A biomimetic cellulose-based elastomer and methods of making and self-healing thereof

Abstract

This invention provides a biomimetic cellulose-based elastomer, its preparation method, and a self-healing method, belonging to the field of polymer elastomer technology. First, this invention constructs a polyacrylamide-cellulose composite gel network. Through induction with an inducing solution, the polyacrylamide molecular chains are induced to change from an extended state to a coiled state, encapsulating cellulose molecules and rigid fillers, macroscopically manifesting as a transformation from gel to elastomer. The coiling and entanglement of the polyacrylamide molecular chains with cellulose enhances the interfacial forces between the cellulose molecular chains, thereby improving the elasticity and strength of the elastomer. The addition of rigid fillers improves the compressive stress and puncture resistance of the elastomer. The induction solution induces a reversible change in the state of the polyacrylamide molecular chains; applying a small amount of water allows the coiled polyacrylamide molecular chains to re-unwind, restoring the gel state. The self-healing capability is achieved through the dynamic chemical bonding of the gel state.

Description

Technical Field

[0001] This invention belongs to the field of polymer elastomer technology, specifically relating to a biomimetic cellulose-based elastomer and its preparation method and self-healing method. Background Technology

[0002] Traditional elastic protective materials have good cushioning performance, flexibility and energy absorption capacity, and are widely used in fields such as cushioning and shock absorption, flexible protection, wearable devices and engineering protection.

[0003] Currently, commercially available elastomer materials mainly include petroleum-based polymers such as polyurethane, silicone rubber, and thermoplastic elastomers. While these materials possess good processing and mechanical properties, they generally suffer from issues such as non-renewable raw materials, difficulty in degradation after disposal, and high energy consumption during production. Moreover, under high-strain compression, impact, or puncture conditions, traditional elastomers are prone to problems such as localized structural damage, insufficient energy dissipation, and performance degradation after deformation recovery, limiting their application in the field of high-performance flexible protection.

[0004] Cellulose, as a natural biomass polymer, is widely available, renewable, biodegradable, and biocompatible, and has been extensively used in the preparation and research of bio-based elastomers in recent years. However, the preparation of existing cellulose-based elastomers faces many challenges: on the one hand, due to the limited interfacial interactions between cellulose molecular chains, the internal network structure of the elastomer lacks stability, resulting in poor compressive strength, impact resistance, and puncture resistance, and local structural damage is difficult to heal; on the other hand, existing preparation methods usually rely on complex cross-linking systems, high-temperature and high-pressure conditions, or multi-step chemical processing, which are characterized by complex processes, high energy consumption, and difficulty in large-scale production. Summary of the Invention

[0005] The purpose of this invention is to provide a biomimetic cellulose-based elastomer, its preparation method, and its self-healing method. The preparation method provided by this invention is simple, energy-efficient, and yields a cellulose-based elastomer with excellent mechanical properties and self-healing capabilities.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a method for preparing a biomimetic cellulose-based elastomer, comprising the following steps: Cellulose, rigid filler, acrylamide, initiator, crosslinking agent and water are mixed to obtain a precursor mixture; The precursor mixture was subjected to a polymerization reaction to obtain a cellulose-based gel. The cellulose-based gel was subjected to induced displacement in an induction solution to obtain a biomimetic cellulose-based elastomer. The induction solution is an organic solvent or a mixture of an organic solvent and water, wherein the mass content of the organic solvent in the mixture is not less than 70%; the organic solvent includes one or more of low-carbon alcohols, acetone and tetrahydrofuran; the low-carbon alcohol is a C1-C4 alcohol.

[0007] Preferably, the mass content of acrylamide in the precursor mixture is 10-20%.

[0008] Preferably, the mass ratio of cellulose, rigid filler and acrylamide is (0.1~5):(0.1~5):100.

[0009] Preferably, the rigid filler includes one or more of diatomaceous earth, kaolin, bentonite, montmorillonite, and synthetic silica.

[0010] Preferably, the cellulose is fibrous and has a diameter of 5 nm to 100 μm.

[0011] Preferably, the polymerization reaction is carried out at a temperature of 60-70°C for 1-3 hours.

[0012] Preferably, the volume ratio of the induction solution to the cellulose-based gel is (5~100):1.

[0013] Preferably, the temperature for inducing the displacement is 0~60℃ and the time is 1~48h.

