through a micro-silver crevice toughening mechanism.

[0003] Common methods for grafting POE with MAH include melt grafting, solution grafting, solid-phase grafting, radiation grafting, and suspension grafting. Among these, melt grafting is the most prevalent method in applied research due to its short reaction time, simple process, low cost, and ability to be continuously produced. In melt grafting, POE, MAH, initiator, and other additives are mixed evenly and then melt-blended at high temperature using a screw extruder. The resulting pellets are then extruded to obtain the grafted product. When the grafted product is used for toughening and modifying polar plastics such as nylon (PA), the anhydride groups of MAH react chemically with the amino groups in PA, enhancing the compatibility and interfacial interaction between the grafted product and PA. Therefore, the grafting rate is an important indicator of the POE-grafted MAH product. The factors influencing the grafting rate are complex, related to the structure of POE and the initiator, the amount of MAH added, and process parameters. In melt grafting reactions, high temperatures accelerate the decomposition of the initiator, generating free radical active sites that initiate the grafting reaction between POE and MAH. The structure of POE and the initiator determines the number of active sites, while monomer concentration and process parameters affect the reaction rate. However, in melt grafting reactions, the presence of numerous free radical active sites increases the probability of collisions between macromolecular free radicals, leading to a strong tendency for POE to crosslink. Therefore, crosslinking side reactions are often unavoidable. Crosslinking side reactions and grafting reactions are competing reactions. Crosslinking not only reduces the flowability of POE, affecting product performance, but also consumes reactive active sites, reducing the grafting rate of the system. When toughening PA materials, it affects compatibility and dispersion in the matrix, weakening the toughening effect on PA. Therefore, how to suppress crosslinking side reactions while ensuring that POE has a high grafting rate and excellent performance is a key research focus.

[0004] For example, invention patent application CN115073672A mixes POE, MAH, and DCP in a certain proportion, then adds a certain amount of styrene and other additives, and performs melt grafting through a twin-screw extruder. Supercritical carbon dioxide is injected during the extrusion process. The extruded material is water-cooled, pelletized, and then dried to obtain toughened and reinforced light yellow POE-grafted MAH granules with a high grafting rate. The addition of a second monomer allows for copolymerization and grafting with MAH, effectively increasing the grafting rate. Another example is invention patent application CN118684829A, which mixes POE, MAH, antioxidants, initiators, and chlorinated hydrocarbons in a certain proportion, then adds a certain amount of chlorinated hydrocarbons. The mixture is then kept at a constant temperature and pressure in supercritical carbon dioxide for a period of time before melt grafting through a twin-screw extruder. The formation of free radicals by the chlorinated hydrocarbons and initiators promotes the grafting reaction of MAH, thereby increasing the grafting rate. However, the formation of a large number of free radicals may promote cross-linking side reactions, and the use of supercritical carbon dioxide increases process costs, which is not conducive to industrial production. Summary of the Invention

[0005] To address the above technical problems, this invention proposes a method for preparing POE-grafted MAH with high grafting rate and low crosslinking degree.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for preparing POE-grafted MAH with high grafting rate and low crosslinking degree includes the following steps:

[0008] POE elastomer is blended with MAH, initiator, and optional additives, and then subjected to a melt grafting reaction in a screw extruder. The mixture is then extruded and granulated to obtain the POE-grafted MAH.

[0009] The POE elastomer has a relative active site content (RAS) of 0.15 or greater and a crosslinking grafting ratio (CRG) of 0.06 or lower at a reaction temperature T.

[0010] The relative active site content (RAS) is defined by the following Equation 1:

[0011] Equation 1

[0012] The cross-linking graft ratio (CRG) is defined by the following equation 2:

[0013] Equation 2

[0014] In the equation, [CR], [CRR], and [CRRR] are respectively obtained through... 13The relative content fractions of methyl, methylene, and methine in POE elastomer measured by C-NMR; E is the bond dissociation energy difference required for methylene to dissociate into methylene radical and methine to dissociate into methine radical, with a value of 8.4 kJ / mol; R is the molar gas constant, with a value of 8.314 J / (mol·K); T is the reaction temperature when POE elastomer undergoes grafting reaction.

