Polyolefin containing thymine and preparation method and application thereof

Abstract

The invention discloses thymine-containing polyolefin as well as a preparation method and application thereof, the structural formula of the polyolefin is shown in the specification, x is equal to 100-400, and R is phenyl. Norbornene monomer NBT containing nuclear basic groups is synthesized and is copolymerized with cyclooctene (COE) through ring-opening metathesis polymerization (ROMP), and long-chain alkane is introduced to improve the toughness of the polymer; and a series of polymers with ultra-high molecular weight are synthesized by changing the proportion. The NBT in the polymer enables the polymer to have good hydrophobic performance, and the NBT as a hot melt adhesive has good adhesion performance to different substrates.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of polymer material preparation, and particularly relates to a thymine-containing polyolefin and a preparation method and application thereof. BACKGROUND

[0002] Underwater adhesives have a wide range of applications in daily life, oceans, medical treatment and other fields. However, the widely used cyanoacrylate adhesives exhibit strong adhesion in air, but when applied to water environment, they will quickly harden to form a hard plastic, ultimately resulting in loss of adhesion. Although commercial epoxy resins and polyurethanes have strong adhesion under water, they usually require a long curing time, and meanwhile, although polyurethane adhesives are elastic, they have insufficient compressive strength and rigidity, and are difficult to meet the requirements of high-load structures. Hydrogel materials can achieve rapid bonding under water, but have weak adhesion.

[0003] Nucleic acids, particularly DNA, have been widely used as biodegradable macromolecules for the manufacture of various bulk polymer materials, such as hydrogels and bioplastics. However, nucleic acids have a rigid and charged backbone, and have large side groups, resulting in weak mechanical properties of related materials. SUMMARY

[0004] The technical problem to be solved by the present application is how to improve the water resistance and mechanical properties of adhesives.

[0005] The present application solves the above technical problems by the following technical means: A thymine-containing polyolefin has the following structural formula: wherein x = 100-400, and R is a phenyl group; stat represents copolymerization.

[0006] Preferably, the thymine-containing polyolefin has x = 100-300 in the structural formula.

[0007] The present application further provides a preparation method of the thymine-containing polyolefin, comprising the following steps: S1, reacting cis-5-norbornene-endo-2,3-dicarboxylic anhydride with ethanolamine to obtain a norbornene monomer ; and performing esterification reaction on the norbornene monomer and thymine-1-acetic acid to obtain a nucleobase-containing norbornene monomer ; S2, using the nucleobase-containing norbornene monomer and a cyclooctene monomer as raw materials, and using Grubbs III catalyst as a catalyst to perform ROMP polymerization to obtain the thymine-containing polyolefin.

[0008] Preferably, in S1, the molar ratio of cis-5-norbornene-endo-2,3-dicarboxylic anhydride to ethanolamine is 1:1.2; the reaction temperature of cis-5-norbornene-endo-2,3-dicarboxylic anhydride with ethanolamine is 120℃, and the reaction time is 24h, and the solvent is toluene.

[0009] Preferably, in S1, the molar ratio of norbornene monomer to thymine-1-acetic acid is 1:1; the esterification reaction temperature is 70℃, the reaction time is 12h, and the solvent is N,N-dimethylformamide.

[0010] Preferably, during the esterification reaction of S1, the raw materials further include 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 4-dimethylaminopyridine, and the molar ratio of thymine-1-acetic acid, 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 4-dimethylaminopyridine is 1:1.2:0.05.

[0011] Preferably, S2 specifically comprises the following steps: mixing the nucleobase-containing norbornene monomer with a cyclooctene monomer, a solvent in a reaction device, sealing and freezing-thawing, adding Grubbs III catalyst under inert gas protection, reacting at room temperature, quenching the reaction with vinyl ethyl ether, and purifying to obtain the thymine-containing polyolefin.

[0012] Preferably, the solvent in S2 is one or a mixture of the two of chloroform and N,N-dimethylacetamide (DMAC).

[0013] Preferably, when x=100-300 in the polyolefin structural formula, the solvent is chloroform, and when x is greater than 300, the solvent is selected to be N,N-dimethylacetamide DMAC.

[0014] Preferably, in S2, the nucleobase-containing norbornene monomer is used in a dosage ratio of 200-400mg:220-680ul with cyclooctene; the nucleobase-containing norbornene monomer is used in a mass ratio of 200-400:1.98-4 with Grubbs III catalyst.

[0015] Preferably, the nucleobase-containing norbornene monomer is used in a dosage ratio of one of 200mg:660ul, 300mg:440ul, 300mg:256ul, and 400mg:220ul with cyclooctene.