[0014] The present invention also provides a biomimetic cellulose-based elastomer prepared by the preparation method described in the above technical solution.

[0015] The present invention also provides a self-healing method for the biomimetic cellulose-based elastomer described in the above technical solution, comprising: adding water to the damaged interface of the biomimetic cellulose-based elastomer to cause the damaged interface to swell and come into contact with each other to form a gel; immersing the obtained product in an induction solution for induced displacement to complete self-healing.

[0016] This invention provides a method for preparing a biomimetic cellulose-based elastomer, comprising the following steps: mixing cellulose, rigid filler, acrylamide, initiator, crosslinking agent, and water to obtain a precursor mixture; subjecting the precursor mixture to a polymerization reaction to obtain a cellulose-based gel; and inducing displacement of the cellulose-based gel in an induction solution to obtain a biomimetic cellulose-based elastomer; wherein the induction solution is an organic solvent or a mixture of an organic solvent and water, and the mass content of the organic solvent in the mixture is not less than 70%; the organic solvent includes one or more of low-carbon alcohols, acetone, and tetrahydrofuran; and the low-carbon alcohol is a C1-C4 alcohol. This invention first constructs a polyacrylamide-cellulose composite gel network. An inducing solution induces the polyacrylamide molecular chains to change from an extended state to a coiled state, encapsulating cellulose molecules and rigid fillers, macroscopically transforming the gel into an elastomer. The coiling and entanglement of the polyacrylamide molecular chains with cellulose increases the interfacial forces between the cellulose molecular chains, thereby improving the elasticity and strength of the elastomer. The addition of rigid fillers enhances the compressive stress and puncture resistance of the elastomer. The inducing solution causes a reversible change in the state of the polyacrylamide molecular chains; applying a small amount of water allows the coiled polyacrylamide molecular chains to re-extension, restoring the gel state. The dynamic chemical bonding within the gel state enables self-healing capabilities. The results of the examples show that the preparation method provided by this invention is simple and under mild conditions; the resulting elastomer can recover from 95% compression and 5 times elongation, exhibits a puncture resistance of 300 mJ, and a compressive impact force of 75 MPa; it possesses self-healing capabilities, and the tensile stress after self-healing can still reach 1.0 MPa. Attached Figure Description

[0017] Figure 1 This is a schematic diagram simulating continuous production of the preparation method in the embodiments of the present invention; Figure 2 The following is a flowchart of the preparation method and self-healing process in the embodiments of the present invention; Figure 3 Here is a photograph of the biomimetic cellulose-based elastomer obtained in Example 2 of this invention; Figure 4 SEM images of cellulose-based gel and biomimetic cellulose-based elastomer obtained in Example 1 of this invention; Figure 5 The rotational rheological curves of cellulose-based gel and biomimetic cellulose-based elastomer obtained in Example 1 of the present invention are shown below. Figure 6 This is a compression test diagram of the biomimetic cellulose-based elastomer obtained in Example 1 of the present invention; Figure 7 The tensile test diagram of the biomimetic cellulose-based elastomer obtained in Example 1 of the present invention is shown. Figure 8The compressive stress-strain curves of different elastomers in Test Example 4 of this invention are shown. Figure 9 The tensile stress-strain curves of different elastomers in Test Example 4 of this invention are shown. Figure 10 This is a stress comparison diagram of different elastomers in Test Example 4 of the present invention; Figure 11 This is a bar chart showing the puncture energy of different elastomers in Test Example 4 of the present invention; Figure 12 This is a photograph of the biomimetic cellulose-based elastomer obtained in Example 1 of Test Example 4 of the present invention to test its puncture resistance. Figure 13 The energy dissipation curve of the biomimetic cellulose-based elastomer obtained in Example 1 of this invention is shown in the cycle test. Figure 14 The stress-strain curve of the biomimetic cellulose-based elastomer obtained in Example 1 of this invention is shown in the impact test. Figure 15 This is a schematic diagram of the self-healing process of the biomimetic cellulose-based elastomer obtained in Example 1 of the present invention; Figure 16 The tensile stress-strain curve of the biomimetic cellulose-based elastomer obtained in Example 1 of this invention after self-healing is shown. Figure 17 The image shows the compressive stress-strain curve of the biomimetic cellulose-based elastomer obtained in Example 1 of this invention after self-healing. Figure 18 The tensile stress-strain curves of the biomimetic cellulose-based elastomer obtained in Example 1 of this invention before and after liquid nitrogen immersion are shown. Detailed Implementation

[0018] All raw materials used in this invention are not particularly limited in their source; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.

