Gypsum / cellulose aerogel fiber and preparation method thereof
By using hemihydrate gypsum, dimethyl sulfoxide and ionic liquid solvent systems in the preparation of aerogel fibers, cellulose is dissolved and gypsum/cellulose aerogel fibers are prepared by normal pressure drying, which solves the problems of high preparation cost, complex process and poor mechanical properties, and achieves a low-cost and high-efficiency preparation method and excellent mechanical properties.
Patent Information
- Application Number
- CN202510405651.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-02
- Publication Date
- 2025-06-20
AI Technical Summary
The preparation cost of aerogel fiber materials is high, the process is complex and the mechanical properties are poor.
After dispersing hemihydrate gypsum in dimethyl sulfoxide solution and adding ionic liquid, cellulose cotton pulp is dissolved to prepare hemihydrate gypsum/cellulose spinning stock solution, and then gypsum/cellulose aerogel fibers are prepared by normal pressure drying.
It reduces the preparation cost, simplifies the process flow, and improves the mechanical properties and thermal insulation properties of the fibers.
Smart Images
Figure CN120174499A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of preparing functional fibers for material modification, and particularly relates to a gypsum / cellulose aerogel fiber and a preparation method thereof. Background Art
[0002] Aerogel is a solid material mainly composed of gas, usually composed of a pore structure formed by air filled in a gel network. Aerogel Fibers are an extended form of aerogel materials, which are aerogel materials with fiber morphology prepared by spinning and other methods, having extremely low density and extremely high specific surface area, and having excellent heat insulation, sound absorption, light transmittance and other properties. Due to the potential applications of aerogel fibers in many fields, it has become a research hotspot in the field of materials science and engineering in recent years.
[0003] Although aerogel fibers show good application prospects in many fields, they still face some challenges. The preparation cost of aerogel materials is relatively high, their raw materials (such as silica, silicon nitride, etc.) are expensive, and the energy consumption in the manufacturing process is large. The synthesis of aerogel usually requires the sol-gel method or other high-temperature and high-pressure processes, especially special processes such as supercritical drying, with high technical costs, large energy consumption and complex processes, which greatly limits its large-scale application. While maintaining the ultra-light characteristics, aerogel fibers are brittle, easy to powder, lack flexibility and drapability, and their mechanical properties (such as tensile strength, toughness, etc.) are often poor. Although aerogel has a relatively high specific strength, due to the high porosity of its internal structure, its compressive, tensile and other properties are poor. Therefore, developing low-cost and high-efficiency preparation methods and improving the strength and toughness of aerogel fibers are the key points of future research. Summary of the Invention
[0004] The main purpose of the present invention is to provide a gypsum / cellulose aerogel fiber and a preparation method thereof, aiming to solve the problems of high preparation cost, complex process and poor mechanical properties of aerogel fiber materials.
[0005] To achieve the above object, in the first aspect, the present invention provides a preparation method of a gypsum / cellulose aerogel fiber, and the preparation method includes the following steps:
[0006] Disperse hemihydrate gypsum in a dimethyl sulfoxide solution to obtain a hemihydrate gypsum / DMSO dispersion;
[0007] Add an ionic liquid to the hemihydrate gypsum / DMSO dispersion and stir to obtain a hemihydrate gypsum / DMSO / ionic liquid mixed solution;
[0008] Dissolve cellulose cotton pulp in the hemihydrate gypsum / DMSO / ionic liquid mixed solution to obtain a hemihydrate gypsum cellulose spinning dope;
[0009] The semi-hydrated gypsum cellulose spinning dope is extruded into a coagulation bath, and after coagulation molding, semi-hydrated gypsum / cellulose hydrogel fibers are obtained.
[0010] After the semi-hydrated gypsum / cellulose hydrogel fibers are subjected to replacement treatment, they are naturally dried to obtain gypsum / cellulose aerogel fibers.
[0011] Furthermore, the cellulose cotton pulp is fragments obtained by pulverizing cellulose cotton paper pulp.
[0012] Furthermore, the cellulose cotton paper pulp has a degree of polymerization of 400-800 and a fragment length of 0.1-0.5 mm.
[0013] Furthermore, in the process of dissolving the cellulose cotton pulp in the semi-hydrated gypsum / DMSO / ionic liquid mixed solution to obtain the semi-hydrated gypsum cellulose spinning dope, the mass fraction of semi-hydrated gypsum is 5-80% of the cellulose solid content.
