Urushiol-based polymer with shape memory characteristics and preparation method therefor

Abstract

The present application discloses a urushiol-based polymer with shape memory characteristics and a preparation method therefor. The method involves using epichlorohydrin and urushiol as monomers to prepare a urushiol glycidyl ether monomer, oxidizing an unsaturated carbon-carbon double bond in urushiol by utilizing the strong oxidation property of 3-chloroperoxybenzoic acid to form epoxidized urushiol glycidyl ether, and then carrying out thermal curing on the epoxidized urushiol glycidyl ether and carboxylic acid to obtain the urushiol-based polymer with shape memory characteristics, which is a urushiol-based epoxy glass polymer. By means of the urushiol epoxidation method, the present application solves the problem of uneven film formation caused by the carbon-carbon double bond in urushiol curing, and greatly increases the epoxy value of the urushiol, which is beneficial to the preparation of a glass-like polymer with better performance. The urushiol-based polymer with the shape memory characteristics as prepared by the present application retains excellent performance of the urushiol as a matrix material and is also provided with improved solvent resistance, shape memory characteristics, and high temperature resistance of the glass-like polymer. The present invention has potential commercial value.

Description

Urushiol-based polymer with shape memory properties and preparation method thereof Technical Field

[0001] The present application relates to an urushiol-based polymer with shape memory properties and a preparation method thereof, belonging to the technical field of epoxy resins. Background Art

[0002] Raw lacquer, also known as "great lacquer" or "national lacquer", is a widely used natural coating obtained from lacquer trees. It has good corrosion resistance, wear resistance, acid resistance, solvent resistance, heat resistance, water and insulation resistance, and high gloss, so it is widely used. Evidence from lacquerware artifacts unearthed in my country shows that raw lacquer has a long history of use in my country and has survived thousands of years without decay, which is enough to prove that raw lacquer has strong advantages as a natural coating. Raw lacquer is a traditional natural resin composed of urushiol, gum, water and other compounds. Urushiol is the main component of raw lacquer. It is a catechol derivative with a long unsaturated hydrocarbon side chain structure. It is composed of urushiol compounds such as saturated urushiol, monourushiol, diene urushiol and triene urushiol. It is the basic reactant for the curing of raw lacquer into film and the formation of the paint film skeleton. Due to the presence of a large number of unsaturated double bonds, urushiol glycidyl ether in epoxy resin coatings cures uneven film formation due to the presence of carbon-carbon double bonds.

[0003] Glassy polymers (vitrimers) are a class of covalently cross-linked polymer networks containing dynamic covalent bonds, combining the advantages of thermosetting and thermoplastic polymers. Under external stimuli, the dynamic covalent bonds in glassy polymers can reversibly break and form, while maintaining a constant cross-link density. This unique property enables them to be reprocessed, recycled, welded, and healed while maintaining a three-dimensional cross-linked network structure. Therefore, glassy polymers have the potential to address the limitations of traditional thermosetting polymers in terms of reprocessing and recycling, promoting resource recycling and sustainable social development. The plasticity and regenerative properties of epoxy resin vitrimers stem from the dynamic covalent bonds they contain. Cross-linked epoxy systems constructed using dynamic covalent bonds not only retain their inherent mechanical properties and heat resistance, but also effectively eliminate internal stress within the resin through topological restructuring, resulting in self-healing properties in their products. However, epoxy resins remain difficult to recycle sustainably.

[0004] Summary of the Invention

[0005] In order to solve the problem of uneven film formation caused by the presence of carbon-carbon double bonds in the curing of urushiol glycidyl ether in epoxy resin coatings and the problem that epoxy resin materials are difficult to recycle sustainably in the above-mentioned prior art, the present application provides a urushiol-based polymer with shape memory properties and a preparation method thereof. By oxidizing the carbon-carbon double bonds in urushiol glycidyl ether into epoxy groups, the problem of uneven film formation caused by the subsequent curing due to the carbon-carbon double bonds is solved, and the epoxy value of urushiol glycidyl ether is improved, which is expected to expand the application range of urushiol glycidyl ether in epoxy resin coatings. In addition, by introducing reversible dynamic chemical bonds into the epoxy resin material system to prepare Vitrimer materials, the ester exchange dynamic bonds are introduced into the epoxy resin cross-linked network obtained by the reaction of epoxy resin with fatty acids or acid anhydrides, giving the material good recyclability and reprocessing performance.

