A preparation method of recyclable self-repairing elastomer composite material

Abstract

The invention discloses a method for preparing a recyclable self-healing elastomer composite material, belonging to the technical field of multifunctional materials; the preparation method comprises the following steps: (1) weighing component A and adding it to deionized water for ball milling, and then freezing the mixed solution after ball milling to obtain ice cubes, wherein component A is any one of tannic acid, chitosan, dopamine, phosphoric acid, polyethyleneimine and gallic acid; (2) mixing the obtained ice cubes with deionized water and aqueous polyurethane solution, stirring until the ice cubes are completely dissolved, and finally filtering and drying to obtain. The method of the invention solves the problem of agglomeration of component A in a polymer matrix by cross-linking step by step at the solid-liquid interface of water by utilizing the melting of ice, and increases the density of dynamic bonds in the polymer matrix. The obtained recyclable self-healing elastomer composite material has super toughness, wide temperature damping performance, excellent self-healing ability, recyclability and shape memory function.

Description

Technical Field

[0001] The invention relates to the technical field of multifunctional materials, and in particular to a method for preparing a recyclable self-repairing elastomer composite material. Background Art

[0002] Polymer composites have the advantages of light weight, chemical corrosion resistance, and good processing performance, so they are widely used in soft machine smart skin, smart textiles, deployable soft actuators, adsorbents, active pigments, and sensors. However, in practical applications, polymer composites are susceptible to irreversible mechanical damage during use, and their mechanical and thermal properties will degrade. For the development of a sustainable economy, elastomers are encouraged to incorporate self-healing and recyclability to reduce the maintenance cost of composites, extend the service life of composites, and reduce the consumption of raw materials. With the continuous deepening of research, the self-healing effect of self-healing materials has evolved from the earliest exogenous self-healing (one-time self-healing achieved by encapsulating self-healing agents) to endogenous self-healing (achieved by dynamic reversible covalent bonds). Therefore, reversible non-covalent interactions such as hydrogen bonds and coordination bonds have attracted much attention. They can reduce the stimulation and influence of the healing environment on the material and achieve repeated self-healing at room temperature.

[0003] Hydrogen bonds are considered as "master bonding interactions in supramolecular chemistry" due to their high selectivity, orientation, dynamics, adjustability and relatively high strength. Hydrogen bonding interactions are essential for controlling the supramolecular structure of materials and enhancing the stability and damping properties of polymers. They can also act as active triggers to endow materials with responsive behaviors. Therefore, composites prepared by hydrogen bonding crosslinking can improve the self-healing efficiency, recyclability and mechanical properties of composites.

[0004] However, the introduction of a large number of hydrogen bonds will lead to the formation of zero-dimensional agglomerated particles, which are composed of short-chain molecules and molecules with high hydrogen bond density, which will significantly affect the mechanical properties of the material. How to solve the problem of mutual constraints between the self-healing properties and mechanical properties of composite materials, and prepare a wide temperature range damping composite material that can simultaneously have high mechanical properties, high self-healing efficiency, and be recyclable and meet engineering standards is a key issue that needs to be solved in the preparation of high-performance multifunctional composite materials. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a method for preparing a recyclable self-healing elastomer composite material, so as to solve the problem that the self-healing performance and mechanical properties of existing composite materials are mutually restricted, and it is difficult to prepare a wide temperature range damping composite material that has high mechanical properties, high self-healing efficiency, is recyclable, and meets engineering standards.

[0006] The technical solution of the present invention to solve the above technical problems is as follows:

[0007] A method for preparing a recyclable self-repairing elastomer composite material comprises the following steps:

[0008] (1) weighing component A, adding it to deionized water for ball milling, and then freezing the mixed solution after ball milling to obtain ice cubes, wherein component A is any one of tannic acid, chitosan, dopamine, phosphoric acid, polyethyleneimine and gallic acid;

[0009] (2) mixing the ice cubes obtained in step (1) with deionized water and an aqueous polyurethane solution, stirring until the ice cubes are completely dissolved, and finally filtering and drying to obtain the product.