[0016] Preferably, the nucleobase-containing norbornene monomer is used in a mass ratio of one of 200:4, 300:4, 300:3, and 400:1.98 with Grubbs III catalyst.

[0017] The application also provides a use of the thymine-containing polyolefin as an adhesive.

[0018] Preferably, the adhesive is a hot melt adhesive.

[0019] The application has the advantages that: The application introduces long-chain alkane to improve the toughness of the polymer by synthesizing thymine-containing nucleobase-containing norbornene monomer NBT and copolymerizing with cyclooctene (COE) through ring-opening metathesis polymerization (ROMP), and changing the proportion to synthesize a series of ultra-high molecular weight polymers through ROMP polymerization. The NBT in the polymer makes the polymer have good hydrophobic performance and good adhesion performance as a hot melt adhesive to different substrates.

[0020] The material prepared by the application has good strength and adhesion performance, and also has good underwater adhesion performance. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 NBT prepared in examples 3-8 of the application X - co -COE (1000-X) NMR spectrum of the polymer; Figure 2 NBT prepared in examples 3-8 of the application X - co -COE (1000-X) Size exclusion chromatogram of the polymer; wherein, X=0 (black), X=100 (red), X=200 (green), X=300 (blue), X=400 (magenta), X=1000 (purple); Figure 3 NBT prepared in examples 3-8 of the application 100 - co -COE 900 DOSY NMR spectrum and its diffusion coefficient of Figure 4 NBT prepared in examples 3-8 of the application 200 - co -COE 800 DOSY NMR spectrum and its diffusion coefficient of Figure 5 NBT prepared in examples 3-8 of the application 300 - co -COE 700 DOSY NMR spectrum and its diffusion coefficient of Figure 6 NBT prepared in examples 3-8 of the application X - co -COE(1000-X) TGA profile of the polymer; where X=0 (black), X=100 (red), X=200 (green), X=300 (blue), X=400 (magenta), X=1000 (purple); Figure 7 NBT prepared in the present application X co -COE (1000-X) Mechanical tensile profile of the polymer and its corresponding Young's modulus and toughness; where X=100 (red), X=200 (green), X=300 (blue); Figure 8 NBT prepared in the present application X co -COE (1000-X) Adhesion of the polymer to metal substrates; X=100 (red), X=200 (green), X=300 (blue), X=400 (magenta); Figure 9 NBT prepared in the present application 300 co -COE 700 Adhesion to metal at different times under water; Figure 10 NBT prepared in the present application X co -COE (1000-X) Shear strength of the polymer on different plastics; Figure 11 NMR hydrogen spectrum and carbon spectrum of monomer NB-OH prepared in Example 1 of the present application; Figure 12 NMR hydrogen spectrum and carbon spectrum of monomer NBT prepared in Example 1 of the present application. DETAILED DESCRIPTION

[0022] In order to make the objectives, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described below in a clear and complete manner in combination with the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0023] The test materials and reagents used in the following examples, and the like, can be obtained from commercial channels if not otherwise specified.

[0024] The specific techniques or conditions not specified in the examples can be carried out according to the techniques or conditions described in the literature in the art or according to the product instructions.

[0025] ​​​​The application uses cis-5-norbornene-outer-2,3-dicarboxylic anhydride as a raw material to synthesize nucleobase-containing norbornene monomer NBT, and a series of polymers are synthesized by ROMP polymerization and copolymerization of different proportions of cyclooctene monomers, and the technical route is as follows:

[0026] In the formula, R is a benzene ring, and x=100-400.

[0027] Example 1 Preparation of nucleobase-containing norbornene monomer NBT Cis-5-norbornene-outer-2,3-dicarboxylic anhydride is used to react with ethanolamine to prepare norbornene monomer (NB-OH), and then NB-OH is esterified with thymine-1-acetic acid to prepare nucleobase-containing norbornene monomer NBT, which specifically includes the following steps: Step 1-1: Preparation of NB-OH: 1 mole equivalent of cis-5-norbornene-outer-2,3-dicarboxylic anhydride (16.4 g) and 1.2 mole equivalents of ethanolamine (7.32 g) are weighed into a 250 ml flask. After adding 105 ml of toluene, the temperature is raised to 120°C and condensed refluxed for 24 hours. After the reaction is completed, the solvent is blown dry, and the target product is obtained by silica gel column chromatography (petroleum ether: ethyl acetate volume ratio = 1:1). The monomer NB-OH has a nuclear magnetic hydrogen spectrum and a carbon spectrum as shown in Figure 11 .

