A dendritic phenylethynyl crosslinking agent, a preparation method and application thereof

Abstract

The present application relates to a kind of dendritic phenylacetylene crosslinking agent and its preparation method and application.The preparation method carries out amidation reaction with dendritic active ester and amino alcohol, and generates intermediate product;Intermediate product is esterified with diacetylene benzoic acid and catalyst, and dendritic phenylacetylene crosslinking agent is generated.The present application is mainly with dendritic phenylacetylene monomer and dendritic phenylacetylene crosslinking agent, utilizes the good water-soluble and temperature sensitivity of crosslinking agent, can be realized monomer temperature sensitive aggregation under the condition of no additive, and then in situ crosslinking polymerization obtains uniform dispersion dendritic helical polyphenylacetylene micro-nano gel, the gel has dynamic regulation, and exhibits good biocompatibility, can have potential application value in the field such as biosensing, chiral drug delivery, biological tissue engineering.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chiral microgel materials, and relates to a dendritic phenylacetylene crosslinking agent, a preparation method and application thereof, in particular to a preparation method, performance and application of micro-nano gel based on amphiphilic dendritic helical polymers. BACKGROUND

[0002] Chirality is widely present in nature and is a basic feature of life molecules (such as amino acids, sugars, nucleic acids, etc.). Inspired by these structural features, chiral polymers and functional materials have developed rapidly. Chiral microgel is a kind of micro-nano gel material with chiral characteristics and cross-linked network structure, which simulates or enhances the natural chiral structure, and expands its wide application in the field of biomedicine. In the field of biological sensing, chiral gel can realize the detection and quantitative analysis of biological molecules by specific binding of target biological molecules; in the field of drug delivery, chiral nanogel can realize the delivery of drugs through chiral recognition mechanism, and improve the targeting and biocompatibility. In the field of biological tissue engineering, chiral microgel can be used as a supporting material for cell culture, and in a suitable microenvironment, chiral gel will affect the growth and differentiation behavior of cells. Chiral gel can also be used as an immunoadjuvant to mediate humoral and cellular immune responses, providing a new idea for immunotherapy of diseases such as tumors.

[0003] The existing preparation methods of chiral microgel mainly include template method, self-assembly method, physical or chemical cross-linking method, etc. Although these preparation methods provide diversified choices for the research and development of chiral micro-nano gel, there are still some challenges in practical application. Traditional methods often require complex synthesis steps and strict reaction conditions, and it is difficult to realize precise control and adjustment of the chiral structure of microgel. In addition, the stability and functional performance of chiral microgel also need to be optimized.

[0004] Therefore, in order to promote the wide application of chiral micro-nano gel in biomedicine, it is necessary to continuously optimize the preparation process and design diversified chemical structures to endow the material with multiple functions. Dendritic topological structure has an important influence on the performance of macromolecules and polymers. Dendritic polymers have a highly branched structure, can form cavities, and can realize the encapsulation and controlled release of guest molecules. Functional groups can also be introduced into the center and end groups of dendritic polymers to endow the polymers with reactivity, stimulus responsiveness and biocompatibility, etc. Studies have shown that some dendritic macromolecules can form restricted hydrophobic microdomains, construct microreactors, or simulate the microenvironment in the body. How to utilize the dendritic polymer topological structure and the dynamic chiral regulation of helical polyphenylacetylene to mass-produce micro-nano gel through a green polymerization method without adding emulsifiers and dispersants is a technical problem that needs to be solved, and this research has important practical value. SUMMARY

[0005] The present application aims to overcome the shortcomings and deficiencies of the prior art, and provides a dendritic phenylacetylene crosslinking agent, a preparation method and application thereof. The dendritic phenylacetylene crosslinking agent has good water solubility and temperature sensitivity, can realize temperature-sensitive aggregation of the dendritic phenylacetylene without adding an additive, and then in-situ crosslinking polymerization to obtain a uniform dispersed dendritic helical polyphenylacetylene micro-nano gel. Meanwhile, the conditions of the crosslinking polymerization reaction are optimized, and the chiral micro-nano gel with uniform size distribution is quickly and efficiently prepared. Moreover, the chiral characteristics of the gel respond to the system temperature, have dynamic regulation, and can be adjusted by selecting the types of hydrophilic and hydrophobic dendritic monomers, so as to exhibit good biocompatibility and have potential application value in the fields of biosensing, chiral drug delivery and biological tissue engineering.

