Mixed simulated gas gel fiber as well as preparation method and application thereof

Abstract

The invention discloses a mixed gas-imitating gel fiber as well as a preparation method and application thereof, and belongs to the technical field of fiber materials. The mixed gas-imitating gel fiber is prepared from the following components: cellulose dispersion liquid, a silane coupling agent and viscose in a mass ratio of (1-3): (0.2-0.8): (5-10), comprising the following steps: adding sodium hydroxide into a cellulose dispersion liquid, adjusting the pH value to be alkaline, adding viscose and a silane coupling agent, and carrying out ultrasonic stirring to prepare a mixed spinning solution; the mixed spinning solution is extruded into a coagulating bath through a wet spinning device to be drafted, wet fibers are obtained, and the mixed gas-imitating gel fibers are obtained after freeze drying. The aerogel fiber disclosed by the invention has low heat conductivity coefficient, high mechanical strength and extreme temperature resistance, can solve the problem that the densification and porosity of a traditional fiber structure are difficult to balance, and effectively expands the application prospect of the aerogel fiber in the fields of cold protection, warm keeping and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of fiber materials, and in particular to a hybrid bionic gas gel fiber and a preparation method and application thereof, which is suitable for protective applications in extreme temperature environments of -50°C to 300°C. Background Art

[0002] Aerogel fibers, as a fiber material with high porosity, low density, and excellent thermal insulation properties, have important applications in extreme environment protection, flexible electronic devices, and smart textiles. However, traditional inorganic aerogel fibers (such as silica-based) generally have problems such as high brittleness and poor tensile strength (tensile strength <1 MPa), and are prone to breakage and failure under dynamic stress or wide temperature range (-50~300℃).

[0003] To solve the above problems, existing technologies have improved the performance of aerogel fibers by combining biomimetic design with renewable materials. For example, the Beijing Forestry University team used a bubble-ice dual template strategy to construct a Fuller dome-structured nanocellulose aerogel fiber, which achieved a power output of 24 mW·m through the synergistic effect of the CNF skeleton and the polyurethane connection points. -1 ·K -1 The ultra-low thermal conductivity and compression rebound rate of 91% are achieved by the existing technologies. However, the process needs to be combined with chemical vapor deposition (CVD) hydrophobic modification, and the energy consumption and cost still need to be optimized. The oxidized bamboo cellulose / polyvinyl alcohol (PVA) composite aerogel fiber (CNPA) developed by Southwest Forestry University shows stable performance in a wide temperature range of -100~500℃, but its preparation relies on multiple oxidation and ultrasonic treatment, and the hydrophilicity of PVA causes the fiber to swell and deform easily in a humid environment. In summary, the main problems of the existing technologies are: (1) weak interface bonding: cellulose / viscose physical blending relies on hydrogen bonding, and thermal expansion differences at extreme temperatures cause delamination; (2) poor process compatibility: biomimetic structures (such as sand-mortar interlocking) require petroleum-based polymers or complex templates, which are difficult to adapt to bio-based materials; (3) unbalanced pore structure: the fibers prepared by freeze-drying have large pores >100μm, and the thermal insulation performance fluctuates greatly. Summary of the Invention

[0004] Technical problems to be solved: In response to the technical problems existing in the background technology, the present invention provides a hybrid bionic aerogel fiber and its preparation method and application. The aerogel fiber has low thermal conductivity, high mechanical strength and extreme temperature resistance, which can solve the difficult problem of balancing the densification and porosity of traditional fiber structures, and effectively expand the application prospects of aerogel fibers in the fields of cold protection and warmth preservation.

[0005] Technical solution: The hybrid bionic biogel fiber described in the present invention is prepared from the following components: the mass ratio of cellulose dispersion, silane coupling agent and viscose is (1~3): (0.2~0.8): (5~10).

[0006] Preferably, the cellulose dispersion is at least one of bacterial cellulose, carboxylated nanocellulose or cellulose nanofibers.

