A poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) and a method for its preparation

Abstract

The application relates to the technical field of polymer preparation, in particular to a kind of poly (6,6-dimethyl-2-vinylbicyclo [3.1.1] hept-2-ene) and its preparation method, with 6,6-dimethyl-2-vinylbicyclo [3.1.1] hept-2-ene as monomer, under inert atmosphere, using metallocene rare earth complex, organic boron salt and alkyl aluminum compound ternary catalytic system for homopolymerization reaction.The number average molecular weight Mn of the obtained polymer can reach 3.0*10 4 , the molecular weight distribution Mw / Mn is 1.54~1.86, the highest yield is 99%, the application realizes the efficient rare earth catalytic polymerization of the monomer, the process is simple, the activity is high, and the product can be applied in surface coating, biological medicine, tissue engineering and other fields.

Description

Technical Field

[0001] This invention relates to the field of polymer synthesis technology, specifically to a poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) and its preparation method. Background Technology

[0002] Petroleum, as a non-renewable petrochemical resource, will eventually be depleted, while human demand for polymer materials continues to increase. To resolve this irreconcilable contradiction, alternatives must be sought from renewable resources. Terpenes are an important bio-derived monomer, containing repeating isoprene units. Isomers include α-pinene, β-pinene, limonene, myrcene, and pinene, among others. Terpenes mostly possess multi-chiral centers and good bioactivity. Introducing them into polymer molecule design can endow polymers with unique stereoconfigurations, good bioactivity, and biocompatibility, expanding their applications in surface coatings, biomedicine, tissue engineering, and other fields. However, monoterpenes are rarely used as starting materials for polymerization reactions.

[0003] Myrtol is a naturally occurring monoterpene compound with a unique camphor-like aroma and various biological activities. It can be efficiently converted into a conjugated diene monomer, 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene, abbreviated as "monomer M1", via the Wittig reaction. However, the bicyclic strained structure of monomer M1 may lead to catalytic deactivation and easy cross-linking, making the polymerization of monomer M1 difficult. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) and its preparation method, which is simple to prepare, has mild reaction conditions, high activity and is not easy to crosslink, and has a high yield.

[0005] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0006] A method for preparing poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) includes the following steps:

[0007] Under inert gas protection, cyclopentadienyl rare earth complexes, organoboron salts, and alkylaluminum compounds are dissolved in an organic solvent to obtain a catalyst composition solution.

[0008] Using 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene as a monomer, a polymerization reaction was initiated under the catalysis of a catalyst composition solution. The double bond of 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene coordinated to the central metal of the rare earth complex to form a four-membered ring intermediate, which then inserted between the metal-carbon bonds to carry out a growth reaction.

[0009] After the reaction was completed, the product was dried to obtain poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene).

[0010] In a preferred embodiment of the present invention, the polymerization reaction temperature is -30℃ to 80℃, and the reaction time is 0.2h to 48h.

[0011] Furthermore, the polymerization reaction temperature is 0℃~80℃.

[0012] In a preferred embodiment of the present invention, the molar ratio of 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene monomer to rare earth complex is 100~10000:1. Further, the molar ratio of 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene monomer to rare earth complex is 100~1000:1, and the molar ratio of cyclopentadiene rare earth complex, organoboron salt and alkylaluminum compound is 1:1:5~20.

[0013] Furthermore, the molar ratio of the cyclopentadiene rare earth complex, organoboron salt, and alkylaluminum compound is 1:1:5~10.

[0014] In a preferred embodiment of the present invention, the polymerization reaction can be carried out in the presence of a solvent through solution polymerization or in the absence of a solvent through bulk polymerization.

[0015] When solution polymerization is used, the organic solvent is selected from one or a mixture of several of saturated alkanes, aromatics, halogenated aromatics and cycloalkanes.

[0016] In a preferred embodiment of the present invention, the organic solvent is most preferably one or a mixture of several of the following: n-hexane, n-heptane, petroleum ether, cyclohexane, decahydronaphthalene, toluene, and chlorobenzene.