[0006] The object of the present application can be achieved by the following scheme:

[0007] In a first aspect, the present application provides a dendritic phenylacetylene crosslinking agent, and the structural formula of the dendritic crosslinking agent is as follows:

[0008] wherein m=0-2, n=1-4, R is Me or Et, and the dendritic alkoxy ether unit includes any one of three arms, four arms and six arms.

[0009] In a second aspect, the present application provides a preparation method of the dendritic phenylacetylene crosslinking agent, and the preparation method comprises the following steps: amidation reaction of a dendritic active ester esterification reaction of the intermediate product and a diacetylene benzoic acid in the presence of a catalyst to generate the dendritic phenylacetylene crosslinking agent

[0010] As an embodiment of the present application, the amidation reaction is carried out under ice bath conditions, and the esterification reaction is carried out under ice-salt bath conditions.

[0011] As an embodiment of the present application, the amino alcohol includes any one of 2-aminoethanol, 3-amino-1-propanol and 4-amino-1-butanol. The diacetylene benzoic acid includes 2,5-diacylbenzoic acid.

[0012] As an embodiment of the present application, the catalyst used in the esterification reaction includes at least one of 4-dimethylaminopyridine and 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride.

[0013] Further, the dendritic phenylacetylene crosslinking agent has good water solubility and temperature sensitivity, and the synthetic route thereof is as follows:

[0014]

[0015] Specifically comprising the following steps:

[0016] S1, under ice bath conditions, the dendritic active ester is mixed with amino alcohol (m = 0-2), and an amidation reaction is carried out to generate an intermediate product

[0017] S2, under ice-salt bath conditions, the intermediate product is mixed with 2,5-dialkyne benzoic acid, 4-dimethylamino pyridine, and 1-ethyl-(3-dimethylamino propyl) carbodiimide hydrochloride, and an esterification reaction is carried out to generate a dendritic phenylacetylene crosslinking agent

[0018] More specifically, the amidation reaction (a) in step S1 specifically comprises the following operations: the dendritic active ester (R n -Pf) is dissolved in dry DCM, different amino alcohols are added under ice bath conditions, and after stirring uniformly, nitrogen replacement is carried out; then, an appropriate amount of triethylamine is added, and then natural cooling to room temperature is carried out for overnight reaction. After the reaction is completely detected by a TLC plate, the reaction is stopped, saturated brine is used for washing, the organic phase is dried with anhydrous magnesium sulfate, filtration is carried out, and the solvent is evaporated to dryness; the crude product is purified by a chromatographic column to obtain the intermediate product R n -m-AP (colorless oily liquid);

[0019] The esterification reaction (b) in step S2 specifically comprises the following operations: the intermediate product R n -m-AP and dialkyne benzoic acid are dissolved in dry DCM, and then 4-dimethylamino pyridine and 1-ethyl-(3-dimethylamino propyl) carbodiimide hydrochloride are added under ice-salt bath conditions; the mixed solution is replaced by nitrogen, and then natural cooling to room temperature is carried out for overnight reaction. After the reaction is completely detected by a TLC plate, the reaction is stopped, saturated brine is used for washing, the organic phase is dried with anhydrous magnesium sulfate, the solvent is evaporated to dryness to obtain the crude product, and then the chromatographic column is used for purification to obtain the dendritic crosslinking agent R n -m-DEB (orange oily liquid).

[0020] In a third aspect, the present application provides a preparation method of dendritic helical polyphenylacetylene micro-nano gel, in which the dendritic phenylacetylene crosslinking agent is mixed with the dendritic monomer under anaerobic conditions, heating is carried out to aggregate (heating is carried out to form an aggregate above the phase transition temperature of the mixed solution), a catalyst is added, and in-situ polymerization reaction of the aggregate is carried out to generate the dendritic helical polyphenylacetylene micro-nano gel.

[0021] As an embodiment of the present application, the structural formula of the dendritic monomer is as follows:

[0022] In which, n = 1-4, and R is Me or Et.

[0023] As an embodiment of the present application, the concentration of the dendronized monomer is 0.5-10 mg·mL -1 ; the molar ratio of the dendronized monomer to the dendronized phenylacetylene crosslinking agent is 5-20:1.

