1. A modified polyolefin, characterized in that the modified polyolefin has a structure represented by the formula (I),

the R group is selected from a hydrogen atom or an alkyl group with 1-4 carbon atoms; x is the polymerization degree of a polyolefin chain segment, y is the polymerization degree of a polyester chain segment, wherein x is 1-10⁷Y is 1 to 5 x 10⁵(ii) a The modified polyolefin has a weight average molecular weight of 2.1X 10²～6×10⁶g/mol。

2. The modified polyolefin according to claim 1, wherein the modified polyolefin has a molecular weight distribution index of 1.1 to 50; optionally, the modified polyolefin has a molecular weight distribution index of 1.5-15.

3. The modified polyolefin according to claim 1, wherein the isotacticity of the polyolefin segment is 80 to 99.5%.

4. A process for preparing a modified polyolefin according to any one of claims 1 to 3, characterized in that it comprises:

in the presence of a solvent, a catalyst and a chain transfer agent, carrying out polymerization reaction on an olefin monomer to obtain a first mixed solution containing polyolefin;

subjecting menthone lactone monomer and the polyolefin in the first mixed solution to ring-opening polymerization reaction to obtain the modified polyolefin, wherein the menthone lactone monomer comprises but is not limited to monomers shown in formula (II) and/or formula (III):

5. the method for preparing a modified polyolefin according to claim 4, wherein the solvent is one or more selected from the group consisting of toluene, o-xylene, p-xylene, m-xylene, 1,2, 4-trimethylbenzene, hexane, pentane, n-octane, cyclohexane and isooctane;

the catalyst is selected from one or more of the group consisting of a titanium complex catalyst, a zirconium complex catalyst and a hafnium complex catalyst;

the chain transfer agent is a metal alkyl chain transfer agent selected from one or more of the group consisting of diethylaluminum chloride, ethylaluminum dichloride, n-butyllithium, triethylaluminum, trimethylaluminum, triisopropylaluminum, diethylzinc, diethylmagnesium, dibutylmagnesium and n-butylethylmagnesium;

the olefin monomer is one or more selected from the group consisting of ethylene, propylene, 1-butene and 4-methyl-1-pentene.

6. The method for producing a modified polyolefin according to claim 4, characterized in that, before the ring-opening polymerization reaction is carried out, the method for producing a modified polyolefin comprises: detecting the weight average molecular weight of the polyolefin, wherein when the weight average molecular weight of the polyolefin is 2 multiplied by 10²～5×10⁶g/mol, and the molecular weight distribution index is 1.1-15, the polymerization reaction is terminated.

7. The method for producing a modified polyolefin according to claim 6, wherein the polymerization reaction temperature is-50 to 200 ℃ and the ring-opening polymerization reaction temperature is 0 to 200 ℃;

optionally, the temperature of the polymerization reaction is-20 to 80 ℃; the temperature of the ring-opening polymerization reaction is 40-120 ℃.

8. The method of claim 7, wherein the molar ratio of the olefin monomer, the chain transfer agent, the catalyst, and the menthone lactone is (1 x 10)⁷～2×10⁹):(5～1×10⁵):(1～5×10³):(2×10⁶～4×10⁸)；

Optionally, the molar ratio of the olefin monomer, the chain transfer agent, the catalyst, and the menthone lactone is (5 x 10)⁷～1×10⁹):(5～2×10³):(1～5×10³):(4×10⁶～2×10⁸)。

9. The method of claim 8, wherein a cocatalyst is added during the polymerization, optionally the cocatalyst is selected from tris (pentafluorophenyl) boron and/or triphenylcarbyltetrakis (pentafluorophenyl) boron;

optionally, the molar ratio of the cocatalyst to the catalyst is (1:2) to (200: 1).

10. A lithium ion battery comprising a battery separator, wherein the battery separator is made using the modified polyolefin of any one of claims 1 to 3.

Background

The polyolefin diaphragm is one of four main materials of the lithium ion battery, plays a role in avoiding short circuit caused by contact of a positive pole piece and a negative pole piece, and also has an important function of rapidly transmitting lithium ions. At present, most lithium ion battery separators are mainly prepared from nonpolar polyethylene and polypropylene materials, and the materials have very poor wettability to polar electrolyte and low liquid retention capacity, so that the lithium ion transmission speed is reduced, and the electrochemical impedance is increased.

The polyolefin-based block copolymer is a resin with different block molecules, and can combine a non-polar polyolefin block with a polar polymer block, so that the polyolefin shows different solution and solid properties, and is widely applied to the material fields of polyolefin diaphragms, high-performance adhesives and the like. For example, the introduction of polycarbonate molecules into polypropylene resins can improve the colorability, impact resistance, and polar solvent wettability of polypropylene; the caprolactone block is introduced into the polyethylene resin, so that the polyethylene can be endowed with certain mechanical properties and potential shape memory properties, and the prepared lithium ion battery diaphragm has self-recovery performance. Therefore, the development of a special material which can be prepared into a high-performance polyolefin battery diaphragm is needed to improve the wettability and other performances of the lithium ion battery diaphragm, and further, the improvement of the ionic conductivity and the charge and discharge performance of the battery is significant.

Disclosure of Invention

The invention mainly aims to provide modified polyolefin, a preparation method thereof and a lithium ion battery, and aims to solve the problems of poor wettability and poor liquid retention of a polyolefin diaphragm and high impedance caused by the poor wettability and the poor liquid retention of the polyolefin diaphragm in the prior art.

In order to achieve the above object, according to one aspect of the present invention, there is provided a modified polyolefin having a structure represented by formula (I),

the R group is selected from a hydrogen atom or an alkyl group with 1-4 carbon atoms; x is the polymerization degree of a polyolefin chain segment, y is the polymerization degree of a polyester chain segment, wherein x is 1-10⁷Y is 1 to 5X 10⁵(ii) a The modified polyolefin had a weight average molecular weight of 2.1X 10²～6×10⁶g/mol。

Further, the molecular weight distribution index of the modified polyolefin is 1.1-50; optionally, the modified polyolefin has a molecular weight distribution index of 1.5 to 15.

Further, the isotacticity of the polyolefin segment is 80-99.5%.

