Branched-chain-containing long-carbon-chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid, and preparation method therefor

Abstract

Disclosed in the present invention are a branched-chain-containing long-carbon-chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid, and a preparation method therefor. Monomers for preparing the polyester elastomer comprise 2,5-furandicarboxylic acid or 2,5-furandicarboxylic acid ester, a dihydric alcohol and a branched-chain-containing long-carbon-chain dibasic acid. The preparation method comprises: (1) performing a melting reaction on furandicarboxylic acid or an ester thereof, a branched-chain-containing long-carbon-chain dibasic acid and a dihydric alcohol to prepare an oligomer; and (2) performing melt polycondensation on the oligomer to synthesize a furandicarboxylic acid-based branched-chain-containing long-carbon-chain polyester elastomer. By means of the branched-chain-containing long-carbon-chain polyester elastomer of the present invention, the molecular structure can be effectively designed, and the molecular weight can be regulated, thereby optimizing mechanical properties, thermal properties, barrier properties, etc. The preparation process thereof is simple, convenient and safe, and the equipment requirements and catalysis cost are relatively low. The raw material 2,5-furandicarboxylic acid used in the present invention is a potential substitute for terephthalic acid, is derived from biomass, has a wide range of sources and is environmentally friendly.

Description

A branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid and its preparation method Technical Field

[0001] The present invention relates to the technical field of polymer materials, and in particular to a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid and a preparation method thereof. Background Art

[0002] Aromatic petroleum-based polyesters, such as terephthalic acid (TPA)-based polyesters, have rigid benzene rings and exhibit excellent mechanical, gas barrier, and thermal properties. They are widely used in a variety of applications, including fibers, films, plastic bottles, packaging, and engineering plastics. However, the production and use of petroleum-based polyesters have had significant negative impacts on the global climate and biosphere. Therefore, the search for bio-based alternatives to TPA has become a hot research topic.

[0003] In 2004, the U.S. Department of Energy evaluated 12 biomass-derived platform compounds, including malic acid, fumaric acid, succinic acid, 3-hydroxypropionic acid, 2,5-furandicarboxylic acid, glucaric acid, aspartic acid, and itaconic acid. These compounds can be used to produce high-value-added bio-based materials. Among them, 2,5-furandicarboxylic acid (FDCA), whose chemical structure contains two carboxyl groups and a rigid furan ring, is similar to that of TPA, a key monomer in synthetic materials. It is considered a potential alternative to TPA and can be used to synthesize high-performance polymers, and therefore has attracted the most attention.

[0004] Bio-based polyesters prepared using FDCA as a starting material include polyethylene furandicarboxylate (PEF), polypropylene furandicarboxylate (PPF), and polybutylene furandicarboxylate (PBF), and have become a new class of bio-based polymers that have attracted considerable attention. However, these homopolyesters often suffer from deficiencies in mechanical or thermal properties. By introducing a functional third monomer through multi-component copolymerization, the chain structure composition characteristics and microscopic condensed state can be changed, further improving or regulating the thermophysical and mechanical properties of polyester materials. This can effectively expand the application range of copolyester materials and enable their application in high-end fields such as new energy vehicles, photovoltaic semiconductors, and intelligent manufacturing, thereby promoting the promotion and use of bio-based materials.

[0005] Chinese patent CN115850671A discloses a poly-2,5-furandicarboxylate-based thermoplastic polyester elastomer and its preparation method. The method involves first polymerizing 2,5-furandicarboxylic acid or dimethyl 2,5-furandicarboxylate with low-molecular-weight polyethylene glycol or polypropylene glycol to produce a dihydroxy- or carboxyl-terminated prepolymer A. The low-molecular-weight polyethylene glycol or polypropylene glycol is then reacted with a dibasic acid, anhydride, and / or acyl chloride to produce a prepolymer B. Finally, A and B are combined with a chain extender to form a polyester elastomer. This preparation method has harsh reaction conditions, complex operations, and difficulty controlling molecular weight. The chain extender and acyl chloride used are toxic and highly polluting.