[0015] As a preferred embodiment of the present invention, the POE elastomer has a relative active site content (RAS) of greater than 0.2 and less than 0.3 at a reaction temperature (T), and a crosslinking grafting ratio (CRG) of greater than 0.04 and less than 0.06.

[0016] As a preferred embodiment of the present invention, in the equation, [CR] represents a relative methyl content fraction of 5-40%, preferably 10-25%, [CRR] represents a relative methylene content fraction of 20-90%, preferably 50-80%, and [CRRR] represents a relative methine content fraction of 5-40%, preferably 10-25%.

[0017] As a preferred embodiment of the present invention, the initiator is selected from low-temperature initiators with a 1-minute half-life temperature between 50-160°C, preferably one or more of tert-butyl peroxycarbonate-2-ethylhexyl, tert-butyl peroxypentanoate, didecanoic acid peroxide, di-tert-butyl peroxide, tert-pentanoate peroxypentanoate, 1,1,3,3-tetramethylbutyl peroxypentanoate, dibutyl peroxydicarbonate, benzoyl peroxide (BPO), and bis(3,3,5-trimethylacetyl) peroxide.

[0018] As a preferred embodiment of the present invention, the adjuvant includes a grafting monomer; and / or,

[0019] The additive is one or more of methyl methacrylate, acrylic acid, styrene, α-methylstyrene, and epoxy resin; and / or,

[0020] The amount of the additive is 0.1-5% of the mass of the POE elastomer.

[0021] In a preferred embodiment of the present invention, the amount of MAH added is 0.5-2% of the mass of the POE elastomer;

[0022] Preferably, the amount of initiator added is 0.1-0.5% of the mass of the POE elastomer.

[0023] As a preferred embodiment of the present invention, the reaction temperature of the melt grafting reaction is 50-160°C, preferably 120-160°C.

[0024] In order to obtain the raw materials required for this invention, the POE elastomer can be selected from commercially available finished products, or it can be synthesized according to the known preparation process of the product, and the possible reaction parameters and process conditions can be adjusted according to the professional ability of the technicians to obtain the POE elastomer that meets the properties defined above.

[0025] As a non-limiting method for preparing the POE elastomer in this invention, it includes, for example, the following steps:

[0026] S1, First-stage polymerization reaction: Ethylene and α-olefin are fed into a reactor and copolymerized in the presence of a main catalyst and a co-catalyst to obtain a prepolymer;

[0027] S2, Two-stage polymerization reaction: An organonitrile catalyst is added to the reactor, and α-olefins are added to continue the reaction to obtain POE elastomer.

[0028] The α-olefin is a C4-C10 α-olefin, preferably one or more of 1-butene, 1-hexene, and 1-octene;

[0029] The main catalyst is a single-active-center metallocene catalyst and / or a post-metallocene catalyst, preferably a metallocene catalyst and / or a post-metallocene catalyst with titanium, zirconium or hafnium as the metal active center, more preferably one or more of dimethicyl(N-tert-butylamino)(tetramethylcyclopentadienyl)titanium chloride, dimethicyl(N-tert-butylamino)(tetramethylcyclopentadienyl)dimethyltitanium, dimethicyl(N-tert-butylamino)(fluorenyl)titanium chloride, dimethylbis(propylcyclopentadienyl)hafnium, bis(n-butylcyclopentadiene)hafnium chloride, diphenylmethylenecyclopentadiene(2,7-di-tert-butyl-fluorenyl)zirconium chloride, diphenylmethylene(cyclopentadiene)(9-fluorenyl)zirconium chloride, and dimethyldimethicylalkylbis(2-methyl-4-phenyl-1-indenyl)zirconium chloride.