[0007] Preferably, the silane coupling agent is at least one of bis(triethoxysilyl)ethane, γ-methacryloxypropyltrimethoxysilane or vinyltrimethoxysilane.

[0008] The present invention discloses a method for preparing a hybrid bionic aerogel fiber, comprising the following steps: Step 1: adding sodium hydroxide to the cellulose dispersion to adjust the pH to alkaline, adding viscose and silane coupling agent, and preparing a mixed spinning solution by ultrasonic stirring; Step 2: The mixed spinning solution is extruded into a coagulation bath through a wet spinning device for drawing to obtain wet fibers, which are then freeze-dried to obtain mixed bionic biogel fibers.

[0009] Preferably, the viscose concentration in step 1 is 5-10 wt%.

[0010] Preferably, in step 2, the diameter of the wet spinning needle hole is 0.5-1 mm, and the extrusion rate is 100-500 μL / min.

[0011] Preferably, the coagulation bath is composed of sulfuric acid, sodium sulfate and water in a mass ratio of (5-10):(5-10):(80-90).

[0012] The present invention also discloses an application of a hybrid bionic gas gel fiber in the preparation of extreme environment protective materials, wherein the protective materials include vehicle interiors, cold-proof clothing or outdoor furniture fabrics.

[0013] The present invention provides a hybrid biomimetic aerogel fiber and a preparation method and application thereof, achieving the following technical effects: 1、The cellulose dispersion liquid, silane coupling agent and viscose are mixed to prepare the cellulose dispersion liquid, the cellulose is used as renewable high-performance reinforcing material, the interface combination with the polymer matrix can be improved through chemical modification (such as silane coupling agent grafting), and the viscose fiber is used as the representative of regenerated cellulose fiber, has the advantages of good hygroscopicity, excellent spinnability and low cost, the wet spinning process is mature, the fiber morphology and mechanical property can be regulated by adjusting the coagulation bath condition, the combination of the two has natural compatibility: on the one hand, the rigid skeleton of cellulose can make up for the defect of insufficient modulus of viscose fiber; on the other hand, the flexible network formed in the coagulation regeneration process of viscose spinning solution can provide physical anchoring points for cellulose, simulate the interlocking mechanism of natural ''sand-slurry'' structure, and thus synergistically improve the strength and toughness of the composite fiber and the structural stability, and meet the needs of bio-based raw materials and low energy consumption process; The prepared viscose aerogel fiber has low thermal conductivity, high mechanical strength and extreme temperature resistance, the tensile strength reaches 62.2MPa (comparative pure viscose aerogel fiber: 13.2MPa), the elongation at break at-50 DEG C low temperature is kept >80%; The problem that the traditional fiber structure densification and porosity are difficult to balance can be solved, and the application prospect of viscose aerogel fiber in cold protection and other fields is effectively expanded; 2、The aerogel fiber adopts a biomimetic multi-level interlocking structure, the cellulose nanofiber modified by a silane coupling agent is used as a rigid skeleton (''sand''), and viscose spinning solution is used as a flexible connecting phase (''slurry''), a sand-cement-like interlocking network is constructed through a wet spinning and freeze drying process, and the modulus advantage of cellulose and the flexibility of viscose are utilized to synergistically improve the fiber strength and toughness; 3、The aerogel fiber has interface chemical-physical synergistic reinforcement, the silane coupling agent forms a covalent bond between the cellulose and the viscose matrix, reduces the interface stress concentration at extreme temperature, inhibits delamination and pore collapse, and the porosity retention rate is >90% after high temperature 250 DEG C; 4、The pore structure of the aerogel fiber is controllable, the gradient pore distribution is formed by adjusting the spinning solution concentration, coagulation bath condition and freeze drying parameter, so that the thermal conductivity fluctuation is reduced, the gradient pore structure (pore diameter 50nm~10um) makes the thermal conductivity stable at 18~22mW·m -1 ·K -1 , and the flexibility of the fiber is maintained at the same time; 5、The preparation process is energy-saving and environment-friendly, there is no water organic solvent throughout the process, and the energy consumption is reduced by 40% (compared with the CVD method). BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 It is a preparation flow chart of the mixed biomimetic aerogel fiber of the application; Figure 2 It is a TEM image of the mixed biomimetic aerogel fiber prepared by the application; Figure 3 It is Figure 2 The breaking strength curve of the mixed biomimetic aerogel fiber; Figure 4 For Figure 2 The thermal infrared imaging diagram of the mixed biomimetic aerogel fiber at high temperature (90℃); Figure 5 For Figure 2 The thermal infrared imaging diagram of the mixed biomimetic aerogel fiber at low temperature (-50℃). DETAILED DESCRIPTION

