Polarized elastomer containing three micro-blocks as well as preparation method and application thereof

Abstract

The invention discloses a polarized elastomer containing three micro-blocks as well as a preparation method and application thereof, and belongs to the field of high polymer materials. The polarized elastomer comprises the following structural units: (a) an ethylene segment; (b) a vinyl acetate segment; and (c) a vinyl alcohol segment. The polyethylene chain segment in the polymer can crystallize, the introduction of hydroxyl enhances the polarity of the polymer, intermolecular hydrogen bonds are easier to form, the mechanical properties of the polymer are improved, and the surface properties are improved. The preparation process is very simple and efficient, the structure of the polymer can be accurately regulated and controlled, and the post-treatment process is simple. As a novel elastomer material, the material can also be used in more fields of plastic modifiers, blending solubilizers, adhesives, sealants and the like, and can meet wider scene requirements.

Description

Technical Field

[0001] The present application relates to a polarized elastomer containing three microblocks and a preparation method and application thereof, belonging to the field of polymer materials. Background Art

[0002] Elastomers are functional materials that combine the elasticity of rubber with the processing properties of plastics. For example, polyolefin elastomers (POE), formed by the copolymerization of ethylene and α-olefins (such as 1-octene), have a semi-crystalline structure that gives them excellent chemical resistance, low density, flexibility, and processability. They are widely used in automotive parts, wire and cable sheathing, footwear, medical devices, and other fields. Styrene-butadiene rubber (SBR), a synthetic rubber made by the copolymerization of styrene and butadiene, has become a core material for tires and industrial rubber products due to its high wear resistance, ease of processing, and low cost. Elastomers can be divided into polar elastomers and non-polar elastomers based on whether they contain polar groups. For non-polar elastomers, the olefin structural unit leads to low surface energy and insufficient interfacial adhesion strength with polar materials, which greatly limits their application in composite materials, coatings, and other fields. To increase polarity, methods such as copolymerization modification, chemical grafting modification, and surface polarization modification are commonly used to introduce polar functional groups such as hydroxyl, carboxyl, and epoxy groups into the polyolefin backbone or side chains. Copolymerization modification often uses coordination polymerization to introduce polar groups into olefin chain segments, but the functionalization rate is usually less than 1%. At the same time, the copolymerization process is limited by harsh reaction conditions and the product microstructure is uncontrollable. Chemical grafting modification performs active grafting on the surface of hydrocarbon chains. Due to the limited active sites in the polymer, its functionalization efficiency is low. Surface polarization modification modifies the surface structure of the polymer to introduce polar functional groups with special functions to improve the surface properties of the polymer, but there are still problems such as low grafting rate.

[0003] Polarized elastomers exhibit higher strength, better oil resistance, and adhesion due to their strong polar groups. For example, polyurethane elastomers contain a large number of polar groups such as ester and ether groups in their structure, which give them good mechanical properties, excellent resilience and good wear resistance. At the same time, due to the lack of olefin structural segments in their structure, they have poor weather resistance and poor compatibility with non-polar materials. Therefore, product research and development for high-end applications is still very difficult. Summary of the Invention

[0004] Ethylene vinyl acetate copolymer (EVA) is a copolymer of ethylene and vinyl acetate monomers. The distribution of its internal polar groups is limited by the copolymerization process. Due to the low polarity and poor crystallinity of vinyl acetate, it has a low melting point and is easily thermally oxidized at high temperatures. At the same time, its low strength, high creep, and insufficient wear resistance limit its scope of application. In this context, chemical modification of EVA—particularly selective alcoholysis—provides a new approach for the preparation of high-performance polar elastomers. Through alcoholysis, the acetate (VA) in EVA can be directionally converted into a vinyl alcohol (VOH) structure, thereby introducing highly polar hydroxyl groups while retaining the properties of the polyolefin matrix. This technology can precisely design the polar group distribution of the product by regulating the reaction conditions, providing an efficient approach for the development of new polar elastomer materials.

