Preparation method of ethylene-maleic anhydride copolymer

Abstract

A preparation method of an ethylene-maleic anhydride copolymer comprises the following steps: adding 30-50 parts of maleic anhydride, 300-500 parts of a solvent and 1-3 parts of an initiator into a reaction kettle, starting stirring, and introducing nitrogen into the reaction kettle for bubbling and deoxidizing for 20 minutes; introducing ethylene gas into the reaction kettle for continuous bubbling, cooling the reaction kettle to-50 DEG C by using liquid nitrogen or dry ice bath, then stopping introducing ethylene, sealing the reaction kettle, heating the reaction kettle to 110-140 DEG C, and reacting for 15-30 hours; cooling the reaction kettle to room temperature, releasing pressure, opening the reaction kettle, centrifugally collecting solid powder in reaction liquid, and performing vacuum drying to obtain an ethylene-maleic anhydride copolymer; according to the preparation method of the ethylene-maleic anhydride copolymer, ultrahigh-pressure special equipment such as an ethylene compressor does not need to be used, the pressure-resistant requirement of reaction equipment is low, the technological process is simple, the cost is low, and industrial production is easy to achieve.

Description

Technical Field

[0001] The invention belongs to the field of polymer synthesis, and specifically relates to a method for preparing an ethylene-maleic anhydride copolymer. Background Art

[0002] Ethylene-maleic anhydride copolymer is formed by the reaction of monomers ethylene and maleic anhydride in a certain molar ratio, and has high thermal stability and good mechanical properties. The polymer main chain contains a large number of highly reactive cyclic anhydride groups, which can easily undergo chain extension reactions, such as reacting with the amine groups in the nylon molecular chain to increase the molecular weight, mechanical properties and anti-freezing stability of nylon. This polymer is also widely used in glass fiber sizing, pigment carriers, adhesives, surfactants, sealants, coatings, etc.

[0003] At present, most commercial ethylene-maleic anhydride copolymers are obtained by randomly grafting maleic anhydride onto polyethylene. Representative brands include Fusabond M603 from Dow and DuPont and AC 573P from Honeywell. They can be used as compatibilizers in wood-plastic composite processing and halogen-free flame-retardant wires and cables. They can also be used as tackifiers in vinyl coatings to enhance the adhesion between the coating and materials such as aluminum foil, stainless steel, glass, PP, and PVC. This type of ethylene-maleic anhydride grafted copolymer has a wide range of applications and a high market share, but this type of grafted copolymer generally has the disadvantages of low grafting rate and difficulty in completely eradicating maleic anhydride monomers in the product. Ethylene-maleic anhydride alternating copolymers completely overcome these disadvantages. Since ethylene has low free radical polymerization activity and a very small chain growth rate at room temperature, and ethylene is a gas with a very low density at room temperature and pressure, the conventional preparation method of ethylene-maleic anhydride alternating copolymer mainly utilizes free radical initiators to carry out free radical polymerization reactions at high temperatures and extremely high ethylene pressures (>100°C, 100MPa). In engineering, even tubular reactors are used to carry out continuous free radical polymerization reactions at high temperatures and extremely high pressures (130-230°C, 150-300MPa), which places very high demands on reaction equipment and harsh production conditions. These problems limit the expansion of the production scale of ethylene-maleic anhydride alternating copolymers and their actual promotion and application.

[0004] Therefore, how to solve the above-mentioned problems existing in this field and develop a method for synthesizing ethylene-maleic anhydride copolymer with mild reaction conditions, low reaction pressure and the ability to be carried out in a common chemical reactor, thereby producing a low-cost ethylene-maleic anhydride copolymer, has become one of the focuses of attention of many cutting-edge researchers in the field. Summary of the invention

[0005] In view of the above problems, the present invention provides a method for preparing an ethylene-maleic anhydride copolymer, which is carried out according to the following steps:

[0006] A1. Take 30-50 parts of maleic anhydride, 300-500 parts of an organic solvent and 1-3 parts of an initiator and add them to a reaction kettle, stir, and introduce nitrogen bubbling into the reaction kettle to deoxygenate; the parts are parts by weight.