[0010] The beneficial effects of the present invention are as follows: the present invention provides a method for preparing a recyclable self-healing elastomer composite material, wherein ice cubes are obtained by ball milling and freezing component A, and the ice cubes are cross-linked with an aqueous polyurethane solution in deionized water. During the melting of the ice cubes, component A is cross-linked step by step with the amide bonds in the aqueous polyurethane through hydrogen bonds at the solid-liquid interface between deionized water and the ice cubes. Since the melting process of the ice cubes prepared by the component A solution is a process that gradually starts from the outside to the inside, the problem of agglomeration caused by a large amount of hydroxyl groups in component A after directly adding the component A solution is effectively avoided. This method greatly increases the amount of polyhydroxy small molecules introduced into the matrix, effectively increases the hydrogen bond density in the prepared material, and improves the self-healing effect, recyclability and mechanical properties of the material.

[0011] Furthermore, in step (1), the mass volume ratio of component A to deionized water is 3-7 g:80-120 mL.

[0012] Preferably, in step (1), the mass volume ratio of component A to deionized water is 4 g:100 mL.

[0013] Furthermore, the ball milling conditions in step (1) are: intermittent ball milling, rotating for 100-150 minutes and stopping for 8-12 minutes, the ball milling time is 24-36 hours, and the rotation speed is 400-500 rpm.

[0014] Preferably, the ball milling conditions in step (1) are: intermittent ball milling, rotating for 120 minutes and stopping for 10 minutes, the ball milling time is 30 hours, and the rotation speed is 450 rpm.

[0015] The beneficial effect of adopting the above further technical solution is that part of the phenolic hydroxyl groups in tannic acid can be oxidized by intermittent ball milling to prevent the formation of intramolecular hydrogen bonds in the polymer matrix.

[0016] Furthermore, the freezing treatment in step (1) is carried out at a temperature of -50 to -30°C and for a time of 6 to 12 hours.

[0017] Preferably, the freezing treatment in step (1) is carried out at a temperature of -40°C and for a period of 9 hours.

[0018] The beneficial effect of adopting the above further technical solution is: by freezing the component A solution, ice cubes are obtained, which can be gradually melted during the subsequent cross-linking with waterborne polyurethane, thereby avoiding the problem of directly adding component A, resulting in the appearance of a large number of hydroxyl groups and causing component A to agglomerate.

[0019] Furthermore, the solid content of the aqueous polyurethane solution in step (2) is 40-60%.

[0020] Preferably, the solid content of the aqueous polyurethane solution in step (2) is 60%.

[0021] Furthermore, in step (2), the mass volume ratio of ice cubes, aqueous polyurethane solution and deionized water is 30-80 g: 1-3 g: 35-75 mL.

[0022] Preferably, in step (2), the mass volume ratio of ice cubes, aqueous polyurethane solution and deionized water is 52.5 g:2 g:50 mL.

[0023] Furthermore, the volume of the solution and the deionized water before the ice cubes freeze is the same.

[0024] Furthermore, in step (2), the stirring speed is 400-700 rpm; the filtration is performed using a polypropylene filter membrane with a pore size of 0.1-0.45 μm; the drying temperature is 20-30° C., and the drying time is 8-24 h.

[0025] Preferably, the stirring speed in step (2) is 450 rpm; the filtration is performed using a polypropylene filter membrane with a pore size of 0.22 μm; the drying temperature is 25° C. and the drying time is 12 h.

[0026] A recyclable self-repairing elastomer composite material is prepared by adopting the above preparation method.

[0027] The beneficial effects of the present invention are as follows: the recyclable self-healing elastomer composite material prepared by the present invention has super toughness, a wide damping temperature range, excellent self-healing ability, recyclability and shape memory function.