[0017] In a preferred embodiment of the present invention, the structure of the cyclopentadiene rare earth complex is as follows: In the formula, Q is selected from formulas II-V:

[0018] ,

[0019] In general formula II-V, R 1 R 2 R 3 R 4 and R5 Each of them can be any one of hydrogen, methyl, ethyl, tert-butyl, cyclohexyl, isopropyl, and phenyl.

[0020] R 6 It is any one of hydrogen, methyl, ethyl, tert-butyl and phenyl, preferably hydrogen or tert-butyl.

[0021] R 4 It is any one of benzyl, trimethylsilyl, N-heterocyclic carbene, 2-methylpyridine, 2,6-dimethylpyridinyl, 8-methylquinoline and 2-methylthiophene, preferably 2-methylpyridine or 2,6-dimethylpyridinyl.

[0022] The rare earth metal Ln is selected from any one of Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, preferably one of Sc, Y, La, Nd, Gd, Dy, Ho, Er, Tm, Yb or Lu; most preferably one of Sc, Y, Nd, Gd, Dy, Ho, Er, Tm, Yb or Lu.

[0023] X 1 and X 2 It is selected from any one of alkyl, silyl, aryl, silamido, alkylamido, allyl, borohydride, chlorine and bromine, preferably methyl, trimethylsilylmethylene, di(trimethylsilyl)methimethylene, o-N,N'-dimethylbenzyl, hexamethylsilamido, tetramethylsilamido, allyl, 2-methylallylbenzyl, p-methylbenzyl, boron tetrahydrogen, chlorine or bromine, most preferably methyl, trimethylsilylmethylene, o-N,N'-dimethylbenzyl, tetramethylsilamido, allyl, 2-methylallylbenzyl, p-methylbenzyl or boron tetrahydrogen.

[0024] L represents tetrahydrofuran, pyridine, and ethylene glycol dimethyl ether; w = 0, 1, or 2.

[0025] In a preferred embodiment of the present invention, the rare earth complex is a cyclopentadienyl rare earth complex selected from any of the following structures:

[0026] .

[0027] In a preferred embodiment of the present invention, the co-catalyst is selected from one or more organoboron salts and alkylaluminum compounds.

[0028] In a preferred embodiment of the present invention, the organoboron salt is one of [Ph3C][B(C6F5)4], [NEt3H][B(C6F5)4], and [PhNMe2H][B(C6F5)4]; the alkylaluminum compound is selected from one or more of alkylaluminum, hydrogenated alkylaluminum, alkylaluminum chloride, and aluminum oxane.

[0029] In a preferred embodiment of the present invention, the alkylaluminum compound is preferably trimethylaluminum, triethylaluminum, tri-n-propylaluminum, tri-n-butylaluminum, triisopropylaluminum, triisobutylaluminum, tripentylaluminum, trihexylaluminum, tricyclohexylaluminum, trioctylaluminum, triphenylaluminum, tri-p-tolylaluminum, tribenzylaluminum, ethyl dibenzylaluminum, ethyl di-p-tolylaluminum, diethylbenzylaluminum, dimethylaluminum hydride, diethylaluminum hydride, di-n-propylaluminum hydride, di-n-butylaluminum hydride, diisopropylaluminum hydride, diisobutylaluminum hydride, dipentylaluminum hydride, dihexylaluminum hydride, dicyclohexylaluminum hydride, or dioctylaluminum hydride. Aluminum, diphenylaluminum hydride, di-p-tolyl aluminum hydride, dibenzyl aluminum hydride, ethylbenzyl aluminum hydride, ethyl-p-tolyl aluminum hydride, dimethyl aluminum chloride, diethyl aluminum chloride, di-n-propyl aluminum chloride, di-n-butyl aluminum chloride, diisopropyl aluminum chloride, diisobutyl aluminum chloride, dipentyl aluminum chloride, dihexyl aluminum chloride, dicyclohexyl aluminum chloride, dioctyl aluminum chloride, diphenyl aluminum chloride, di-p-tolyl aluminum chloride, dibenzyl aluminum chloride, ethylbenzyl aluminum chloride, ethyl-p-tolyl aluminum chloride, methylaluminoxane, ethylaluminoxane, n-propylaluminoxane, and n-butylaluminoxane are all selected from one or more of these. More preferably, it is one or more of the following: trimethylaluminum, triethylaluminum, tri-n-butylaluminum, triisobutylaluminum, dimethylaluminum hydride, diethylaluminum hydride, di-n-butylaluminum hydride, diisobutylaluminum hydride, dimethylaluminum chloride, diethylaluminum chloride, diisopropylaluminum chloride, diisobutylaluminum chloride, methylaluminoxane, ethylaluminoxane, n-propylaluminoxane, and n-butylaluminoxane.