In order to achieve the above object, another aspect of the present invention also provides a method for preparing the above modified polyolefin, the method comprising: in the presence of a solvent, a catalyst and a chain transfer agent, carrying out polymerization reaction on an olefin monomer to obtain a first mixed solution containing polyolefin; performing ring-opening polymerization reaction on menthone lactone monomer and the polyolefin in the first mixed solution to obtain modified polyolefin, wherein the menthone lactone monomer comprises but is not limited to monomers shown in formula (II) and/or formula (III):

further, the solvent is selected from one or more of the group consisting of toluene, o-xylene, p-xylene, m-xylene, 1,2, 4-trimethylbenzene, hexane, pentane, n-octane, cyclohexane and isooctane; the catalyst is selected from one or more of the group consisting of a titanium complex catalyst, a zirconium complex catalyst and a hafnium complex catalyst; the chain transfer agent is a metal alkyl chain transfer agent, and the metal alkyl chain transfer agent is one or more selected from the group consisting of diethylaluminum chloride, ethylaluminum dichloride, n-butyllithium, triethylaluminum, trimethylaluminum, triisopropylaluminum, diethylzinc, diethylmagnesium, dibutylmagnesium and n-butylethylmagnesium; the olefin monomer is one or more selected from the group consisting of ethylene, propylene, 1-butene and 4-methyl-1-pentene.

Further, the method for preparing the modified polyolefin before the ring-opening polymerization reaction includes: the weight average molecular weight of the polyolefin is detected when the weight average molecular weight of the polyolefin is 2 x 10²～5×10⁶g/mol, and the molecular weight distribution index is 1.1-15, terminating the polymerization reaction.

Further, the temperature of the polymerization reaction is-50-200 ℃, and the temperature of the ring-opening polymerization reaction is 0-200 ℃; optionally, the temperature of the polymerization reaction is-20 to 80 ℃; the temperature of the ring-opening polymerization reaction is 40-120 ℃.

Further, the molar ratio of the olefin monomer, the chain transfer agent, the catalyst and the menthone lactone is (1X 10)⁷～2×10⁹):(5～1×10⁵):(1～5×10³):(2×10⁶～4×10⁸) (ii) a Alternatively, the molar ratio of olefin monomer, chain transfer agent, catalyst and menthone lactone is (5X 10)⁷～1×10⁹):(5～2×10³):(1～5×10³):(4×10⁶～2×10⁸)。

Furthermore, a cocatalyst is added in the polymerization reaction process, and is selected from tri (pentafluorophenyl) boron and/or triphenyl carbonyl tetrakis (pentafluorophenyl) boron; optionally, the molar ratio of cocatalyst to catalyst is (1:2) to (200: 1).

The invention also provides a lithium ion battery which comprises a battery diaphragm, wherein the battery diaphragm is made of the modified polyolefin.

By applying the technical scheme of the invention, the modified polyolefin is prepared by introducing the polar polyester chain segment into the polyolefin material, so that the wettability and the liquid retention of the polyolefin diaphragm are improved. Meanwhile, the modified polyolefin has strong adaptability, and the modified polyolefin with different structures is prepared by adjusting the type and mass ratio of the polyolefin chain segment and the polyester chain segment contained in the structure of the modified polyolefin, so that the subsequently prepared modified polyolefin diaphragm can adapt to different electrolyte environments.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 shows a modified polyolefin according to example 4 of the present invention¹H NMR spectrum;

FIG. 2 shows a gel permeation chromatogram of a modified polyolefin according to example 5 of the present invention;

fig. 3 shows a schematic contact angle diagram of a modified polyolefin separator and a commercial polypropylene hydrocarbon separator according to example 3 of the present invention.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail with reference to examples.

As described in the background art, the existing polyolefin-based separator has problems of poor wettability and poor liquid retention. In order to solve the above-mentioned problems, the present application provides, in a first aspect, a modified polyolefin having a structure represented by formula (I),

the R group includes but is not limited to a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; x is the polymerization degree of a polyolefin chain segment, y is the polymerization degree of a polyester chain segment, wherein x is 1-10⁷Y is 1 to 5X 10⁵(ii) a The weight average molecular weight of the modified polyolefin is 2.1X 10²～6×10⁶g/mol。

The polar polyester chain segment has strong polarity, has better hydrophilicity in polar electrolyte, and can improve the wettability and the liquid retention of the polyolefin diaphragm by introducing the polar polyester chain segment into a polyolefin material. Meanwhile, modified polyolefin with different structures can be prepared by adjusting the types and the polymerization degrees of the polyolefin chain segment and the polyester chain segment contained in the structure of the modified polyolefin membrane, the modified polyolefin membrane has wide application range, and the subsequently prepared modified polyolefin membrane is convenient to adapt to different electrolyte environments.

In order to improve the wettability and the liquid absorption rate of the modified polyolefin to the electrolyte, in a preferred embodiment, the molecular weight distribution index of the modified polyolefin is 1.1 to 50. Limiting the molecular weight distribution index of the modified polyolefin within the above range enables the overall properties of the modified polyolefin to be more stable. Meanwhile, in order to further improve the wettability and the liquid absorption rate of the modified polyolefin in the electrolyte, optionally, the molecular weight distribution index of the modified polyolefin is 1.5-15.

Isotacticity affects the crystallinity of polyolefins, and generally the higher the isotacticity, the higher the crystallinity. And low isotacticity, high product viscosity and poor fluidity. In order to improve the crystallinity of the polyolefin segment, improve the processability of the polyolefin segment, and further improve the wettability and the liquid absorption rate of the modified polyolefin to the electrolyte, in a preferred embodiment, the isotacticity of the polyolefin segment is 80 to 99.5%.

In a second aspect, the present application provides a process for preparing a modified polyolefin. The preparation method of the modified polyolefin comprises the following steps: in the presence of a solvent, a catalyst and a chain transfer agent, carrying out polymerization reaction on an olefin monomer to obtain a first mixed solution containing polyolefin; performing ring-opening polymerization reaction on a menthone lactone monomer and the polyolefin in the first mixed solution to obtain modified polyolefin, wherein the menthone lactone monomer comprises but is not limited to a monomer shown in a formula (II) and/or a formula (III);

the menthone lactone monomer has a cyclic lactone structure and can generate ring-opening polymerization reaction with polyolefin. By adopting the preparation method, polar menthone lactone polyester chain segments can be introduced into the polyolefin, so that the wettability and the liquid absorption rate of the polyolefin in the electrolyte can be greatly improved. Meanwhile, the preparation method of the modified polyolefin adopts a semi-batch polymerization method, so that the obtained modified polyolefin has simple post-treatment process and can reduce the production cost.