[0015] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the following will be combined with the accompanying drawings to describe the embodiments of the present application in detail. Figure 1-Figure 5 The technical solutions of the embodiments of the present application are described clearly and completely. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the described embodiments of the present application, all other embodiments obtained by those skilled in the art belong to the scope of protection of the present application.

[0016] The present application discloses a kind of mixed biomimetic aerogel fiber, it is prepared from the following components: cellulose dispersion, the mass ratio of silane coupling agent and viscose is (1~3):(0.2~0.8):(5~10);The cellulose dispersion is at least one of bacterial cellulose, carboxylated nanocellulose or cellulose nanofiber;The silane coupling agent is at least one of bis (triethoxysilyl) ethane, γ-methacryloyloxypropyltrimethoxysilane or vinyltrimethoxysilane.

[0017] As Figure 1 The present application discloses a kind of preparation method of mixed biomimetic aerogel fiber, including the following steps: Step 1: sodium hydroxide is added to cellulose dispersion to adjust pH to alkaline, viscose and silane coupling agent are added, and mixed spinning solution is prepared by ultrasonic stirring;Wherein the viscose concentration is 5~10wt%.

[0018] Step 2: the mixed spinning solution is extruded to the coagulation bath by wet spinning device and is drawn, to obtain wet fiber, and mixed biomimetic aerogel fiber is obtained after freeze drying;Wherein, the diameter of wet spinning needle hole is 0.5~1mm, and the extrusion rate is 100~500 μL / min;The coagulation bath is composed of sulfuric acid, sodium sulfate and water according to the mass ratio (5~10):(5~10):(80~90).

[0019] The present application further discloses a kind of mixed biomimetic aerogel fiber in the application of preparing extreme environment protection material, and the protection material includes vehicle interior, cold-weather clothing or outdoor furniture fabric.

[0020] Example 1: A 2 wt% carboxylated nanocellulose dispersion was adjusted to pH 11 with NaOH; 0.5 wt% bis(triethoxysilyl)ethane and 8 wt% viscose were added, and ultrasonic stirring was performed for 30 minutes to prepare a mixed spinning solution. The mixed spinning solution was then added to a wet spinning apparatus and wet-spun at a needle diameter of 0.8 mm and an extrusion rate of 300 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H₂SO₄:Na₂SO₄:H₂O of 5:5:90. The wet fibers were frozen at -50°C for 24 hours and then vacuum-dried to obtain mixed biomimetic biogel fibers with a diameter of 200 μm.

[0021] Example 2: A 1 wt% carboxylated nanocellulose dispersion was adjusted to pH 11 with NaOH; 0.6 wt% bis(triethoxysilyl)ethane and 8 wt% viscose were added, and ultrasonic stirring was performed for 30 minutes to prepare a mixed spinning solution. The mixed spinning solution was then added to a wet spinning apparatus and wet-spun at a needle diameter of 0.5 mm and an extrusion rate of 300 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H2SO4:Na2SO4:H2O = 5:10:90. The wet fibers were frozen at -50°C for 24 hours and then vacuum-dried to obtain mixed biomimetic biogel fibers with a diameter of 200 μm.