[0007] A2. Ethylene gas was continuously bubbled into the reactor, the reactor was cooled to -50 ° C with liquid nitrogen or a dry ice bath, the ethylene was stopped, the reactor was sealed, and the reactor was heated to 110-140 ° C for 15h-30h.

[0008] A3. After the reaction is completed, the reactor is cooled to room temperature, the pressure is released, the reactor is opened, the solid powder in the reaction solution is collected by centrifugation, and ethylene-maleic anhydride copolymer is obtained after vacuum drying.

[0009] Preferably, the organic solvent in step A1 is toluene, o-xylene, m-xylene or a mixture of any proportions of the above.

[0010] Preferably, the initiator in step A1 is cumene hydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide or di-tert-butyl peroxide.

[0011] Preferably, nitrogen is introduced into the reactor for deoxygenation by bubbling for 20 minutes.

[0012] Preferably, the initiator is cumene hydroperoxide.

[0013] Preferably, in step A2, the introduction of ethylene is stopped, the reactor is sealed, and the temperature of the reactor is raised to 130° C. for reaction for 30 hours.

[0014] Preferably, a method for preparing an ethylene-maleic anhydride copolymer is carried out according to the following steps:

[0015] A1. Take 50.0 parts of maleic anhydride, 30 parts of m-xylene, and 1.0 part of cumene hydroperoxide and add them to a reactor. Start stirring and introduce nitrogen into the reactor to deoxygenate for 20 minutes. The parts mentioned are all parts by weight. A2. Introduce ethylene gas into the reactor and continue bubbling. Cool the reactor to -50°C with liquid nitrogen or dry ice bath. Then stop introducing ethylene, seal the reactor, and heat the reactor to 130°C for 30 hours.

[0016] A3. Cool the reactor to room temperature and release the pressure. Open the reactor and collect the solid powder in the reaction solution by centrifugation.

[0017] After vacuum drying, ethylene-maleic anhydride copolymer was obtained.

[0018] The beneficial effects of the present invention are as follows: the preparation method of the ethylene-maleic anhydride copolymer does not require the use of ultra-high pressure special equipment such as an ethylene compressor, the pressure resistance requirement of the reaction equipment is low, the process flow is simple, the cost is low, and it is easy to realize industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a graph showing changes in temperature and pressure over time in a reactor during the preparation of ethylene-maleic anhydride copolymer in Example 1 of the present invention.

[0020] Figure 2 It is the appearance diagram of the ethylene-maleic anhydride copolymer prepared by the present invention.

[0021] Figure 3 It is the GPC elution curve of the ethylene-maleic anhydride copolymer prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described in detail below through specific implementation methods. The described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] The test characterization method of the polymer prepared in the embodiment of the present invention is as follows:

[0024] 1) Determination of reaction product yield (Yield.%)

[0025] Yield.%=98.1*m2 / 126.1*m1×100%

[0026] In the above formula, m1 is the mass of maleic anhydride monomer added before the reaction, and m2 is the mass of the dried ethylene-maleic anhydride copolymer after the reaction.

[0027] 2) Determination of molecular weight of ethylene-maleic anhydride copolymer

[0028] The number average molecular weight of the ethylene-maleic anhydride copolymer was measured by gel permeation chromatography (GPC). The copolymer powder was dissolved in tetrahydrofuran (THF) to prepare a sample, and the sample was measured on a SHIMADZU LC-16 gel permeation chromatography system. The system was equipped with a SHIMADZU Essentia LC-16 chromatography pump, a SHIMADZU Essentia CTO-16 column oven, a SHIMADZU RID-20A refractive index detector, and a Styragel HR-4E chromatography column (4.6×300 mm, molecular weight range: 50-1.0×10 5Da). The column oven temperature was 35°C, the mobile phase was THF, and the flow rate was 0.3 mL / min. A series of PMMA standard polymers (American Polymer Standards Corp., USA) were used to generate a GPC calibration curve to calculate the molecular weight of ethylene-maleic anhydride copolymer.

[0029] Example 1

[0030] In the embodiment of the present invention, the operation steps of the method for preparing ethylene-maleic anhydride copolymer are as follows:

[0031] (1) 30.0 g of maleic anhydride, 300 g of toluene, and 2.0 g of cumene hydroperoxide were added to a reaction kettle, stirring was started, and nitrogen was bubbled into the reaction kettle for deoxygenation for 20 min.