[0006] Chinese patent CN110205072B discloses a 2,5-furandicarboxylic acid-based copolyester hot melt adhesive and its preparation method. The method involves first adding a mixture of 2,5-furandicarboxylic acid, 1,6-hexanoic acid, and sebacic acid, a mixture of polyethylene glycol 400, and a catalyst to a reactor for esterification. A stabilizer is then added and polycondensed for 2-4 hours. Finally, an antioxidant is added and the mixture is reacted in a vacuum for 15 minutes to obtain the copolyester hot melt adhesive. This method involves multiple additions of reaction aids, which can easily compromise the airtightness of the system and complicate equipment operation.

[0007] Chinese patent CN114057998A discloses a 2,5-furandicarboxylic acid copolyester and its preparation method. Specifically, 2,5-furandicarboxylic acid, 2,5-tetrahydrofuran dimethanol, and a diol mixture are melt-polymerized in the presence of a catalyst to produce the 2,5-furandicarboxylic acid copolyester. This synthesis method requires high pressure control and a long reaction time.

[0008] Chinese patent CN107312167A discloses a thermoplastic polyester elastomer based on biomass-based 2,5-furandicarboxylic acid and its preparation method. Specifically, 2,5-furandicarboxylic acid, an aliphatic diol, and an aliphatic lactone react in the presence of an esterification catalyst and a ring-opening catalyst to produce a prepolymer, which is then subjected to reduced-pressure polymerization to produce the polyester elastomer. The elastomer prepared by this method is difficult to control in terms of structure, and the ring-opening process requires stringent conditions.

[0009] The existing preparation technology of 2,5-furandicarboxylic acid thermoplastic polyester elastomer cannot achieve the controllable molecular structure and molecular weight, the process flow is complex, the reaction conditions are harsh, the equipment requirements are high, and the product color performance is poor, which limits its application areas.

[0010] Therefore, the branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid prepared by the present invention has a designable molecular structure, controllable molecular weight, simple preparation process and low equipment requirements, and is obviously of great research significance.

[0011] Summary of the Invention

[0012] The purpose of the present invention is to provide a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid and a preparation method thereof. The elastomer has a designable molecular structure, controllable molecular weight, simple process operation, low equipment requirements and good mechanical properties.

[0013] To achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid, which is polymerized by 2,5-furandicarboxylic acid or its ester, a branched long carbon chain dibasic acid, and a diol, and has the following structure:

[0014] Wherein, R1 is selected from C2-C 18 An alkyl group; R2 is selected from C 11 -C 36 A long carbon chain alkyl group containing a branch.

[0015] Preferably, the furandicarboxylate comprises at least one of dimethyl furandicarboxylate, diethyl furandicarboxylate, and dibutyl furandicarboxylate.

[0016] Preferably, the diol includes but is not limited to ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and a mixture of one or more of the long-chain diols in any proportion.

[0017] Preferably, the branched long carbon chain dibasic acid comprises C 11 -C 36 One or a mixture of any proportion of two or more branched long carbon chain dibasic acids.

[0018] The present application also claims a method for preparing a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid, which is used to prepare the polyolefin-like long carbon chain polyester elastomer as described above, comprising the following steps:

[0019] S1. Esterification reaction to form oligomers: Under inert gas protection, furandicarboxylic acid or its esterified product, diol, branched long carbon chain dibasic acid and catalyst are placed in a three-necked flask in appropriate proportions, and the temperature and stirring speed are controlled to react;

[0020] S2. Polycondensation reaction to obtain a polymer: Under vacuum conditions, the above oligomers are subjected to a polycondensation reaction to obtain a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid.

[0021] Preferably, the catalyst in step S1 is selected from at least one of titanium-based catalysts, and the titanium-based catalysts include tetrabutyl titanate, tetraisopropyl titanate, titanium dioxide, and titanium ethylene glycol.