[0022] Example 3: A 3 wt% carboxylated nanocellulose dispersion was adjusted to pH 11 with NaOH; 0.6 wt% bis(triethoxysilyl)ethane and 8 wt% viscose were added, and ultrasonic stirring was performed for 30 minutes to prepare a mixed spinning solution. The mixed spinning solution was then added to a wet spinning apparatus and wet-spun at a needle diameter of 0.8 mm and an extrusion rate of 500 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H2SO4:Na2SO4:H2O = 5:10:80. The wet fibers were frozen at -50°C for 24 hours and then vacuum-dried to obtain mixed biomimetic biogel fibers with a diameter of 200 μm.

[0023] Example 4: A 2 wt% carboxylated nanocellulose dispersion was adjusted to pH 11 with NaOH; 0.2 wt% bis(triethoxysilyl)ethane and 8 wt% viscose were added, and ultrasonic stirring was performed for 30 minutes to prepare a mixed spinning solution. The mixed spinning solution was then added to a wet spinning apparatus and wet-spun at a needle diameter of 0.8 mm and an extrusion rate of 100 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H2SO4:Na2SO4:H2O of 10:5:90. The wet fibers were frozen at -50°C for 24 hours and then vacuum-dried to obtain mixed biomimetic biogel fibers with a diameter of 200 μm.

[0024] Example 5: A 2 wt% carboxylated nanocellulose dispersion was adjusted to pH 11 with NaOH; 0.4 wt% bis(triethoxysilyl)ethane and 8 wt% viscose were added, and ultrasonic stirring was performed for 30 min to prepare a mixed spinning solution. The mixed spinning solution was then added to a wet spinning apparatus and wet-spun at a needle diameter of 1.0 mm and an extrusion rate of 300 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H2SO4:Na2SO4:H2O of 10:10:80. The wet fibers were frozen at -50°C for 24 h and then vacuum-dried to obtain mixed biomimetic biogel fibers with a diameter of 200 μm.

[0025] Example 6: A 2 wt% carboxylated nanocellulose dispersion was adjusted to pH 11 with NaOH; 0.8 wt% bis(triethoxysilyl)ethane and 8 wt% viscose were added, and ultrasonic stirring was performed for 30 min to prepare a mixed spinning solution. The mixed spinning solution was added to a wet spinning apparatus and wet-spun at a needle diameter of 1.0 mm and an extrusion rate of 500 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H2SO4:Na2SO4:H2O = 10:10:90. The wet fibers were frozen at -50°C for 24 h and then vacuum-dried to obtain mixed biomimetic biogel fibers with a diameter of 200 μm.

[0026] Example 7: A 2 wt% carboxylated nanocellulose dispersion was adjusted to pH 11 with NaOH; 0.6 wt% bis(triethoxysilyl)ethane and 5 wt% viscose were added, and ultrasonic stirring was performed for 30 min to prepare a mixed spinning solution. The mixed spinning solution was then added to a wet spinning apparatus and wet-spun at a needle diameter of 0.5 mm and an extrusion rate of 500 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H2SO4:Na2SO4:H2O = 5:5:80. The wet fibers were frozen at -50°C for 24 h and then vacuum-dried to obtain mixed biomimetic aerogel fibers with a diameter of 200 μm.

[0027] Example 8: A 2 wt% carboxylated nanocellulose dispersion was adjusted to pH 11 with NaOH; 0.6 wt% bis(triethoxysilyl)ethane and 10 wt% viscose were added, and ultrasonic stirring was performed for 30 minutes to prepare a mixed spinning solution. The mixed spinning solution was added to a wet spinning apparatus and wet-spun at a needle diameter of 0.8 mm and an extrusion rate of 300 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H2SO4:Na2SO4:H2O = 7:7:85. The wet fibers were frozen at -50°C for 24 hours and then vacuum-dried to obtain mixed biomimetic aerogel fibers with a diameter of 200 μm.