In a preferred embodiment, the solvent includes, but is not limited to, one or more of the group consisting of toluene, o-xylene, p-xylene, m-xylene, 1,2, 4-trimethylbenzene, hexane, pentane, n-octane, cyclohexane and isooctane. The above catalyst includes, but is not limited to, one or more of the group consisting of a titanium complex catalyst, a zirconium complex catalyst and a hafnium complex catalyst. The chain transfer agent is a metal alkyl chain transfer agent including, but not limited to, one or more of the group consisting of diethylaluminum chloride, ethylaluminum dichloride, n-butyllithium, triethylaluminum, trimethylaluminum, triisopropylaluminum, diethylzinc, diethylmagnesium, dibutylmagnesium, and n-butylethylmagnesium. The above olefin monomers include, but are not limited to, one or more of the group consisting of ethylene, propylene, 1-butene and 4-methyl-1-pentene.

In order to determine the time for terminating the reaction and effectively monitor the extent of the reaction, in a preferred embodiment, the process for preparing the modified polyolefin comprises, prior to carrying out the ring-opening polymerization reaction: the weight average molecular weight of the polyolefin is detected when the weight average molecular weight of the polyolefin is 2 x 10²～5×10⁶g/mol, and the molecular weight distribution index is 1.1-15, terminating the polymerization reaction.

In a preferred embodiment, the polymerization reaction is carried out at a temperature of-50 to 200 ℃. Compared with other temperature ranges, the temperature of the polymerization reaction is limited in the range, so that more appropriate reaction conditions can be provided for the polymerization reaction, and the precise synthesis of the target product, namely the modified polyolefin, is facilitated. In order to further improve the synthesis efficiency of the polyolefin, optionally, the temperature of the polymerization reaction is-20 to 80 ℃.

In a preferred embodiment, the temperature of the ring-opening polymerization reaction is 0 to 200 ℃. Compared with other temperature ranges, the temperature of the ring-opening polymerization reaction is limited in the range, so that more appropriate reaction conditions can be provided for the ring-opening polymerization reaction, the ring-opening polymerization reaction can be carried out more thoroughly, and the yield of the modified polyolefin can be improved. In order to further improve the reaction rate and yield of the ring-opening polymerization product, optionally, the temperature of the ring-opening polymerization reaction is 40-120 ℃.

In a preferred embodiment, the molar ratio of the olefin monomer, the chain transfer agent, the catalyst and the menthone lactone is (1 × 10)⁷～2×10⁹):(5～1×10⁵):(1～5×10³):(2×10⁶～4×10⁸). The molar ratio of the olefin monomer, the chain transfer agent, the catalyst and the menthone lactone is limited within the range, so that the modified polyolefin with the structure shown in the formula (I) can be accurately synthesized, the synthesized modified polyolefin has a polyolefin chain segment with a proper polymerization degree, a polyester chain segment and a molecular weight, the modified polyolefin prepared by the reaction has stronger polarity, and the wettability and the liquid absorption rate of the modified polyolefin to the electrolyte are improved. In order to further improve the polarity of the modified polyolefin and the wettability and liquid absorption rate of the electrolyte and further reduce the impedance of the battery separator made of the modified polyolefin, optionally, the molar ratio of the olefin monomer, the chain transfer agent, the catalyst and the menthone lactone is (5 × 10)⁷～1×10⁹):(5～2×10³):(1～5×10³):(4×10⁶～2×10⁸)。

In a preferred embodiment, a cocatalyst is also added during the polymerization. The addition of the cocatalyst can improve the activity of the catalyst, further improve the reaction rate of the polymerization reaction and simultaneously improve the selectivity of the catalyst. To further increase the reaction rate of the polymerization reaction, optionally, the co-catalyst includes, but is not limited to, tris (pentafluorophenyl) boron and/or triphenylcarbenium tetrakis (pentafluorophenyl) boron.

In order to further improve the reaction rate and selectivity of the polymerization reaction, optionally, the molar ratio of the cocatalyst to the catalyst is (1:2) to (200: 1); in order to further improve the reaction rate and selectivity of the above polymerization reaction, optionally, the molar ratio of the cocatalyst to the catalyst is (1:1) to (50: 1).

In a third aspect, the present application provides a lithium ion battery, which includes a battery separator, wherein the battery separator is made of the modified polyolefin. Because the polar menthone lactone polyester chain segment is introduced into the modified polyolefin material, the wettability and the liquid retention of the polyolefin diaphragm are improved. Meanwhile, the modified polyolefin has wide application range, and the modified polyolefin with different structures is prepared by adjusting the types and the polymerization degrees of the polyolefin chain segment and the polyester chain segment contained in the structure of the modified polyolefin, so that the subsequently prepared modified polyolefin diaphragm is convenient to adapt to different electrolyte environments.

The present application is described in further detail below with reference to specific examples, which should not be construed as limiting the scope of the invention as claimed.

Example 1

400mL of toluene and 850mmol of ethylene monomer were charged into a dry 1000mL polymerization reactor under an argon atmosphere, and after stirring for 10min, the reaction temperature was adjusted to 70 ℃ and 0.3mL of triethylaluminum (0.5mmol/L) was added as a chain transfer agent, followed by 0.05mL of 1mmol/L triphenylcarbyltetrakis (pentafluorophenyl) boron ([ Ph)₃C][B(C₆F₅)₄]) The toluene solution is used as a cocatalyst, and 0.01mL of 0.1mmol/L titanium complex catalyst (the manufacturer is Jiangsuxinnoco catalyst Co., Ltd; model number 202756-29-4). The molar ratio of the added triphenylcarbyl tetrakis (pentafluorophenyl) boron cocatalyst to the titanium complex catalyst is 5:1, and the polymerization reaction is carried out for 5min under the stirring action. When it was determined that the weight average molecular weight of the polyethylene obtained after the above polymerization reaction was 576000g/mol and the molecular weight distribution index was 2.3, the above polymerization reaction was terminated.

Then 2mmol/L of II type menthone lactone monomer is added into the mixed liquid containing the polyethylene, and the molar ratio of the ethylene monomer, the triethyl aluminum chain transfer agent, the titanium complex catalyst and the menthone lactone is 850000000:150:1: 340000000. And raising the reaction temperature to 80 ℃, carrying out ring-opening polymerization reaction for 6 hours, and then terminating the reaction to obtain a mixed solution containing the modified polyethylene.

Pouring the mixed solution containing the modified polyethylene into methanol for precipitation, and then filtering, washing and vacuum drying the mixture to obtain the modified polyethylene.

According to¹H NMR and thermogravimetric analysis test results are obtained, and the chemical structure of the modified polyethylene is obtained through analysis. The modified polyethylene has the following structure,wherein, the R group is hydrogen atom, the polymerization degree x of the polyethylene chain segment is 12000, the polymerization degree y of the polyester chain segment is 200, and the weight-average molecular weight is 803000 g/mol. The molecular weight distribution index of the modified polyethylene is 2.5 by gel permeation chromatography test.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of wetting of the commercial electrolyte on the modified polyethylene separator was 8.5cm, while the average length of wetting on the commercial polyethylene separator was 3.1 cm.