[0028] Step 1-2: Preparation of NBT: 1 mole equivalent of thymine-1-acetic acid (9.21 g), 1 mole equivalent of NB-OH (10.36 g), 1.2 mole equivalents of 1-ethyl-(3-dimethylaminopropyl) carbonyldiimidazole hydrochloride (EDC.HCl, 11.5 g), and 0.05 mole equivalents of 4-dimethylaminopyridine (DMAP, 310 mg) are added to a flask; after adding 200 ml of N,N-dimethylformamide (DMF), heating to 70°C for 12 hours. After the reaction is completed, the solvent is blown dry, and the target product is obtained by silica gel column chromatography (petroleum ether: ethyl acetate volume ratio = 1:2), and the monomer NBT has a nuclear magnetic hydrogen spectrum and a carbon spectrum as shown in Figure 12 . The flow chart is as shown below:

[0029] NB-OHNBT Example 2 Preparation of Grubbs Ⅲ catalyst Weigh 10.0 mg of Grubbs II catalyst and add it to a 3 mL glass reactor, followed by 300 μL of pyridine solvent. Stir magnetically for 5 min at room temperature. Add 3 mL of n-hexane and continue stirring for 5 min. A green flocculent precipitate gradually forms in the solvent. Transfer the suspension to a 1.5 mL centrifuge tube, centrifuge to remove the supernatant, and wash the precipitate twice with n-hexane. Dissolve the precipitate in 200 μL of dichloromethane and transfer to a microcentrifuge tube for later use. Concentrate 50 μL of the solution to constant weight and calculate the catalyst working solution concentration using the differential method.

[0030]

[0031] Grubbs II catalyst Grubbs III catalyst Example 3 Weigh 110 mg of COE into an ampoule, add 2.2 mL of chloroform (CHCl3), and seal the ampoule. After three freeze-thaw cycles, dissolve 0.728 mg of freshly prepared Grubbs III catalyst in 200 μL of chloroform and add the solution to the ampoule under nitrogen purging. React at room temperature for 2 h. After the reaction is complete, quench the reaction with 200 μL of vinyl ether and purify to obtain the PCOE polymer, i.e., PCOE. 1000 .

[0032] Example 4 Weigh 660 μL of COE (110.2 g / mol) and 200 mg of NBT (373.37 g / mol) into an ampoule, add 17.4 mL of chloroform (CHCl3), and seal the ampoule. After three freeze-thaw cycles, dissolve 4 mg of freshly prepared Grubbs III catalyst in 200 μL of chloroform and add it to the ampoule under nitrogen purging. React at room temperature for 2 h. After the reaction is complete, add 200 μL of vinyl ether to quench the reaction and purify to obtain a polymer with a COE:NBT molar ratio of 9:1, i.e., NBT. 100 - co -COE 900 The structural formula is , where x=100 and R is a benzene ring.

[0033] Example 5 Weigh 440 μL of COE and 300 mg of NBT into an ampoule, add 14.8 mL of chloroform (CHCl3), and seal the ampoule. After three freeze-thaw cycles, dissolve 4 mg of freshly prepared Grubbs III catalyst in 200 μL of chloroform and add it to the ampoule under nitrogen purging. React at room temperature for 2 h. After the reaction is complete, add 200 μL of vinyl ether to quench the reaction and purify to obtain a polymer with a COE:NBT molar ratio of 8:2, i.e., NBT.200 - co -COE 800 , the structural formula is , wherein x = 200, R is a benzene ring.

[0034] Example 6 Take 256ul COE and 300mg NBT into the ampoule, add 16.6ml chloroform (CHCl3), seal the ampoule. After three freeze-thaw cycles, dissolve 3mg Grubbs III catalyst in 200ul chloroform, add to the ampoule under nitrogen, and react at room temperature for 2h. After the reaction is completed, add 200ul of vinyl ether to quench the reaction, and purify to obtain a polymer with a monomer COE:NBT molar ratio of 7:3, i.e. NBT 300 - co -COE 700 , the structural formula is , wherein x = 300, R is a benzene ring.

[0035] Example 7 Take 220ul COE and 400mg NBT into the ampoule, add 12.2ml DMAC, seal the ampoule. After three freeze-thaw cycles, dissolve 1.98mg Grubbs III catalyst in 200ul DMAC, add to the ampoule under nitrogen, and react at room temperature for 2h. After the reaction is completed, add 200ul of vinyl ether to quench the reaction, and purify to obtain a polymer with a monomer COE:NBT molar ratio of 6:4, i.e. NBT 400 - co -COE 600 , the structural formula is , wherein x = 400, R is a benzene ring.