[0022] Preferably, in step 1), the molar ratio of the sum of the 2,5-furandicarboxylic acid or its ester and the branched long carbon chain dicarboxylic acid to the diol is 1.0:1.0-2.0, more preferably 1.0:1.1-1.8.

[0023] Preferably, the molar ratio of 2,5-furandicarboxylic acid or its ester to the branched long carbon chain dibasic acid is 10:90 to 90:10, more preferably 30:70 to 70:30.

[0024] Preferably, the amount of the catalyst is 0.2% of the total molar amount of 2,5-furandicarboxylic acid or its ester and the branched long carbon chain dibasic acid.

[0025] Preferably, the reaction temperature in step S1 is 160-240° C., and the reaction time is 2-4 h; the reaction temperature in step S2 is 200-280° C., the reaction time is 2-4 h, and the reaction vacuum degree is 150-250 Pa.

[0026] More preferably, the reaction temperature in step S1 is 180-220° C., and the reaction time is 2.5-3 h; the reaction temperature in step S2 is 220-260° C., the reaction time is 2.5-3 h, and the reaction vacuum degree is 180-220 Pa.

[0027] Preferably, the reaction in step S1 is carried out under the protection of an inert gas, which means that nitrogen is introduced three times and then the nitrogen is introduced at a constant speed.

[0028] Preferably, in step S1, when the amount of water generated by the reaction collected in the condensed portion reaches more than 90-95% of the theoretical amount of water, the esterification reaction is completed.

[0029] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0030] 1. The thermoplastic polyester elastomer prepared by the present invention can effectively design the molecular structure and control the molecular weight, thereby optimizing its melt crystallization, mechanical properties, barrier properties, etc.

[0031] 2. The raw material 2,5-furandicarboxylic acid used in the present invention is a platform chemical derived from biomass. It is an aromatic diacid monomer, environmentally friendly, and widely available.

[0032] 3. The catalyst used in the present invention can be used not only as a catalyst for esterification (transesterification) reaction, but also as a catalyst for polycondensation reaction. It can be added once during the reaction process, making the experimental operation simple and safe, and the synthesis efficiency high;

[0033] 4. The present invention adopts the melt polycondensation method, which does not require a solvent, has a high concentration of reactants, and the product after polymerization is in a molten state and can be directly processed. The operation is simple and easy to control, the energy consumption is significantly reduced, and the production efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, a brief introduction is given below to the drawings required for use in the specific embodiments or the description of the prior art. Obviously, some of the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] FIG1 is a Fourier transform infrared spectroscopy FTIR curve of the 2,5-furandicarboxylic acid polyester elastomer in Example 1, wherein the abscissa represents the wave number and the ordinate represents the transmittance;

[0036] FIG2 is a differential scanning calorimetry (DSC) curve of the 2,5-furandicarboxylic acid polyester elastomer in Example 1, wherein the abscissa represents temperature and the ordinate represents heat flow;

[0037] Figure 3 is an engineering stress-strain curve of the 2,5-furandicarboxylic acid polyester elastomer in Example 1, where the abscissa is the elongation at break and the ordinate is the tensile strength;

[0038] FIG4 is a dynamic mechanical thermal analysis DMTA curve of the 2,5-furandicarboxylic acid polyester elastomer in Example 1, wherein the abscissa represents temperature and the ordinate represents elastic modulus.

[0039] FIG5 is an X-ray diffraction analysis XRD curve of the 2,5-furandicarboxylic acid polyester elastomer in Example 1, wherein the abscissa represents the diffraction angle and the ordinate represents the diffraction intensity. DETAILED DESCRIPTION

[0040] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0041] Unless otherwise specified, the raw materials and catalysts used in the examples of this application were purchased from commercial sources. 2,5-Furandicarboxylic acid or its esters, diols, and branched long-chain dicarboxylic acids were obtained from MacLean Biochemical Technology Co., Ltd., and the catalyst was purchased from Titan Technology Co., Ltd.