[0019] There are no particular restrictions on the purity of any of the raw materials used in this invention. However, this invention preferably uses raw materials of industrial purity or conventional purity in the field of polymer elastomers.

[0020] This invention provides a method for preparing a biomimetic cellulose-based elastomer, comprising the following steps: Cellulose, rigid filler, acrylamide, initiator, crosslinking agent and water are mixed to obtain a precursor mixture; The precursor mixture was subjected to a polymerization reaction to obtain a cellulose-based gel. The cellulose-based gel was subjected to induced displacement in an induction solution to obtain a biomimetic cellulose-based elastomer. The induction solution is an organic solvent or a mixture of an organic solvent and water, wherein the mass content of the organic solvent in the mixture is not less than 70%; the organic solvent includes one or more of low-carbon alcohols, acetone and tetrahydrofuran; the low-carbon alcohol is a C1-C4 alcohol.

[0021] The present invention mixes cellulose, rigid filler, acrylamide, initiator, crosslinking agent and water to obtain a precursor mixture.

[0022] In this invention, the cellulose is preferably fibrous, and the diameter of the cellulose is preferably 5 nm to 100 μm, more preferably 100 nm to 10 μm. A diameter within this range facilitates the formation of a composite network with the polyacrylamide molecular chains, further improving the elasticity and strength of the elastomer. This invention does not impose a particular limitation on the length of the cellulose; cellulose of conventional length is sufficient.

[0023] In one embodiment of the present invention, the cellulose may be one or more of pulp cellulose, bamboo cellulose, cotton cellulose, straw cellulose and flax cellulose.

[0024] In this invention, the rigid filler preferably includes one or more of diatomaceous earth, kaolin, bentonite, montmorillonite, and synthetic silica, more preferably diatomaceous earth. These materials all possess good rigidity, which can improve the compressive stress and puncture resistance of the elastomer. In embodiments of this invention, the diatomaceous earth used has a pore size distribution of 5-100 nm.

[0025] In this invention, the preferred mass ratio of cellulose, rigid filler, and acrylamide is (0.1~5):(0.1~5):100, more preferably (0.5~2.5):(0.5~2.5):100. Maintaining the mass ratio of cellulose, rigid filler, and acrylamide within the above range can further improve the elasticity and strength of the elastomer.

[0026] In one embodiment of the present invention, the initiator may be a persulfate, specifically ammonium persulfate, and the amount used may be 0.5% of the mass of acrylamide.

[0027] In one embodiment of the present invention, the crosslinking agent may be N,N'-methylenebisacrylamide, and the amount used may be 0.1% of the mass of acrylamide.

[0028] As one embodiment of the present invention, the mixing may include the following steps: Cellulose was ultrasonically dispersed in water to prepare a 2% cellulose suspension. Rigid packing material is ultrasonically dispersed in water to prepare a 2% packing material suspension; the ultrasonic power can be 50~200W and the time can be 5~30min. Acrylamide is dissolved in water, and a crosslinking agent and dispersant are added to prepare a monomer solution. The mass concentration of acrylamide can be 20%. The cellulose suspension, the filler suspension, and the monomer solution are stirred and mixed to obtain a precursor mixture; the stirring and mixing rate can be 500~1000 rpm, and the stirring and mixing time can be 1 hour; the stirring and mixing can be done by magnetic stirring.

[0029] In this invention, the mass content of acrylamide in the precursor mixture is preferably 10-20%, more preferably 13-16%. A mass content of acrylamide in the precursor mixture within the above range is beneficial for the formation of cellulose gel and subsequent induced displacement.

[0030] After obtaining the precursor mixture, the present invention performs a polymerization reaction on the precursor mixture to obtain a cellulose-based gel.

[0031] In one embodiment of the present invention, the precursor mixture can be vacuum degassed before the polymerization reaction. The present invention does not particularly limit the parameters for the vacuum degassed mixture; conventional parameters in the art can be used to remove air bubbles from the precursor mixture.