[0028] The above-mentioned recyclable self-healing elastomeric composite material is used in the preparation of soft machine smart skin, smart textiles, deployable soft actuators, adsorbents, active pigments or sensors.

[0029] The present invention has the following beneficial effects:

[0030] (1) The present invention provides a method for interface coordination and cross-linking in the preparation of a recyclable self-healing elastomer composite material. By utilizing the melting of ice and gradually cross-linking at the solid-liquid interface of water, the agglomeration problem of tannic acid in a polymer substrate is solved, and the density of dynamic bonds in the polymer substrate is increased.

[0031] (2) The recyclable self-healing elastomer composite material prepared by the present invention has super toughness, and the toughness can reach 284MJ·m 3 ; Wide damping temperature range The damping temperature range is greater than 80℃, and the loss factor tanδ is greater than 0.3; Excellent self-healing ability, the self-healing efficiency of toughness, stress and strain are 74%, 84% and 88% respectively; Recyclability and shape memory function.

[0032] (3) The preparation process of the method of the present invention is simple, controllable, stable, mild under reaction conditions, and low cost. The overall process is conducive to large-scale industrial processing and provides a new material design concept and idea for high-performance polymer composite materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 The Fourier transform infrared spectra in Experimental Example 1, wherein (a) is tannic acid, and (b) is different melting stages of tannic acid ice cubes;

[0034] Figure 2 The mechanical properties test results of the composite materials prepared in Example 1 and Comparative Example 1 in Test Example 2;

[0035] Figure 3 The damping performance test results of the composite materials prepared in Example 1 and Comparative Example 1 in Test Example 3;

[0036] Figure 4 The self-healing ability test result of the composite material prepared in Example 1 in Test Example 4;

[0037] Figure 5 These are the mechanical property test results of the composite material prepared in Example 1 in Test Example 4 after being subjected to hot pressing and solvent recovery treatments. DETAILED DESCRIPTION

[0038] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples are only used to explain the present invention and are not used to limit the scope of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0039] Embodiment 1:

[0040] A method for preparing a recyclable self-repairing elastomer composite material comprises the following steps:

[0041] (1) Weigh 4 g of tannic acid and put it into a ball mill filled with 100 mL of deionized water. The ball mill was symmetrically placed in a ball mill for ball milling. The ball milling was performed at a speed of 450 rpm for 30 h. The condition of the intermittent ball milling was to stop the ball milling for 10 min after each 120 min rotation.

[0042] (2) The solution after ball milling in step (1) is taken out and frozen at a temperature of -40°C for 9 hours to obtain ice cubes.

[0043] (3) The ice cubes obtained in step (2), the aqueous polyurethane solution (solid content of 60%) and deionized water were mixed in a mass volume ratio of 52.5 g: 2 g: 50 mL, and stirred at a speed of 400 rpm until the ice cubes were completely dissolved. Finally, the mixture was filtered through a polypropylene filter membrane with a pore size of 0.22 μm, and dried at 25° C. for 12 h to obtain a recyclable self-healing elastomer composite material.

[0044] Embodiment 2:

[0045] A method for preparing a recyclable self-repairing elastomer composite material comprises the following steps:

[0046] (1) Weigh 3 g of chitosan and put it into a ball mill filled with 100 mL of deionized water. The ball mill was symmetrically placed in a ball mill for ball milling. The ball milling was performed at a speed of 400 rpm for 36 h. The condition of intermittent ball milling was to stop the ball milling for 10 min after each 120 min rotation.

[0047] (2) The solution after ball milling in step (1) is taken out and frozen at a temperature of -50°C for 6 hours to obtain ice cubes.

[0048] (3) The ice cubes obtained in step (2), the aqueous polyurethane solution (solid content of 60%) and deionized water were mixed in a mass volume ratio of 51.5 g: 1 g: 50 mL, stirred at a speed of 600 rpm until the ice cubes were completely dissolved, and finally filtered through a polypropylene filter membrane with a pore size of 0.22 μm, and dried at 25° C. for 15 h to obtain a recyclable self-healing elastomer composite material.