[0005] In summary, EVA with an appropriate VA content (40wt%) was selected for functionalization. By partially converting the acetate groups into hydroxyl groups, its structure contained both hydroxyl and acetate groups. The structural segments containing hydroxyl groups easily formed intermolecular hydrogen bonds, forming crystalline regions, making the molecular chains more regularly arranged, enhancing the mechanical properties of the polymer, and improving the polarity and weather resistance of the polymer, thereby obtaining a new polar elastomer containing three microblocks.

[0006] According to one aspect of the present invention, a novel polarized elastomer containing three microblocks is provided. The aggregated structure of this microblock polarized elastomer is composed of polyethylene crystalline regions, vinyl acetate groups, and ethylene segments containing hydroxyl functional groups. Intermolecular hydrogen bonding between the ethylene segments and the hydroxyl-containing segments forms crystalline regions, significantly enhancing the polymer's rigidity. By adjusting the vinyl acetate ratio, the content and structural arrangement of ethylene, vinyl acetate, and hydroxyl groups in the polymer chain are regulated, resulting in different structural properties. In the prepared polarized elastomer, crystallization occurs between both the polyethylene segments and the hydroxyl-containing segments in the hydroxyl-containing block copolymer. The vinyl acetate-containing block copolymer exhibits plastic processing properties at high temperatures and exhibits elastomeric properties at room temperature, making it a thermoplastic elastomer. These structural characteristics give the polarized polyethylene elastomer of the present invention superior performance. Compared to traditional thermoplastic polyolefin elastomers, this polymer possesses stronger polar groups, better mechanical properties, and superior heat resistance, extending its application range.

[0007] A polarized elastomer containing three microblocks, wherein the polarized elastomer contains the following structural units: (a) ethylene segment; (b) vinyl acetate segment; (c) vinyl alcohol segment;

[0008] The structural formula of its structural unit is shown in Formula 1:

[0009] Formula 1:

[0010]

[0011] The structural formula of EVA polymer is shown in Formula 2:

[0012] Formula 2:

[0013]

[0014] m, n, x, and y are the numbers of various structural units;

[0015] The value of m / n is 0.15 to 0.22;

[0016] The value of x / m is 0.3 to 1;

[0017] The value of y / m is 0.3 to 1;

[0018] The value of x is 0.05 to 0.2;

[0019] Among them, the number of ethylene structural units on the main chain of the polymer is represented by m; the number of structural units containing ester groups is represented by n; in the polymer after the reaction, the number of structural units containing ester groups is represented by x; and the number of structural units containing hydroxyl groups is represented by y.

[0020] Optionally, the value of m / n is 0.19 to 0.21;

[0021] The value of x / m is 0.5 to 1;

[0022] The value of y / m is 0.5 to 1;

[0023] The value of x is 0.08 to 0.17.

[0024] Optionally, the molecular weight of the polarized elastomer is 30,000 to 45,000.

[0025] Preferably, the molecular weight of the polarized elastomer is 37,000 to 40,000.

[0026] Optionally, the polydispersity index (PDI) of the polarized elastomer is 1.00 to 2.50.

[0027] Preferably, the polydispersity index (PDI) of the polarized elastomer is 1.55 to 2.40.

[0028] Optionally, the alcoholysis degree of the polarized elastomer is 40-100%.

[0029] Preferably, the alcoholysis degree of the polarized elastomer is 50-90%.

[0030] Preferably, the alcoholysis degree of the polarized elastomer is independently selected from any value among 40%, 50%, 60%, 70%, 80%, 90%, 100%, or any range between the two.

[0031] Optionally, the polarized elastomer has a crystallinity of 0 to 30%.

[0032] Preferably, the polarized elastomer has a crystallinity of 2 to 20%.

[0033] Optionally, the crystallization peak temperature of the polarized elastomer is 20°C to 120°C.

[0034] Preferably, the crystallization peak temperature of the polarized elastomer is 30°C to 90°C.

