A high molecular weight ethylene-maleic anhydride copolymer and its preparation method and application

Abstract

A high molecular weight ethylene-maleic anhydride copolymer and its preparation method and application. The present invention belongs to the field of polymer synthesis technology. The purpose of the present invention is to solve the technical problems of low efficiency, high cost and low molecular weight in the preparation of current ethylene-maleic anhydride alternating copolymers. The high molecular weight ethylene-maleic anhydride copolymer of the present invention has a number average molecular weight of >8w. The method of the present invention: using a binuclear organic boron compound as an auxiliary agent, ethylene and maleic anhydride are copolymerized in a solvent via a free radical initiator. The present invention uses a binuclear organic boron compound as a co-catalyst, which not only improves the reaction activity, but more importantly, the binuclear monoboron group stabilizes the free radicals inserted into the ethylene chain segments, suppresses the probability of free radical coupling termination and the occurrence of chain transfer, and produces high molecular weight copolymers more efficiently. The preparation method is simple and easy, the process conditions are mild, and it is suitable for industrial production and promotion and application. It can be applied to the fields of adhesives and coatings.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer synthesis, and particularly relates to a high molecular weight ethylene-maleic anhydride copolymer and a preparation method and application thereof. Background Art

[0002] Compared to monomers like styrene and α-olefins, ethylene monomers lack substituent groups, have a dipole moment of zero, are less susceptible to polarization, and exhibit a low conjugation effect. Consequently, their copolymerization activity with maleic anhydride is significantly reduced. Even in the presence of a free radical initiator, maleic anhydride conversion can only be achieved at high temperatures, high ethylene pressures (>2 MPa), and after prolonged polymerization (15 to 18 hours). Furthermore, the maximum weight-average molecular weight does not exceed 100,000. This prolonged polymerization at high temperatures and pressures results in high production costs, limiting scalable production.

[0003] To address these issues, patent CN202310395202.X reports a method for preparing ethylene-maleic anhydride copolymers by free radical copolymerization of ethylene and maleic anhydride using a Lewis acid as a catalyst. While the presence of the Lewis acid as a cocatalyst significantly accelerates the copolymerization rate of ethylene and maleic anhydride, the ethylene-maleic anhydride copolymers prepared by this method have a maximum number-average molecular weight of only 66,000, which is still far from reaching higher values. Therefore, the preparation of high-molecular-weight ethylene-maleic anhydride copolymers has become a highly challenging research topic. Summary of the Invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a high molecular weight ethylene-maleic anhydride copolymer and a preparation method and application thereof.

[0005] The purpose of the present invention is to achieve through the following technical solutions:

[0006] One of the purposes of the present invention is to provide a high molecular weight ethylene-maleic anhydride copolymer, which is an alternating copolymer of ethylene and maleic anhydride and has a number average molecular weight greater than 8w.

[0007] A second object of the present invention is to provide a method for preparing a high molecular weight ethylene-maleic anhydride copolymer, which is carried out by the following steps:

[0008] Using a binuclear organic boron compound as an auxiliary agent, ethylene and maleic anhydride are copolymerized in a solvent via a free radical initiator.

[0009] The structure of the binuclear organoboron compound is shown in Formulas I to III:

[0010]

[0011] Where Ar 1 and Ar2 Each is independently selected from pentafluorophenyl, 2,3,5,6-tetrafluorophenyl, 2,6-difluorophenyl, p-fluorophenyl, o-fluorophenyl, m-fluorophenyl, 3,5-trifluoromethylphenyl or phenyl, and R is fluorine or hydrogen.

[0012] Preferably, the binuclear organoboron compound is one of B-1 to B-11:

[0013]

[0014] Preferably, the free radical initiator includes organic peroxides and / or azo compounds, redox initiators, inorganic peroxide initiators;

[0015] The solvent includes one or more of an alkane solvent, an aromatic hydrocarbon solvent, a halogenated alkane solvent, and a halogenated aromatic hydrocarbon solvent.