[0032] In this invention, the polymerization temperature is preferably 60-70°C, more preferably 65°C. A polymerization temperature within this range is beneficial for the polymerization reaction. The polymerization time is preferably 1-3 hours, more preferably 2 hours. During the polymerization reaction, acrylamide undergoes polymerization under the action of a crosslinking agent and an initiator to form polyacrylamide. When the polymerization parameters are within the above range, the polymerization rate can be increased and the reaction time shortened.

[0033] In one embodiment of the present invention, the precursor mixture can be placed in a polytetrafluoroethylene mold and polymerized in a vacuum oven.

[0034] After obtaining the cellulose-based gel, the present invention performs induced displacement of the cellulose-based gel in an induction solution to obtain a biomimetic cellulose-based elastomer.

[0035] In this invention, the inducing solution is an organic solvent or a mixture of an organic solvent and water; the organic solvent includes one or more of lower alcohols, acetone, and tetrahydrofuran; the lower alcohol is a C1-C4 alcohol. The above-mentioned inducing solution can cause the molecular chains of polyacrylamide to change from stretched to coiled, transforming the cellulose-based gel into an elastomer.

[0036] In this invention, the lower alcohol preferably includes methanol, ethanol, isopropanol or tert-butanol.

[0037] In this invention, the organic solvent content in the mixed solution is not less than 70%, preferably 80-90%. The organic solvent content in the mixed solution is within the above range, which ensures sufficient replacement of water in the cellulose-based gel and guarantees the mechanical properties of the biomimetic cellulose-based elastomer.

[0038] In this invention, the volume ratio of the inducing solution to the cellulose-based gel is preferably (5~100):1, more preferably (10~20):1. The inducing solution can replace the water in the gel and induce the polyacrylamide molecular chains to coil. As the polyacrylamide molecular chains coil, the gel system collapses, extruding the inducing solution to form an elastomer. The volume ratio of the inducing solution to the cellulose-based gel within the above range is beneficial for the inducing solution to replace the water in the gel.

[0039] In this invention, the temperature for inducing displacement is preferably 0~60℃, more preferably 20~30℃; as one embodiment of this invention, the inducing displacement can be carried out at room temperature. Temperatures within the above range can promote the inducing displacement process.

[0040] In this invention, the induced replacement time is preferably 1 to 48 hours, more preferably 12 to 24 hours. A induced replacement time within this range is beneficial for the induced replacement to proceed fully, further improving the elasticity and strength of the elastomer.

[0041] In one embodiment of the present invention, the induction solution can be replaced once during the induced displacement process to improve the efficiency of the induced displacement.

[0042] The preparation method provided by this invention is illustrated in the schematic diagram of a continuous production process, as shown below. Figure 1 As shown, the process includes: mixing various raw materials to obtain a biomimetic cellulose-based elastomer precursor mixture, performing thermal polymerization on a molding device including a heating device to obtain a cellulose-based gel, collecting and reusing the generated water vapor; pulling the molded cellulose-based gel into an ethanol bath device for structural induction design by a dragging device, and then cutting the biomimetic cellulose-based elastomer according to requirements through a cutting process.

[0043] This invention first constructs a polyacrylamide and cellulose composite gel network. An inducing solution induces the polyacrylamide molecular chains to change from an extended state to a coiled state, encapsulating cellulose molecules and rigid fillers, macroscopically transforming the gel into an elastomer. The coiling and entanglement of the polyacrylamide molecular chains with cellulose enhances the interfacial forces between the cellulose molecular chains, thereby improving the elasticity and strength of the elastomer. The addition of rigid fillers improves the compressive stress and puncture resistance of the elastomer. The inducing solution causes a reversible change in the state of the polyacrylamide molecular chains; applying a small amount of water allows the coiled polyacrylamide molecular chains to re-extension, restoring the gel state. This dynamic chemical bonding within the gel state enables self-healing capabilities.

[0044] The present invention also provides a biomimetic cellulose-based elastomer prepared by the preparation method described in the above technical solution.

[0045] The microstructure of the biomimetic cellulose-based elastomer provided by this invention is similar to that of leeches.

[0046] The present invention also provides a self-healing method for the biomimetic cellulose-based elastomer described in the above technical solution, comprising: adding water to the damaged interface of the biomimetic cellulose-based elastomer to cause the damaged interface to swell and come into contact with each other to form a gel; immersing the obtained product in an induction solution for induced displacement to complete self-healing.