[0006] This application adopts the following technical solutions:

[0007] A shape memory urushiol-based polymer having a structural formula shown in Formula I:

[0008] Wherein R0 is selected from at least one structure represented by the structural formulas of Formula Ia, Formula Ib, and Formula Ic;

[0009] R3 is a C2-C 12 The hydrocarbon chain, or R3 is C 34 ~C 51 Long hydrocarbon chains;

[0010] n is 0 or 1.

[0011] The urushiol-based polymer with shape memory properties prepared in this application is an urushiol-based epoxy-type glass polymer. The ester bonds formed by the ring-opening of carboxylic acid and epoxy groups within the urushiol-based epoxy-type glass polymer network undergo an increased transesterification reaction rate at high temperatures, accelerating the rate of topological network reorganization in the material and shortening the relaxation time, resulting in a glass-like polymer material with excellent shape memory properties.

[0012] Optionally, the urushiol-based polymer with shape memory properties has a gel content of 71.7 to 99.2% when immersed in an organic solvent for 24 hours;

[0013] Optionally, the organic solvent is selected from at least one of n-hexane, toluene, ethyl acetate, chloroform, acetone, N,N-dimethylformamide, methanol, ethanol, tetrahydrofuran, acetonitrile, and dichloromethane.

[0014] Optionally, the urushiol-based polymer having shape memory properties has an initial thermal decomposition temperature greater than 280°C.

[0015] Optionally, the urushiol-based polymer with shape memory properties has a tensile strength greater than 400 KPa and an elongation at break greater than 80%.

[0016] Optionally, the urushiol-based polymer with shape memory properties has a shape memory function, and the time for complete shape recovery at 90° C. is less than or equal to 20 seconds.

[0017] According to another aspect of the present application, a method for preparing the above-mentioned urushiol-based polymer having shape memory properties is provided, comprising the following steps:

[0018] S1, adding a sodium hydroxide aqueous solution dropwise to a mixture containing the monomer mixture and epichlorohydrin, and then reacting I to obtain an urushiol glycidyl ether monomer having a structure shown in Formula 1b;

[0019] The monomer mixture includes epichlorohydrin and urushiol having a structure shown in formula 1a;

[0020] wherein R1 is selected from one of the structures shown in Formula 1b-1, 1b-2, and 1b-3;

[0021] S2, adding dropwise a mixture of 3-chloroperbenzoic acid and dichloromethane to the urushiol glycidyl ether monomer of formula 1b in step S1, and performing reaction II to obtain epoxidized urushiol glycidyl ether of formula 2a;

[0022] wherein R2 is selected from one of the structures shown in Formula 2a-1, 2a-2, and 2a-3;

[0023] S3, adding a catalyst to an ethanol solution containing the epoxidized urushiol glycidyl ether of the structure represented by Formula 2a and the acid of the structure represented by Formula 3a, and performing a thermal curing polymerization reaction to obtain the urushiol-based polymer having shape memory properties;

[0024] R3 is a C2-C 12 The hydrocarbon chain, or R3 is C 34 ~C 51 Long hydrocarbon chains;

[0025] n is 0 or 1.

[0026] The preparation process of this application is shown as follows:

[0027] The preparation process of step S1 is as shown in process I, using epichlorohydrin and urushiol monomer with the structure shown in formula 1a as raw materials to prepare urushiol glycidyl ether monomer with the structure shown in formula 1b;

[0028] The preparation process of step S2 is shown in Formula II, using the strong oxidizing property of 3-chloroperoxybenzoic acid to oxidize the carbon-carbon double bond in the urushiol glycidyl ether monomer to obtain the epoxidized urushiol glycidyl ether of the structure shown in Formula 2a;

[0029] The preparation process of step S3 is shown in formula III, wherein the epoxidized urushiol glycidyl ether and the acid are subjected to a thermal curing polymerization reaction to obtain the urushiol-based polymer with shape memory properties.