[0042] Example 1

[0043] First, 0.06 mol of 2,5-furandicarboxylic acid and 0.1 mol of dimer acid were added to a three-necked flask equipped with a mechanical stirrer, a nitrogen inlet, and a condenser. 0.288 mol of 1,4-butanediol was then added, and 0.00032 mol of tetrabutyl titanate was used as the catalyst. The flask was placed in an oil bath and, under a nitrogen atmosphere, gradually heated to 180°C to initiate the reaction. The reaction continued at 180°C for 1 hour, 200°C for 0.5 hour, and 220°C for 1 hour. When the amount of water generated by the reaction, collected by condensation, reached more than 90% of the theoretical amount, the reaction system was switched to a vacuum environment and continued. In the second stage, polycondensation was carried out under reduced pressure at 250 Pa for 1 hour. The temperature was then raised to 240°C for 1 hour, and finally to 260°C for 1 hour. The product exhibited spherical spinning, at which point the reaction was stopped and discharged. The product was then dried under vacuum at 50°C for 12 hours to obtain the final product.

[0044] As can be seen from Figures 1 to 5, the intrinsic viscosity of the final product obtained in this example is 0.89 dL / g, the number average molecular weight measured by gel permeation chromatography is 3.21×104, the glass transition temperature is -45.26°C, the tensile strength of the spline is 3.04 MPa, the tensile modulus is 3.58 MPa, and the elongation at break is 1018.52%.

[0045] Example 2

[0046] First, 0.1 mol of 2,5-furandicarboxylic acid and 0.1 mol of dimer acid were added to a three-necked flask equipped with a mechanical stirrer, a nitrogen inlet, and a condenser. 0.36 mol of 1,4-butanediol was then added, and 0.0004 mol of tetrabutyl titanate was used as a catalyst. The flask was placed in an oil bath and, under a nitrogen atmosphere, gradually heated to 180°C to initiate the reaction. The reaction continued at 180°C for 1 hour, 200°C for 1 hour, and 220°C for 1 hour. When the amount of water generated by the reaction, collected by condensation, reached over 90% of the theoretical amount, the reaction system was switched to a vacuum environment and continued. In the second stage, polycondensation was carried out under reduced pressure at 250 Pa for 1 hour. The temperature was then raised to 240°C for 1 hour, and finally to 260°C for 1.5 hours. The product exhibited spooling, at which point the reaction was stopped and discharged. The product was then dried under vacuum at 50°C for 12 hours to obtain the final product.

[0047] The final product obtained in this example has an intrinsic viscosity of 1.1 dL / g, a number average molecular weight of 6.36×104 as measured by gel permeation chromatography, a glass transition temperature of -39.86°C, a melting point of 98.05°C, a strip tensile strength of 9.22 MPa, a tensile modulus of 5.24 MPa, and an elongation at break of 1372.52%.

[0048] Example 3

[0049] First, 0.12 mol of 2,5-furandicarboxylic acid and 0.08 mol of dimer acid were added to a three-necked flask equipped with a mechanical stirrer, a nitrogen inlet, and a condenser. 0.36 mol of 1,4-butanediol was then added, and 0.0004 mol of tetrabutyl titanate was used as a catalyst. The flask was placed in an oil bath and, under a nitrogen atmosphere, gradually heated to 180°C to initiate the reaction. The reaction continued at 180°C for 1 hour, 200°C for 1.5 hours, and 220°C for 1 hour. When the amount of water generated by the reaction, collected from the condensate, reached over 90% of the theoretical amount, the reaction system was switched to a vacuum environment and continued. In the second stage, polycondensation was carried out under reduced pressure and vacuum at 200 Pa for 1 hour. The temperature was then raised to 240°C for 1 hour, and finally to 260°C for 1.5 hours. The product exhibited spherical spinning, at which point the reaction was stopped and discharged. The product was then dried under vacuum at 50°C for 12 hours to obtain the final product.

[0050] The final product obtained in this example has an intrinsic viscosity of 0.85 dL / g, a number average molecular weight of 4.51×104 as measured by gel permeation chromatography, a glass transition temperature of -35.1°C, a melting point of 125.63°C, a tensile strength of 21 MPa, a tensile modulus of 11 MPa, and an elongation at break of 1127%.