[0032] (2) Ethylene gas was introduced into the reactor and bubbled continuously. The reactor was cooled to -50°C using liquid nitrogen or a dry ice bath. Then the introduction of ethylene was stopped, the reactor was sealed, and the temperature of the reactor was raised to 130°C for 17 hours.

[0033] (3) The reactor was cooled to room temperature and the pressure was released. The reactor was opened and the solid powder in the reaction solution was collected by centrifugation. The solid powder was vacuum dried to obtain an ethylene-maleic anhydride copolymer. The yield of the polymerization product was measured by weighing method to be 79.2%.

[0034] The temperature and ethylene pressure in the reactor change with time during the reaction. Figure 1 The product appearance of ethylene-maleic anhydride copolymer is shown in the attached Figure 2 The GPC elution curve of the ethylene-maleic anhydride copolymer is shown in the attached Figure 3 As shown, the number average molecular weight of the ethylene-maleic anhydride copolymer is calculated to be 17610 Da.

[0035] Example 2

[0036] (1) 50.0 g of maleic anhydride, 300 g of m-xylene, and 1.0 g of cumene hydroperoxide were added to a reaction kettle, stirring was started, and nitrogen was bubbled into the reaction kettle for deoxygenation for 20 min.

[0037] (2) Ethylene gas is introduced into the reactor and continuously bubbled. The reactor is cooled to -50°C using liquid nitrogen or a dry ice bath. Then the introduction of ethylene is stopped, the reactor is sealed, and the temperature of the reactor is raised to 130°C for reaction for 30 hours.

[0038] (3) The reactor was cooled to room temperature and the pressure was released. The reactor was opened and the solid powder in the reaction solution was collected by centrifugation. After vacuum drying, ethylene-maleic anhydride copolymer was obtained. The yield of the polymerization product was measured by weighing method to be 82.4%. The number average molecular weight of the ethylene-maleic anhydride copolymer was measured by GPC to be 25240 Da.

[0039] Example 3

[0040] (1) 35.0 g of maleic anhydride, 400 g of m-xylene and 3.0 g of di-tert-butyl peroxide were added to a reaction kettle, stirring was started, and nitrogen was bubbled into the reaction kettle for deoxygenation for 20 min.

[0041] (2) Ethylene gas is introduced into the reactor and continuously bubbled. The reactor is cooled to -50°C using liquid nitrogen or a dry ice bath. Then the introduction of ethylene is stopped, the reactor is sealed, and the temperature of the reactor is raised to 140°C for reaction for 15 hours.

[0042] (3) The reactor was cooled to room temperature and the pressure was released. The reactor was opened and the solid powder in the reaction solution was collected by centrifugation. After vacuum drying, ethylene-maleic anhydride copolymer was obtained. The yield of the polymerization product was measured by weighing method to be 67.1%. The number average molecular weight of the ethylene-maleic anhydride copolymer was measured by GPC to be 14570 Da.

[0043] Example 4

[0044] (1) 30.0 g of maleic anhydride, 500 g of o-xylene and 2.2 g of tert-butyl hydroperoxide were added to a reaction kettle, stirring was started, and nitrogen was bubbled into the reaction kettle for deoxygenation for 20 min.

[0045] (2) Ethylene gas is introduced into the reactor and continuously bubbled. The reactor is cooled to -50°C using liquid nitrogen or a dry ice bath. Then the introduction of ethylene is stopped, the reactor is sealed, and the temperature of the reactor is raised to 110°C for reaction for 20 hours.

[0046] (3) The reactor was cooled to room temperature and the pressure was released. The reactor was opened and the solid powder in the reaction solution was collected by centrifugation. After vacuum drying, ethylene-maleic anhydride copolymer was obtained. The polymerization yield was measured by weighing method to be 60.9%. The number average molecular weight of the ethylene-maleic anhydride copolymer was measured by GPC to be 11700 Da.

[0047] Example 5

[0048] (1) 35.0 g of maleic anhydride, 300 g of m-xylene and 2.25 g of dicumyl peroxide were added to a reaction kettle, stirring was started, and nitrogen was bubbled into the reaction kettle for deoxygenation for 20 min.