Example 2

500mL of toluene and 800mmol of propylene monomer were charged into a dry 1000mL polymerization reactor under an argon atmosphere, stirred for 5min, the reaction temperature was adjusted to 60 ℃ and 0.1mL of triethylaluminum (0.5mmol/L) was added as a chain transfer agent, followed by 5mL of 1mmol/L of [ Ph ]₃C][B(C₆F₅)₄]The toluene solution was used as a cocatalyst, and 1mL of 0.5mmol/L toluene solution of the hafnium complex catalyst was added. Adding [ Ph ]₃C][B(C₆F₅)₄]The molar ratio of the cocatalyst to the hafnium complex catalyst (made by Bailingwei science and technology Co., Ltd.; model number 158515-16-3) was 5:1, and the polymerization was carried out for 2min under stirring. When the polypropylene obtained after the polymerization reaction is detectedThe weight average molecular weight of the olefin was 80000g/mol, the molecular weight distribution index was 3.0, and the above polymerization reaction was terminated.

Then 5mmol/L of type II menthone lactone monomer is added into the mixed liquid containing polypropylene, and the molar ratio of the propylene monomer, the triethyl aluminum chain transfer agent, the hafnium complex catalyst and the menthone lactone is 800000000:50:500: 200000000. And (3) heating the reaction temperature to 80 ℃, carrying out ring-opening polymerization reaction for 12h, and then terminating the reaction to obtain a mixed solution containing the modified polypropylene.

And pouring the mixed solution containing the modified polypropylene into ethanol for precipitation, and then filtering, washing and vacuum drying to obtain the modified polypropylene.

The test methods were the same as in example 1, and the test results were as follows: the modified polypropylene has the following structure,wherein the R group is methyl, the polymerization degree x of the polypropylene chain segment is 750, the polymerization degree y of the polyester chain segment is 300, and the weight-average molecular weight is 136000 g/mol; the molecular weight distribution index of the modified polypropylene is 3.1; the isotacticity of the polypropylene segment was 97.0%.

The contact angle of the modified polypropylene diaphragm prepared by the modified polypropylene is smaller than that of a commercial polypropylene diaphragm; under the same test time of 3min, the average wetting length of the commercial electrolyte on the modified polypropylene membrane is 9.3 cm.

Example 3

500mL of toluene and 450mmol of propylene monomer were charged into a dry 1000mL polymerization reactor under an argon atmosphere, and after stirring for 5min, the reaction temperature was adjusted to 45 ℃ and 0.1mL of triethylaluminum (0.5mmol/L) was added as a chain transfer agent, followed by 5mL of 1mmol/L of [ Ph ]₃C][B(C₆F₅)₄]The toluene solution was used as a cocatalyst, and 0.1mL of 0.5mmol/L toluene solution of zirconium complex catalyst was finally added. Adding [ Ph ]₃C][B(C₆F₅)₄]The molar ratio of the cocatalyst to the zirconium complex catalyst (Sigma-Aldrich; model 100163-29-9) is 10:1, and polymerization is carried out under the stirring actionAnd (5) carrying out a synthesis reaction for 2 min. When the weight average molecular weight of the polypropylene obtained after the polymerization reaction was detected to be 110000g/mol and the molecular weight distribution index was 2.2, the polymerization reaction was terminated.

Then 11mmol/L of type II menthone lactone monomer is added into the mixed liquid containing polypropylene, and the molar ratio of the propylene monomer, the triethyl aluminum chain transfer agent, the zirconium complex catalyst and the menthone lactone is 45000000:5:5: 15000000. And (3) heating the reaction temperature to 80 ℃, carrying out ring-opening polymerization reaction for 24 hours, and then terminating the reaction to obtain a mixed solution containing the modified polypropylene.

And pouring the mixed solution containing the modified polypropylene into methanol for precipitation, and then filtering, washing and vacuum drying to obtain the modified polypropylene.

The test methods were the same as in example 1, and the test results were as follows: the modified polypropylene has the following structure,wherein the R group is methyl, the polymerization degree x of the polypropylene chain segment is 1400, the polymerization degree y of the polyester chain segment is 350, and the weight-average molecular weight is 238000 g/mol; the molecular weight distribution index of the modified polypropylene is 2.2; the isotacticity of the polypropylene segment was 96.5%.

As shown in fig. 3, the contact angle of the modified polypropylene separator made of the above-described modified polypropylene was 27 °, while the contact angle of the commercial polypropylene separator was 121%; under the same test time of 3min, the average wetting length of the commercial electrolyte on the modified polypropylene separator was 7.7 cm.

Example 4

100mL of toluene and 500mmol of 4-methyl-1-pentene monomer were charged into a dry 1000mL polymerization reactor under an argon atmosphere, stirred for 5min, the reaction temperature was adjusted to 25 ℃ and 0.01mL of diethyl zinc (0.5mmol/L) was added as a chain transfer agent, followed by 1mL of 10mmol/L of [ Ph ]₃C][B(C₆F₅)₄]The toluene solution was used as a cocatalyst, and 2mL of 0.1mmol/L toluene solution of zirconium complex catalyst was added. Adding [ Ph ]₃C][B(C₆F₅)₄]The molar ratio of the cocatalyst to the zirconium complex catalyst (product is Ministry science and technology Co., Ltd.; model number is 1291-32-3) is 50:1, and the polymerization reaction is carried out for 28min under the stirring action. When it was confirmed that the weight average molecular weight of the poly-4-methyl-1-pentene obtained after the above polymerization was 480000g/mol and the molecular weight distribution index was 1.8, the above polymerization was terminated.

Then 25mmol/L of type II mentholactone monomer is added into the mixed solution containing poly 4-methyl-1-pentene, so that the molar ratio of the 4-methyl-1-pentene monomer, the diethyl zinc chain transfer agent, the zirconium complex catalyst and the menthone lactone is 500000000:5:200: 1. Heating the reaction temperature to 90 ℃, carrying out ring-opening polymerization reaction for 8 hours, and then terminating the reaction to obtain a mixed solution containing the modified poly-4-methyl-1-pentene.

Pouring the mixed solution containing the modified poly-4-methyl-1-pentene into methanol and acetone for precipitation, and then filtering, washing and vacuum drying to obtain the modified poly-4-methyl-1-pentene.