[0035] Optionally, the crystallization peak temperature of the polarized elastomer is independently selected from any value among 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 100°C, or any range therebetween.

[0036] Optionally, the surface water contact angle of the polarized elastomer is 50° to 105°.

[0037] Preferably, the surface water contact angle of the polarized elastomer is 60° to 100°.

[0038] Optionally, the surface water contact angle of the polarized elastomer is independently selected from any value among 50°, 60°, 70°, 80°, 90°, 100°, 105°, or any range between the two.

[0039] At present, the preparation method of polarized polyolefins still has inevitable problems, such as harsh reaction conditions and low polarization efficiency. The present invention provides a novel polarized elastomer containing three microblocks and a preparation method thereof. By modifying it with a simple chemical method, using sodium methoxide as a catalyst, EVA is subjected to alcoholysis, and polar group hydroxyl groups are introduced into the EVA segments, thereby obtaining a microblock polarized elastomer with strong polarity and controllable structure. According to different reaction conditions, the content, sequence structure and microstructure of the functional groups in the polymer are precisely regulated, and the degree of reaction is controlled to flexibly adjust the content of hydroxyl groups in the polymer to achieve the functionalization of polyethylene. The polarized elastomer prepared by this method contains polar group hydroxyl groups, and intermolecular hydrogen bonds can be generated between the ethylene segments and the hydroxyl-containing segments in the segments, which easily form crystalline regions and improve the rigidity and thermal stability of the polymer. These excellent structural features give it more excellent performance and a wider range of applications.

[0040] Another aspect of the present application is a method for preparing a polarized elastomer containing three microblocks. This method offers milder reaction conditions, lower energy consumption, and reduced operational risks, making it suitable for industrialization. EVA is chemically modified through simple alcoholysis using sodium methoxide as a catalyst. By varying the catalyst dosage and reaction time, polarized polyethylene elastomers with varying block structures can be obtained. The present method is simple and effective, and a polarized polyolefin material containing hydroxyl functional groups is obtained through the alcoholysis of EVA.

[0041] The method for preparing the polarized elastomer described above comprises the following steps:

[0042] S1: adding EVA polymer to an organic solvent, stirring and mixing, heating and dissolving to form a homogeneous solution;

[0043] S2 adds a catalyst to the homogeneous solution to undergo alcoholysis reaction to obtain a polarized elastomer containing three microblocks.

[0044] Optionally, in step S1, the weight percentage of ester groups in the EVA polymer is 9% to 40%, preferably 40% by weight.

[0045] Optionally, in step S1, the concentration of the monomer in the homogeneous solution is 5% to 10%, preferably 8% to 10%. Monomers in this mass fraction range are preferably easier to control temperature changes during the polymerization reaction and their solubility in the solution.

[0046] Optionally, in step S1, the temperature for heating and dissolving is 80-120°C, preferably 90-100°C.

[0047] Optionally, in step S1, the dissolution time is 30 min to 2 h, preferably 1 h to 2 h.

[0048] Optionally, in step S1, the organic solvent is at least one of cyclohexane, anhydrous ethanol, methanol, and xylene, preferably xylene.

[0049] Optionally, in step S1, the stirring rate is 300 rpm to 1200 rpm, preferably 500 rpm to 800 rpm.

[0050] Optionally, in step S2, the catalyst is at least one of NaOH, NaOH / CH3OH, and CH3ONa, preferably NaOH / CH3OH and CH3ONa.

[0051] Optionally, in step S2, the molar ratio of the added amount of the catalyst to the ester group in the EVA polymer is 0.1-2, preferably 0.2-2.

[0052] Optionally, in step S2, the temperature of the alcoholysis reaction is 80-110°C, preferably 90-100°C.

[0053] Optionally, in step S2, the alcoholysis reaction time is 1 h to 8 h, preferably 1 h to 6 h.

[0054] Optionally, the method further includes step S3:

[0055] The product is transferred to water, stirred and washed, and ethanol is added to wash repeatedly, and dried to obtain the product.