[0047] In one embodiment of the present invention, the water can be dripped onto the damaged interface. The present invention does not have a particular limitation on the amount of water used, as long as it is sufficient to cause the damaged interface to swell.

[0048] In an embodiment of the present invention, the preparation and self-healing process flow diagram of the biomimetic cellulose-based elastomer is shown below. Figure 2 As shown, the process includes: mixing cellulose raw materials, diatomaceous earth raw materials, and acrylamide solution, then polymerizing them in an oven to obtain a cellulose-based gel; performing solvent replacement in an 80wt% ethanol solution to obtain a biomimetic cellulose-based elastomer and a mixed solution; the biomimetic cellulose-based elastomer achieves self-healing using water and an 80wt% ethanol solution, exhibiting properties similar to the initial biomimetic cellulose-based elastomer; the mixed solution recovers the ethanol solution through rotary evaporation for recycling.

[0049] The technical solutions of this invention will be clearly and completely described below with reference to the embodiments thereof. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0050] Example 1 A method for preparing a biomimetic cellulose-based elastomer, comprising the following steps: Dried pulp cellulose was ultrasonically dispersed in deionized water at a concentration of 2 wt% to obtain a cellulose suspension; diatomaceous earth was ultrasonically dispersed in deionized water at a concentration of 2 wt% to obtain a diatomaceous earth suspension; an acrylamide aqueous solution (concentration 20 wt%) was prepared, and ammonium persulfate (0.5% of the mass of acrylamide monomer) and N,N'-methylenebisacrylamide (0.1% of the mass of acrylamide monomer) were added to obtain a monomer solution; the above monomer solution, cellulose suspension, and diatomaceous earth suspension were mixed at a mass ratio of 24:5:5 and stirred on a magnetic stirrer for 10 minutes. Stir at 00 rpm for 1 hour to obtain a precursor mixture; transfer the precursor mixture to a polytetrafluoroethylene mold (a cylinder with a diameter of 5 cm and a height of 5 cm), degas under vacuum, and polymerize in a vacuum oven at 65°C for 2 hours to obtain a cellulose-based gel with a diameter of 5 cm and a height of 5 cm; immerse the cellulose-based gel in 5 times the gel volume of an ethanol aqueous solution (ethanol mass fraction of 80%), and place at room temperature (25°C) for 12 hours, replacing the ethanol solution every 6 hours to obtain a biomimetic cellulose-based elastomer with a diameter of 2.5 cm and a height of 2.5 cm, designated B1.

[0051] Example 2 A method for preparing a biomimetic cellulose-based elastomer, the steps are the same as in Example 1, except that a mold with dimensions of 150cm × 50cm × 0.5cm is used, and the resulting biomimetic cellulose-based elastomer has dimensions of 100cm × 25cm × 0.3cm, designated B2. A photograph of the resulting biomimetic cellulose-based elastomer is shown below. Figure 3 As shown.

[0052] Example 3 A method for preparing a biomimetic cellulose-based elastomer, the steps of which are the same as in Example 1, except that the monomer solution, cellulose suspension and diatomaceous earth suspension are mixed in a mass ratio of 20:5:5, and the resulting biomimetic cellulose-based elastomer is designated as B3.

[0053] Example 4 A method for preparing a biomimetic cellulose-based elastomer, the steps are the same as in Example 1, except that an 80% acetone aqueous solution is used for induced displacement, and the resulting biomimetic cellulose-based elastomer is designated as B4.

[0054] Examples 5-7 A method for preparing a biomimetic cellulose-based elastomer, the steps are the same as in Example 1, except that the induction solutions are anhydrous ethanol (Example 5), 80% methanol aqueous solution (Example 6), and 80% isopropanol aqueous solution (Example 7), respectively.

[0055] The resulting elastomers all had a white appearance and good elasticity.

[0056] Comparative Example 1 A method for preparing a cellulose-based gel, the steps of which are the same as in Example 1, except that no induction solution is used for induced displacement.

[0057] The resulting gel was soft and, when tested with a universal tensile testing machine, it broke under a slight pressure of 0.6 MPa, exhibiting low compressive strength.

[0058] Comparative Example 2 A method for preparing a cellulose-based elastomer, the steps are the same as in Example 1, except that diatomaceous earth is omitted.

[0059] The results of testing with a universal tensile testing machine showed that the elastomer had a low compressive stress of only 35.38 MPa and a decreased puncture resistance of only 15.6 N, indicating that the rigid support function of diatomaceous earth is indispensable.