The test methods were the same as in example 1, and the test results were as follows: process for preparing modified poly-4-methyl-1-pentene¹The H-NMR spectrum is shown in FIG. 1. The modified poly-4-methyl-1-pentene has the following structure,wherein the R group is isobutyl, the polymerization degree x of the poly 4-methyl-1-pentene chain segment is 3200, the polymerization degree y of the polyester chain segment is 310, and the weight average molecular weight is 152000 g/mol; the molecular weight distribution index of the modified poly-4-methyl-1-pentene is 3.1; the isotacticity of the poly-4-methyl-1-pentene segment was 97.0%.

The contact angle of the modified poly-4-methyl-1-pentene membrane prepared from the modified poly-4-methyl-1-pentene is smaller than that of the commercialized poly-4-methyl-1-pentene membrane; the average length of wetting of the commercial electrolyte on the modified poly 4-methyl-1-pentene membrane was 6.2cm under the same test time of 3 min.

Example 5

500mL of toluene and 600mmol of 1-butene monomer were charged into a dry 1000mL polymerization reactor under an argon atmosphere, stirred for 10min, and then adjustedThe reaction temperature was raised to 55 ℃ and 0.1mL of dibutyl zinc (0.5mmol/L) was added as a chain transfer agent, followed by 3mL of tris (pentafluorophenyl) boron ([ B (C) ([ 15mmol/L ]))₆F₅)₃]) The toluene solution was used as a cocatalyst, and 10mL of 0.1mmol/L toluene solution of the titanium complex catalyst was added. Adding [ B (C) ]₆F₅)₃]The molar ratio of the cocatalyst to the titanium complex catalyst (manufactured by Xinnaoko catalyst Co., Ltd.; model number 202756-29-4) was 4.5:1, and the polymerization was carried out for 50min under stirring. When it was determined that the weight average molecular weight of polybutene obtained after the polymerization was 400000g/mol and the molecular weight distribution index was 3.8, the polymerization was terminated.

Then 10mmol/L type III mentholactone monomer is added into the mixed liquid containing polybutene, and the molar ratio of the 1-butene monomer, the dibutyl zinc chain transfer agent, the titanium complex catalyst and the menthone lactone is 60000000:5:100: 1091000. And (3) heating the reaction temperature to 95 ℃, carrying out ring-opening polymerization reaction for 16h, and then terminating the reaction to obtain a mixed solution containing the modified polybutene.

And pouring the mixed solution containing the modified polybutene into methanol and normal hexane for precipitation, and then filtering, washing and vacuum drying to obtain the modified polybutene.

The test methods were the same as in example 1, and the test results were as follows: the gel permeation chromatogram of the modified polybutene prepared above is shown in FIG. 2. The modified polybutene has the following structure,wherein the R group is ethyl, the polymerization degree x of the polyethylene chain segment is 1900, the polymerization degree y of the polyester chain segment is 30, the weight average molecular weight of the polybutene is 580000g/mol, and the weight average molecular weight of the modified polybutene is 20000 g/mol; the molecular weight distribution index of the modified polybutene is 2.7; the isotacticity of the polybutene segment was 98%.

The contact angle of the modified polybutylene diaphragm made of the modified polyethylene is smaller than that of a commercial polybutylene diaphragm; under the same test time of 3min, the average length of the commercial electrolyte soaked on the modified polybutene membrane was 5.3 cm.

Example 6

500mL of toluene and 500mmol of ethylene monomer were charged into a dry 1000mL polymerization reactor under an argon atmosphere, stirred for 5min, the reaction temperature was adjusted to 25 ℃, 0.5mL of triisobutylaluminum (0.5mmol/L) was added as a chain transfer agent, and then 2mL of 3mmol/L of [ Ph ] was added₃C][B(C₆F₅)₄]The toluene solution was used as a cocatalyst, and 1mL of 0.5mmol/L toluene solution of the titanium complex catalyst was added. Adding [ Ph ]₃C][B(C₆F₅)₄]The molar ratio of the cocatalyst to the titanium complex catalyst (manufactured by Inokay technologies Co., Ltd.; model number 162763-85-1) was 12:1, and the polymerization was carried out for 10min under stirring. When it was determined that the weight average molecular weight of the polyethylene obtained after the polymerization was obtained was 460000g/mol and the molecular weight distribution index was 3.3, the polymerization was terminated.

Then 10mmol/L type III mentholactone monomer is added into the mixed liquid containing polyethylene, and the molar ratio of the ethylene monomer, the triisobutyl aluminum chain transfer agent, the titanium complex catalyst and the menthone lactone is 50000000:25:50: 833000. And raising the reaction temperature to 95 ℃, carrying out ring-opening polymerization for 16h, and then terminating the reaction to obtain a mixed solution containing the modified polyethylene.

Pouring the mixed solution containing the modified polyethylene into methanol and n-hexane for precipitation, and then filtering, washing and vacuum drying the mixture to obtain the modified polyethylene.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has the following structure,wherein, the R group is hydrogen atom, the polymerization degree x of the polyethylene chain segment is 5800, the polymerization degree y of the polyester chain segment is 400, and the weight-average molecular weight is 700000 g/mol; the molecular weight distribution index of the modified polyethylene is 3.4; the isotacticity of the polyethylene segment was 97%.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; the average infiltration length of the commercial electrolyte on the modified polyethylene diaphragm is 7.2cm under the same test time of 3 min.

Example 7

500mL of toluene and 650mmol of ethylene monomer were charged into a dry 1000mL polymerization reactor under an argon atmosphere, stirred for 10min, the reaction temperature was adjusted to 55 deg.C, 0.1mL of dibutyl zinc (0.5mmol/L) was added as a chain transfer agent, and then 7mL of 15mmol/L of [ Ph ] was added₃C][B(C₆F₅)₄]Toluene solution as cocatalyst, and finally 1mL of 5mmol/L toluene solution of zirconium complex catalyst was added to the solution₃C][B(C₆F₅)₄]The molar ratio of the cocatalyst to the zirconium complex catalyst (Sigma-Aldrich; model 121009-93-6) was 17:1, and polymerization was carried out for 50min with stirring. When it was determined that the weight average molecular weight of the polyethylene obtained after the above polymerization reaction was 250000g/mol and the molecular weight distribution index was 2.4, the above polymerization reaction was terminated.

Then 10mmol/L of II type menthone lactone monomer is added into the mixed liquid containing the polyethylene, and the molar ratio of the ethylene monomer, the dibutyl zinc chain transfer agent, the zirconium complex catalyst and the menthone lactone is 65000000:5:500: 65. And raising the reaction temperature to 95 ℃, carrying out ring-opening polymerization for 16h, and then terminating the reaction to obtain a mixed solution containing the modified polyethylene.