[0056] The method for preparing the polarized elastomer described above comprises the following steps:

[0057] (S1) Using xylene as a solvent, adding an EVA polymer into the xylene solvent, stirring and mixing, and heating and dissolving at 100° C. to form a homogeneous solution.

[0058] (S2) NaOH / CH3OH or CH3ONa catalyst is added to the solution, and alcoholysis reaction is carried out for 1-5 hours to prepare a new polarized elastomer containing three microblocks.

[0059] (S3) The product was transferred to deionized water at 90° C. and stirred for washing for 30 minutes. After repeated washing three times, anhydrous ethanol was added and repeated washing three times to obtain the product.

[0060] Optionally, in step (S3), the amount of deionized water added is 1000ml to 6000ml, preferably 2000ml to 3000ml. Solutions and water in this mass concentration range are more likely to remove the catalyst and sodium salt in the system.

[0061] Optionally, in step (S3), 100 ml to 500 ml, preferably 200 ml to 300 ml, of deionized water is added per 1 kg of solution.

[0062] Optionally, in step (S3), the water washing time is 10 min to 60 min, preferably 30 min to 40 min.

[0063] Optionally, in step (S3), the amount of anhydrous ethanol added is 1000ml to 6000ml, preferably 2000ml to 3000ml. Solutions and water in this mass concentration range are more likely to remove xylene and sodium salt from the system.

[0064] Optionally, in step (S3), 100 to 500 ml, preferably 200 to 300 ml, of anhydrous ethanol is added per 1 kg of solution.

[0065] Optionally, in step (S3), the washing time is 10 min to 60 min, preferably 30 min to 40 min.

[0066] According to another aspect of the present application, an application of a polarized elastomer containing three microblocks is provided.

[0067] The polar elastomers described above are used in plastic modifiers, blending solubilizers, adhesives, and sealants.

[0068] The beneficial effects of this application include:

[0069] (1) The microblock polarized elastomer provided in this application has a polymer in which the polyethylene segments are capable of crystallization. The introduction of hydroxyl groups enhances the polarity of the polymer, making it easier to form intermolecular hydrogen bonds, thereby enhancing its mechanical properties and improving its surface properties. Therefore, the polarized elastomer is in a plastic state at room temperature. The microstructure, crystallinity, thermal stability, aging resistance, stress-strain behavior, and various mechanical properties such as modulus, strength, elongation, and hardness of the elastomer are highly similar to those of polyethylene. In addition, due to the presence of polar groups containing hydroxyl groups, the sample has better hydrophilicity than polyethylene, and its application field is broader.

[0070] (2) The present invention provides a method for preparing a novel polarized elastomer containing three microblocks. Compared with existing preparation technologies, the present invention uses a saponification method using sodium methoxide as a catalyst. The preparation process is very simple and efficient, the polymer structure can be precisely controlled, and the post-processing process is simple. The catalytic process, efficiency, and reproducibility of the present invention are very high. The prepared elastomer has a stable and controllable structure. The introduction of hydroxyl functional groups expands the application range of the material. As a new elastomer material, it can also be used in plastic modifiers, blending solubilizers, adhesives, sealants, and other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 These are the DSC heating and cooling curves of the polarized elastomer prepared in this application, where (a) represents the heating curve and (b) represents the cooling curve.

[0072] Figure 2 This is the stress-strain curve of the polarized elastomer prepared in the application.

[0073] Figure 3 Surface water contact angle of the prepared polarized elastomer. DETAILED DESCRIPTION

[0074] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0075] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0076] Unless otherwise specified, conventional methods were used for testing, and instrument settings were those recommended by the manufacturer.

[0077] The analysis method in the examples of this application is as follows:

[0078] The relative molecular weight and distribution of the polymers were determined using an LC1260 GPC instrument produced by Agilent Corporation of the United States.