[0030] R3 is a C2-C 12 The hydrocarbon chain, or R3 is C 34 ~C 51 Long hydrocarbon chains;

[0031] n is 0 or 1.

[0032] Optionally, in step S1, the molar ratio of urushiol of the structure represented by formula 1a to epichlorohydrin is 1:10-20.

[0033] Optionally, in step S1, the molar ratio of urushiol with the structure represented by formula 1a to sodium hydroxide is 1:2-3.

[0034] Optionally, the concentration of sodium hydroxide in the sodium hydroxide aqueous solution is 8 to 12 mol / L.

[0035] Optionally, in step S1, the conditions for reaction I include: a reaction temperature of 50 to 80° C. and a reaction time of 5 to 8 hours. The reaction time is measured from the completion of the dropwise addition of the sodium hydroxide solution.

[0036] Optionally, after the reaction I, the product is further subjected to post-treatment, wherein the post-treatment comprises extraction, washing, drying, and vacuum concentration to remove excess epichlorohydrin.

[0037] Optionally, the post-treatment is to extract the product of reaction I with ethyl acetate, wash the product with saturated brine and let it stand for stratification, dry the obtained organic layer, concentrate it, remove excess epichlorohydrin, and obtain urushiol glycidyl ether.

[0038] Optionally, the purity of the urushiol of the structure represented by Formula 1a is greater than or equal to 95%;

[0039] Alternatively, the urushiol of the structure shown in Formula 1a is obtained by the following method:

[0040] The raw lacquer is filtered with gauze to remove mechanical impurities in the raw lacquer, and then anhydrous ethanol is added, stirred, allowed to stand, filtered, and washed, and this process is repeated 3 to 5 times. The filtrates are combined and concentrated in vacuo at 60°C. The concentrate is a crude urushiol extract, and the crude urushiol extract is repeatedly extracted with petroleum ether for 1 to 5 times, allowed to stand, separated, and the extracts are combined. The extracts are concentrated in vacuo at 60°C, and the solvent is recovered to obtain urushiol with a purity of more than 95%.

[0041] Optionally, in step S2, the molar ratio of the urushiol glycidyl ether monomer of the structure represented by formula 1b to 3-chloroperoxybenzoic acid is 1:1-2.

[0042] Optionally, in step S2, the molar ratio of the urushiol glycidyl ether monomer of the structure represented by Formula 1b to 3-chloroperbenzoic acid is selected from any value of 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, or any range therebetween.

[0043] Optionally, in step S2, the conditions of reaction II are: reaction temperature is 30-50° C., and reaction time is 3-5 h.

[0044] Optionally, in step S2, in the conditions of reaction II, the reaction temperature is selected from any value of 30°C, 35°C, 40°C, 45°C, 50°C, or any range therebetween.

[0045] Optionally, the conditions of the reaction II further include: during the reaction, when the epoxy value of the epoxidized urushiol glycidyl ether of the structure shown in formula 2a reaches 0.2 to 0.5 mol / 100g, the reaction is terminated.

[0046] Optionally, the conditions of reaction II also include: the epoxy value of the epoxidized urushiol glycidyl ether of the structure shown in formula 2a that terminates the reaction during the reaction is selected from any value among 0.2 mol / 100 g, 0.25 mol / 100 g, 0.3 mol / 100 g, 0.35 mol / 100 g, 0.4 mol / 100 g, 0.45 mol / 100 g, 0.5 mol / 100 g, or any range value therebetween.

[0047] The epoxy value was tested by the hydrochloric acid-acetone method.

[0048] Optionally, after the reaction II, the product is further treated: the product after the reaction is extracted with ethyl acetate, the product is washed with saturated brine and allowed to stand for stratification, and then washed with saturated sodium sulfite solution, saturated sodium bicarbonate solution, and saturated brine solution for 3 to 5 times respectively, and tested with starch potassium iodide test paper until the test paper does not change color, and then the solution is dried with anhydrous sodium sulfate for 20 to 28 hours, and concentrated in vacuo at 40 to 50°C.

[0049] Optionally, in step S3, the molar ratio of the epoxidized urushiol glycidyl ether of the structure represented by formula 2a to the acid of the structure represented by formula 3a is 1:0.6-1 in terms of epoxy group:carboxyl group.