Pouring the mixed solution containing the modified polyethylene into methanol and n-hexane for precipitation, and then filtering, washing and vacuum drying the mixture to obtain the modified polyethylene.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has the following structure,wherein the R group is hydrogen atom, the polymerization degree x of the polyethylene chain segment is 4300, the polymerization degree y of the polyester chain segment is 350, and the weight average molecular weight is 280000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.5.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 8.1 cm.

Example 8

600mL of toluene and 670mmol of 1-butene monomer were charged into a dry 1000mL polymerization reactor under an argon atmosphere, stirred for 5min, the reaction temperature was adjusted to 20 ℃ and 3mL of dibutylmagnesium (1.1mmol/L) was added as a chain transfer agent, followed by 35mL of 1mmol/L tris (pentafluorophenyl) boron ([ B (C)₆F₅)₃]) The toluene solution was used as a cocatalyst, and 5mL of 0.6mmol/L toluene solution of the hafnium complex catalyst was added. Adding [ B (C) ]₆F₅)₃]The molar ratio of the cocatalyst to the hafnium complex catalyst (manufactured by Aladdin chemical reagent Co., Ltd.; model number 85722-08-3) was 12:1, and the polymerization was carried out for 100min under stirring. When it was determined that the weight average molecular weight of the poly-1-butene obtained after the polymerization was obtained was 450000g/mol, and the molecular weight distribution index was 2.7, the polymerization was terminated.

Then 16mmol/L of II type menthone lactone monomer is added into the mixed liquid containing the poly-1-butene, so that the molar ratio of the 1-butene monomer, the dibutyl magnesium chain transfer agent, the hafnium complex catalyst and the menthone lactone is 6700000:33:30: 418750. And (3) heating the reaction temperature to 85 ℃, carrying out ring-opening polymerization reaction for 16h, and then terminating the reaction to obtain a mixed solution containing the modified polybutene.

And pouring the mixed solution containing the modified polybutene into methanol and normal hexane for precipitation, and then filtering, washing and vacuum drying to obtain the modified polybutene.

The test methods were the same as in example 1, and the test results were as follows: the modified polybutene has the following structure,wherein the R group is ethyl, the polymerization degree x of the polybutylene chain segment is 2300, the polymerization degree y of the polyester chain segment is 140, and the weight-average molecular weight is 510000 g/mol; the molecular weight distribution index of the modified polybutene was 3.0; polybutylene segmentThe isotacticity of (A) was 97.3%.

The contact angle of the modified polybutene membrane prepared from the modified polybutene is smaller than that of the commercialized polybutene membrane; under the same test time of 3min, the average length of the commercial electrolyte soaked on the modified polybutene membrane was 6.2 cm.

Example 9

400mL of toluene, 1300mmol of propylene monomer and 20mmol of 4-methyl-1-pentene monomer were charged into a dry 1000mL polymerization reactor under an argon atmosphere, and after stirring for 10min, the reaction temperature was adjusted to 70 ℃ and 0.3mL of triethylaluminum (0.5mmol/L) was added as a chain transfer agent, followed by 6mL of 1mmol/L of [ Ph ]₃C][B(C₆F₅)₄]Toluene solution was used as cocatalyst. Finally, 20mL of a 0.1mmol/L solution of zirconium complex catalyst in toluene was added. Adding [ Ph ]₃C][B(C₆F₅)₄]The molar ratio of the cocatalyst to the zirconium complex catalyst (manufactured by Xinnaoko catalyst Co., Ltd.; model number 126642-97-5) was 3:1, and the polymerization was carried out for 5min under stirring. When it was confirmed that the weight average molecular weight of the propylene copolymer obtained after the polymerization reaction was 640000g/mol and the molecular weight distribution index was 2.6, the polymerization reaction was terminated.

Then 6mmol/L of type II mentholactone monomer is added into the mixed solution containing the propylene-4 methyl-1-pentene copolymer, so that the molar ratio of the propylene monomer, the 4-methyl-1-pentene monomer, the triethyl aluminum chain transfer agent, the zirconium complex catalyst and the menthone lactone is 130000000:2000000:15:200: 1000000. The reaction temperature is increased to 80 ℃, the ring opening polymerization reaction is carried out for 6h, and then the reaction is terminated, thus obtaining the mixed solution containing the modified propylene-4 methyl-1-pentene copolymer.

And pouring the mixed solution containing the modified propylene copolymer into methanol for precipitation, and then filtering, washing and vacuum drying to obtain the modified propylene copolymer.

The test methods were the same as in example 1, and the test results were as follows: the modified propylene copolymer has the following structure,wherein the polymerization degree x of a propylene chain segment in the modified propylene copolymer is 5100, the polymerization degree of 4-methyl-1-pentene is 740, the polymerization degree y of a polyester chain segment is 300, and the weight-average molecular weight is 800000 g/mol; the molecular weight distribution index of the modified propylene copolymer was 2.7; the isotacticity of the polypropylene segment was 96.8%.

The contact angle of the modified propylene copolymer membrane prepared from the modified propylene copolymer is smaller than that of the commercial propylene copolymer membrane; the average length of wetting of the commercial electrolyte on the modified propylene copolymer separator was 7.6cm under the same test time of 3 min.

Example 10

400mL of toluene and 900mmol of a vinyl monomer and 25mmol of a 4-methyl-1-pentene monomer were charged into a dry 1000mL polymerization reactor under an argon atmosphere, stirred for 10min, then the reaction temperature was adjusted to 70 ℃ and 0.3mL of triethylaluminum (0.5mmol/L) was added as a chain transfer agent, followed by 2mL of 1mmol/L of [ Ph ]₃C][B(C₆F₅)₄]The toluene solution was used as a cocatalyst, and 10mL of 0.1mmol/L toluene solution of the titanium complex catalyst was added. Adding [ Ph ]₃C][B(C₆F₅)₄]The molar ratio of the cocatalyst to the titanium complex catalyst (Sigma-Aldrich; type 1282-40-2) was 2:1, and polymerization was carried out for 5min with stirring. When it was determined that the weight average molecular weight of the polyethylene obtained after the polymerization reaction was 360000g/mol and the molecular weight distribution index was 2.1, the polymerization reaction was terminated.