[0030] The cocatalyst comprises an aluminum additive and optionally an organoboron additive; wherein the aluminum additive is selected from at least one of alkylaluminum, aluminum oxanes and their modifiers, preferably one or more of methylaluminoxane, modified methylaluminoxane, ethylaluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum, trioctylaluminum, monochloroethylaluminum, sesquiethylaluminum, and dichloroethylaluminum. The organoboron additive is selected from one or more of triphenylmethyltetra(pentafluorophenyl)borate, tri(pentafluorophenyl)borate compounds, tetra(pentafluorophenyl)borate, N,N-dimethylanilinetetra(pentafluorophenyl)borate, dioctadecylmethyltertiary aminetetra(pentafluorophenyl)borate, and dihydrotallowylmethyltertiary aminetetra(pentafluorophenyl)borate.

[0031] Preferably, the molar ratio (Al / M) of metallic aluminum in the aluminum additive to the metal element in the main catalyst can be 50-1000, more preferably 100-500;

[0032] Preferably, the molar ratio (denoted as B / M) of boron in the organoboron additive to the metal element in the main catalyst can be 1-3, more preferably 1.5-2.5.

[0033] Preferably, the reaction in step S1 is carried out in an organic solvent; the organic solvent is selected from aliphatic hydrocarbon solvents and / or aromatic hydrocarbon solvents;

[0034] Preferably, the aliphatic hydrocarbon solvent is selected from one or more of n-butane, isobutane, n-pentane, cyclopentane, methylcyclopentane, methylenecyclopentane, n-hexane, cyclohexane, methylcyclohexane, ethylcyclohexane, n-heptane, n-octane, n-nonane, and Isopar E; the aromatic hydrocarbon solvent is selected from one or more of benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, and dichlorotoluene.

[0035] Preferably, the amount of the main catalyst added is based on a concentration of 0.1-1.5 μmol / L in the solvent.

[0036] In step S1 above, the molar ratio of α-olefin to ethylene is 1:(0.5-4);

[0037] In step S1, the reaction temperature is 100-200℃, the reaction time is 5-18 min, and the ethylene pressure is 1-6 MPa gauge pressure.

[0038] In step S2, the molar ratio of α-olefin to ethylene is 1:(0.5-4).

[0039] The organonitrile catalyst is selected from organic coordination compounds having at least one ligand structure among phosphine ligands, carboxylic acid ligands, and nitrogen ligands, and is preferably selected from one or more of bis(tri-tert-butylphosphine)nickel, chloro(1-naphthalene)bis(triphenylphosphine)-nickel, (1,1'-bis(diphenylphosphine)ferrocene)dichloride, and tetra(triphenylphosphine)nickel.

[0040] Preferably, the amount of the organic nickel catalyst added is based on a concentration of 0.1-1.5 μmol / L in the solvent.

[0041] In step S2, the reaction temperature is 100-240℃, the reaction time is 10-50 min, and the ethylene pressure is 1-6 MPa gauge pressure.

[0042] The beneficial effects of this invention are as follows:

[0043] In its in-depth study of the effects of grafting rate and crosslinking degree on POE grafting MAH, this invention found that by optimizing the physical properties of the POE elastomer raw material, when it has a relative active site content (RAS) of 0.15 or greater and a crosslinking grafting ratio (CRG) of 0.06 or lower, the grafting reaction can obtain POE grafted particles with high grafting rate and low crosslinking degree at a lower initiation temperature. These particles have wider applicability when used as toughening aids (such as PA toughening materials). Detailed Implementation

[0044] The present invention will be further illustrated below with specific embodiments. These embodiments are merely illustrative and do not limit the scope of the invention.

[0045] Unless otherwise specified, all raw materials and reagents used in the following embodiments of the present invention can be purchased commercially.