[0024] As an embodiment of the present application, the temperature of the heating focus is 30-80℃; the time of the polymerization reaction is 5-30 min. The present application realizes the micro and macro aggregation of the molecules by using temperature to induce the dehydration collapse of the alkoxy ether group.

[0025] As an embodiment of the present application, the catalyst comprises [Rh(nbd)Cl]2.

[0026] As an embodiment of the present application, the polymerization reaction is carried out under stirring, and the stirring rate is 200-800 rpm.

[0027] As an embodiment of the present application, the specific preparation steps of the polymerization reaction comprise: dissolving the dendronized crosslinking agent (R n -m-DEB) and the dendronized monomer (PA-R n ) in (20 mL) distilled water in a certain proportion, and then adding into a three-necked flask, using nitrogen to bubble to remove oxygen. Under mechanical stirring, the mixed solution is heated by an oil bath to reach a preset reaction temperature, and after the temperature is stable, a micro-syringe is used to add a catalyst to start the reaction. After a certain time of reaction, the stirring is stopped. After the solution is cooled, three centrifugal washings are carried out to remove the polymers which are not effectively crosslinked. Then, the solution is dispersed in deionized water in a certain concentration for other tests.

[0028] The fluid mechanics radius of the dendronized helical polyphenylacetylene micro-nano gel of the present application is 100-700 nm. The microgel of the present application has good temperature sensitivity, and the volume shrinkage performance of the microgel can be controlled by temperature.

[0029] Compared with the prior art, the present application has the following beneficial effects:

[0030] 1. The dendronized group is used to modify the diacetylene crosslinking agent in the present application, so that the dendronized phenylacetylene crosslinking agent designed and synthesized has good water solubility and temperature sensitivity, can be in-situ crosslinked and polymerized with the dendronized monomer through aggregation to prepare a large amount of micro-nano gel without any additives (emulsifiers, stabilizers, organic solvents, etc.), and the use of toxic chemical additives is avoided; at the same time, the synthesis path is efficient, the experimental operation is simple, the reaction time is short (about 10 minutes), and the yield is as high as 95% or more.

[0031] 2, The chiral feature of the micro-nano gel responds to temperature, has dynamic regulation, and can adjust the dynamic and static performance of the gel chirality by selecting the types of hydrophilic and hydrophobic dendritic monomers, thereby affecting the recognition of the micro-nano gel chirality and the slow release of chiral drugs, even the internal microenvironment control chiral catalytic reaction, and has potential application value.

[0032] 3, The dendritic helical polyphenylacetylene micro-nano gel has a novel chemical structure, is temperature-sensitive, can realize volume shrinkage and chiral dynamic change under temperature regulation, has good biocompatibility, and has application potential in the fields of biosensing, recognition and slow release of chiral drugs, cell micro-reactors and biological tissue engineering. BRIEF DESCRIPTION OF DRAWINGS

[0033] Other features, objects and advantages of the present application will become more apparent from the following detailed description of non-limiting embodiments, made with reference to the accompanying drawings:

[0034] Figure 1 Me is an intermediate product of Example 1 2 NMR hydrogen spectrum of -1-AP;

[0035] Figure 2 Me is a crosslinking agent of Example 1 2 NMR hydrogen spectrum of -1-DEB;

[0036] Figure 3 Turbidity curve of the aqueous solution of the crosslinking agent of Example 1

[0037] Figure 4 Hydrodynamic radius of the dendritic helical polyphenylacetylene microgel prepared in Examples 2 and 3

[0038] Figure 5 Atomic force microscope morphology of the dendritic helical polyphenylacetylene micro-nano gel prepared in Example 2

[0039] Figure 6 Trend of the change of the hydrodynamic radius of the dendritic helical polyphenylacetylene micro-nano gel prepared in Examples 2 and 3 with temperature

[0040] Figure 7 Circular dichroism spectrum absorption curve of the dendritic helical polyphenylacetylene micro-nano gel prepared in Examples 2 and 3 with temperature

[0041] Figure 8 Cytotoxicity of the dendritic helical polyphenylacetylene micro-nano gel in Example 2

[0042] Figure 9 Crosslinking polymerization process

[0043] Figure 10 Figure 2 shows the real image of the dendronized polyphenylacetylene micro-nano gel in Example 1. DETAILED DESCRIPTION

[0044] The present application will be described in detail below with reference to the drawings and specific examples. The following examples are implemented on the premise of the technical solutions of the present application, and detailed implementation modes and specific operation processes are provided, which will help those skilled in the art to further understand the present application. It should be pointed out that the protection scope of the present application is not limited to the following examples, and several adjustments and improvements made on the premise of the concept of the present application all belong to the protection scope of the present application.