[0050] Optionally, in step S3, the acid having the structure represented by formula 3a is selected from at least one of a long hydrocarbon polybasic acid, 2,2'-dithiodibenzoic acid, and citric acid.

[0051] Optionally, in step S3, the content of 2,2'-dithiodibenzoic acid in the acid having the structure represented by formula 3a is 10-50%.

[0052] Optionally, in step S3, the content of 2,2'-dithiodibenzoic acid in the acid of the structure represented by formula 3a is selected from any value of 10%, 20%, 30%, 40%, 50%, or any range therebetween.

[0053] Optionally, in step S3, the long hydrocarbon group polyacid is selected from at least one of dimer acid and trimer acid.

[0054] Optionally, in step S3, the catalyst is selected from at least one of acetylacetone copper zinc and 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

[0055] Optionally, in step S3, the amount of the catalyst used is 4-6% of the molar amount of the acid carboxyl groups in the acid having the structure shown in formula 3a.

[0056] Optionally, in step S3, the conditions for the heat curing polymerization reaction include: heating at 55-65°C for 3-5 hours, heating at 115-125°C for 12-18 hours, and heating at 145-155°C for 3-6 hours.

[0057] According to another aspect of the present application, a heat-curing film with shape memory properties is provided. The heat-curing film is prepared according to any one of the preparation methods described above.

[0058] Optionally, step 3 further comprises quickly pouring the reaction mixture before heat curing polymerization into a preheated polytetrafluoroethylene mold, and then vacuum degassing until bubbles completely disappear, and then performing heat curing polymerization reaction.

[0059] In the present application, "hydrocarbon group" refers to a group formed by losing any hydrogen atom from a hydrocarbon compound molecule.

[0060] In this application, C2~C 12 、C 34 ~C 51 The subscripts in the group represent the number of carbon atoms contained in the group. For example, C2~C 12 The hydrocarbon group refers to a hydrocarbon group having 2 to 12 carbon atoms.34 ~C 51 The hydrocarbon group refers to a hydrocarbon group having 34 to 51 carbon atoms.

[0061] The beneficial effects of this application include:

[0062] The preparation method of the urushiol-based polymer with shape memory properties provided in the present application oxidizes the carbon-carbon double bonds in the unoxidized urushiol glycidyl ether into epoxy groups, further increasing the epoxy value of the urushiol glycidyl ether; after the carbon-carbon double bonds are oxidized, the uneven curing problem caused by the carbon-carbon double bonds can be solved during the subsequent thermal curing of the epoxy resin, and the application range of the urushiol glycidyl ether for further preparing epoxy resin coatings can be expanded; the preparation method adopts biomass raw materials, which are renewable, have abundant resource reserves, and can ensure the sustainable utilization of raw materials, and the preparation product has the characteristics of biodegradability and environmental friendliness. It has potential commercial value. The urushiol-based polymer with shape memory properties prepared in the present application is a fully bio-based glass polymer prepared by thermally curing the urushiol glycidyl ether and a long alkyl polyacid. It has good solvent resistance, self-repairing properties, high temperature resistance, excellent film-forming properties, easy processing and molding, simple preparation process, easy industrialization, and convenient promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] FIG1 is an infrared spectrum of urushiol glycidyl ether (UGE) and oxidized urushiol glycidyl ether (OUGE).

[0064] FIG2 is a stress relaxation test spectrum of the urushiol-based polymer with shape memory properties synthesized in this embodiment.

[0065] FIG3 is a graph showing the mechanical properties of the urushiol-based polymer with shape memory properties prepared in this embodiment.

[0066] FIG4 shows the solvent resistance test results of the urushiol-based polymer with shape memory properties prepared in this embodiment.

[0067] FIG5 is a TG test spectrum of the urushiol-based polymer with shape memory properties prepared in this embodiment.

[0068] FIG6 is a DSC test spectrum of the urushiol-based polymer with shape memory properties prepared in this embodiment.

[0069] FIG. 7 is a diagram showing the shape memory properties of the urushiol-based polymer prepared in this embodiment. DETAILED DESCRIPTION

[0070] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0071] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0072] Unless otherwise specified, conventional methods were used for testing, and instrument settings were those recommended by the manufacturer.