[0016] Preferably, the molar ratio of the binuclear organoboron compound to maleic anhydride is (0.1-500):1000;

[0017] The molar ratio of the free radical initiator to maleic anhydride is (0.1-90):100;

[0018] The molar ratio of ethylene to maleic anhydride structural units in the ethylene-maleic anhydride copolymer is 1:1.

[0019] Preferably, the concentration of maleic anhydride in the solvent is 0.1 to 5.0 mol / L;

[0020] The pressure of ethylene is 1.0 to 250.0 bar.

[0021] Preferably, the copolymerization reaction temperature is 30 to 160° C., and the time is 0.1 to 24 hours.

[0022] A third object of the present invention is to provide a high molecular weight ethylene-maleic anhydride copolymer for use as an adhesive.

[0023] A fourth object of the present invention is to provide an application of a high molecular weight ethylene-maleic anhydride copolymer in coatings.

[0024] Compared with the prior art, the present invention has the following significant effects:

[0025] The present invention provides a method for preparing a high-molecular-weight ethylene-maleic anhydride alternating copolymer and the resulting high-molecular-weight ethylene-maleic anhydride alternating copolymer. A binuclear organoboron compound is creatively used as a co-catalyst. During the reaction process, the binuclear organoboron compound can not only activate maleic anhydride monomers and reduce the reaction energy barrier between maleic anhydride and free radicals, but also reduce the reaction energy barrier between the maleic anhydride free radical chain end and ethylene, thereby improving the reaction activity. More importantly, while the binuclear organoboron compound coordinates and activates the maleic anhydride chain end, another boron group acts with a free radical initiator, stabilizing the free radicals inserted into the ethylene chain segment, suppressing the probability of free radical coupling termination and the occurrence of chain transfer, and generating longer ethylene-maleic anhydride molecular chains. Therefore, under the same conditions as the existing preparation process, the high-molecular-weight ethylene-maleic anhydride copolymer can be produced more efficiently, while improving production efficiency.

[0026] The preparation method of the invention is simple and easy to implement, has mild process conditions, and is suitable for industrial production and popularization and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the high molecular weight ethylene-maleic anhydride copolymer prepared in Example 7;

[0028] Figure 2 This is the DSC curve of the high molecular weight ethylene-maleic anhydride copolymer prepared in Example 7. DETAILED DESCRIPTION

[0029] The present invention provides a high molecular weight ethylene-maleic anhydride copolymer, which is an alternating copolymer of ethylene and maleic anhydride and has a number average molecular weight greater than 8w.

[0030] In a specific embodiment of the present invention, the number average molecular weight of the copolymer is preferably >10w; more preferably, the number average molecular weight of the copolymer is >15w; most preferably, the number average molecular weight of the copolymer is >18w.

[0031] The present invention also provides a specific embodiment of preparing a high molecular weight ethylene-maleic anhydride copolymer, wherein the method is carried out according to the following steps:

[0032] Using a binuclear organic boron compound as an auxiliary agent, ethylene and maleic anhydride are copolymerized in a solvent via a free radical initiator.

[0033] In a specific embodiment of the present invention, the structures of the binuclear organoboron compounds are shown in Formulas I to III:

[0034]

[0035] Where Ar 1 and Ar 2Each is independently selected from pentafluorophenyl, 2,3,5,6-tetrafluorophenyl, 2,6-difluorophenyl, p-fluorophenyl, o-fluorophenyl, m-fluorophenyl, 3,5-trifluoromethylphenyl or phenyl, and R is fluorine or hydrogen.

[0036] Preferably, the binuclear organoboron compound is one of B-1 to B-11:

[0037]

[0038] More preferably, the binuclear organoboron compound is one of B-1, B-2, B-3, B-4, B-5, B-6, B-9, B-10, and B-11; further preferably, the binuclear organoboron compound is one of B-1, B-2, B-4, B-5, B-9, and B-10; most preferably, the binuclear organoboron compound is one of B-1, B-2, B-4, and B-9.