[0045] Synthesis of dendronized active ester (compound 1a-1b in the literature): Li W., Zhang, X., et al. Doubly dendronized chiral polymers showing thermoresponsive properties [J]. J. Polym. Pol. Chem. 2013, 51(23), 5143-5152.

[0046] Synthesis of dendronized alkoxy ether chiral monomer (compound PA-Ace and PA-ACm in the literature): Wang F., Zhou C., et al. Thermoresponsive Dendronized Poly(phenylacetylene)s Showing Tunable Helicity. Macromolecules 2019, 52(22), 8631-8642.

[0047] The present application will be described in detail below with reference to the drawings and specific examples. The following examples are implemented on the premise of the technical solutions of the present application, and detailed implementation modes and specific operation processes are provided, which will help those skilled in the art to further understand the present application. It should be pointed out that the protection scope of the present application is not limited to the following examples, and several adjustments and improvements made on the premise of the concept of the present application all belong to the protection scope of the present application.

[0048] Example 1

[0049] In this example, a kind of preparation of dendronized phenylacetylene crosslinking agent, the specific steps are as follows:

[0050] Step a. Synthesis of Me by amidation reaction 2 -1-AP process

[0051] Synthesis of dendronized active ester Me 2- Pf (1 g, 1.29 mmol) was dissolved in dry DCM (15 mL) and 3-amino-1-propanol (123 mg, 1.64 mmol) was added under ice-bath conditions. After mixing, the reaction was left to reach room temperature while being under nitrogen flow overnight. After the reaction was complete, as determined by TLC plate, the reaction was stopped. The organic phase was washed with saturated NaCl solution and a small amount of saturated NaSO4. The organic phase was dried over MgSO4, filtered and the solvent was evaporated. The crude product was purified by column chromatography to obtain the pure product Me 2 -1-AP;

[0052] The intermediate product was tested for structural characterization;

[0053] 1 H NMR (DMSO-d6, 25°C): δ = 1.62-1.69 (m, 2H, CH2), 3.23 (d, J = 2.9 Hz, 9H, CH3), 3.29 (q, J = 6.5 Hz, 2H, CH2), 3.39-3.62 (m, 26H, CH2), 3.67-3.77 (dt, J = 47.8, 4.8 Hz, 6H, CH2), 4.05-4.15 (dt, J = 39.8, 4.9 Hz, 6H, CH2), 4.48 (t, J = 5.2 Hz, 1H, OH), 7.16 (s, 2H, Ar-H), 8.36 (t, J = 5.6 Hz, 1H, NH). The hydrogen nuclear magnetic resonance spectrum is shown in Figure 1 ;

[0054] Step b. Esterification reaction to synthesize the cross-linker Me 2 -1-DEB process

[0055] Compound Me 2 -1-AP (778 mg, 1.17 mmol) and 2,5-diynylbenzoic acid (203 mg, 1.02 mmol) were dissolved in dry DCM (15 mL) and 4-dimethylaminopyridine (43 mg, 0.35 mmol) and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride (450 mg, 2.34 mmol) were added under ice-salt bath conditions. After nitrogen replacement, the reaction was left to reach room temperature overnight. After the reaction was complete, as determined by TLC plate, the reaction was stopped. The organic phase was washed with saturated NaCl solution and dried over anhydrous MgSO4. The solvent was evaporated. The crude product was purified by column chromatography to obtain the pure product Me 2 -1-DEB, a dendronized phenylacetylene cross-linker, the hydrogen nuclear magnetic resonance spectrum of which is shown in Figure 2 ;

[0056] The target product was tested for structural analysis:

[0057] 1 H NMR (DMSO-d6, 25℃): δ = 1.97-1.99 (p, J = 6.6 Hz, 2H, CH2), 3.22 (d, J = 4.1 Hz, 9H, CH3), 3.40-3.61 (m, 26H, CH2), 3.65-3.76 (m, 6H, CH2), 4.04-4.14 (m, 6H, CH2), 4.32 (t, J = 6.3 Hz, 2H, CH2), 4.47 (s, 1H, CH), 4.59 (s, 1H, CH), 7.16 (s, 2H, Ar-H), 7.60-7.70 (m, 2H, Ar-H), 7.91 (d, J = 1.7 Hz, 1H, Ar-H), 8.44-8.49 (t, 1H, NH).