[0030] In a preferred embodiment of the present invention, the alkylaluminum compound is most preferably one or more selected from trimethylaluminum, triethylaluminum, tri-n-butylaluminum, triisobutylaluminum, diethylaluminum hydride, diisobutylaluminum hydride, methylaluminoxane, and ethylaluminoxane.

[0031] In a preferred embodiment of the present invention, after polymerization is completed, a 10% (v / v) hydrochloric acid-ethanol solution is added to terminate the polymerization reaction, and the reaction solution is poured into methanol to settle.

[0032] Another object of the present invention is to provide a poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) prepared by any of the above-described methods, having a repeating unit structure as shown in Formula I: Formula I: The value of n ranges from 100 to 10000.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. This invention provides a method for preparing poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene), using a catalyst composition solution composed of a cyclopentadiene rare earth complex, an organoboron salt, and an alkylaluminum compound. 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene is used as the monomer. Under the catalysis of the catalyst composition solution, a polymerization reaction is initiated. The double bond of 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene coordinates to the central metal of the rare earth complex, forming a four-membered ring intermediate, which then inserts into the metal-carbon bond for a growth reaction. This invention discovers that rare earth catalysts can catalyze the homopolymerization of 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene monomers. The preparation method is simple, the reaction conditions are mild, it has high activity and is not easily cross-linked, and the yield is high.

[0035] 2. The present invention provides a method for preparing poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene). Through the synergistic effect of a ternary catalytic system, the steric hindrance effect of the bicyclic ring is overcome, and the polymerization activity reaches 99% yield. Therefore, the poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) polymer prepared by the present invention has unique stereoconfiguration, good bioactivity and biocompatibility, etc., and can replace the existing polymer materials. It can be applied in the fields of surface coating, biomedicine and tissue engineering. Attached Figure Description

[0036] Figure 1 The above is the 1H NMR spectrum of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) prepared in Example 1 of this invention. Detailed Implementation

[0037] The following detailed description, in conjunction with embodiments of the present invention and accompanying drawings, provides a clear and complete illustration of the technical solutions in these embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0038] It should be noted that all technical terms used in this invention are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of this invention. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in the following embodiments of this invention can be purchased from the market or prepared by existing methods.

[0039] Example 1

[0040] A method for preparing poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) includes the following steps:

[0041] (1) Under anhydrous and oxygen-free conditions, 10 μmol of cyclopentadienyl rare earth complex 1, 10 μmol of organoboron salt [Ph3C][B(C6F5)4] and 100 μmol of alkylaluminum Al were added. i Bu3 was dissolved in 1 mL of toluene solution to obtain a catalyst composition solution.

[0042] (2) At a reaction temperature of 25°C, the catalyst composition solution, 1 mL toluene solution and 1 mmol of 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene monomer were placed in a 10 mL reaction flask. The molar ratio of monomer 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene to the main catalyst rare earth complex was 100:1. After the polymerization reaction was carried out for 1 h, 100 mL of ethanol solution was added to terminate the polymerization reaction.

[0043] (3) Then the reaction solution was poured into a small amount of methanol containing hydrochloric acid and stabilizer BHT100 mL to settle. The obtained polymer was placed in a vacuum drying oven at 40℃ and dried for 48 hours to obtain a polymer with a net weight of 0.128 g and a yield of 87%.

[0044] (4) Using nuclear magnetic resonance hydrogen spectrum 1 The homopolymer of 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene was obtained by 1H NMR analysis. GPC analysis showed that its number-average molecular weight Mn was 13,700 and its molecular weight distribution Mw / Mn was 2.32.

[0045] Example 2

[0046] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 2, and the polymerization reaction time was changed from 1 h to 0.5 h.