[0079] The microstructure of the polymer was analyzed using a Nicolet-iz10 Fourier transform infrared imaging spectrometer produced by Nicolet Corporation of the United States.

[0080] The AV-600 NMR instrument produced by Bruker Company of Germany was used to analyze the sequence structure of the product and calculate the degree of alcoholysis.

[0081] The crystallization temperature and glass transition temperature of the polymers were determined using a Netzsch differential thermal calorimeter (model DSC21400A-0800-L).

[0082] The surface water contact angle of the samples was tested using an OCA20 optical contact angle meter to analyze the surface hydrophilicity and hydrophobicity of the samples.

[0083] Performance evaluation of polar elastomers: The crystallization temperature and glass transition temperature of the polymer were characterized using a Netzsch differential thermal calorimeter. The surface hydrophilicity and hydrophobicity of the sample were characterized by surface water contact angle testing. The mechanical properties of the hot-pressed EVALVA film were characterized using a universal materials testing machine and a wide-angle laser scattering spectrometer (WAXS).

[0084] The polar elastomers prepared in the examples are labeled as EVALVA-50%, EVALVA-60%, EVALVA-68%, and EVALVA-80% according to the alcoholysis degree of 50%, 60%, 68%, and 80%, respectively.

[0085] Example 1

[0086] (1) Add 120 ml of xylene and 10 g of EVA to a 250 ml bottle, pump it out three times, introduce nitrogen, and heat and stir at 100 °C to dissolve the mixture to form a homogeneous solution.

[0087] (2) Adding a catalyst NaOH / CH3OH solution to the solution prepared in step (1), wherein the catalyst amount is a molar ratio of 1:0.1 to the ester group, NaOH is 0.186 g, CH3OH is 10 ml, and the reaction time is 20 minutes.

[0088] (3) The product was transferred to deionized water at 90°C (water to product mass ratio of 1:2), stirred and washed for 30 minutes, and washed repeatedly three times; anhydrous ethanol (anhydrous ethanol to product mass ratio of 1:2) was added and washed repeatedly three times, filtered and vacuum dried for 12 hours to obtain the product polar elastomer EVALVA-20%, and the alcoholysis degree was measured to be 20%.

[0089] Example 2

[0090] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 1, except that: in step (2), the catalyst is a NaOH / CH3OH solution, the catalyst amount is a molar ratio of 1:0.1 to the ester group, wherein NaOH is 0.186 g, CH3OH is 10 ml, the reaction time is 50 minutes, and the product polarized elastomer EVALVA-30% is obtained, and the measured alcoholysis degree is 30%.

[0091] Example 3

[0092] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 1, except that: in step (2), the catalyst is a NaOH / CH3OH solution, the catalyst amount is a molar ratio of 1:0.1 to the ester group, wherein NaOH is 0.186 g and CH3OH is 10 ml, the reaction time is 1 hour, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 43%.

[0093] Example 4

[0094] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 1, except that: in step (2), the catalyst is a NaOH / CH3OH solution, the catalyst amount is a molar ratio of 1:0.1 to the ester group, wherein NaOH is 0.186 g and CH3OH is 10 ml, the reaction time is 3 hours, and the product polarized elastomer EVALVA-50% is obtained, and the measured alcoholysis degree is 50%.

[0095] Example 5

[0096] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 1, except that: in step (2), the catalyst is a NaOH / CH3OH solution, the catalyst amount is a molar ratio of 1:0.1 to the ester group, wherein NaOH is 0.186 g and CH3OH is 10 ml. The reaction time is 3.5 hours, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 56%.

[0097] Example 6

[0098] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 1, except that: in step (2), the catalyst is a NaOH / CH3OH solution, the catalyst amount is a molar ratio of 1:0.1 to the ester group, wherein NaOH is 0.186 g and CH3OH is 10 ml, the reaction time is 5 hours, and the product polarized elastomer EVALVA-60% is obtained, and the measured alcoholysis degree is 60%.