[0046] The performance testing method involved in this invention is as follows:

[0047] (1) Grafting rate determination

[0048] Weigh 0.5 g of sample, add 200 ml of xylene, heat and stir for 1 h, cool to room temperature, then pipette 10 ml of potassium hydroxide-ethanol solution (0.05 mol / L), heat under reflux for 2 h, then add 3 drops of 1 wt% phenolphthalein ethanol solution as an indicator, and back titrate with a hydrogen chloride-isopropanol solution (0.05 mol / L). Record the volume of hydrogen chloride-isopropanol solution consumed. The grafting rate is then calculated using the following formula.

[0049] Grafting rate (GD, %) =

[0050] The volume of potassium hydroxide-ethanol solution consumed. This represents the molar concentration of the potassium hydroxide-ethanol solution. The volume of hydrogen chloride-isopropanol solution consumed. denoted as , where is the molar concentration of the hydrogen chloride-isopropanol solution, and m is the sample mass.

[0051] (2) Melt index determination

[0052] The melt flow index of the sample was tested according to GB / T 3682—2000 at 190℃ and 2.16kg load. The test time interval was 30s. The test sample was granular. The sample was measured in parallel 5 times and the average value was taken.

[0053] (3) Determination of gelation rate

[0054] Accurately weigh 0.4 g of the sample to be tested, and extract it by refluxing with xylene using a Soxhlet extractor for 24 hours. Then wash it several times with ethanol and filter it. Dry the solid residue in a vacuum oven at 80°C for 12 hours until the mass no longer changes. Accurately measure the weight of the residue and calculate the gel content (GC) according to the following formula:

[0055]

[0056] Where m1 represents the mass of the residue and m0 represents the mass of the sample to be tested.

[0057] (4) Carbon nuclear magnetic resonance spectrum ( 13 (C NMR)

[0058] Polymer structural unit content through 13 C10 NMR measurements were performed. Data were collected using a Bruker 400MHz spectrometer equipped with a Bruker cryoprobe. Data were acquired using 160 scans, a 6-second pulse repetition delay, and at a sample temperature of 120°C. All measurements were performed on a non-spin sample in locked mode. The sample was allowed to equilibrate for 7 minutes before data acquisition.

[0059] Preparation Example 1

[0060] POE elastomer A was prepared according to the following method:

[0061] S1. Ethylene (351 g / h), 1-octene (714 g / h), Isopar E solvent (2169 g / h), and modified methylaluminoxane (7% wt Al) (289.3 mg / h) were fed into a preheated reactor with stirring at 140°C and a reaction pressure of 3 MPa. Diphenylmethylenecyclopentadiene (2,7-di-tert-butyl-fluorenyl)zirconium dichloride, a main catalyst (1.105 mg / h), was injected into the reactor for copolymerization for 15 min, yielding a prepolymer.

[0062] S2. Increase the reactor temperature to 160℃, keep the reaction pressure constant, and add 4.494 mg / h of chloro(1-naphthalene)bis(triphenylphosphine)-nickel. Adjust the 1-octene addition to 875 g / h and continue the reaction for 30 min. After the reaction, the obtained polymer solution enters a flash tank (170℃, 2 MPa) from the reactor outlet for flash evaporation for 10 min. Then, it enters the primary devolatilization (210℃, 3 bar) and secondary devolatilization (220℃, 1 bar) systems sequentially. Add 12 mg / h of H2O through a static mixer. Finally, granulate the solution through a twin-screw extruder to obtain POE elastomer A.

[0063] The physical properties of POE elastomer A are shown in Table 1.

[0064] Preparation Example 2

[0065] POE elastomer B was prepared according to the following method:

[0066] S1. 234 g / h of ethylene, 583 g / h of 1-butene, 2200 g / h of solvent methylcyclohexane, 10.8 mg / h of ethylaluminoxane, and 3.32 mg / h of triphenylcarbazone (pentafluorophenyl)borate were fed into a preheated reactor with stirring at 140°C and a reaction pressure of 2 MPa. 1.105 mg / h of the main catalyst, dimethicyl (N-tert-butylamino)(tetramethylcyclopentadienyl)dimethyltitanium, was injected into the reactor for copolymerization for 15 min, yielding a prepolymer.