[0036] Example 8 Take 500mg NBT into the ampoule, add 9.8ml N,N-dimethylacetamide (DMAC), seal the ampoule. After three freeze-thaw cycles, dissolve 1mg Grubbs III catalyst in 200ul DMAC, add to the ampoule under nitrogen, and react at room temperature for 2h. After the reaction is completed, add 200ul of vinyl ether to quench the reaction, and purify to obtain a polymer PNBT, i.e. PNBT 1000 .

[0037] Example 9 Prepare each ratio of polymer NBT X - co -COE (1000-X)Take 1.1 g, dissolved in 6 ml of chloroform or N, N-dimethylacetamide (DMAC), completely dissolved and poured into a polytetrafluoroethylene (PTFE) mold. The mold is placed on a 50°C hot table to dry for 12 h to remove most of the solvent; then put into a vacuum drying oven at 50°C for 12 h to remove residual solvent. After the solvent is removed, the polymer is cut into dumbbell-shaped samples. At room temperature, carry out lap shear test on a universal mechanical tensile testing machine at a constant speed of 10 mm / min -1 , unless otherwise specified, each test is carried out 3 times. The results are shown in Figure 7 , the increase of the proportion of cyclooctene increases the strain of the polymer, which can reach 560%. With the increase of core base monomer NBT, the tensile strength of the polymer increases from 10.2 Mpa to 40 Mpa. When NBT is more than 30%, the polymer becomes too brittle to carry out tensile test. In addition, the Young's modulus increases from 75.1 to 800, while the toughness index also decreases synchronously.

[0038] Example 10 Take 1.1 g, dissolved in 6 ml of chloroform or N, N-dimethylacetamide (DMAC), completely dissolved and poured into a polytetrafluoroethylene (PTFE) mold. The mold is placed on a 50°C hot table to dry for 12 h to remove most of the solvent; then put into a vacuum drying oven at 50°C for 12 h to remove residual solvent. After the solvent is removed, the polymer is cut into dumbbell-shaped samples. At room temperature, carry out lap shear test on a universal mechanical tensile testing machine at a constant speed of 10 mm / min X - co -COE (1000-X) Take 10 mg, fixed between the surfaces of the tested substrate (stainless steel, aluminum) by clamps. By heating in an 80°C drying oven for 4 h, the polymer is melted into a low viscosity liquid, then deposited on the surface to adhere the two surfaces (connection area: 10 mm x 10 mm), and cooled to room temperature. The adhered sample is fixed to the clamps of the tensile machine to measure the shear strength of the adhesive layer. As shown in Figure 8 , the core base-containing norbornene polymer NBT X - co -COE (1000-X) has good adhesion to metals, with a maximum of 23 Mpa and an average of 20.4 MPa for stainless steel; while the aluminum substrate is too soft, with a maximum of 15 Mpa and an average of 13.7 Mpa.

[0039] Example 11 Take 1.1 g, dissolved in 6 ml of chloroform or N, N-dimethylacetamide (DMAC), completely dissolved and poured into a polytetrafluoroethylene (PTFE) mold. The mold is placed on a 50°C hot table to dry for 12 h to remove most of the solvent; then put into a vacuum drying oven at 50°C for 12 h to remove residual solvent. After the solvent is removed, the polymer is cut into dumbbell-shaped samples. At room temperature, carry out lap shear test on a universal mechanical tensile testing machine at a constant speed of 10 mm / min X - co -COE (1000-X) Take 10 mg, fixed between the surfaces of the tested substrate (stainless steel, aluminum) by clamps. By heating in an 80°C drying oven for 4 h, the polymer is melted into a low viscosity liquid, then deposited on the surface to adhere the two surfaces (connection area: 10 mm x 10 mm), and cooled to room temperature. The adhered sample is fixed to the clamps of the tensile machine to measure the shear strength of the adhesive layer. As shown in Figure 9 , the adhesive still has good adhesion after 7 days.

[0040] Example 12 The prepared polymer NBT X - co -COE (1000-X) Take 10 mg, fixed by clamp between the surface of the measured substrate (PC, PMMA, PS, PE, PTFE, PP). By heating in 80 °C drying box for 4 h, the polymer is melted into a low viscosity liquid, then deposited on the surface to adhere two surfaces (connection area: 10 mm x 10 mm), cooled to room temperature. To measure the shear strength of the adhesive layer, as Figure 10 As shown, the prepared hot melt adhesive of the polymer has good adhesion effect in air for different plastic substrates, such as PC, PMMA, which is best up to 1.6 Mpa.