[0028] Example 9: A 2 wt% bacterial cellulose dispersion was adjusted to pH 11 with NaOH; 0.6 wt% bis(triethoxysilyl)ethane and 8 wt% viscose were added, and ultrasonic stirring was performed for 30 minutes to prepare a mixed spinning solution. The mixed spinning solution was added to a wet spinning apparatus and wet-spun at a needle diameter of 0.8 mm and an extrusion rate of 300 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H2SO4:Na2SO4:H2O = 5:5:90. The wet fibers were frozen at -50°C for 24 hours and then vacuum-dried to obtain mixed biomimetic biogel fibers with a diameter of 200 μm.

[0029] Example 10: A 2 wt% cellulose nanofiber dispersion was adjusted to pH 11 with NaOH; 0.6 wt% bis(triethoxysilyl)ethane and 8 wt% viscose were added, and ultrasonic stirring was performed for 30 minutes to prepare a mixed spinning solution. The mixed spinning solution was added to a wet spinning apparatus and wet-spun at a needle diameter of 0.8 mm and an extrusion rate of 300 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H2SO4:Na2SO4:H2O = 5:5:90. The wet fibers were frozen at -50°C for 24 hours and then vacuum-dried to obtain mixed biomimetic aerogel fibers with a diameter of 200 μm.

[0030] Example 11: A 2 wt% carboxylated nanocellulose dispersion was adjusted to pH 11 with NaOH; 0.6 wt% γ-methacryloxypropyltrimethoxysilane and 8 wt% viscose were added, and ultrasonic stirring was performed for 30 minutes to prepare a mixed spinning solution. The mixed spinning solution was then added to a wet spinning apparatus and wet-spun at a needle diameter of 0.8 mm and an extrusion rate of 300 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H2SO4:Na2SO4:H2O = 5:5:90. The wet fibers were frozen at -50°C for 24 hours and then vacuum-dried to obtain mixed biomimetic aerogel fibers with a diameter of 200 μm.

[0031] Example 12: A 2 wt% carboxylated nanocellulose dispersion was adjusted to pH 11 with NaOH; 0.6 wt% vinyltrimethoxysilane and 8 wt% viscose were added, and ultrasonic stirring was performed for 30 minutes to prepare a mixed spinning solution. The mixed spinning solution was then added to a wet spinning apparatus and wet-spun at a needle diameter of 0.8 mm and an extrusion rate of 300 μL / min. The fibers were then drawn in a coagulation bath with a mass ratio of H2SO4:Na2SO4:H2O = 5:5:90. The wet fibers were frozen at -50°C for 24 hours and then vacuum-dried to obtain mixed biomimetic aerogel fibers with a diameter of 200 μm.

[0032] Comparative Example 1: Pure viscose aerogel fibers were used as a comparative example. The pure viscose aerogel fibers were commercially available.

[0033] The properties of the bionic aerogel fibers obtained in Examples 1 to 12 and the pure viscose aerogel fibers of Comparative Example 1 were analyzed, as shown in Table 1.

[0034] Table 1 Performance test results of the biomimetic aerogel fibers of Examples 1 to 12 and the pure viscose aerogel fiber of Comparative Example 1: project Tensile strength / MPa <![CDATA[导热系数 / (mW·m -1 ·K -1 )]]> -50℃ Retention rate of elongation at break / % Example 1 62.2 19.1 83 Example 2 52.1 23.6 76 Example 3 53.2 24.2 82 Example 4 56.5 24.5 74 Example 5 59.8 21.5 78 Example 6 53.8 18.6 82 Example 7 48.5 19.0 79 Example 8 66.2 24.5 83 Example 9 55.1 20.4 82 Example 10 54.9 21.5 81 Example 11 54.8 19.6 80 Example 12 55.0 19.4 80 Comparative Example 1 13.2 35.6 42

[0035] As can be seen from Table 1, the tensile strength and -50°C elongation retention rate of the bionic aerogel fiber prepared by the method of the present invention are limitedly improved, and the thermal conductivity is significantly reduced, thereby effectively improving heat conduction in extreme altitude or low temperature environments, thereby maintaining the temperature stability of the human body to a large extent.