[0014] Furthermore, in the process of adding an ionic liquid to the gypsum / DMSO dispersion and stirring to obtain the semi-hydrated gypsum / DMSO / ionic liquid mixed solution, the ionic liquid: dimethyl sulfoxide = 1:4.
[0015] Furthermore, the ionic liquid is one of 1-ethyl-3-methylimidazolium acetate ([EMIM]Ac), 1-allyl-3-methylimidazolium chloride ([AMIM]Cl), 1-allyl-3-methylimidazolium acetate ([AMIM]Ac), and 1-butyl-3-methylimidazolium acetate ([BMIM]Ac).
[0016] Furthermore, in the process of dissolving the cellulose cotton pulp in the semi-hydrated gypsum / DMSO / ionic liquid mixed solution to obtain the semi-hydrated gypsum cellulose spinning dope, the dissolution temperature is 75-80 °C and the dissolution time is 2-12 h.
[0017] Furthermore, in the replacement treatment, the number of replacement times is 6 times, and each time is 30 min.
[0018] Furthermore, the natural drying time is 1-2 h.
[0019] In a second aspect, the present invention provides a gypsum / cellulose aerogel fiber, which is prepared by the preparation method of a gypsum / cellulose aerogel described in the first aspect.
[0020] The present invention has the following advantages:
[0021] (1) Considering that hemihydrate gypsum has unique crystallization properties, its crystallization upon contact with water can form a hard network skeleton, and the formed skeleton has tiny pores, having certain heat insulation and heat preservation properties. Therefore, the gypsum / cellulose aerogel fiber prepared by dissolving cellulose pulp in a DMSO / ionic liquid mixed solution containing hemihydrate gypsum and then through the atmospheric drying method has good pore structure, excellent mechanical properties, and heat insulation and heat preservation properties compared with the cellulose aerogel fiber prepared by the traditional atmospheric drying method.
[0022] (2) In the present invention, hemihydrate gypsum is first mixed with a dimethyl sulfoxide (DMSO) solution, and after being dispersed evenly, an ionic liquid is added to obtain a hemihydrate gypsum / DMSO / ionic liquid mixed solution. Then, cellulose cotton pulp is dissolved in the hemihydrate gypsum / DMSO / ionic liquid mixed solution, reducing the agglomeration of hemihydrate gypsum, thereby avoiding clogging of the spinneret during the wet spinning process and facilitating the smooth progress of the wet spinning process.
[0023] (3) The present invention uses a dimethyl sulfoxide / ionic liquid solvent system to dissolve cellulose cotton pulp. Compared with the traditional solvent system, it requires a lower dissolution temperature, a shorter dissolution time, and a higher dissolution efficiency. Moreover, the introduction of dimethyl sulfoxide reduces the viscosity of the spinning dope, facilitating the smooth progress of wet spinning.
[0024] (4) Compared with the traditional preparation method, the preparation method of the gypsum / cellulose aerogel fiber provided by the present invention has a short preparation time and a simple preparation process. Description of the Drawings
[0025] Figure 1 is a flowchart for preparing a gypsum / cellulose aerogel fiber provided in Examples 2 - 3 of the present invention.
[0026] Figure 2 is a morphological diagram of three spinning solutions prepared in Examples 1 - 3 of the present invention. Among them, (a) is a cellulose solution without adding hemihydrate gypsum, (b) is a cellulose solution adding hemihydrate gypsum with a content of 10% of the cellulose solid content, and (c) is a cellulose solution adding hemihydrate gypsum with a content of 20% of the cellulose solid content.
[0027] Figure 3 is a shear rheological test diagram of three spinning solutions prepared in Examples 1 - 3 of the present invention. Among them, (a) is a frequency sweep diagram of a cellulose solution without adding hemihydrate gypsum, (b) is a frequency sweep diagram of a cellulose solution adding hemihydrate gypsum with a content of 10% of the cellulose solid content, (c) is a frequency sweep diagram of a cellulose solution adding hemihydrate gypsum with a content of 20% of the cellulose solid content, and (d) is a strain rate - viscosity diagram of the three spinning solutions.
[0028] Figure 4SEM image of the gypsum / cellulose aerogel fiber prepared in Example 2 of the present invention.
[0029] Figure 5 Micro-CT visualization image of the gypsum / cellulose aerogel fiber prepared in Example 2 of the present invention.
[0030] Figure 6 Mechanical property diagrams of the cellulose aerogel fibers prepared in Examples 1-3, 6-8 of the present invention.
[0031] The realization, functional features and advantages of the object of the present invention will be further described with reference to the embodiments and the accompanying drawings. Detailed implementation manners
[0032] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.