[0060] Comparative Example 3 A method for preparing a cellulose-based elastomer, the steps are the same as in Example 1, except that cellulose is dissolved using a 1-butyl-3-methylimidazolium chloride ionic liquid.

[0061] The resulting product is hard and, when tested with a universal tensile testing machine, has a high tensile strength of up to 18.53 MPa, but lacks elasticity.

[0062] Comparative Examples 4-6 A method for preparing a biomimetic cellulose-based elastomer, the steps are the same as in Example 1, except that the inducing solutions are ethanol aqueous solutions with a mass fraction of 10%, 30%, and 50%, respectively, and the resulting biomimetic cellulose-based elastomers are numbered B5 (Comparative Example 4), B6 ​​(Comparative Example 5), and B7 (Comparative Example 6), respectively.

[0063] The resulting elastomers were still relatively soft, with compressive strengths of 2.31 MPa (B5), 5.62 MPa (B6), and 13.97 MPa (B7), respectively, indicating that no effective induced structure was formed.

[0064] Comparative Examples 7-9 A method for preparing a cellulose-based elastomer, the steps are the same as in Example 1, except that the inducing solutions are 80% hexane suspension, 80% dimethyl sulfoxide solution and 80% glacial acetic acid solution, respectively. The resulting cellulose-based elastomers are numbered B8 (Comparative Example 7), B9 (Comparative Example 8) and B10 (Comparative Example 9), respectively.

[0065] The resulting product was in a gel state with a soft texture and did not form an elastomer, indicating that no induced structure was formed.

[0066] Test Example 1 The cellulose-based gel and biomimetic cellulose-based elastomer in Example 1 were observed using a scanning electron microscope, and the SEM images are shown below. Figure 4 As shown. Figure 4 In the image, the left image is a SEM image of a cellulose-based gel, the middle image is a SEM image of a biomimetic cellulose-based elastomer, and the right image is a SEM image of a leech.

[0067] Depend on Figure 4 It can be seen that the biomimetic cellulose-based elastomer prepared in Example 1 exhibits a porous and dense interwoven structure, similar to the structure of a leech; this indicates that the molecular chains in contact with the induction solution are entangled and have a dense structure, while the molecular chains not in contact with the induction solution are relatively loose and exhibit a porous structure.

[0068] Test Example 2 The cellulose-based gel and biomimetic cellulose-based elastomer in Example 1 were tested using a rotational rheometer, and the rotational rheological curves are shown below. Figure 5 As shown.

[0069] from Figure 5 It can be seen that, within the measured frequency range, the storage modulus and loss modulus of the biomimetic cellulose-based elastomer are both higher than those of the cellulose-based gel. The network stiffness of the biomimetic cellulose-based elastomer is enhanced compared to that of the cellulose-based gel, thus improving its energy dissipation capacity. Furthermore, the larger gap between the storage modulus and loss modulus curves of the biomimetic cellulose-based elastomer highlights its more robust viscoelastic behavior, indicating that the network can effectively alleviate local strain concentration under stress.

[0070] Test Example 3 The biomimetic cellulose-based elastomer obtained in Example 1 was subjected to compression testing using a universal testing machine. The sample was placed between the two pressure plates of the universal testing machine, and a downward force was applied along the principal axis of both end faces of the sample at a rate of 10 mm / min, causing the sample to shorten axially and increase radially, resulting in compressive deformation, until the sample broke or the deformation reached a predetermined value of 95%. The sample size was an elastomer column with a diameter of 2 cm and a height of 2 cm; the testing procedure was as follows: Figure 6 As shown; tensile testing is performed: the specimen is placed between the upper and lower clamps of the universal testing machine, and a tensile force is applied along the longitudinal axis of both end faces of the specimen at a rate of 5 mm / min, causing the specimen to elongate axially and shrink radially, producing tensile deformation until the specimen breaks. The sample size is an elastomer strip of 3.2 cm × 1 cm × 0.3 cm; the testing procedure is as follows. Figure 7 As shown.

[0071] from Figure 6 It can be seen that the biomimetic cellulose-based elastomer obtained in Example 1 can be compressed to 95%; from Figure 7 It can be seen that the biomimetic cellulose-based elastomer obtained in Example 1 can be stretched to 5 times its own length.