[0099] Example 7

[0100] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 1, except that: in step (2), the catalyst is a NaOH / CH3OH solution, the catalyst amount is a molar ratio of 1:0.2 to the ester group, wherein NaOH is 0.372g and CH3OH is 10ml, the reaction time is 1 hour, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 45.4%.

[0101] Example 8

[0102] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 1, except that: in step (2), the catalyst is a NaOH / CH3OH solution, the catalyst amount is a molar ratio of 1:0.2 to the ester group, wherein NaOH is 0.372 g and CH3OH is 10 ml, the reaction time is 4 hours, and the product polarized elastomer EVALVA-68% is obtained, and the measured alcoholysis degree is 68%.

[0103] Example 9

[0104] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 1, except that: in step (2), the catalyst is a NaOH / CH3OH solution, the catalyst amount is a molar ratio of 1:0.2 to the ester group, wherein NaOH is 0.372g and CH3OH is 10ml, the reaction time is 5 hours, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 72%.

[0105] Example 10

[0106] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 1, except that: in step (2), the catalyst is a NaOH / CH3OH solution, the catalyst amount is a molar ratio of 1:0.5 to the ester group, wherein NaOH is 0.929 g and CH3OH is 10 ml, the reaction time is 20 minutes, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 52.5%.

[0107] Example 11

[0108] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 1, except that: in step (2), the catalyst is a NaOH / CH3OH solution, the catalyst amount is a molar ratio of 1:0.5 to the ester group, wherein NaOH is 0.929 g, CH3OH is 10 ml, the reaction time is 40 minutes, and the alcoholysis degree of the obtained polar elastomer is measured to be 69%.

[0109] Example 12

[0110] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 1, except that: in step (2), the catalyst is a NaOH / CH3OH solution, the catalyst amount is a molar ratio of 1:0.5 to the ester group, wherein NaOH is 0.929 g, CH3OH is 10 ml, the reaction time is 1 hour, and the product polarized elastomer EVALVA-80% is obtained, and the measured alcoholysis degree is 80%.

[0111] The polarized elastomers prepared in Examples 1-12 were analyzed for alcoholysis degree using HNMR, the crystallization temperature and crystallinity of the polymers were determined using a Netzsch differential thermal calorimeter, and the elongation at break and tensile strength of the elastomers were determined using a universal material testing machine. The data are shown in Table 1.

[0112] Table 1

[0113]

[0114]

[0115] Example 13

[0116] (1) Add 240 ml of xylene and 20 g of EVA to a 500 ml three-necked flask, pump it three times, introduce nitrogen, and heat and stir at 100 °C to dissolve the mixture to form a homogeneous solution.

[0117] (2) Add a CH3ONa solution as a catalyst to the solution prepared in step (1), with a catalyst amount of 0.143 ml of CH3ONa solution in a molar ratio of 1:0.2 to the ester group, and react for 10 minutes.

[0118] (3) The product was transferred to deionized water at 90° C. (water to product mass ratio of 1:2), stirred and washed for 30 minutes, and washed repeatedly three times; anhydrous ethanol (anhydrous ethanol to product mass ratio of 1:2) was added and washed repeatedly three times, filtered and vacuum dried for 12 hours to obtain the polarized elastomer of the product, and the alcoholysis degree was measured to be 82%.

[0119] Example 14

[0120] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 13, except that: in step 2, the catalyst is a CH3ONa solution, the catalyst amount is a molar ratio of 1:0.2 to the ester group, the CH3ONa solution is 0.143 ml, the reaction time is 20 minutes, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 86%.

[0121] Example 15

[0122] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 13, except that: in step 2, the catalyst is a CH3ONa solution, the catalyst amount is a molar ratio of 1:0.2 to the ester group, the CH3ONa solution is 0.143 ml, the reaction time is 30 minutes, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 87.5%.

[0123] Example 16

[0124] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 13, except that: in step 2, the catalyst is a CH3ONa solution, the catalyst amount is a molar ratio of 1:0.2 to the ester group, the CH3ONa solution is 0.143 ml, the reaction time is 30 minutes, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 89%.