[0033] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) in the embodiments of the present invention, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.
[0034] In addition, if there are descriptions such as "first" and "second" in the embodiments of the present invention, the descriptions of "first" and "second" are only for descriptive purposes, and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the meaning of "and / or" appearing throughout the text includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution where A and B are satisfied simultaneously. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present invention.
[0035] Hemihydrate gypsum has unique crystallization properties. When it encounters water, it can form a network skeleton, enabling the aerogel fiber to form a good pore structure through atmospheric drying in a short time.
[0036] Based on this, the present invention provides a method for preparing gypsum / cellulose aerogel fibers, and the method comprises the following steps:
[0037] Disperse hemihydrate gypsum in a dimethyl sulfoxide solution to obtain a hemihydrate gypsum / DMSO dispersion;
[0038] Add an ionic liquid to the hemihydrate gypsum / DMSO dispersion and stir to obtain a hemihydrate gypsum / DMSO / ionic liquid mixed solution;
[0039] Dissolve cellulose cotton pulp in the hemihydrate gypsum / DMSO / ionic liquid mixed solution to obtain a hemihydrate gypsum cellulose spinning dope;
[0040] Extrude the hemihydrate gypsum cellulose spinning dope into a coagulation bath, and after coagulation and shaping, wash it with water to obtain hemihydrate gypsum / cellulose hydrogel fibers;
[0041] After performing a replacement treatment on the hemihydrate gypsum / cellulose hydrogel fibers, air-dry them naturally to obtain gypsum / cellulose aerogel fibers.
[0042] In this embodiment, the gypsum / cellulose aerogel fibers prepared by dissolving cellulose cotton pulp in a hemihydrate gypsum / DMSO / ionic liquid mixed solution and then through an atmospheric drying method have a good pore structure and excellent mechanical properties.
[0043] Further, the cellulose cotton pulp is fragments obtained by pulverizing cellulose cotton paper pulp.
[0044] In this embodiment, it is easier to dissolve the cellulose cotton paper pulp after pulverizing it into cellulose cotton pulp, which is beneficial to the wet spinning process.
[0045] Further, the degree of polymerization of the cellulose cotton paper pulp is 400 - 800, and the fragment length is 0.1 - 0.5 mm.
[0046] In this embodiment, the cellulose cotton paper pulp with a degree of polymerization of 400 - 800 has optimal solubility, reactivity, mechanical strength, and processing efficiency, which can improve the preparation efficiency; the cellulose cotton pulp with a fragment length of 0.1 - 0.5 mm can improve the dissolution efficiency.
[0047] Further, in the step of dissolving cellulose cotton pulp in the hemihydrate gypsum / DMSO / ionic liquid mixed solution to obtain a hemihydrate gypsum cellulose spinning dope, the mass fraction of hemihydrate gypsum is 5 - 80% of the cellulose solid content.
[0048] In this embodiment, adding hemihydrate gypsum with a mass fraction of 5 - 80% of the cellulose solid content improves the viscosity and spinning efficiency of the spinning dope.
[0049] Further, an ionic liquid is added to the gypsum / DMSO dispersion, and after stirring, a hemihydrate gypsum / DMSO / ionic liquid mixed solution is obtained, where the ionic liquid:DMSO = 1:4.
[0050] In this example, a hemihydrate gypsum / DMSO / ionic liquid mixed solution with a ratio of ionic liquid to DMSO of 1:4 is used to dissolve cellulose cotton pulp. The required dissolution temperature is lower, the dissolution time is shorter, and the dissolution efficiency is higher.
[0051] Further, the ionic liquid is one of 1-ethyl-3-methylimidazolium acetate, 1-allyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium acetate, and 1-butyl-3-methylimidazolium acetate.
[0052] In this example, any one of 1-ethyl-3-methylimidazolium acetate, 1-allyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium acetate, and 1-butyl-3-methylimidazolium acetate mixed with DMSO can improve the dissolution efficiency of cellulose cotton pulp.
[0053] Further, when dissolving cellulose cotton pulp in the hemihydrate gypsum / DMSO / ionic liquid mixed solution to obtain a hemihydrate gypsum cellulose spinning dope, the dissolution temperature is 75 - 80 °C, and the dissolution time is 2 - 12 h.
[0054] In this example, with a dissolution temperature of 75 - 80 °C and a dissolution time of 2 - 12 h, the cellulose cotton pulp can be better dissolved in the hemihydrate gypsum / DMSO / ionic liquid mixed solution.