[0073] The analysis method of the urushiol-based polymer with shape memory properties in the examples of this application is as follows:

[0074] 1 H NMR was measured on a Bruker AVANCE III 400 MHz NMR instrument with tetramethylsilane (TMS) as the internal standard and DMSO-d6 as the solvent.

[0075] Tensile strength and elongation at break were tested using an Instron 1211 electronic tensile testing machine in accordance with national standard GB13022-91 at a rate of 0.5 mm / min. The active portion of the tensile specimen measured 40 mm in length, 5 mm in width, and approximately 35 microns in thickness. Five specimens were tested for each sample, and the average result was calculated.

[0076] Thermogravimetric analysis was carried out using a TG 209F3 thermogravimetric analyzer under a nitrogen atmosphere, and the test temperature was increased from 30°C to 800°C at a rate of 10°C / min.

[0077] Stress relaxation was analyzed using a dynamic thermomechanical analyzer (TA Q800) at test temperatures of 120°C, 140°C, 160°C, and 180°C.

[0078] Solvent resistance: Take about 20 mg of sample and record the original data as m0. Soak it in n-hexane, toluene, ethyl acetate, dichloromethane, acetone, tetrahydrofuran, methanol, acetonitrile, water, dimethylformamide, and chloroform for 24 hours respectively. After drying, weigh it (m1). The solvent resistance of the film is measured by (m1 / m0)×100%.

[0079] The epoxy value of the oxidized urushiol glycidyl ether was tested using the hydrochloric acid-acetone method.

[0080] Example 1

[0081] (1) Urushiol purification:

[0082] Take 2000g of raw lacquer, filter with gauze to remove mechanical impurities in the raw lacquer, then add a certain amount of anhydrous ethanol, stir, let stand, filter, wash, repeat 3 times, combine the filtrate, concentrate in vacuum at 60°C, the concentrate is the crude urushiol extract, and then repeatedly extract the crude urushiol extract with petroleum ether 3 times, let stand, separate, combine the extracts, concentrate in vacuum at 60°C, recover the solvent, and obtain urushiol with a purity of more than 95% for later use;

[0083] (2) Synthesis of urushiol glycidyl ether:

[0084] Epichlorohydrin was used as the solvent and the urushiol and sodium hydroxide molar ratio was 1:2 for stirring reaction: sodium hydroxide was prepared into a 10 mol / L solution, 140.0 g of epichlorohydrin and 31.4 g of urushiol were added to a four-necked flask, 20.0 mL of sodium hydroxide aqueous solution was added dropwise to the sodium hydroxide aqueous solution. After the addition was complete, the reaction temperature was controlled to 60°C and the reaction time was 6 h. The reaction product was extracted, washed, dried, and concentrated in vacuo at 65°C to remove excess epichlorohydrin to obtain urushiol glycidyl ether, recorded as UE;

[0085] (3) Carbon-carbon double bonds in urushiol glycidyl ether:

[0086] Using dichloromethane as solvent, a stirring reaction was carried out with a molar ratio of 1:1 between urushiol glycidyl ether and 3-chloroperbenzoic acid: 8.6 g of 3-chloroperbenzoic acid was dissolved in 20.0 mL of dichloromethane, and then added dropwise to a three-necked flask containing 21.3 g of urushiol glycidyl ether within 20 minutes, stirred, and reacted at a constant temperature of 40°C for 3 hours. After the reaction was completed, 100.0 g of ethyl acetate was added to make the solution in the upper layer position for easy separation operation. Subsequently, it was washed with saturated sodium sulfite solution, saturated sodium bicarbonate solution, and saturated salt water solution for multiple times. During the washing period, starch potassium iodide test paper was used for testing until the test paper did not change color. The solution was dried with anhydrous sodium sulfate for 24 hours and concentrated in vacuo at 45°C to obtain the oxidized urushiol glycidyl ether product, recorded as OUGE.

[0087] Example 2

[0088] The preparation steps and parameters were the same as those in Example 1, with the only difference being that in step (3), the molar ratio of urushiol glycidyl ether to 3-chloroperbenzoic acid used in this example was 1:1.5, i.e., 13.0 g of 3-chloroperbenzoic acid was dissolved in 30 mL of dichloromethane, and then added dropwise to a three-necked flask containing 21.3 g of urushiol glycidyl ether over 30 min.