[0067] S2. Increase the reactor temperature to 160℃, keep the reaction pressure constant, and add 1.396 mg / h of bis(tri-tert-butylphosphine)nickel. Adjust the 1-butene addition to 653 g / h and continue the reaction for 30 min. After the reaction, the obtained polymer solution enters a flash tank (170℃, 2 MPa) from the reactor outlet for flash evaporation for 10 min. Then, it enters the primary devolatilization (220℃, 3 bar) and secondary devolatilization (230℃, 1 bar) systems sequentially. Add 2.7 mg / h of H2O through a static mixer. Finally, granulate the solution through a twin-screw extruder to obtain POE elastomer B.

[0068] The physical properties of POE elastomer B are shown in Table 1.

[0069] Preparation Example 3

[0070] POE elastomer C was prepared according to the following method:

[0071] S1. Ethylene (234 g / h), 1-hexene (583 g / h), Isopar E solvent (2169 g / h), and triisobutylaluminum (329.2 mg / h) were fed into a preheated reactor with stirring at 140°C and a reaction pressure of 2 MPa. Diphenylmethylene (cyclopentadiene) (9-fluorenyl)zirconium dichloride, the main catalyst (1.669 mg / h), was injected into the reactor for copolymerization for 15 min, yielding the prepolymer.

[0072] S2. Increase the reactor temperature to 160℃, keep the reaction pressure constant, and add 2.034 mg / h of (1,1'-bis(diphenylphosphine)ferrocene) nickel dichloride. Adjust the 1-hexene addition to 653 g / h and continue the reaction for 30 min. After the reaction, the obtained polymer solution enters a flash tank (200℃, 3 MPa) from the reactor outlet for flash evaporation for 10 min. Then, it enters a primary devolatilization (200℃, 3 bar) and a secondary devolatilization (230℃, 0 bar) system sequentially. Add 6 mg / h of ethanol through a static mixer. Finally, granulate the granules using a twin-screw extruder to obtain POE elastomer C.

[0073] The physical properties of POE elastomer C are shown in Table 1.

[0074] Preparation Example 4

[0075] POE elastomer D was prepared according to the following method:

[0076] S1. Ethylene (351 g / h), 1-butene (583 g / h), Isopar E solvent (2169 g / h), and modified methylaluminoxane (7% wt Al) (115.7 mg / h) were fed into a preheated reactor with stirring at 140°C and a reaction pressure of 3 MPa. Diphenylmethylenecyclopentadiene (2,7-di-tert-butyl-fluorenyl)zirconium dichloride, a main catalyst (1.994 mg / h), was injected into the reactor for copolymerization for 15 min, yielding a prepolymer.

[0077] S2. Increase the reactor temperature to 160℃, keep the reaction pressure constant, and add 3.324 mg / h of tetra(triphenylphosphine)nickel. Adjust the 1-butene addition to 653 g / h and continue the reaction for 30 min. After the reaction, the obtained polymer solution enters a flash tank (170℃, 2 MPa) from the reactor outlet for flash evaporation for 10 min. Then, it enters the primary devolatilization (210℃, 3 bar) and secondary devolatilization (220℃, 1 bar) systems sequentially. Add 6 mg / h of H2O through a static mixer. Finally, granulate the solution through a twin-screw extruder to obtain POE elastomer D.

[0078] The physical properties of POE elastomer D are shown in Table 1.