[0049] Embodiment 3:

[0050] A method for preparing a recyclable self-repairing elastomer composite material comprises the following steps:

[0051] (1) Weigh 7 g of dopamine and put it into a ball mill filled with 100 mL of deionized water. The ball mill was symmetrically placed in a ball mill for ball milling. The ball mill was intermittently milled at a speed of 500 rpm for 24 h. The condition of intermittent ball milling was to stop the ball mill for 10 min after each 120 min rotation.

[0052] (2) The solution after ball milling in step (1) was taken out and frozen at a temperature of -30°C for 12 hours to obtain ice cubes.

[0053] (3) The ice cubes obtained in step (2), the aqueous polyurethane solution (solid content of 60%) and deionized water were mixed in a mass volume ratio of 53.5 g:3 g:50 mL, stirred at a speed of 600 rpm until the ice cubes were completely dissolved, and finally filtered through a polypropylene filter membrane with a pore size of 0.22 μm, and dried at 25° C. for 15 h to obtain a recyclable self-healing elastomer composite material.

[0054] Embodiment 4:

[0055] A method for preparing a recyclable self-repairing elastomer composite material comprises the following steps:

[0056] (1) Weigh 5 g of phosphoric acid and put it into a ball mill filled with 100 mL of deionized water. The ball mill is symmetrically placed in a ball mill for ball milling. The ball mill is intermittently milled at a speed of 450 rpm for 30 h. The condition of intermittent ball milling is to stop the ball mill for 10 min after each 120 min rotation.

[0057] (2) The solution after ball milling in step (1) is taken out and frozen at a temperature of -40°C for 9 hours to obtain ice cubes.

[0058] (3) The ice cubes obtained in step (2), the aqueous polyurethane solution (solid content of 60%) and deionized water were mixed in a mass volume ratio of 52.5 g: 2 g: 50 mL, stirred at a speed of 600 rpm until the ice cubes were completely dissolved, and finally filtered through a polypropylene filter membrane with a pore size of 0.22 μm, and dried at 25° C. for 15 h to obtain a recyclable self-healing elastomer composite material.

[0059] Embodiment 5:

[0060] A method for preparing a recyclable self-repairing elastomer composite material comprises the following steps:

[0061] (1) Weigh 3 g of polyethyleneimine and put it into a ball mill filled with 100 mL of deionized water. The ball mill is symmetrically placed in a ball mill for ball milling. The ball mill is intermittently milled at a speed of 400 rpm for 36 h. The condition of intermittent ball milling is to stop the rotation for 10 min after each 120 min rotation.

[0062] (2) The solution after ball milling in step (1) is taken out and frozen at a temperature of -50°C for 6 hours to obtain ice cubes.

[0063] (3) The ice cubes obtained in step (2), the aqueous polyurethane solution (solid content of 60%) and deionized water were mixed in a mass volume ratio of 51.5 g: 1 g: 50 mL, stirred at a speed of 600 rpm until the ice cubes were completely dissolved, and finally filtered through a polypropylene filter membrane with a pore size of 0.22 μm, and dried at 25° C. for 15 h to obtain a recyclable self-healing elastomer composite material.

[0064] Embodiment 6:

[0065] A method for preparing a recyclable self-repairing elastomer composite material comprises the following steps:

[0066] (1) Weigh 7 g of gallic acid and put it into a ball mill filled with 100 mL of deionized water. The ball mill was symmetrically placed in a ball mill for ball milling. The ball mill was intermittently milled at a speed of 500 rpm for 24 h. The condition of intermittent ball milling was to stop the ball mill for 10 min after each 120 min rotation.