[0047] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 80%, and its number-average molecular weight Mn was 14,000 and its molecular weight distribution Mw / Mn was 1.73, as determined by GPC analysis.

[0048] Example 3

[0049] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 3, and the molar ratio of monomer 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene to cyclopentadienyl rare earth complex was changed from 100:1 to 200:1.

[0050] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 88%, and its number-average molecular weight Mn was 19,000 and its molecular weight distribution Mw / Mn was 1.72, as determined by GPC analysis.

[0051] Example 4

[0052] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 4, and the molar ratio of monomer 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene to cyclopentadienyl rare earth complex was changed from 100:1 to 300:1.

[0053] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 86%, and its number-average molecular weight Mn was 27,000 and its molecular weight distribution Mw / Mn was 1.78, as determined by GPC analysis.

[0054] Example 5

[0055] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 5, the reaction temperature was changed from 25°C to 80°C, and the polymerization reaction time was changed from 1h to 0.2h.

[0056] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 91%, and its number-average molecular weight Mn was 22,000 and its molecular weight distribution Mw / Mn was 1.69, as determined by GPC analysis.

[0057] Example 6

[0058] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 6, and the molar ratio of monomer 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene to cyclopentadienyl rare earth complex was changed from 100:1 to 250:1.

[0059] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 84%, and its number-average molecular weight Mn was 22,000 and its molecular weight distribution Mw / Mn was 1.73, as determined by GPC analysis.

[0060] Example 7

[0061] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 7, the organoboron salt [Ph3C][B(C6F5)4] was changed to [NEt3H][B(C6F5)4], and the polymerization reaction time was changed from 1h to 2h.

[0062] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 79%, and its number-average molecular weight Mn was 19,000 and its molecular weight distribution Mw / Mn was 1.75, as determined by GPC analysis.

[0063] Example 8

[0064] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 8, and the polymerization reaction time was changed from 1 hour to 5 hours.

[0065] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 84%, and its number-average molecular weight Mn was 13,000 and its molecular weight distribution Mw / Mn was 1.54, as determined by GPC analysis.

[0066] Example 9

[0067] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 9, and the polymerization reaction time was changed from 1 hour to 3 hours.

[0068] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 99%, and its number-average molecular weight Mn was 15,000 and its molecular weight distribution Mw / Mn was 1.57, as determined by GPC analysis.

[0069] Example 10

[0070] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 10, and the molar ratio of monomer 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene to cyclopentadienyl rare earth complex was changed from 100:1 to 250:1.

[0071] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 86%, and its number-average molecular weight Mn was 26,000 and its molecular weight distribution Mw / Mn was 1.86, as determined by GPC analysis.

[0072] Example 11

[0073] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 2, and 100 μmol Al was added. i Bu3 was replaced with 200 μmol Al i The polymerization temperature of Bu3 is changed from 25℃ to 40℃.

[0074] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 90%, and its number-average molecular weight Mn was 28,000 and its molecular weight distribution Mw / Mn was 1.66, as determined by GPC analysis.

[0075] Example 12

[0076] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 2, and 100 μmol Al was added. i Bu3 replaced with 50 μmol Al i The polymerization temperature of Bu3 was changed from 25℃ to 60℃, and the polymerization time was changed from 1h to 0.5h.

[0077] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 92%, and its number-average molecular weight Mn was 29,000 and its molecular weight distribution Mw / Mn was 1.57, as determined by GPC analysis.

[0078] Example 13

[0079] Based on Example 1, the main catalyst was replaced from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 2, and the organoboron salt [Ph3C][B(C6F5)4] was replaced with [PhNMe2H][B(C6F5)4].

[0080] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 87%, and its number-average molecular weight Mn was 20,000 and its molecular weight distribution Mw / Mn was 1.75, as determined by GPC analysis.

[0081] Example 14

[0082] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 2, the reaction temperature was changed from 25°C to 0°C, and the reaction time was changed from 1 hour to 4 hours.

[0083] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 85%, and its number-average molecular weight Mn was 24,000 and its molecular weight distribution Mw / Mn was 1.82, as determined by GPC analysis.