[0089] Example 3

[0090] The preparation steps and parameters are the same as those in Example 2, with the only difference being that in step (3), the reaction conditions adopted in this example are: constant temperature at 30° C. for 3 h.

[0091] Example 4

[0092] The preparation steps and parameters are the same as those in Example 2, with the only difference being that in step (3), the reaction conditions adopted in this example are: constant temperature 50° C. for reaction for 3 h.

[0093] Example 5

[0094] Preparation of urushiol-based polymers with shape memory properties:

[0095] 28.5 g of the oxidized urushiol glycidyl ether product prepared in Example 3 was mixed with 50.8 g of dimer acid and 3.1 g of 2,2'-dithiodibenzoic acid (2,2'-dithiodibenzoic acid content was 10%), and thermally cured in the presence of 0.7 g of 1,5,7-triazabicyclo[4.4.0]dec-5-ene as a catalyst to obtain an urushiol-based polymer with shape memory properties, which was named OTD. 0.1 .

[0096] The molar ratio of the oxidized urushiol glycidyl ether product, the mixed acid, and the catalyst is 1:1:0.05 based on epoxy group:carboxyl group:catalyst.

[0097] Example 6

[0098] The preparation process and parameters are the same as those in Example 5, except that the amount of the mixed acid used is a mixed acid of 45.2 g of dimer acid and 6.1 g of 2,2'-dithiodibenzoic acid (the content of 2,2'-dithiodibenzoic acid is 20%).

[0099] The urushiol-based polymer with shape memory properties was named OTD. 0.2 .

[0100] Example 7

[0101] The preparation process and parameters are the same as those in Example 5, except that the amount of the mixed acid used is: a mixed acid of 39.5 g of dimer acid and 9.2 g of 2,2'-dithiodibenzoic acid (2,2'-dithiodibenzoic acid content is 30%).

[0102] The urushiol-based polymer with shape memory properties was named OTD. 0.3 .

[0103] Example 8

[0104] The preparation process and parameters are the same as those in Example 5, except that the amount of the mixed acid used is a mixed acid of 33.9 g of dimer acid and 12.3 g of 2,2'-dithiodibenzoic acid (the content of 2,2'-dithiodibenzoic acid is 40%).

[0105] The urushiol-based polymer with shape memory properties was named OTD. 0.4 .

[0106] Example 9

[0107] The preparation process and parameters are the same as those in Example 5, except that the amount of the mixed acid used is a mixed acid of 28.2 g of dimer acid and 15.3 g of 2,2'-dithiodibenzoic acid (the content of 2,2'-dithiodibenzoic acid is 50%).

[0108] The urushiol-based polymer with shape memory properties was named OTD. 0.5 .

[0109] Test Case

[0110] The epoxy value of the double-bond oxidized urushiol glycidyl ether obtained in Examples 1 to 4 was tested using the hydrochloric acid-acetone method. 0.5 g of the oxidized urushiol glycidyl ether was accurately weighed and placed in a conical flask. 20 mL of freshly prepared hydrochloric acid-acetone solution was then accurately pipetted into the conical flask, stored in the dark for 30 minutes, and titrated with 0.1017 mol / L sodium hydroxide standard solution using methyl red as an indicator until the solution turned orange-yellow. A blank control was also performed, and the epoxy value was calculated according to the following formula.

[0111] Where:

[0112] Ev is the epoxy value, mol / 100g;

[0113] V0 is the volume of sodium hydroxide standard solution consumed by the blank sample, mL;

[0114] V is the volume of sodium hydroxide standard solution consumed by the sample, mL;

[0115] c0 is the concentration of sodium hydroxide standard solution, mol / L;

[0116] m is the mass of the sample, g.

[0117] The results are shown in Table 1. The epoxy values ​​of the urushiol glycidyl ether after double bond oxidation in Examples 1 to 4 are 0.265, 0.283, 0.351, and 0.211 mol / 100 g, respectively.