[0051] Example 4

[0052] First, 0.14 mol of 2,5-furandicarboxylic acid and 0.06 mol of dimer acid were added to a three-necked flask equipped with a mechanical stirrer, a nitrogen inlet, and a condenser. 0.36 mol of 1,4-butanediol was then added, and 0.0004 mol of tetrabutyl titanate was used as a catalyst. The flask was placed in an oil bath and, under a nitrogen atmosphere, gradually heated to 180°C to initiate the reaction. The reaction continued at 180°C for 1 hour, 200°C for 1.5 hours, and 220°C for 1 hour. When the amount of water generated by the reaction, collected from the condensate, reached over 90% of the theoretical amount, the reaction system was switched to a vacuum environment and continued. In the second stage, polycondensation was carried out under reduced pressure and vacuum at 200 Pa for 1 hour. The temperature was then raised to 240°C for 1 hour, and finally to 260°C for 1.5 hours. The product exhibited spherical ...

[0053] The final product obtained in this example has an intrinsic viscosity of 0.79 dL / g, a number average molecular weight of 5.27×104 as measured by gel permeation chromatography, a glass transition temperature of -28.38°C, a melting point of 145.05°C, a tensile strength of 33 MPa, a tensile modulus of 44 MPa, and an elongation at break of 854%.

[0054] Example 5

[0055] First, 0.1 mol of 2,5-furandicarboxylic acid and 0.1 mol of dimer acid were added to a three-necked flask equipped with a mechanical stirrer, a nitrogen inlet, and a condenser. 0.36 mol of 1,4-butanediol was then added, and 0.0004 mol of titanium ethylene glycol was used as a catalyst. The flask was placed in an oil bath and, under a nitrogen atmosphere, gradually heated to 180°C to initiate the reaction. The reaction continued at 180°C for 1 hour, 200°C for 1 hour, and 220°C for 1 hour. When the amount of water generated by the reaction, collected by condensation, reached over 90% of the theoretical amount, the reaction system was switched to a vacuum environment and continued. In the second stage, polycondensation was carried out under reduced pressure at 220 Pa for 1 hour. The temperature was then raised to 240°C for 2 hours, and finally to 260°C for 1 hour. The product exhibited spooling, at which point the reaction was stopped and discharged. The product was then dried under vacuum at 50°C for 12 hours to obtain the final product.

[0056] The final product obtained in this example has an intrinsic viscosity of 0.82 dL / g, a number average molecular weight of 3.36×104 as measured by gel permeation chromatography, a glass transition temperature of -33.86°C, a melting point of 78.05°C, a strip tensile strength of 7.24 MPa, a tensile modulus of 3.74 MPa, and an elongation at break of 972.52%.

[0057] Example 6

[0058] First, 0.1 mol of 2,5-furandicarboxylic acid and 0.1 mol of dimer acid were added to a three-necked flask equipped with a mechanical stirrer, a nitrogen inlet, and a condenser. 0.3 mol of 1,6-hexanediol was then added, and 0.000384 mol of tetrabutyl titanate was used as the catalyst. The flask was placed in an oil bath and, under a nitrogen atmosphere, gradually heated to 180°C to initiate the reaction. The reaction continued at 180°C for 1 hour, 200°C for 0.5 hour, and 220°C for 1 hour. When the amount of water generated by the reaction, collected from the condensate, reached over 90% of the theoretical amount, the reaction system was switched to a vacuum environment and continued. In the second stage, polycondensation was carried out under reduced pressure at 250 Pa for 1 hour. The temperature was then raised to 240°C for 1 hour, and finally to 260°C for 1.5 hours. The product exhibited spooling, at which point the reaction was stopped and discharged. The product was then dried under vacuum at 50°C for 12 hours to obtain the final product.