[0084] Example 15

[0085] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 2, and alkyl aluminum Al i Bu3 was replaced with AlMe3, and the reaction time was changed from 1 hour to 2 hours.

[0086] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 90%, and its number-average molecular weight Mn was 22,000 and its molecular weight distribution Mw / Mn was 1.77, as determined by GPC analysis.

[0087] Example 16

[0088] Based on Example 1, the main catalyst was changed from cyclopentadienyl rare earth complex 1 to cyclopentadienyl rare earth complex 2, and alkyl aluminum Al i Bu3 was replaced with AlEt3, and the reaction time was changed from 1 hour to 4 hours.

[0089] The yield of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was 92%, and its number-average molecular weight Mn was 30,000 and its molecular weight distribution Mw / Mn was 1.62, as determined by GPC analysis.

[0090] Results Analysis

[0091] High-activity polymerization of monomer M1 was achieved using rare earth metal complexes, resulting in the preparation of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene). Table 1 summarizes the material ratios, reaction conditions, and test results of Examples 2 to 16 of this invention. Combined with Example 1, it can be seen that by changing the type and amount of the main catalyst, the type and amount of the co-catalyst, the polymerization time, and the polymerization temperature, the polymerization activity and the molecular weight of the polymer can be controlled. In Example 9, the main catalyst was selected as cyclopentadiene rare earth complex 9, and the alkyl aluminum was selected as Al. i Bu3, with the organoboron salt selected as [Ph3C][B(C6F5)4], and the molar ratio of monomer to main catalyst cyclopentadienyl rare earth complex being 100:1, and the polymerization reaction temperature being 25℃ and the polymerization reaction time being 3h, yielded the highest poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene), reaching 99%.

[0092] Table 1 summarizes the material ratios, reaction conditions, and test results of Examples 2 to 16 of this invention. Note: According to this invention, the organic boron reagent containing [B(C6F5)4]¯ anions is defined as follows: B1 is [Ph3C][B(C6F5)4], B2 is [NEt3H][B(C6F5)4], and B3 is [PhNMe2H][B(C6F5)4].

[0093]

[0094] Figure 1 The 1H NMR spectrum of poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) prepared in Example 1 of this invention shows that poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) was successfully synthesized.

[0095] It should be noted that when numerical ranges are involved in this invention, it should be understood that both endpoints of each numerical range and any value between the two endpoints can be selected. Since the steps and methods used are the same as in the embodiments, preferred embodiments are described here to avoid redundancy. Although preferred embodiments of the invention have been described, those skilled in the art, once they understand the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this invention.

[0096] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for preparing poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene), characterized in that, Includes the following steps: Under inert gas protection, cyclopentadienyl rare earth complexes, organoboron salts and alkylaluminum compounds are dissolved in an organic solvent to obtain a catalyst composition solution; Using 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene as a monomer, a polymerization reaction was initiated under the catalysis of a catalyst composition solution. The double bond of 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene coordinated to the central metal of the rare earth complex to form a four-membered ring intermediate, which then inserted between the metal-carbon bonds to carry out the growth reaction. After the reaction was completed, the product was dried to obtain poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene). The cyclohexane rare earth complex is specifically selected from any of the following structures: ； The organoboron salt is one or more of [Ph3C][B(C6F5)4], [NEt3H][B(C6F5)4], and [PhNMe2H][B(C6F5)4]; the alkylaluminum compound is selected from one or more of alkylaluminum, hydrogenated alkylaluminum, alkylaluminum chloride, and aluminum oxane.

2. The method for preparing poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) according to claim 1, characterized in that, The polymerization reaction temperature is 0℃~80℃, and the reaction time is 0.2h~48h.

3. The method for preparing poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) according to claim 1, characterized in that, The molar ratio of 6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene monomer to cyclopentadiene complex is 100~1000:1, and the molar ratio of cyclopentadiene complex, organoboron salt and alkylaluminum compound is 1:1:5~10.

4. The method for preparing poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) according to claim 1, characterized in that, The polymerization reaction is either solution polymerization or bulk polymerization.

5. A poly(6,6-dimethyl-2-vinylbicyclo[3.1.1]hept-2-ene) prepared by the method according to any one of claims 1-4.

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