[0067] (2) The solution after ball milling in step (1) was taken out and frozen at a temperature of -30°C for 12 hours to obtain ice cubes.

[0068] (3) The ice cubes obtained in step (2), the aqueous polyurethane solution (solid content of 60%) and deionized water were mixed in a mass volume ratio of 53.5 g:3 g:50 mL, stirred at a speed of 600 rpm until the ice cubes were completely dissolved, and finally filtered through a polypropylene filter membrane with a pore size of 0.22 μm, and dried at 25° C. for 15 h to obtain a recyclable self-healing elastomer composite material.

[0069] Comparative Example 1:

[0070] A method for preparing a composite material comprises the following steps:

[0071] (1) Weigh 5 g of tannic acid and put it into a ball mill filled with 100 mL of deionized water. The ball mill is symmetrically placed in a ball mill for ball milling. The ball milling is performed at a speed of 450 rpm for 30 h. The condition of the intermittent ball milling is to stop the ball milling for 10 min after each 120 min rotation to obtain a tannic acid solution.

[0072] (2) The tannic acid solution, aqueous polyurethane solution (solid content 60%) and deionized water prepared in step (1) were mixed in a mass volume ratio of 50 mL:2 g:50 mL, stirred at a speed of 600 rpm until the ice cubes were completely dissolved, and finally filtered through a polypropylene filter membrane with a pore size of 0.22 μm, and dried at 25° C. for 15 h to obtain a composite material.

[0073] Test Example 1: Fourier Transform Infrared Spectroscopy Test

[0074] Tannic acid and the tannic acid ice cubes prepared in Example 1 were tested by Fourier transform infrared spectroscopy at different melting stages, and the different melting stages were Stage 1 (initial ice cube stage), Stage 1 (second test performed 5 minutes after the first test) and Stage 1 (third test performed 5 minutes after the second test). The experimental results are shown in Figure 1. Figure 1 shown.

[0075] According to the results in the figure, the relative peak intensities of the functional groups of tannic acid are different in different stages. The carbonyl peak (1700cm -1 The relative peak intensity of about 100 nm (about 100 nm) was that in the first stage, no carbonyl peak was detected, a weak carbonyl peak was detected in the second stage, and an obvious carbonyl peak was detected in the third stage. The results show that the functional groups of tannic acid are gradually exposed during the melting of ice cubes. This further proves the feasibility of the present invention to use ice melting to crosslink at the solid-liquid interface.

[0076] Test Example 2: Mechanical Properties Test

[0077] The composite materials obtained in Example 1 and Comparative Example 1 were tested using a tensile testing machine. The experimental results are as follows: Figure 2 shown.

[0078] according to Figure 2 It can be seen from the experimental results that compared with the comparative example 1 without freezing treatment, the recyclable self-healing elastomer composite material prepared in Example 1 of the present invention exhibits higher stress and strain. The main reason is that the present invention solves the agglomeration problem of tannic acid in the polymer substrate by utilizing the melting of ice and cross-linking step by step at the solid-liquid interface of water, thereby increasing the density of dynamic bonds in the polymer substrate, thereby increasing the cross-linking hydrogen bonding force between tannic acid and waterborne polyurethane, and effectively improving the mechanical properties of the prepared composite material.

[0079] Test Example 3: Damping Performance Test

[0080] The loss factor (tan δ) of the composite materials obtained in Example 1 and Comparative Example 1 was tested with a dynamic mechanical analyzer to determine the temperature variation curve. When tan δ>0.3, it indicates that the composite materials have damping properties. The experimental results are as follows: Figure 3 shown.

[0081] according to Figure 3The experimental results show that compared with the comparative example 1 without freezing treatment, the recyclable self-healing elastomer composite material prepared in Example 1 of the present invention exhibits a higher loss factor (tanδ) at 10-90°C, indicating that the composite material has damping performance in this temperature range and has the characteristics of wide temperature range damping performance. However, the composite material prepared in comparative example 1 only exhibits damping performance in the range of about -50 to -20°C and does not have wide temperature range damping performance.