[0079] Preparation Example 5

[0080] POE elastomer E is prepared according to the following method:

[0081] S1. Ethylene (468 g / h), 1-butene (512 g / h), hexane (2000 g / h), triisobutylaluminum (32.9 mg / h), and triphenylcarbontetra(pentafluorophenyl)borate (4.43 mg / h) were fed into a preheated reactor with stirring at 140°C and a reaction pressure of 4 MPa. Diphenylmethylenecyclopentadiene (2,7-di-tert-butyl-fluorenyl)zirconium dichloride, a main catalyst of 1.105 mg / h, was injected into the reactor for copolymerization for 15 min, yielding a prepolymer.

[0082] S2. Increase the reactor temperature to 160℃, keep the reaction pressure constant, and add 2.247 mg / h of chloro(1-naphthalene)bis(triphenylphosphine)-nickel. Adjust the 1-butene addition to 583 g / h and continue the reaction for 30 min. After the reaction, the obtained polymer solution enters a flash tank (210℃, 3 MPa) from the reactor outlet for flash evaporation for 10 min. Then, it enters the primary devolatilization (220℃, 3 bar) and secondary devolatilization (230℃, 1 bar) systems sequentially. Add 2.7 mg / h of ethanol through a static mixer. Finally, granulate the POE elastomer E through a twin-screw extruder.

[0083] The physical properties of POE elastomer E are shown in Table 1.

[0084] Preparation Example 6

[0085] POE elastomer F was prepared according to the following method:

[0086] S1. 234 g / h of ethylene, 583 g / h of 1-octene, 2169 g / h of Isopar E solvent, and 115.7 mg / h of modified methylaluminoxane (7% wt Al) were fed into a preheated reactor with stirring at 140°C and a reaction pressure of 2 MPa. 1.105 mg / h of the main catalyst, dimethicyl (N-tert-butylamino) (tetramethylcyclopentadienyl) titanium dichloride, was injected into the reactor for copolymerization for 15 min, yielding the prepolymer.

[0087] S2. Increase the reactor temperature to 160℃, keep the reaction pressure constant, and add 2.247 mg / h of chloro(1-naphthalene)bis(triphenylphosphine)-nickel. Adjust the 1-octene addition to 653 g / h and continue the reaction for 30 min. After the reaction, the obtained polymer solution enters a flash tank (170℃, 2 MPa) from the reactor outlet for flash evaporation for 10 min. Then, it enters the primary devolatilization (210℃, 3 bar) and secondary devolatilization (220℃, 1 bar) systems sequentially. Add 6 mg / h of H2O through a static mixer. Finally, granulate the solution through a twin-screw extruder to obtain POE elastomer F.

[0088] The physical properties of POE elastomer F are shown in Table 1.

[0089] Comparison with Example 1

[0090] ENGAGE™ 8100, purchased from Dow Chemical, will be used as POE elastomer G.

[0091] Comparison with Example 2

[0092] WANSUPER®5007, purchased from Wanhua Chemical, will be used as POE elastomer H.

[0093] Table 1. Physical properties of POE elastomers

[0094]

[0095] Examples 1-6

[0096] POE elastomer, MAH, initiator, and grafting monomer were mixed uniformly using a high-speed mixer. The reaction temperature inside the twin-screw extruder was set to 120-160℃ (the highest temperature inside the barrel is denoted as T), and the screw speed was set to 200 r / min. The mixed raw materials were added for melt grafting, and the extruded material was then water-cooled, pelletized, and thoroughly dried to obtain POE-grafted MAH. The raw material dosage (parts by mass) and reaction temperature, among other process conditions, are shown in Table 2 for each embodiment.

[0097] Table 2

[0098]

[0099] The grafting rate, melt index, and gelation rate of the POE-grafted MAH prepared in each embodiment and comparative example were tested, and the results are shown in Table 3.

[0100] Application examples

[0101] The POE-grafted MAH prepared above was blended with PA6 at a dosage of 10% of PA6, and then extruded and granulated using a twin-screw extruder, followed by injection molding to obtain the corresponding toughened nylon standard samples (80mm*10mm*4mm). The twin-screw extrusion temperatures were as follows: 200℃, 220℃, 240℃, 240℃, 240℃, 240℃, 240℃, 240℃, 240℃, 240℃, 240℃; twin-screw feed rate: 10kg / h; twin-screw speed: 200rpm; injection pressure during injection molding: 65Bar for stage 1, 65Bar for stage 2, and 20Bar for stage 3; injection speed: 35% for stage 1, 35% for stage 2, and 20% for stage 3.