[0059] The final product obtained in this example has an intrinsic viscosity of 0.85 dL / g, a number average molecular weight of 5.36×104 as measured by gel permeation chromatography, a glass transition temperature of -35.1°C, a melting point of 101.63°C, a strip tensile strength of 10.89 MPa, a tensile modulus of 7.46 MPa, and an elongation at break of 1157.2%.

[0060] Example 7

[0061] First, 0.1 mol of 2,5-furandicarboxylic acid and 0.1 mol of dimer acid were added to a three-necked flask equipped with a mechanical stirrer, a nitrogen inlet, and a condenser. 0.3523 mol of 1,10-decanediol was then added, and 0.000458 mol of tetrabutyl titanate was used as the catalyst. The flask was placed in an oil bath and, under a nitrogen atmosphere, gradually heated to 180°C to initiate the reaction. The reaction continued at 180°C for 1 hour, 200°C for 1 hour, and 220°C for 1 hour. When the amount of water generated by the reaction, collected by condensation, reached over 90% of the theoretical amount, the reaction system was switched to a vacuum environment and continued. In the second stage, polycondensation was carried out under reduced pressure and vacuum at 250 Pa for 1 hour. The temperature was then raised to 240°C for 1 hour, then to 240°C for 0.5 hour, and finally at 260°C for 1 hour. If the product exhibited swirl, the reaction was stopped and discharged. The product was then dried at 50°C under vacuum for 12 h to obtain the final product.

[0062] The final product obtained in this example has an intrinsic viscosity of 0.93 dL / g, a number average molecular weight of 6.12×104 as measured by gel permeation chromatography, a glass transition temperature of -30.58°C, a melting point of 136°C, a strip tensile strength of 21.52 MPa, a tensile modulus of 11.12 MPa, and an elongation at break of 1180.18%.

[0063] Example 8

[0064] First, 0.1 mol of 2,5-furandicarboxylic acid and 0.1 mol of dimer acid were added to a three-necked flask equipped with a mechanical stirrer, a nitrogen inlet, and a condenser. 0.203 mol of 1,12-dodecanediol was then added, and 0.000506 mol of tetrabutyl titanate was used as the catalyst. The flask was placed in an oil bath and, under a nitrogen atmosphere, gradually heated to 160°C to initiate the reaction. The reaction continued at 160°C for 1 hour, 180°C for 1 hour, and 200°C for 1 hour. When the amount of water generated by the reaction, collected by condensation, reached more than 90% of the theoretical amount, the reaction system was switched to a vacuum environment and continued. In the second stage, polycondensation was carried out under reduced pressure and vacuum at 250 Pa for 1 hour. The temperature was then raised to 220°C for 1 hour, then to 240°C for 1 hour, and finally at 260°C for 0.5 hour. The product exhibited swirl, at which point the reaction was stopped and discharged. The product was then dried at 50°C under vacuum for 12 h to obtain the final product.

[0065] The final product obtained in this example has an intrinsic viscosity of 0.98 dL / g, a number average molecular weight of 5.73×104 as measured by gel permeation chromatography, a glass transition temperature of -28.38°C, a melting point of 145.05°C, a tensile strength of 32.55 MPa, a tensile modulus of 43.55 MPa, and an elongation at break of 1201.63%.

[0066] Example 9

[0067] First, 0.1 mol of 2,5-furandicarboxylic acid and 0.1 mol of dimer acid were added to a three-necked flask equipped with a mechanical stirrer, a nitrogen inlet, and a condenser. 0.202 mol of 1,18-octadecanediol was then added, and 0.0004 mol of tetrabutyl titanate was used as a catalyst. The flask was placed in an oil bath and, under a nitrogen atmosphere, gradually heated to 160°C to initiate the reaction. The reaction continued at 160°C for 1 hour, 180°C for 1 hour, and 200°C for 1 hour. When the amount of water generated by the reaction, collected from the condensate, reached over 90% of the theoretical amount, the reaction system was switched to a vacuum environment and continued. In the second stage, polycondensation was carried out under reduced pressure and vacuum at 200 Pa for 1 hour. The temperature was then raised to 220°C for 1 hour, then to 240°C for 0.5 hour, and finally at 260°C for 0.5 hour. If the product began to spin around the paddle, the reaction was stopped and discharged. The product was then dried at 50°C under vacuum for 12 h to obtain the final product.