[0082] Test Example 4: Self-healing ability and recyclability

[0083] (1) The composite material prepared in Example 1 was characterized by using a tensile testing machine to test the stress, strain and toughness of the composite material in its initial state and after self-healing (the specimen was completely cut off and the contact section was healed at room temperature for 12 hours). The experimental results are shown in Figure 2. Figure 4 shown.

[0084] according to Figure 4 From the experimental results, it can be seen that the recyclable self-healing elastomer composite material prepared in Example 1 of the present invention exhibits a strong self-healing ability. It is self-healed after the first tensile test. The self-healed composite material still exhibits high stress, strain and toughness, and shows a high self-healing efficiency. The stress change is 83.9% of the original, the strain change is 88.3% of the original, and the toughness change is 73.6% of the original.

[0085] (2) The composite material obtained in Example 1 was characterized by using a tensile testing machine, and the mechanical properties of the composite material in the initial state, the first hot pressing treatment, the second hot pressing treatment, the first solvent recovery and the second solvent recovery were tested; the hot pressing treatment was performed by hot pressing at 100°C for 30 minutes and then cold pressing for 20 minutes, and the solvent recovery used dimethylformamide as the solvent. The experimental results are shown in FIG. Figure 5 shown.

[0086] according to Figure 5 It can be seen from the experimental results that the recyclable self-healing elastomer composite material prepared in Example 1 of the present invention still exhibits high stress and strain after two hot pressing treatments, which reflects the pressure resistance and high temperature resistance of the recyclable self-healing elastomer composite material prepared by the present invention. In addition, the present invention can recycle the prepared composite material by solvent recovery, which can solve the problem that traditional composite materials are inconvenient to recycle and reuse after use, and the mechanical properties of the recycled composite material are reduced.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a recyclable self-repairing elastomer composite material, characterized in that: The following steps are involved: (1) Weighing component A, adding it to deionized water for ball milling, and then freezing the mixed solution after ball milling to obtain ice cubes, wherein component A is any one of tannic acid, chitosan and dopamine; (2) mixing the ice cubes obtained in step (1) with deionized water and an aqueous polyurethane solution, stirring until the ice cubes are completely dissolved, and finally filtering and drying to obtain; The mass volume ratio of component A to deionized water in step (1) is 3-7 g: 80-120 mL; The ball milling conditions in step (1) are: intermittent ball milling, rotating for 100-150 minutes and stopping for 8-12 minutes, the ball milling time is 24-36 hours, and the rotation speed is 400-500 rpm; The solid content of the aqueous polyurethane solution in step (2) is 40-60%; In step (2), the mass volume ratio of ice cubes, aqueous polyurethane solution and deionized water is 30-80 g: 1-3 g: 35-75 mL.

2. The method for preparing the recyclable self-healing elastomer composite material according to claim 1, characterized in that: The freezing treatment in step (1) is carried out at a temperature of -50 to -30 °C and for a period of 6 to 12 h.

3. The method for preparing the recyclable self-healing elastomer composite material according to claim 1, characterized in that: In the step (2), the volume of the solution before the ice cubes freeze is the same as that of the deionized water.

4. The method for preparing the recyclable self-healing elastomer composite material according to claim 1, characterized in that: In the step (2), the stirring speed is 400-700 rpm; the filtration is performed using a polypropylene filter membrane with a pore size of 0.1-0.45 μm; the drying temperature is 20-30°C and the drying time is 8-24 h.

5. A recyclable self-repairing elastomer composite material, characterized in that: The method is prepared by the preparation method according to any one of claims 1 to 4.

6. Use of the recyclable self-healing elastomeric composite material according to claim 5 in the preparation of soft machine intelligent skin, intelligent textiles, deployable soft actuators, adsorbents, active pigments or sensors.

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