[0125] Example 17

[0126] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 13, except that: in step 2, the catalyst is a CH3ONa solution, the catalyst amount is a molar ratio of 1:0.5 to the ester group, the CH3ONa solution is 0.36 ml, the reaction time is 10 minutes, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 88%.

[0127] Example 18

[0128] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 13, except that: in step 2, the catalyst is a CH3ONa solution, the catalyst amount is a molar ratio of 1:0.5 to the ester group, the CH3ONa solution is 0.36 ml, the reaction time is 30 minutes, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 90%.

[0129] Example 19

[0130] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 13, except that: in step 2, the catalyst is a CH3ONa solution, the catalyst amount is a molar ratio of 1:0.5 to the ester group, the CH3ONa solution is 0.36 ml, the reaction time is 1 hour, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 93%.

[0131] Example 20

[0132] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 13, except that: in step 2, the catalyst is a CH3ONa solution, the catalyst amount is a molar ratio of 1:0.5 to the ester group, the CH3ONa solution is 0.36 ml, the reaction time is 2 hours, and the product polarized elastomer EVALVA-95% is obtained, and the measured alcoholysis degree is 95%.

[0133] Example 21

[0134] The experimental steps in the EVA alcoholysis reaction process are basically the same as those in Example 13, except that: in step 2, the catalyst is a CH3ONa solution, the catalyst amount is a molar ratio of 1:0.5 to the ester group, the CH3ONa solution is 0.36 ml, the reaction time is 3 hours, and the product polarized elastomer is obtained, and the measured alcoholysis degree is 98%.

[0135] The polarized elastomers prepared in Examples 13-21 were used to calculate the alcoholysis degree using HNMR, the crystallization temperature and crystallinity of the polymers were measured using a Netzsch differential thermal calorimeter, and the elongation at break and tensile strength of the elastomers were measured using a universal material testing machine. The data are shown in Table 2.

[0136] Table 2

[0137]

[0138] As shown in Tables 1 and 2, polarized elastomers with different alcoholysis degrees and different structures can be prepared by controlling the type, dosage and reaction time of the catalyst.

[0139] The tests were conducted on EVA40 as is, EVALVA-50% prepared in Example 4, EVALVA-60% prepared in Example 6, EVALVA-68% prepared in Example 8, EVALVA-80% prepared in Example 12, and EVALVA-95% prepared in Example 20. Figure 1 、 2As we know, the thermodynamics, crystallinity and mechanical properties of EVA40 at different alcoholysis degrees show significant regular changes. With the increase of EVA alcoholysis degree, the hydroxyl content increases, the intermolecular hydrogen bonding effect is enhanced, the chain segment arrangement tends to be closer, the crystallization temperature and melting temperature are getting higher and higher, and the heat resistance is significantly improved. Compared with EVA, the mechanical properties are significantly improved, and can reach the basic mechanical strength of TPU. The maximum tensile strength of EVALVA when the alcoholysis degree is 60% is 24.3MPa, the elastic modulus gradually increases, and the elongation at break gradually decreases, from 1318% to 216%; the Shore hardness increases with the increase of alcoholysis degree, from 50.6 to 97.2. The mechanical properties of the sample are significantly improved compared with EVA, and the temperature resistance is improved. By Figure 3 It can be observed that the introduction of hydroxyl functional groups enhances the polarity of the polymer, improves its surface properties, and enhances its surface adsorption. The surface water contact angle decreases from 100° to 62°, and the surface changes from hydrophobic to hydrophilic.

[0140] The present invention features a simple preparation process and facile post-processing, making it readily industrializable. This preparation method can be tailored to the specific material requirements, allowing for the design of different molecular structures and functionalization modifications to synthesize products with diverse physicochemical properties. This allows the preparation of microblock polarized elastomers with diverse structures and properties, which can be used as a novel elastomeric material and in a wide range of applications, including plastic modifiers, blending solubilizers, adhesives, sealants, and more.