[0118] Table 1 Comparison of epoxy values ​​of urushiol glycidyl ethers after double bond oxidation obtained in Examples 1 to 4

[0119] The infrared spectra of the urushiol glycidyl ether (UGE) and the oxidized urushiol glycidyl ether (OUGE) obtained in the preparation process of Example 1 were tested. The results are shown in Figure 1. -1 is the absorption peak of the carbon-carbon double bond in UGE. After oxidation reaction, 3007 cm -1 The absorption peak disappears, indicating that the carbon-carbon double bond in UGE is successfully oxidized; 912 cm -1 , 836cm -1 This is the absorption peak of the epoxy group, proving the successful synthesis of the epoxy group.

[0120] The shape memory properties of the urushiol-based polymer OTD synthesized in Example 50.1 Stress relaxation tests were conducted, and the results, shown in Figure 2, show that the relaxation time of the urushiol-based polymer with shape memory properties significantly decreases with increasing temperature. The relaxation time was 5514 seconds at 120°C, 1280 seconds at 140°C, and 616 seconds at 160°C. As the temperature increases, the relaxation time decreases from 5514 seconds at 120°C to 616 seconds at 160°C.

[0121] The shape memory urushiol-based polymer OTD synthesized in Examples 5 to 9 0.1 ~OTD 0.5 Mechanical properties tests were conducted, and the results are shown in FIG3 , showing good mechanical properties, with a tensile strength higher than 400 KPa and an elongation at break exceeding 80%.

[0122] The shape memory properties of the urushiol-based polymer OTD synthesized in Example 5 0.1 Solvent resistance test was conducted, and the results are shown in Figure 4. After immersion in various organic solvents (n-hexane, toluene, ethyl acetate, chloroform, acetone, N,N-dimethylformamide, methanol, ethanol, tetrahydrofuran, acetonitrile, and dichloromethane) for 24 hours, the gel content was calculated to be above 71.7%, with the highest reaching 99.2%.

[0123] The shape memory urushiol-based polymer OTD synthesized in Examples 5 to 9 0.1 ~OTD 0.5 TG test was carried out, and the results are shown in Figure 5. The initial thermal decomposition temperature was higher than 280°C.

[0124] The shape memory urushiol-based polymer OTD synthesized in Examples 5 to 9 0.1 ~OTD 0.5 The DSC test was carried out and the results are shown in Figure 6. 0.1 ~OTD 0.5 The glass transition temperatures are -0.5℃, 4℃, 8℃, 10℃ and 20℃ respectively.

[0125] The shape memory properties of the urushiol-based polymer OTD synthesized in Example 5 0.1 The shape memory is shown in FIG7 . At 90° C., the shape is completely recovered after 20 seconds.

[0126] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An urushiol-based polymer having shape memory properties, characterized in that: The urushiol-based polymer having shape memory properties has a structural formula shown in Formula I: Wherein R0 is selected from at least one structure represented by the structural formulas of Formula Ia, Formula Ib, and Formula Ic; R3 is a C2-C 12 The hydrocarbon chain, or R3 is C 34 ~C 51 Long hydrocarbon chains; n is 0 or 1.

2. The urushiol-based polymer having shape memory properties according to claim 1, wherein The gel content of the urushiol-based polymer with shape memory properties is 71.7-99.2% when immersed in an organic solvent for 24 hours.

3. The urushiol-based polymer having shape memory properties according to claim 1 or 2, characterized in that: The initial thermal decomposition temperature of the urushiol-based polymer with shape memory properties is greater than 280°C.

4. The urushiol-based polymer having shape memory properties according to any one of claims 1 to 3, characterized in that: The urushiol-based polymer with shape memory properties has a tensile strength greater than 400 KPa and an elongation at break greater than 80%.

5. The urushiol-based polymer having shape memory properties according to any one of claims 1 to 4, characterized in that: The urushiol-based polymer with shape memory properties has a shape memory function, and the time for complete shape recovery at 90° C. is less than or equal to 20 seconds.