[0039] In a specific embodiment of the present invention, the molar ratio of the binuclear organoboron compound to maleic anhydride is (0.1-500):1000; preferably (1-500):1000; more preferably (2-200):1000; further preferably (5-100):1000; most preferably (5-50):1000.

[0040] In a specific embodiment of the present invention, the free radical initiator includes an organic peroxide and / or an azo compound, a redox initiator, and an inorganic peroxide initiator; preferably, the free radical initiator is azobisisobutyl cyanide (AIBN), azobisisoheptonitrile, dimethyl azobisisobutyrate (AIBME), dibenzoyl peroxide, tert-butyl peroxide 2-ethylhexanoate, lauroyl peroxide, 1,1-bis(tert-amyl peroxy)cycloalkane, 1,1-bis(tert-amyl peroxy)-3,3,5-trimethylcyclohexane, diisopropyl peroxide, tert-amyl peroxyacetate, tert-amyl peroxybenzoate, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate, or more thereof. more preferably one or more of dibenzoyl peroxide, azobisisobutyl cyanide, tert-butyl peroxide 2-ethylhexanoate, lauroyl peroxide, 1,1-bis(tert-amyl peroxy)cycloalkane, 1,1-bis(tert-amyl peroxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide, tert-amyl peroxyacetate, and tert-amyl peroxybenzoate; most preferably dibenzoyl peroxide, azobisisobutyl cyanide, tert-butyl peroxide 2-ethylhexanoate, lauroyl peroxide, 1,1-bis(tert-amyl peroxy)cycloalkane, 1,1-bis(tert-amyl peroxy)-3,3,5-trimethylcyclohexane, dicumyl peroxide, tert-amyl peroxyacetate, or tert-amyl peroxybenzoate.

[0041] In a specific embodiment of the present invention, the molar ratio of the free radical initiator to maleic anhydride is (0.1-90):100; preferably (0.1-20):100, more preferably (0.2-10):100, and most preferably (0.5-2):100.

[0042] In a specific embodiment of the present invention, the molar ratio of ethylene to maleic anhydride structural units in the ethylene-maleic anhydride copolymer is 1:1.

[0043] In a specific embodiment of the present invention, the solvent includes one or more of an alkane solvent, an aromatic hydrocarbon solvent, a halogenated alkane solvent, and a halogenated aromatic hydrocarbon solvent;

[0044] More preferably, the solvent is selected from one or more of pentane, n-hexane, petroleum ether, cyclohexane, benzene, toluene, xylene, chlorobenzene and decahydronaphthalene.

[0045] In a specific embodiment of the present invention, the concentration of maleic anhydride in the solvent is 0.1 to 5.0 mol / L; more preferably 1.0 to 4.0 mol / L, and most preferably 2.0 to 3.0 mol / L.

[0046] In a specific embodiment of the present invention, the pressure of ethylene is 1.0 to 250.0 bar, preferably 2.0 to 200.0 bar, more preferably 4.0 to 150.0 bar, further preferably 6.0 to 100.0 bar, and most preferably 10.0 to 50.0 bar.

[0047] In a specific embodiment of the present invention, the copolymerization temperature is 30-160°C, preferably 50-140°C, more preferably 60-120°C, further preferably 60-100°C, and most preferably 60-80°C.

[0048] In a specific embodiment of the present invention, the copolymerization reaction time is 0.1 to 24 hours, preferably 1 to 20 hours, more preferably 2 to 12 hours, further preferably 4 to 12 hours, and most preferably 6 to 10 hours.

[0049] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0050] The experimental methods used in the following examples are conventional methods unless otherwise specified. The materials, reagents, methods, and instruments used are conventional in the art and can be obtained commercially by those skilled in the art unless otherwise specified.

[0051] The molecular weight of the polymer was determined by gel chromatography at room temperature at 40°C using DMF as the mobile phase (containing 0.5 wt% N n Bu4Br), and standard polystyrene was used as the reference sample for testing.