[0058] The target product was subjected to temperature-sensitive characterization, and the turbidity curve of the crosslinking agent aqueous solution is shown in Figure 3 It can be seen that it has good water solubility and temperature sensitivity.

[0059] Example 2

[0060] Referring to the crosslinking polymerization reaction process shown in Figure 9 , in this example, microgels were prepared from methoxy dendritic monomer (PA-Me 2 ) and crosslinking agent (Me 2 -1-DEB), and the specific steps are as follows: the dendritic monomer was dissolved in distilled water to prepare a solution of 1 mg·mL -1 , 20 mL of the monomer aqueous solution was taken, and 4.1 mg of crosslinking agent Me 2 -1-DEB (molar ratio of monomer and crosslinking agent was 5:1) was added. The mixed solution was added to a three-necked flask, and nitrogen was used for bubbling to remove oxygen. Under mechanical stirring (the rotation speed was set to 400 rpm), the mixed solution was heated to 70℃ by oil bath, and after the temperature was stable, [Rh(nbd)Cl]2 was added by microsyringe to start the reaction. The molar ratio of [Rh(nbd)Cl]2 to monomer was 1 / 250. After a certain time of reaction, the stirring was stopped. After the solution was cooled, three centrifugal washings were performed to remove the polymers that were not effectively crosslinked. Then it was reconfigured into a gel solution of 1 mg·mL -1 (96% of reaction yield), and the actual gel is shown in Figure 10 .

[0061] Example 3

[0062] In this example, ethoxy dendritic monomer (PA-Et 2 ) and crosslinking agent (Et2 -1-DEB, the synthesis method of which is prepared in reference example 1). The specific steps are as follows: the dendritic monomer is dissolved in distilled water to prepare a 1 mg·mL -1 solution, 20 mL of the monomer aqueous solution is taken, and 4.3 mg of the crosslinking agent Et 2 -1-DEB (the molar ratio of monomer and crosslinking is 5:1) is added. The mixed solution is added to a three-necked flask, and nitrogen is used for bubbling to remove oxygen. Under mechanical stirring (the rotation speed is set to 400 rpm), the mixed solution is heated to 40°C by oil bath, and after the temperature is stable, [Rh(nbd)Cl]2 is added by micro-syringe to start the catalytic reaction. The molar ratio of [Rh(nbd)Cl]2 to monomer is 1 / 250. After a certain period of time, the stirring is stopped. After the solution is cooled, three centrifugal washings are performed to remove the ineffective crosslinked polymers. Then it is reconfigured into a 1 mg·mL -1 gel solution (the reaction yield is 95%).

[0063] Example 4

[0064] In this example, the size and distribution of the gels prepared in examples 2 and 3 are analyzed, and the characterization tests of their hydrated state and dry state are carried out. The specific steps are as follows:

[0065] Step a. The microgel solution is diluted to 0.1 mg·mL -1 , and then tested by a dynamic light scattering instrument. The R h is measured to be 152 nm and 572 nm, respectively, and the polydispersity index is 0.03 and 0.29, respectively.

[0066] wherein the hydrodynamic radius of the dendritic helical polyphenylenevinylene microgel is shown as Figure 4 .

[0067] Step b. The morphology of the microgel prepared in example 2 is observed by atomic force microscopy (AFM). The prepared gel aqueous solution (0.05 mg·mL -1 ) is coated on a mica substrate by a spin coater, and after the solvent is volatilized and completely dried, the AFM test is carried out.

[0068] wherein the morphology characterization of the dendritic helical polyphenylenevinylene microgel is shown as Figure 5 A. As shown in Figure 5 B, the gel diameter of the nanogel prepared in example 2 in the dry state is 201±21 nm, and the height is 27±3 nm.