[0072] Test Example 4 The biomimetic cellulose-based elastomers obtained in Example 1, as well as foamed ethylene propylene diene monomer (EEPDM, Hebei Yujie Rubber & Plastic Products Co., Ltd.), foamed fluororubber (EFKM, Bopai Rubber & Plastic Technology Nantong Co., Ltd.), foamed nitrile butadiene rubber (ENBR, Hebei Jiexing Rubber & Plastic Sealing Parts Co., Ltd.), foamed silicone rubber (ESiR, Hebei Lidong Rubber & Plastic Products Technology Co., Ltd.), foamed polyurethane (EPU, Qinyang Huayan Trading Co., Ltd.), foamed chloroprene rubber (ECR, Qinghe Yingsen Rubber Products Co., Ltd.), and foamed polyethylene (EPE, Zhoukou Demonstration Zone Yuheng Packaging Materials Firm), underwent compressive stress-strain, tensile stress-strain, and flexural stress tests using a universal testing machine. The specimens were placed on the lower bending support of the universal testing machine, and a downward force was applied along the span of the specimen using the upper indenter at a rate of 10 mm / min, causing the specimen to bend until it broke. The sample size was an elastomer strip of 6 cm × 1 cm × 0.3 cm. Puncture resistance testing was performed using a universal tensile testing machine: The specimen was fixed on the annular clamping device of the universal testing machine, and a force was applied downwards along the thickness direction of the specimen through the puncture needle at a rate of 50 mm / min, causing localized puncture deformation until the specimen was punctured. The sample size was an elastomer piece with a diameter of 5 cm and a thickness of 0.3 cm. The compressive stress-strain curve was obtained as shown below. Figure 8 As shown, the tensile stress-strain curve is as follows: Figure 9 As shown in the figure, a comparison diagram of different stresses is presented. Figure 10 As shown in the bar chart, the puncture energy is as follows: Figure 11 As shown, a physical image of the biomimetic cellulose-based elastomer obtained in Example 1, tested for its puncture resistance, is shown below. Figure 12 As shown. Figure 11 The middle illustration is a photograph of the puncture resistance test.

[0073] from Figure 8 It can be seen that the compressive strength of the biomimetic cellulose-based elastomer obtained in Example 1 is superior to that of other rubber elastomers, reaching 90.23 MPa.

[0074] from Figure 9 It can be seen that the tensile strength of the biomimetic cellulose-based elastomer obtained in Example 1 is better than that of other rubber elastomers, reaching 2.58 MPa.

[0075] from Figure 10 As can be seen, the biomimetic cellulose-based elastomer obtained in Example 1 has high compressive strength, high tensile strength and high flexural strength, all of which are superior to other rubber elastomers, reaching 90.23 MPa, 2.85 MPa and 2.06 MPa respectively.

[0076] from Figure 11It can be seen that the puncture energy of the biomimetic cellulose-based elastomer obtained in Example 1 is superior to that of other rubber elastomers, reaching 304.22 mJ.

[0077] from Figure 12 It can be seen that the biomimetic cellulose-based elastomer obtained in Example 1 can resist puncture well and can recover quickly after testing.

[0078] Test Example 5 The biomimetic cellulose-based elastomer obtained in Example 1 was subjected to cyclic compression tests using a universal tensile testing machine, and the energy dissipation curve was obtained, as shown in the figure. Figure 13 As shown.

[0079] from Figure 13 It can be seen that the biomimetic cellulose-based elastomer obtained in Example 1 exhibits very little change in energy dissipation capacity and damping capacity during cycles of 1, 6, 11, 16, 21, 26, 31, 36, 41, 46, and 51, remaining essentially consistent, indicating that the biomimetic cellulose-based elastomer possesses a stable energy dissipation mechanism.

[0080] Test Example 6 Impact tests were conducted on the biomimetic cellulose-based elastomer obtained in Example 1 using a Hopkinson bar, and the impact stress-strain curves are shown below. Figure 14 As shown, Figure 14 The inset is a photograph of the sample after the impact test.

[0081] from Figure 14 It can be seen that the biomimetic cellulose-based elastomer obtained in Example 1 can withstand impacts at speeds of 5 m / s, 10 m / s, 20 m / s, and 30 m / s and maintain its shape integrity.