[0141] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A polarized elastomer containing three microblocks, characterized in that: The polarized elastomer contains the following structural units: (a) ethylene segment; (b) vinyl acetate segment; (c) vinyl alcohol segment; The structural formula of its structural unit is shown in Formula 1: Formula 1: The structural formula of EVA polymer is shown in Formula 2: Formula 2: m, n, x, and y are the numbers of various structural units; The value of m / n is 0.15 to 0.22; The value of x / m is 0.3 to 1; The value of y / m is 0.3 to 1; The value of x is 0.05 to 0.2; Among them, the number of ethylene structural units on the main chain of the polymer is represented by m; the number of structural units containing ester groups is represented by n; in the polymer after the reaction, the number of structural units containing ester groups is represented by x; and the number of structural units containing hydroxyl groups is represented by y.

2. The polarized elastomer according to claim 1, characterized in that The value of m / n is 0.19 to 0.21; The value of x / m is 0.5 to 1; The value of y / m is 0.5 to 1; The value of x is 0.08 to 0.

17.

3. The polarized elastomer according to claim 1, characterized in that The molecular weight of the polarized elastomer is 30,000 to 45,000; Preferably, the molecular weight of the polarized elastomer is 37,000 to 40,000; Preferably, the polydispersity index (PDI) of the polarized elastomer is 1.00 to 2.50; Preferably, the polydispersity index (PDI) of the polarized elastomer is 1.55 to 2.

40.

4. The polarized elastomer according to claim 1, characterized in that The alcoholysis degree of the polarized elastomer is 40 to 100%; Preferably, the alcoholysis degree of the polarized elastomer is 50 to 90%; Preferably, the polarized elastomer has a crystallinity of 0 to 30%; Preferably, the polarized elastomer has a crystallinity of 2 to 20%; Preferably, the crystallization peak temperature of the polarized elastomer is 20°C to 120°C; Preferably, the crystallization peak temperature of the polarized elastomer is 30°C to 90°C; Preferably, the surface water contact angle of the polarized elastomer is 50° to 105°; Preferably, the surface water contact angle of the polarized elastomer is 60° to 100°.

5. The method for preparing a polarized elastomer according to any one of claims 1 to 4, characterized in that: The following steps are involved: S1: adding EVA polymer to an organic solvent, stirring and mixing, heating and dissolving to form a homogeneous solution; S2 adds a catalyst to the homogeneous solution to undergo alcoholysis reaction to obtain a polarized elastomer containing three microblocks.

6. The preparation method according to claim 5, characterized in that In step S1, the mass proportion of ester groups in the EVA polymer is 9% to 40%; Preferably, in step S1, in the homogeneous solution, the concentration of the monomer in the solution is 5% to 10%, preferably 8% to 10%.

7. The preparation method according to claim 5, characterized in that In step S1, the temperature for heating and dissolving is 80-120°C, preferably 90-100°C; Preferably, in step S1, the organic solvent is at least one of cyclohexane, anhydrous ethanol, methanol, and xylene.

8. The preparation method according to claim 5, characterized in that In step S2, the catalyst is at least one of NaOH, NaOH / CH3OH, and CH3ONa; Preferably, in step S2, the molar ratio of the amount of the catalyst added to the ester group in the EVA polymer is 0.1-2, preferably 0.2-2; Preferably, in step S2, the temperature of the alcoholysis reaction is 80-110°C, preferably 90-100°C; Preferably, in step S2, the alcoholysis reaction time is 1 h to 8 h, preferably 1 h to 6 h.

9. The preparation method according to claim 5, characterized in that Also includes step S3: The product is transferred to water, stirred and washed, and ethanol is added to wash repeatedly, and dried to obtain the product.

10. Use of the polar elastomer according to any one of claims 1 to 4 in plastic modifiers, blending solubilizers, adhesives and sealants.

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