[0069] Example 5

[0070] In this example, the temperature sensitivity and chirality of the microgel are tested, and the specific steps are as follows:

[0071] Step a. The aqueous solution of the gel prepared in Examples 2 and 3 was diluted to 0.05 mg·mL-1 -1 The hydrodynamic radius of the gel was then tracked as a function of temperature by dynamic light scattering;

[0072] wherein the chirality of the dendronized helical polyphenylacetylene microgels as a function of temperature is shown in h The hydrodynamic radius of the gel was then tracked as a function of temperature by dynamic light scattering; Figure 6 The hydrodynamic radius of the gel was then tracked as a function of temperature by dynamic light scattering;

[0073] Step b. The aqueous solution of the gel prepared in Examples 2 and 3 was diluted to 0.1 mg·mL-1 -1 The chirality of the dendronized helical polyphenylacetylene microgels was then tracked as a function of temperature by circular dichroism spectroscopy;

[0074] wherein the chirality of the dendronized helical polyphenylacetylene microgels as a function of temperature is shown in Figure 7 The hydrodynamic radius of the gel was then tracked as a function of temperature by dynamic light scattering;

[0075] Example 6

[0076] In this example, the nanogel obtained in Example 2 was dissolved in cell culture medium to prepare a cell suspension with human cancer cells. After different days, the cell suspension was aspirated, the cells were stained, and then observed and recorded under a confocal laser scanning microscope (CLSM). Then the cell activity photos were analyzed to evaluate the survival rate of the cells. Through 7-day observation of the cells, the cells had a high survival rate, indicating that the dendronized polyphenylacetylene micro-nano gel spheres had good biocompatibility and were expected to be applied in the fields of biological medicine, etc. The cytotoxicity of the dendronized helical polyphenylacetylene microgels is shown in Figure 8 The cytotoxicity of the dendronized helical polyphenylacetylene microgels is shown in

[0077] The above describes the embodiments of the present application in conjunction with the drawings, but the present application is not limited to the above-described embodiments, and various changes can be made according to the purpose of the inventive creation of the present application. Any change, modification, replacement, combination, simplification made in accordance with the spirit and principles of the technical solution of the present application shall be an equivalent replacement manner, as long as it meets the purpose of the present application and does not deviate from the technical principles and inventive concept of the present application based on the preparation method of the chiral microgel prepared by in-situ cross-linking reaction of dendronized chiral phenylacetylene monomers.

Claims

1. A dendronized phenylacetylene crosslinker, characterized in that, The structural formula of the dendritic phenylacetylene crosslinking agent is as follows: ; wherein m = 0-2, n = 1-4, and R is Me or Et.

2. A method for preparing the dendronized phenylacetylene crosslinker according to claim 1, characterized by, The preparation method comprises: carrying out an amidation reaction on the dendritic active ester with an amino alcohol to generate an intermediate product ; and carrying out an esterification reaction on the intermediate product with 2,5-dialkyne benzoic acid in the presence of a catalyst to generate a dendritic phenylacetylene cross-linking agent .

3. The production method according to claim 2, characterized by, The amino alcohol includes any one of 2-aminoethanol, 3-amino-1-propanol and 4-amino-1-butanol.

4. The preparation method according to claim 2, characterized in that The catalyst includes at least one of 4-dimethylaminopyridine and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride.

5. A method for preparing dendronized polyphenylacetylene micro-nano gel, characterized in that, The preparation method comprises the following steps: mixing the dendritic phenylacetylene crosslinking agent with dendritic monomers under an oxygen-free condition, heating and gathering, adding a catalyst, and gathering in-situ polymerization to generate a dendritic helical polyphenylacetylene micro-nano gel.

6. The production method according to claim 5, wherein The structural formula of the dendritic monomer is as follows: ; wherein n = 1-4 and R is Me or Et.

7. The preparation method according to claim 5, characterized in that The concentration of the dendritic monomer is 0.5-10 mg·mL -1 The molar ratio of the dendritic monomer to the dendritic phenylacetylene crosslinking agent is 5-20:

1.

8. The preparation method according to claim 5, characterized in that The temperature of the heating and gathering is 30-80 DEG C, and the polymerization time is 5-30 min.

9. The preparation method according to claim 5, characterized in that The catalyst includes [Rh(nbd)Cl]2.

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