[0049] (2) Ethylene gas is introduced into the reactor and continuously bubbled. The reactor is cooled to -50°C using liquid nitrogen or a dry ice bath. Then the introduction of ethylene is stopped, the reactor is sealed, and the temperature of the reactor is raised to 120°C for reaction for 20 hours.

[0050] (3) The reactor was cooled to room temperature and the pressure was released. The reactor was opened and the solid powder in the reaction solution was collected by centrifugation. After vacuum drying, ethylene-maleic anhydride copolymer was obtained. The polymerization yield was measured by weighing method to be 68.7%. The number average molecular weight of the ethylene-maleic anhydride copolymer was measured by GPC to be 16390 Da.

[0051] Example 6

[0052] (1) 40.0 g of maleic anhydride, 100 g of toluene, 100 g of m-xylene, 100 g of o-xylene, and 2.0 g of dicumyl peroxide were added to a reactor, stirring was started, and nitrogen was bubbled into the reactor for deoxygenation for 20 min.

[0053] (2) Ethylene gas is introduced into the reactor and continuously bubbled. The reactor is cooled to -50°C using liquid nitrogen or a dry ice bath. Then the introduction of ethylene is stopped, the reactor is sealed, and the temperature of the reactor is raised to 130°C for reaction for 25 hours.

[0054] (3) The reactor was cooled to room temperature and the pressure was released. The reactor was opened and the solid powder in the reaction solution was collected by centrifugation. After vacuum drying, ethylene-maleic anhydride copolymer was obtained. The polymerization yield was measured by weighing method to be 70.4%. The number average molecular weight of the ethylene-maleic anhydride copolymer was measured by GPC to be 18540 Da.

[0055] The above description of the present invention is only part of the preferred embodiments of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing an ethylene-maleic anhydride copolymer, comprising the steps of: A1. Take 30-50 parts of maleic anhydride, 300-500 parts of an organic solvent and 1-3 parts of an initiator and add them to a reactor, stir, and deoxygenate by bubbling nitrogen into the reactor; the parts are all parts by weight; A2. Ethylene gas was continuously bubbled into the reactor, the reactor was cooled to -50 ° C with liquid nitrogen or dry ice bath, the ethylene was stopped, the reactor was sealed, and the reactor was heated to 110-140 ° C for 15h-30h; A3. After the reaction is completed, the reactor is cooled to room temperature, the pressure is released, the reactor is opened, the solid powder in the reaction solution is collected by centrifugation, and ethylene-maleic anhydride copolymer is obtained after vacuum drying.

2. The method for preparing ethylene-maleic anhydride copolymer according to claim 1, wherein: The organic solvent in step A1 is toluene, o-xylene, m-xylene or a mixture of any proportion of the above.

3. The method for preparing ethylene-maleic anhydride copolymer according to claim 1, wherein: The initiator described in step A1 is cumene hydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide or di-tert-butyl peroxide.

4. The method for preparing the ethylene-maleic anhydride copolymer according to claim 1, characterized in that The nitrogen bubbling deoxygenation time in the reactor is 20 minutes.

5. The method for preparing the ethylene-maleic anhydride copolymer according to claim 1, characterized in that The initiator is cumene hydroperoxide.

6. The method for preparing the ethylene-maleic anhydride copolymer according to claim 1, characterized in that Step A2: stop introducing ethylene, seal the reactor, and heat the reactor to 130° C. for 30 h.

7. The method for preparing the ethylene-maleic anhydride copolymer according to claim 1, characterized in that The maleic anhydride copolymer was prepared as follows: A1. Take 50.0 parts of maleic anhydride, 30 parts of m-xylene and 1.0 parts of cumene hydroperoxide and add them to a reactor. Start stirring and introduce nitrogen bubbling into the reactor to deoxygenate for 20 minutes. The parts are all parts by weight. A2. Ethylene gas was continuously bubbled into the reactor, and the reactor was cooled to -50°C with liquid nitrogen or a dry ice bath, and then the ethylene was stopped, the reactor was sealed, and the reactor was heated to 130°C for 30h; A3. Cool the reactor to room temperature and release the pressure. Open the reactor and collect the solid powder in the reaction solution by centrifugation. After vacuum drying, ethylene-maleic anhydride copolymer was obtained.

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