6. The method for preparing the urushiol-based polymer having shape memory properties according to any one of claims 1 to 5, characterized in that: The steps include: S1, adding a sodium hydroxide aqueous solution dropwise to a mixture containing the monomer mixture and epichlorohydrin, and then reacting I to obtain an urushiol glycidyl ether monomer having a structure shown in Formula 1b; The monomer mixture includes epichlorohydrin and urushiol having a structure shown in formula 1a; wherein R1 is selected from one of the structures shown in Formula 1b-1, 1b-2, and 1b-3; S2, adding dropwise a mixture of 3-chloroperbenzoic acid and dichloromethane to the urushiol glycidyl ether monomer of formula 1b in step S1, and performing reaction II to obtain epoxidized urushiol glycidyl ether of formula 2a; wherein R2 is selected from one of the structures shown in Formula 2a-1, 2a-2, and 2a-3; S3, adding a catalyst to an ethanol solution containing the epoxidized urushiol glycidyl ether of the structure represented by Formula 2a and the acid of the structure represented by Formula 3a, and performing a thermal curing polymerization reaction to obtain the urushiol-based polymer having shape memory properties; R3 is a C2-C 12 The hydrocarbon chain, or R3 is C 34 ~C 51 Long hydrocarbon chains; n is 0 or 1.

7. The preparation method according to claim 6, characterized in that In step S1, the molar ratio of urushiol of the structure represented by formula 1a to epichlorohydrin is 1:10-20.

8. The preparation method according to claim 6 or 7, characterized in that In step S1, the molar ratio of urushiol with the structure represented by formula 1a to sodium hydroxide is 1:2-3.

9. The preparation method according to any one of claims 6 to 8, characterized in that The concentration of sodium hydroxide in the sodium hydroxide aqueous solution is 8 to 12 mol / L.

10. The preparation method according to any one of claims 6 to 9, characterized in that: In step S1, the conditions of reaction I include: reaction temperature of 50-80° C., and reaction time of 5-8 h.

11. The preparation method according to any one of claims 6 to 10, characterized in that: After the reaction I, the product is subjected to post-treatment, which includes extraction, washing, drying, and vacuum concentration to remove excess epichlorohydrin.

12. The preparation method according to any one of claims 6 to 11, characterized in that: In step S2, the molar ratio of the urushiol glycidyl ether monomer of the structure represented by formula 1b to 3-chloroperoxybenzoic acid is 1:1-2.

13. The preparation method according to any one of claims 6 to 12, characterized in that: In step S2, the conditions of reaction II are: reaction temperature is 30-50° C., and reaction time is 3-5 h.

14. The preparation method according to any one of claims 6 to 13, characterized in that: The conditions of the reaction II also include: during the reaction, when the epoxy value of the epoxidized urushiol glycidyl ether of the structure shown in formula 2a reaches 0.2 to 0.5 mol / 100g, the reaction is terminated.

15. The preparation method according to any one of claims 6 to 14, characterized in that: In step S3, the molar ratio of the epoxidized urushiol glycidyl ether of the structure represented by formula 2a to the acid of the structure represented by formula 3a is 1:0.6-1 in terms of epoxy group:carboxyl group.

16. The preparation method according to any one of claims 6 to 15, characterized in that: In step S3, the acid having the structure represented by formula 3a is selected from at least one of a long hydrocarbon polybasic acid, 2,2'-dithiodibenzoic acid, and citric acid.

17. The preparation method according to any one of claims 6 to 16, characterized in that: In step S3, the long hydrocarbon group polybasic acid is selected from at least one of dimer acid and trimer acid.

18. The preparation method according to any one of claims 6 to 17, characterized in that: In step S3, the catalyst is selected from at least one of acetylacetone copper zinc and 1,5,7-triazabicyclo[4.4.0]dec-5-ene.

19. The preparation method according to any one of claims 6 to 18, characterized in that: In step S3, the amount of the catalyst used is 4-6% of the molar amount of the acid carboxyl groups in the acid having the structure shown in formula 3a.

20. The preparation method according to any one of claims 6 to 19, characterized in that: In step S3, the conditions for the thermal curing polymerization reaction include: heating at 55-65° C. for 3-5 hours, heating at 115-125° C. for 12-18 hours, and heating at 145-155° C. for 3-6 hours.

21. A heat-cured film with shape memory properties, characterized in that: The thermally cured film is prepared according to the preparation method according to any one of claims 6 to 20.

Images