[0052] The glass transition temperature of the polymer was measured using a differential scanning calorimeter (DSC) with a heating and cooling rate of 10°C / min and a scanning range of 25-300°C.

[0053] The polymer proton spectrum structure was determined using a Bruker AV500 nuclear magnetic resonance spectrometer. The test temperature was 25° C., and the deuterated reagent was deuterated acetone or deuterated dimethyl sulfoxide.

[0054] Example 1

[0055] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 2 mmol of binuclear organoboron compound B-1, 1 mmol of AIBN, and 200 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After reacting in a 60°C oil bath for 12 hours, the mixture was precipitated in anhydrous methanol and vacuum dried to obtain 24 g of the product. The polymer product Mn = 18.01×10 4 g / mol, molecular weight distribution 1.72. See Table 1 for details.

[0056] Example 2

[0057] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 2 mmol of binuclear organoboron compound B-1, 1 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 6 bar. After reacting in a 60°C oil bath for 10 hours, the reaction was precipitated in anhydrous methanol and vacuum dried to obtain 23 g of product. The polymer product Mn = 18.43×10 4 g / mol, molecular weight distribution 1.54. See Table 1 for details.

[0058] Example 3

[0059] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 2 mmol of binuclear organoboron compound B-1, 1 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 10 bar. After reacting in a 60°C oil bath for 10 hours, the reaction was precipitated in anhydrous methanol and vacuum dried to obtain 28 g of the product. The polymer product Mn = 19.14×10 4 g / mol, molecular weight distribution 1.63. See Table 1 for details.

[0060] Example 4

[0061] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 2 mmol of binuclear organoboron compound B-1, 1 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 50 bar. After reacting in a 60°C oil bath for 6 hours, the reaction was precipitated in anhydrous methanol and vacuum dried to obtain 29 g of the product. The polymer product Mn = 19.23×10 4 g / mol, molecular weight distribution 1.74. See Table 1 for details.

[0062] Example 5

[0063] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 2 mmol of binuclear organoboron compound B-1, 1 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 10 bar. After reacting in an 80°C oil bath for 10 hours, the reaction was precipitated in anhydrous methanol and vacuum dried to obtain 21 g of product. The polymer product had an Mn of 8.62 × 10 4 g / mol, molecular weight distribution 1.58. See Table 1 for details.

[0064] Example 6

[0065] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 2 mmol of binuclear organoboron compound B-1, 4 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 10 bar. After reacting in a 60°C oil bath for 10 hours, the mixture was precipitated in anhydrous methanol and vacuum dried to obtain 29 g of the product. The polymer product Mn = 15.34 × 10 4 g / mol, molecular weight distribution 1.69. See Table 1 for details.

[0066] Example 7

[0067] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 10 mmol of binuclear organoboron compound B-1, 1 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 10 bar. After reacting in a 60°C oil bath for 6 hours, the mixture was precipitated in anhydrous methanol and vacuum dried to obtain 29 g of the product. The polymer product Mn = 18.62×10 4 g / mol, molecular weight distribution 1.57. See Table 1 for details.

[0068] Example 8

[0069] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 2 mmol of binuclear organoboron compound B-1, 1 mmol of AIBME, and 100 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 10 bar. After reacting in a 60°C oil bath for 10 hours, the reaction was precipitated in anhydrous methanol and vacuum dried to obtain 27 g of the product. The polymer product Mn = 15.28×10 4 g / mol, molecular weight distribution 1.69. See Table 1 for details.

[0070] Example 9

[0071] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 2 mmol of binuclear organoboron compound B-1, 1 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 30 bar. After reacting in a 60°C oil bath for 6 hours, the reaction was precipitated in anhydrous methanol and vacuum dried to obtain 26 g of product. The polymer product Mn = 16.72×10 4 g / mol, molecular weight distribution 1.76. See Table 1 for details.