Then, 23mmol/L of type III mentholide monomer was added to the above mixed solution containing an ethylene copolymer so that the molar ratio of the ethylene monomer, 4-methyl-1-pentene monomer, triethyl aluminum chain transfer agent, titanium complex catalyst and menthone lactone was 900000:25000:150:1: 25000. And (3) heating the reaction temperature to 80 ℃, carrying out ring-opening polymerization reaction for 6 hours, and then terminating the reaction to obtain a mixed solution containing the modified ethylene copolymer.

And pouring the mixed solution containing the modified ethylene copolymer into methanol for precipitation, and then filtering, washing and vacuum drying to obtain the mixed solution of the modified ethylene copolymer.

The test methods were the same as in example 1, and the test results were as follows: the modified ethylene copolymer has the following structure,wherein the polymerization degree x of ethylene in the modified ethylene copolymer is 6950, the polymerization degree of 4-methyl-1-pentene is 56, the polymerization degree of a polyester chain segment is 50, and the weight-average molecular weight is 395000 g/mol; the molecular weight distribution index of the modified ethylene copolymer was 2.2.

The contact angle of the modified ethylene-4 methyl-1-pentene copolymer membrane prepared from the above modified ethylene-4 methyl-1-pentene copolymer is smaller than that of the commercialized ethylene-4 methyl-1-pentene copolymer membrane; under the same test time of 3min, the average wetting length of the commercial electrolyte on the modified ethylene-4 methyl-1-pentene copolymer membrane was 7.8 cm.

Example 11

The difference from example 1 is that: the molar ratio of the ethylene monomer, the triethyl aluminum chain transfer agent, the titanium complex catalyst and the menthone lactone is 1 x 10⁷:5:1:2×10⁶. The molar ratio of vinyl monomer to menthone lactone is 5000: 1.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in a formula (I), the polymerization degree x of a polyethylene chain segment is 14000, the polymerization degree y of a polyester chain segment is 220, and the weight-average molecular weight is 894000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.4.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 8.6 cm.

Example 12

The difference from example 1 is that: the molar ratio of the ethylene monomer, the triethyl aluminum chain transfer agent, the titanium complex catalyst and the menthone lactone is 2 x 10⁹:1×10⁵:5×10³:4×10⁸。

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in formula (I), the polymerization degree x of a polyethylene chain segment is 19000, the polymerization degree y of a polyester chain segment is 260, and the weight-average molecular weight is 1150000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.3.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 7.9 cm.

Example 13

The difference from example 1 is that: the molar ratio of the ethylene monomer, the triethyl aluminum chain transfer agent, the titanium complex catalyst and the menthone lactone is 3000:10:1: 1.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in formula (I), the polymerization degree x of a polyethylene chain segment is 20000, the polymerization degree y of a polyester chain segment is 30, and the weight-average molecular weight is 1260000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.3.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 4.1 cm.

Example 14

The difference from example 1 is that: the molar ratio of the ethylene monomer, the triethyl aluminum chain transfer agent, the titanium complex catalyst and the menthone lactone is 5 x 10⁷:2×10³:1:2×10⁶。

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in a formula (I), the polymerization degree x of a polyethylene chain segment is 11000, the polymerization degree y of a polyester chain segment is 500, and the weight-average molecular weight is 740000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.3.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; the average length of wetting of the commercial electrolyte on the modified polyethylene separator was 9.4cm under the same test time of 3 min.

Example 15

The difference from example 1 is that: the molar ratio of ethylene monomer, triethyl aluminum chain transfer agent, hafnium complex catalyst and menthone lactone is 1 x 10⁹:5:10:2×10⁸。

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in a formula (I), the polymerization degree x of a polyethylene chain segment is 9000, the polymerization degree y of a polyester chain segment is 700, and the weight-average molecular weight is 788000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.4.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 9.6 cm.

Example 16

The difference from example 1 is that: the cocatalyst added is tris (pentafluorophenyl) boron B (C)₆F₅)₃。

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in a formula (I), the polymerization degree x of a polyethylene chain segment is 14000, the polymerization degree y of a polyester chain segment is 250, and the weight-average molecular weight is 908000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.4.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 8.7 cm.

Example 17

The difference from example 1 is that: added [ Ph₃C][B(C₆F₅)₄]The molar ratio of the cocatalyst to the titanium complex catalyst (from Okinawa technologies, Inc.; model 918151-45-8) was 1: 2.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in a formula (I), wherein the polymerization degree x of a polyethylene chain segment is 16000, the polymerization degree y of a polyester chain segment is 230, and the weight-average molecular weight is 880000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.1.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 8.1 cm.

Example 18

The difference from example 1 is that: added [ Ph₃C][B(C₆F₅)₄]The molar ratio of cocatalyst to hafnium complex catalyst (made by Bailingwei technologies, Inc.; model number 162763-85-1) was 200: 1.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in formula (I), the polymerization degree x of a polyethylene chain segment is 15000, the polymerization degree y of a polyester chain segment is 210, and the weight-average molecular weight is 908000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.3.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 8.3 cm.

Example 19

The difference from example 1 is that: added [ Ph₃C][B(C₆F₅)₄]The molar ratio of the cocatalyst to the hafnium complex catalyst (Sigma-Aldrich; model 123927-75-3) was 1: 5.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in a formula (I), wherein the polymerization degree x of a polyethylene chain segment is 18000, the polymerization degree y of a polyester chain segment is 60, and the weight-average molecular weight is 1140000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.66.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 5.1 cm.

Example 20

The difference from example 1 is that: the polymerization temperature of the olefin was 200 ℃.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in a formula (I), wherein the polymerization degree x of a polyethylene chain segment is 18000, the polymerization degree y of a polyester chain segment is 260, and the weight-average molecular weight is 1180000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.5.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 8.6 cm.

Example 21

The difference from example 1 is that: the temperature of the polymerization of the olefin was-50 ℃.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in formula (I), wherein the polymerization degree x of a polyethylene chain segment is 13000, the polymerization degree y of a polyester chain segment is 160, and the weight-average molecular weight is 770000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.4.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 8.1 cm.

Example 22

The difference from example 1 is that: the polymerization temperature of the olefin was 230 ℃.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in a formula (I), wherein the polymerization degree x of a polyethylene chain segment is 18000, the polymerization degree y of a polyester chain segment is 45, and the weight-average molecular weight is 1090000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.5.

The contact angle of the modified polyethylene diaphragm prepared by the modified polyethylene is less than 4.9 percent of that of the commercial polyethylene diaphragm; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 3.1 cm.

Example 23

The difference from example 1 is that: the temperature of the polymerization of the olefin was-20 ℃.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in a formula (I), the polymerization degree x of a polyethylene chain segment is 14000, the polymerization degree y of a polyester chain segment is 620, and the weight-average molecular weight is 1002000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.3.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 9.3 cm.