[0082] Test Example 7 The biomimetic cellulose-based elastomer obtained in Example 1 was subjected to a self-healing test, and the flowchart is shown below. Figure 15 As shown, the specific process is as follows: 20 ml of distilled water was applied to the healing ends of two elastomer columns with a diameter of 1.5 cm and a length of 2.5 cm, or they were soaked in 20 ml of distilled water for 5 minutes. Then, at room temperature, the healing ends were tightly pressed together, and appropriate compressive force was applied to both ends of the elastomer for fixation. They were then placed in an induction solution and kept close together for 24 hours. Subsequently, their tensile and compressive properties after healing were measured using a universal tensile testing machine.

[0083] Tensile tests were performed on the self-healing biomimetic cellulose-based elastomer, and the tensile stress-strain curves were obtained as follows: Figure 16 As shown; a compression test was performed, and the compression stress-strain curve was obtained, as shown. Figure 17 As shown.

[0084] from Figure 16It can be seen that the self-healing biomimetic cellulose-based elastomer has good tensile properties, with a tensile strength of 1.19 MPa, which is 78.9% of the initial biomimetic cellulose-based elastomer's tensile strength of 1.51 MPa.

[0085] from Figure 17 It can be seen that the self-healing biomimetic cellulose-based elastomer has good compressibility, with a compressive strength of 66.23 MPa, which is 75.0% of the initial biomimetic cellulose-based elastomer's compressive strength of 88.30 MPa.

[0086] Test Example 8 The biomimetic cellulose-based elastomer obtained in Example 1 was subjected to a low-temperature resistance test: The biomimetic cellulose-based elastomer was cut into strips of 3cm × 1cm × 0.3cm, subjected to a tensile test, and then placed in liquid nitrogen at -196℃ for 3 minutes. After removal, it was twisted. Figure 18 As shown, a tensile test was then performed, and the tensile stress-strain curve was obtained as follows. Figure 18 As shown.

[0087] from Figure 18 It can be seen that after being treated with liquid nitrogen, the biomimetic cellulose-based elastomer can still be deformed and bent, and the tensile strength before and after treatment is similar, indicating that the biomimetic cellulose-based elastomer has excellent low-temperature resistance.

[0088] As can be seen from the above embodiments and comparative examples, the preparation method provided by the present invention can obtain a biomimetic cellulose-based elastomer with high compressive strength, high tensile strength, puncture resistance and self-healing ability.

[0089] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing a biomimetic cellulose-based elastomer, comprising the following steps: mixing cellulose, rigid filler, acrylamide, initiator, crosslinking agent and water to obtain a precursor mixture; polymerizing the precursor mixture to obtain a cellulose-based gel; inducing replacement of the cellulose-based gel in an inducing solution to obtain the biomimetic cellulose-based elastomer; the inducing solution is an organic solvent or a mixed solution of an organic solvent and water, the mass content of the organic solvent in the mixed solution is not less than 70%, the organic solvent includes one or more of low-carbon alcohol, acetone and tetrahydrofuran, and the low-carbon alcohol is C1-C4 alcohol.

2. The production method according to claim 1, characterized by, The mass content of acrylamide in the precursor mixture is 10-20%.

3. The production method according to claim 2, characterized by, The mass ratio of the cellulose, the rigid filler and the acrylamide is (0.1-5) :(0.1-5) :

100.

4. The method of claim 1, wherein, The rigid filler includes one or more of diatomite, kaolin, bentonite, montmorillonite and synthetic silicon dioxide.

5. The preparation method according to claim 1, characterized in that, The cellulose is fibrous, and the diameter of the cellulose is 5 nm-100 μm.

6. The method of claim 1, wherein, The temperature of the polymerization is 60-70 ℃, and the time is 1-3 h.

7. The preparation method according to claim 1, characterized in that, The volume ratio of the inducing solution to the cellulose-based gel is (5-100) :

1.

8. The preparation method according to claim 7, characterized in that, The temperature of the inducing replacement is 0-60 ℃, and the time is 1-48 h. 9.The biomimetic cellulose-based elastomer prepared by the method of any one of claims 1-8.

10. The self-healing method of the biomimetic cellulose-based elastomer according to claim 9, characterized in that, comprising: adding water to the damaged interface of the biomimetic cellulose-based elastomer to swell the damaged interface and make them contact with each other to form a gel; and immersing the obtained product in an inducing solution to induce replacement and complete self-healing.

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