[0041] From Figure 1 1 H NMR spectrum analysis shows that the olefin peak of monomer NBT and COE in the copolymer completely disappears at 5.64 and 6.30 ppm, and a new olefin peak appears between 5.38 ~ 5.68 ppm, which proves the successful copolymerization of NBT and COE.

[0042] From Figures 3 to 5 It can be seen that the obtained NBT X - co -COE （1000-X） The copolymer is further characterized by two-dimensional DOSY NMR. NBT 300 - co - COE 700 The two-dimensional DOSY NMR spectrum of the copolymer has only one diffusion coefficient except DMSO and water. In addition, the two-dimensional DOSY NMR spectrum of the copolymer NBT 100 - co - COE 900 And NBT 200 - co - COE 800 The two-dimensional DOSY also has only one diffusion coefficient, which confirms the successful copolymerization of NBT and COE.

[0043] Figure 2 NBT X - co -COE (1000-X) The size exclusion chromatogram of the polymer, from Figure 2 It can be seen that SEC successfully proves the successful preparation of thymine-containing polyolefin, and the molecular weight of the copolymer gradually increases with the increase of NBT.

[0044] Figure 6 NBTX - co -COE (1000-X) The thermal gravimetric analysis curves of the polymers, from Figure 6 It can be seen that the polymers all have good thermal stability, and the decomposition temperature is above 250℃.

[0045] The above examples are only used to illustrate the technical solutions of the present application, but not to limit it; although the present application has been described in detail with reference to the foregoing examples, those skilled in the art should understand that the technical solutions recorded in the foregoing examples can be modified, or some technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A thymidine-containing polyolefin, characterized by: The structural formula is as follows: wherein x = 100-400, R is a phenyl ring.

2. The thymidine-containing polyolefin of claim 1, wherein: x=100-300。 3. A process for the preparation of a thymidine-containing polyolefin as claimed in claim 1 or 2, characterized in that: The method comprises the following steps: S1, using cis-5-norbornene-endo-2,3-dicarboxylic anhydride and ethanolamine to obtain a norbornene-based monomer ; and esterifying the norbornene-based monomer with thymine-1-acetic acid to obtain a nucleobase-containing norbornene-based monomer ; S2, a nucleobase-containing norbornene monomer The thymine-containing polyolefin is obtained by ROMP polymerization using a cyclooctene monomer as a raw material and Grubbs III catalyst as a catalyst.

4. The method for preparing thymine-containing polyolefins according to claim 3, characterized in that: In S1, the molar ratio of cis-5-norbornene-endo-2,3-dicarboxylic anhydride to ethanolamine is 1:1.2; the reaction temperature of cis-5-norbornene-endo-2,3-dicarboxylic anhydride with ethanolamine is 120 DEG C, the reaction time is 24 h, and the solvent is toluene.

5. The method of making thymidine-containing polyolefins according to claim 3, characterized in that: In S1, norbornene-based monomer The molar ratio of thymine-1-acetic acid was 1:1; the temperature of esterification reaction was 70°C, the time was 12h, and the solvent was N,N-dimethylformamide.

6. The method of making thymidine-containing polyolefins according to claim 3, characterized in that: In the esterification reaction of S1, the raw materials further comprise 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 4-dimethylaminopyridine, and the molar ratio of thymine-1-acetic acid, 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 4-dimethylaminopyridine is 1:1.2:0.

05.

7. The method of making thymidine-containing polyolefins according to claim 3, characterized in that: S2 specifically comprises the following steps: mixing a nucleobase-containing norbornene monomer with a cyclooctene monomer, a solvent in a reaction device, after sealing, freeze-thaw cycle, under the protection of inert gas, Grubbs III catalyst is added, room temperature reaction, after quenching reaction with vinyl ethyl ether, purification to obtain the thymine-containing polyolefin.

8. The method of claim 7, wherein the thymidine-containing polyolefin is prepared by: In S2, the solvent is one of chloroform, N,N-dimethylacetamide or a mixture of the two.

9. The method of preparing a thymidine-containing polyolefin according to any one of claims 3-8, characterized in that: In S2, there are nucleobase-containing norbornene monomers. The dosage ratio of cyclooctene to cyclooctene is 200-400 mg: 220-680 μL; containing nucleobase norbornene monomers. The mass ratio of the catalyst to Grubbs III is 200-400:1.98-4.

10. Use of the thymine-containing polyolefin as claimed in claim 1 or 2 as an adhesive.

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