[0036] Figure 2 This is an electron microscope image of the bionic aerogel fiber obtained in Example 1. The microstructure of the bionic aerogel fiber presents a bionic "sand-mortar" interlocking structure, and the cellulose skeleton is embedded in the viscose matrix, thereby synergistically improving the strength and structural stability of the composite fiber, taking into account the requirements of bio-based raw materials and low-energy consumption processes; the obtained viscose aerogel fiber has low thermal conductivity, high mechanical strength and extreme temperature resistance, with a tensile strength of 62.2MPa (comparative example pure viscose aerogel fiber: 13.2MPa), and the elongation at break remains >80% at a low temperature of -50°C; it can solve the problem of balancing the densification and porosity of traditional fiber structures, and effectively expand the application prospects of viscose aerogel fibers in cold protection and other fields.

[0037] Figure 3 This is the breaking strength curve of the hybrid bionic aerogel fiber, which is significantly improved compared with pure viscose aerogel fiber.

[0038] Figure 4 and Figure 5 These are thermal infrared images under high and low temperature conditions respectively. The thermal insulation uniformity of the bionic aerogel fiber is limitedly improved, and there are no local cold spots under low temperature conditions. The temperature difference between the aerogel fiber fabric and the background hot stage in extreme environments is greater than 20°C, proving that it has excellent thermal insulation properties.

[0039] Application Example 1: The bionic aerogel fiber obtained in Example 1 is woven into a fabric for preparing polar cold-proof clothing. In a -50°C environment (wind speed 10 m / s), the inner surface temperature of the polar cold-proof clothing is 8.2°C higher than that of conventional materials.

[0040] Application Example 2: The bionic gas gel fiber obtained in Example 1 is used as a tent fabric interlayer to prepare a mountaineering tent; in a -50°C environment (wind speed 10m / s), the inner surface temperature of the polar cold-proof clothing is 10.5°C higher than that of conventional materials.

[0041] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A hybrid bionic aerogel fiber, characterized in that: The invention is prepared from the following components: the mass ratio of cellulose dispersion, silane coupling agent and viscose is (1-3): (0.2-0.8): (5-10).

2. The hybrid bionic biogel fiber according to claim 1, characterized in that: The cellulose dispersion is at least one of bacterial cellulose, carboxylated nanocellulose or cellulose nanofiber.

3. The hybrid bionic biogel fiber according to claim 1, characterized in that: The silane coupling agent is at least one of bis(triethoxysilyl)ethane, γ-methacryloxypropyltrimethoxysilane or vinyltrimethoxysilane.

4. A method for preparing the hybrid biomimetic biogel fiber according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: adding sodium hydroxide to the cellulose dispersion to adjust the pH to alkaline, adding viscose and silane coupling agent, and preparing a mixed spinning solution by ultrasonic stirring; Step 2: The mixed spinning solution is extruded into a coagulation bath through a wet spinning device for drawing to obtain wet fibers, which are then freeze-dried to obtain mixed bionic biogel fibers.

5. The method for preparing the hybrid bionic biogel fiber according to claim 1, characterized in that: The viscose concentration in step 1 is 5-10wt%.

6. The method for preparing the hybrid biomimetic biogel fiber according to claim 1, characterized in that: In step 2, the diameter of the wet spinning needle hole is 0.5~1mm, and the extrusion rate is 100~500μL / min.

7. The method for preparing the hybrid bionic biogel fiber according to claim 1, characterized in that: The coagulation bath is composed of sulfuric acid, sodium sulfate and water in a mass ratio of (5-10):(5-10):(80-90).

8. Use of the hybrid bionic gas gel fiber according to any one of claims 1 to 3 in preparing extreme environment protective materials, wherein the protective materials include vehicle interiors, cold-proof clothing or outdoor furniture fabrics.

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