[0055] Further, in the replacement treatment, the number of replacement times is 6 times, and each time is 30 min.
[0056] In this example, with 6 replacement times and each time being 30 min, the original solvent can be replaced to a greater extent, preventing structural collapse during atmospheric drying.
[0057] Further, the natural drying time is 1 - 2 h.
[0058] In this example, natural drying for 1 - 2 h can reduce the residual solvent and obtain a gypsum / cellulose aerogel fiber with better material properties.
[0059] Example 1
[0060] A preparation method of a cellulose aerogel fiber, which is carried out according to the following steps:
[0061] (1) Crush the cellulose cotton pulp with a degree of polymerization of 400 - 800 into fragments with a length of 0.1 - 0.5 mm, and dry them in an oven at 60 °C for 12 hours.
[0062] (2) Add 7.72 g of dimethyl sulfoxide solution and 1.93 g of 1-ethyl-3-methylimidazolium acetate to a beaker, stir with a magnetic stirrer, and heat to 80 °C to obtain a dimethyl sulfoxide / ionic liquid mixed solution.
[0063] (3) Put 0.35 g of cellulose cotton pulp into the dimethyl sulfoxide / ionic liquid mixed solution, keep the temperature at 80 °C, and continuously stir for 2 h to obtain a transparent cellulose spinning dope.
[0064] (4) Add the cellulose spinning dope into a syringe, extrude it through a push pump, use water as the coagulation bath, the air gap between the needle and the coagulation bath is 10 mm, the perfusion flow rate is 0.2 ml / m, and spin cellulose filaments through the push pump at room temperature. After solidification and molding, cellulose hydrogel fibers are obtained.
[0065] (5) Replace the cellulose hydrogel fibers with acetone, 30 min each time, for 3 times, and then replace them with pentane, 30 min each time, for 3 times.
[0066] (6) Naturally dry the cellulose hydrogel fibers after replacement at room temperature for 1 - 2 h to obtain cellulose aerogel fibers.
[0067] Example 2
[0068] A preparation method of gypsum / cellulose aerogel fibers, which is carried out according to the following steps:
[0069] (1) Crush the cellulose cotton pulp with a degree of polymerization of 400 - 800 into fragments with a length of 0.1 - 0.5 mm, and dry them in an oven at 60 °C for 12 hours.
[0070] (2) Weigh 7.72 g of dimethyl sulfoxide solution and 0.035 g of hemihydrate gypsum, add the hemihydrate gypsum to the dimethyl sulfoxide solution while stirring, and continuously stir for 30 min to obtain a uniformly dispersed hemihydrate gypsum / dimethyl sulfoxide solution.
[0071] (3) Weigh 1.93 g of 1-ethyl-3-methylimidazolium acetate, add it to the hemihydrate gypsum / dimethyl sulfoxide solution, heat to 80 °C, and stir to obtain a hemihydrate gypsum / dimethyl sulfoxide / ionic liquid mixed solution.
[0072] (4) Put 0.35 g of cellulose cotton pulp into the hemihydrate gypsum / dimethyl sulfoxide / ionic liquid mixed solution, keep the temperature at 80 °C, and continuously stir for 2 h to obtain a hemihydrate gypsum cellulose spinning dope with a hemihydrate gypsum content of 5%.
[0073] (5) Add the hemihydrate gypsum cellulose spinning dope into a syringe, extrude it through a push pump, use water as the coagulation bath, the air gap between the needle and the coagulation bath is 10 mm, the perfusion flow rate is 0.2 ml / m, and spin cellulose filaments through the push pump at room temperature. After coagulation and forming, hemihydrate gypsum / cellulose hydrogel fibers are obtained.
[0074] (6) Replace the hemihydrate gypsum / cellulose hydrogel fibers with acetone, 30 minutes each time, for 3 times, and then replace them with pentane, 30 minutes each time, for 3 times.
[0075] (7) Naturally dry the replaced hemihydrate gypsum / cellulose hydrogel fibers at room temperature for 1 - 2 h to obtain gypsum / cellulose aerogel fibers.
[0076] Example 3
[0077] A preparation method of gypsum / cellulose aerogel fibers, compared with Example 2, the difference is that the content of hemihydrate gypsum in step (2) is changed to 20% of the cellulose solid content. Except for the above differences, other operations are the same and will not be elaborated here.