[0068] The final product obtained in this example has an intrinsic viscosity of 0.86 dL / g, a number average molecular weight of 6.01×104 as measured by gel permeation chromatography, a glass transition temperature of -42.36°C, a melting point of 78.28°C, a strip tensile strength of 4.64 MPa, a tensile modulus of 2.27 MPa, and an elongation at break of 1258.57%.

[0069] Comparative Example 1

[0070] First, 0.1 mol of 2,5-furandicarboxylic acid and 0.1 mol of succinic acid were added to a three-necked flask equipped with a mechanical stirrer, a nitrogen inlet, and a condenser. 0.36 mol of 1,4-butanediol was then added, and 0.0004 mol of tetrabutyl titanate was used as a catalyst. The flask was placed in an oil bath and, under a nitrogen atmosphere, gradually heated to 180°C to initiate the reaction. The reaction continued at 180°C for 1 hour, 200°C for 1 hour, and 220°C for 1 hour. When the amount of water generated by the reaction, collected by condensation, reached more than 90% of the theoretical amount, the reaction system was switched to a vacuum environment and continued. In the second stage, polycondensation was carried out under reduced pressure and vacuum at 180 Pa for 1 hour. The temperature was then raised to 240°C for 1 hour, and then to 260°C for 1.5 hours. If the product exhibited spooling, the reaction was stopped and discharged. The product was then dried under vacuum at 50°C for 12 hours to obtain the final product.

[0071] The final product obtained in this comparative example has an intrinsic viscosity of 1.02 dL / g, a number average molecular weight of 5.08×10 4 as measured by gel permeation chromatography, a glass transition temperature of -4.87°C, a strip tensile strength of 23 MPa, a tensile modulus of 48 MPa, and an elongation at break of 1069%.

[0072] As is apparent from Examples 1-4, adjusting the ratio of the soft and hard segments allows for the production of high-molecular-weight 2,5-furandicarboxylate-based thermoplastic polyester elastomers with varying tensile strengths and elongations at break. These elastomers exhibit excellent, controllable mechanical properties, with tensile strengths ranging from 3.04 to 33 MPa and elongations at break ranging from 854 to 1372.52%.

[0073] By comparing Example 2 with Comparative Example 1, it can be concluded that copolymerization with dimer acid can improve the toughness and ductility of polyester, and there is an optimal dimer acid addition amount. Among them, when the soft and hard segment ratio is 1:1, the elongation at break is as high as 1372%. Too high a dimer acid content will reduce the strength and elongation of the copolyester.

[0074] It can be seen from Examples 2 and 5 that by changing the type of polymerization catalyst, poly-2,5-furandicarboxylate-based thermoplastic polyester elastomers with different molecular weights can be obtained, thereby affecting the tensile strength, elongation at break, thermal properties, etc. of the elastomer.

[0075] It can be concluded from Examples 1-4 and 6, 7, 8 and 9 that different types of poly-2,5-furandicarboxylate-based thermoplastic polyester elastomers can be obtained by changing the type of diol reaction monomer.

[0076] In the above, the product testing and characterization methods used in Examples 1-9 and Comparative Example 1 of the present invention are as follows:

[0077] Intrinsic viscosity test method: The intrinsic viscosity of the copolyester was measured using an NCY-4 automatic viscometer from Shanghai Starda Co., Ltd. The solvent used was a 1:1 phenol / 1,1,2,2-tetrachloroethane mixture, and an Ubbelohde viscometer with an inner diameter of 0.84 mm. The test was conducted in a constant temperature water bath at (25±0.05)°C.

[0078] Molecular weight test method: The molecular weight of the sample was determined by a Waters 1515 gel permeation chromatograph, using an Agilent PLgel 5 μm MIXED-C column, tetrahydrofuran as the mobile phase, a flow rate of 1 mL / min, and polystyrene as the standard.