Example 24

The difference from example 1 is that: the temperature of the polymerization of the olefin was 80 ℃.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in formula (I), wherein the polymerization degree x of a polyethylene chain segment is 13000, the polymerization degree y of a polyester chain segment is 650, and the weight-average molecular weight is 1050000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.5.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; the average length of wetting of the commercial electrolyte on the modified polyethylene separator was 9.4cm under the same test time of 3 min.

Example 25

The difference from example 1 is that: the temperature of the ring-opening polymerization reaction was 0 ℃.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in a formula (I), the polymerization degree x of a polyethylene chain segment is 11000, the polymerization degree y of a polyester chain segment is 210, and the weight-average molecular weight is 777000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.6.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 8.3 cm.

Example 26

The difference from example 1 is that: the temperature of the ring-opening polymerization reaction was 200 ℃.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in formula (I), wherein the polymerization degree x of a polyethylene chain segment is 13000, the polymerization degree y of a polyester chain segment is 240, and the weight-average molecular weight is 914000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.6.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 8.6 cm.

Example 27

The difference from example 1 is that: the temperature of the ring-opening polymerization reaction was-10 ℃.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in a formula (I), wherein the polymerization degree x of a polyethylene chain segment is 16000, the polymerization degree y of a polyester chain segment is 80, and the weight-average molecular weight is 993000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.6.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 5.7 cm.

Example 28

The difference from example 1 is that: the temperature of the ring-opening polymerization was 40 ℃.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in formula (I), the polymerization degree x of a polyethylene chain segment is 14000, the polymerization degree y of a polyester chain segment is 400, and the weight-average molecular weight is 1050000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.6.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 9.3 cm.

Example 29

The difference from example 1 is that: the temperature of the ring-opening polymerization was 120 ℃.

The test methods were the same as in example 1, and the test results were as follows: the modified polyethylene has a structure shown in formula (I), wherein the polymerization degree x of a polyethylene chain segment is 13000, the polymerization degree y of a polyester chain segment is 700, and the weight-average molecular weight is 899000 g/mol; the molecular weight distribution index of the modified polyethylene was 2.1.

The contact angle of the modified polyethylene separator prepared from the modified polyethylene is smaller than that of a commercial polyethylene separator; under the same test time of 3min, the average length of the impregnation of the commercial electrolyte on the modified polyethylene membrane was 9.6 cm.

Comparative example 1

A commercial polyethylene separator was used.

The test methods were the same as in example 1, and the contact angle of the commercial polyethylene separator was 110 °; the average length of the impregnation on the commercial polyethylene membrane was 3.1cm at the same test time of 3 min.

Comparative example 2

A commercial polypropylene separator was used.

The test methods were the same as in example 1, and the contact angle of the commercial polypropylene separator was 107 °; the average length of the impregnation on the commercial polypropylene membrane was 3.4cm at the same test time of 3 min.

Comparative example 3

A commercial poly 4-methyl-1-pentene separator was used.

The test methods were the same as in example 1, and the contact angle of a commercial poly 4-methyl-1-pentene separator was 105 °; the average length of the impregnation on the commercial polypropylene membrane was 3.3cm at the same test time of 3 min.

Comparative example 4

Commercial polybutene separators were used.

The test methods were all the same as in example 1, with a contact angle of 107 ° for a commercial polybutene membrane; the average length of the infiltrations on the commercial polybutene membrane was 3.5cm at the same test time of 3 min.

Comparative example 5

A commercial propylene-4 methyl-1 pentene copolymer separator was used.

The test methods were the same as in example 1, and the contact angle of the commercial propylene-4 methyl-1-pentene copolymer separator was 108 °; the average length of the impregnation on the commercial propylene-4 methyl-1-pentene copolymer separator was 3.3cm under the same test time of 3 min.

Comparative example 6

A commercial ethylene-4 methyl-1-pentene copolymer separator was used.

The test methods were the same as in example 1, and the contact angle of a commercial copolymer separator of ethylene and 4 methyl-1-pentene was 108 °; the average length of the impregnation on the commercial ethylene-4 methyl-1-pentene copolymer separator was 3.6cm under the same test time of 3 min.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:

as is clear from comparison of examples 1 and 11 to 15, the modified polyolefin having the structure of formula (I) can be precisely synthesized by limiting the molar ratio of the olefin monomer, the chain transfer agent, the catalyst and the menthone lactone to the preferable range in the present application, and the synthesized modified polyolefin can have a polyolefin segment and a polyester segment having an appropriate polymerization degree and an appropriate molecular weight, respectively, so that the modified polyolefin obtained by the reaction has a stronger polarity, and the wettability thereof with respect to the electrolyte and the liquid absorption rate thereof can be improved.

Comparing examples 1 and 16, it is understood that the reaction rate of the above polymerization reaction can be further improved by limiting the kind of the co-catalyst to the preferable range of the present application.

Comparing examples 1 and 17 to 19, it is understood that the reaction rate and selectivity of the above polymerization reaction can be further improved by limiting the molar ratio of the cocatalyst to the catalyst within the preferred range of the present application.

Comparing examples 1 and 20 to 24, it can be seen that limiting the temperature of the polymerization reaction within the preferred range of the present application provides more suitable reaction conditions for the above polymerization reaction, which is beneficial to precisely synthesizing the target product, i.e., the modified polyolefin, and further improving the polyolefin synthesis efficiency.

It is understood from comparative examples 1 and 25 to 29 that limiting the temperature of the ring-opening polymerization reaction to the preferred range of the present application provides more suitable reaction conditions for the above-mentioned ring-opening polymerization reaction, and that the ring-opening polymerization reaction proceeds more completely, which is advantageous in increasing the yield of the modified polyolefin.

It can be seen from comparing examples 1 to 29 and comparative examples 1 to 6 that, by applying the technical scheme of the present invention, the modified polyolefin is prepared by introducing the polar polyester segment into the polyolefin material, and the wettability and the liquid retention of the polyolefin-based separator are improved. Meanwhile, the modified polyolefin has strong adaptability, and the modified polyolefin with different structures is prepared by adjusting the type and mass ratio of the polyolefin chain segment and the polyester chain segment contained in the structure of the modified polyolefin, so that the subsequently prepared modified polyolefin diaphragm can adapt to different electrolyte environments. The preparation method of the modified polyolefin adopts a semi-batch polymerization method, the obtained modified polyolefin has simple post-treatment process, and the production cost can be reduced.

It is noted that the terms first, second and the like in the description and in the claims of the present application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those described or illustrated herein.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.