[0072] Example 10

[0073] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 2 mmol of binuclear organoboron compound B-2, 1 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 30 bar. After reacting in a 60°C oil bath for 6 hours, the reaction was precipitated in anhydrous methanol and vacuum dried to obtain 21 g of product. The polymer product Mn = 11.52×10 4 g / mol, molecular weight distribution 1.62. See Table 1 for details.

[0074] Example 11

[0075] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 2 mmol of binuclear organoboron compound B-4, 1 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 30 bar. After reacting in a 60°C oil bath for 6 hours, the reaction was precipitated in anhydrous methanol and vacuum dried to obtain 19 g of product. The polymer product Mn = 10.57 × 10 4 g / mol, molecular weight distribution 1.71. See Table 1 for details.

[0076] Example 12

[0077] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 2 mmol of binuclear organoboron compound B-9, 1 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 30 bar. After reacting in a 60°C oil bath for 6 hours, the mixture was precipitated in anhydrous methanol and vacuum dried to obtain 26 g of product. The polymer product Mn = 18.45 × 10 4 g / mol, molecular weight distribution 1.64. See Table 1 for details.

[0078] Comparative Example 1

[0079] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 1 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the bottle was replaced with ethylene, and the ethylene pressure was maintained at 30 bar. After reacting in a 60°C oil bath for 6 hours, the reaction was precipitated in anhydrous methanol and vacuum dried to obtain 14 g of product. The polymer product Mn = 5.41×10 4 g / mol, molecular weight distribution 1.58.

[0080] Comparative Example 2

[0081] Under high-purity nitrogen, 0.2 mol of maleic anhydride monomer, 4 mmol of B(C6F5)3, 1 mmol of AIBN, and 100 mL of toluene were added to the reactor. The gas in the flask was replaced with ethylene, and the ethylene pressure was maintained at 30 bar. After reacting in a 60°C oil bath for 6 hours, the reaction was precipitated in anhydrous methanol and vacuum dried to obtain 28 g of the product. The polymer product Mn = 6.37×10 4 g / mol, molecular weight distribution 1.84.

[0082] Table 1. Data of ethylene and maleic anhydride copolymerization

[0083]

[0084] The foregoing are merely preferred embodiments of the present invention. These embodiments are all different implementations based on the overall concept of the present invention. The scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A method for preparing a high molecular weight ethylene-maleic anhydride copolymer, characterized in that: The copolymer is an alternating copolymer of ethylene and maleic anhydride, with a number average molecular weight greater than 8w; The preparation method of the high molecular weight ethylene-maleic anhydride copolymer: Using a binuclear organic boron compound as an auxiliary agent, ethylene and maleic anhydride are copolymerized in a solvent via a free radical initiator. The structures of binuclear organoboron compounds are shown in Formulas I to III: ； Where Ar 1 and Ar 2 Each is independently selected from pentafluorophenyl, 2,3,5,6-tetrafluorophenyl, 2,6-difluorophenyl, p-fluorophenyl, o-fluorophenyl, m-fluorophenyl, 3,5-trifluoromethylphenyl or phenyl, R is fluorine or hydrogen; The molar ratio of the binuclear organic boron compound to maleic anhydride is (0.1-500):1000, the molar ratio of the free radical initiator to maleic anhydride is (0.1-90):100, and the molar ratio of ethylene to maleic anhydride structural units in the ethylene-maleic anhydride copolymer is 1:

1.

2. The method according to claim 1, characterized in that The binuclear organoboron compound is one of B-1 to B-11: 。 3. The method according to claim 1, characterized in that The free radical initiator includes organic peroxides and / or azo compounds, redox initiators, and inorganic peroxide initiators. The solvent includes one or more of an alkane solvent, an aromatic solvent, a halogenated alkane solvent, and a halogenated aromatic solvent.

4. The method according to claim 1, wherein The concentration of maleic anhydride in the solvent is 0.1~5.0 mol / L, and the pressure of ethylene is 1.0~250.0 bar.

5. The method according to claim 1, wherein The copolymerization reaction temperature is 30~160℃, and the time is 0.1~24h.

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