[0079] Melting and crystallization temperature testing methods: A TA DSC25 differential scanning calorimeter (USA) was used to study the thermal properties of the copolyester. Under a nitrogen atmosphere, the sample was heated from 30°C to 200°C at a rate of 50°C / min, then held at 200°C for 5 minutes to eliminate thermal history. Subsequently, the temperature was decreased to -70°C at a rate of 10°C / min and held at -70°C for 5 minutes. Finally, the sample was heated again to 200°C at a rate of 10°C / min. Curves from the first and second heating processes were recorded for analysis of thermal behavior.

[0080] Mechanical Properties: The tensile properties of the copolyester were tested using a universal testing machine, an Instron 3367 from the United States. The copolymer was heat-pressed into a 1mm thick film, which was then cut into dumbbell-shaped strips. The samples were allowed to stand at room temperature for a period of time before being tensile tested at a speed of 50mm / min. Each sample was tested at least five times.

[0081] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid, characterized in that: It is polymerized from 2,5-furandicarboxylic acid or its ester, long carbon chain dibasic acid with branched chains, and diols. The structure is as follows: Wherein, R1 is selected from C2-C 18 An alkyl group; R2 is selected from C 11 -C 36 A long carbon chain alkyl group containing a branch.

2. The biomass-based 2,5-furandicarboxylic acid-based long carbon chain polyester elastomer according to claim 1, characterized in that: The furandicarboxylate comprises at least one of dimethyl furandicarboxylate, diethyl furandicarboxylate and dibutyl furandicarboxylate.

3. The biomass-based 2,5-furandicarboxylic acid-based long carbon chain polyester elastomer according to claim 1, characterized in that: The diols include but are not limited to ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and a mixture of one or more of the long-chain diols in any proportion.

4. The biomass-based 2,5-furandicarboxylic acid-based long carbon chain polyester elastomer according to claim 1, characterized in that: The branched long carbon chain dibasic acid includes C 11 -C 36 One or a mixture of any proportion of two or more branched long carbon chain dibasic acids.

5. A method for preparing a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid, characterized in that: The method for preparing the polyolefin-like long carbon chain polyester elastomer according to any one of claims 1 to 4 comprises the following steps: S1. Esterification reaction to form oligomers: Under inert gas protection, furandicarboxylic acid or its esterified product, diol, branched long carbon chain dibasic acid and catalyst are placed in a three-necked flask in appropriate proportions, and the temperature and stirring speed are controlled to react; S2. Polycondensation reaction to obtain a polymer: Under vacuum conditions, the above oligomers are subjected to a polycondensation reaction to obtain a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid.

6. The method for preparing a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid according to claim 5, characterized in that: The catalyst in step S1 is selected from at least one of titanium-based catalysts, and the titanium-based catalysts include tetrabutyl titanate, tetraisopropyl titanate, titanium dioxide, and titanium ethylene glycol.

7. The method for preparing a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid according to claim 5, characterized in that: In step 1), the molar ratio of the sum of the 2,5-furandicarboxylic acid or its ester and the branched long carbon chain dibasic acid to the diol is 1.0:1.0-2.

0.

8. The method for preparing a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid according to claim 5, characterized in that: The molar ratio of 2,5-furandicarboxylic acid or its ester to the branched long carbon chain dibasic acid is 10:90 to 90:

10.

9. The method for preparing a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid according to claim 8, characterized in that: The amount of the catalyst is 0.2% of the total molar amount of 2,5-furandicarboxylic acid or its ester and the branched long carbon chain dibasic acid.

10. The method for preparing a branched long carbon chain polyester elastomer based on biomass-based 2,5-furandicarboxylic acid according to claim 8, characterized in that: The reaction temperature in step S1 is 160-240° C., and the reaction time is 2-4 hours; the reaction temperature in step S2 is 200-280° C., and the reaction time is 2-4 hours, and the reaction vacuum degree is 150-250 Pa.

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