[0102] Notched impact strength tests were conducted on the toughened nylon standard specimens prepared for each application example, and the results are shown in Table 3.

[0103] Table 3

[0104]

[0105] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and additions without departing from the method of the present invention, and these improvements and additions should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a high grafting rate and low crosslinking degree POE grafted MAH, characterized in that, The process comprises the following steps: blending the POE elastomer with MAH, initiator, optional auxiliary agent, carrying out a melt grafting reaction in a screw extruder, extruding and granulating to obtain the POE grafted with MAH; the POE elastomer has a relative active site content RAS greater than or equal to 0.2 and less than 0.3 and a crosslinking grafting ratio CRG of 0.06 or less at a reaction temperature T; the relative active site content RAS is defined by the following equation 1: Equation 1 the crosslinking grafting ratio CRG is defined by the following equation 2: Equation 2 In the equations, [CR], [CRR] and [CRRR] are the relative content fractions of methyl, methylene and methine groups, respectively, as measured by 13 C-NMR measured relative content fractions of methyl, methylene, and methine groups in the POE elastomer; E is the bond dissociation energy difference required for methylene to dissociate into a methylene radical and for methine to dissociate into a methine radical, with a value of 8.4 kJ / mol; R is the molar gas constant, with a value of 8.314 J / (mol·K); and T is the reaction temperature of the POE elastomer during the grafting reaction.

2. The method of claim 1, wherein the POE grafted MAH has a high grafting rate and a low crosslinking degree. the POE elastomer has a relative active site content RAS greater than or equal to 0.2 and less than 0.3 and a crosslinking grafting ratio CRG greater than 0.04 and less than 0.06 at a reaction temperature T.

3. The method of claim 1, wherein the POE grafted MAH has a high grafting rate and a low crosslinking degree. In the equation, the relative content fraction of [CR] is 5-40%, the relative content fraction of [CRR] is 20-90%, and the relative content fraction of [CRRR] is 5-40%; or, In the equation, the relative content fraction of [CR] is 10-25%, the relative content fraction of [CRR] is 50-80%, and the relative content fraction of [CRRR] is 10-25%.

4. The method of claim 1-3, wherein the method is characterized by, the initiator is selected from one or more of the following: a low-temperature initiator with a 1 min half-life temperature between 50-160℃; or the initiator is selected from one or more of the following: tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxypivalate, didecanoyl peroxide, di-tert-butyl peroxide, tert-pentyl peroxypivalate, 1,1,3,3-tetramethylbutyl peroxypivalate, dibutyl peroxydicarbonate, dibenzoyl peroxide, and di(3,3,5-trimethylacetyl) peroxide.

5. The method of claim 1-3, wherein the method is characterized by, the auxiliary agent comprises a grafting auxiliary monomer; and / or the auxiliary agent is one or more of the following: methyl methacrylate, acrylic acid, styrene, alpha-methyl styrene, and epoxy resin; and / or the auxiliary agent is added in an amount of 0.1-5% of the mass of the POE elastomer.

6. The method of claim 1-3, wherein the method of preparing a high grafting rate and low crosslinking degree POE grafted MAH is characterized in that, the MAH is added in an amount of 0.5-2% of the mass of the POE elastomer; and / or the initiator is added in an amount of 0.1-0.5% of the mass of the POE elastomer.

7. The process for preparing a high grafting rate and low crosslinking degree POE grafted MAH according to any one of claims 1-3, characterized in that, the reaction temperature of the melt grafting reaction is 50-160℃; or the reaction temperature of the melt grafting reaction is 120-160℃.

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