[0078] Examples 4 - 5
[0079] A preparation method of gypsum / cellulose aerogel fibers, compared with Example 2, the difference is that in Example 4, the content of hemihydrate gypsum in step (2) is changed to 5% of the cellulose solid content, and in Example 5, the content of hemihydrate gypsum in step (2) is changed to 80% of the cellulose solid content. Except for the above differences, other operations are the same and will not be elaborated here.
[0080] In Example 4, adding hemihydrate gypsum with a content of 5% of the cellulose solid content can moderately increase the viscosity of the spinning dope and improve the spinnability of the spinning dope, reduce broken filaments, and the prepared gypsum / cellulose aerogel fibers have a smooth surface and enhanced mechanical properties.
[0081] In Example 5, adding hemihydrate gypsum with a content of 80% of the cellulose solid content can shorten the atmospheric pressure drying time of the gypsum / cellulose hydrogel fibers, and the prepared gypsum / cellulose aerogel fibers have better mechanical properties.
[0082] Example 6
[0083] A preparation method of cellulose aerogel fibers, the preparation method is carried out according to the following steps:
[0084] (1) Crush the cellulose cotton pulp with a polymerization degree of 400 - 800 into fragments with a length of 0.1 - 0.5 mm, and dry them in an oven at 60 °C for 12 hours.
[0085] (2) Add 7.72 g of dimethyl sulfoxide solution and 1.93 g of 1-ethyl-3-methylimidazolium acetate into a beaker, stir with a magnetic stirrer, and heat at 80 °C to obtain a dimethyl sulfoxide / ionic liquid mixed solution.
[0086] (3) Put 0.35 g of cellulose cotton pulp into the dimethyl sulfoxide / ionic liquid mixed solution, keep the temperature at 80 °C, and continuously stir for 2 h to obtain a transparent cellulose spinning dope.
[0087] (4) Add the cellulose spinning dope into a syringe, extrude it through a push pump, use water as the coagulation bath, the air gap between the needle and the coagulation bath is 10 mm, the perfusion flow rate is 0.2 ml / m, and spin out cellulose filaments through the push pump at room temperature. After solidification and molding, cellulose hydrogel fibers are obtained.
[0088] (5) Replace the cellulose hydrogel fibers with acetone, 30 min each time, for 3 times, and then replace them with pentane, 30 min each time, for 3 times.
[0089] (6) Dry the cellulose hydrogel fibers after replacement by supercritical carbon dioxide drying method to obtain cellulose aerogel fibers.
[0090] Example 7
[0091] A preparation method of gypsum / cellulose aerogel fibers, the preparation method is carried out according to the following steps:
[0092] (1) Crush cellulose cotton pulp with a polymerization degree of 400 - 800 into fragments with a length of 0.1 - 0.5 mm, and dry in an oven at 60 °C for 12 hours.
[0093] (2) Weigh 7.72 g of dimethyl sulfoxide solution and 0.035 g of hemihydrate gypsum, add hemihydrate gypsum to the dimethyl sulfoxide solution while stirring, and continuously stir for 30 min to obtain a uniformly dispersed hemihydrate gypsum / dimethyl sulfoxide solution.
[0094] (3) Weigh 1.93 g of 1-ethyl-3-methylimidazolium acetate, add it to the hemihydrate gypsum / dimethyl sulfoxide solution, heat at 80 °C, and stir to obtain a hemihydrate gypsum / dimethyl sulfoxide / ionic liquid mixed solution.
[0095] (4) Put 0.35 g of cellulose cotton pulp into the hemihydrate gypsum / dimethyl sulfoxide / ionic liquid mixed solution, keep the temperature at 80 °C, and continuously stir for 2 h to obtain a hemihydrate gypsum cellulose spinning dope with a hemihydrate gypsum content of 10%.
[0096] (5) Add the hemihydrate gypsum cellulose spinning dope into a syringe, extrude it through a pushing pump, use water as the coagulation bath, the air gap between the needle and the coagulation bath is 10 mm, the perfusion flow rate is 0.2 ml / m, and spin out the cellulose filaments through the pushing pump at room temperature. After solidification and molding, hemihydrate gypsum / cellulose hydrogel fibers are obtained.
[0097] (6) Replace the hemihydrate gypsum / cellulose hydrogel fibers with acetone, 30 minutes each time, for 3 times, and then replace them with pentane, 30 minutes each time, for 3 times.
[0098] (7) Dry the hemihydrate gypsum / cellulose hydrogel fibers after replacement by the supercritical carbon dioxide drying method to obtain gypsum / cellulose aerogel fibers.
[0099] Example 8
[0100] A method for preparing gypsum / cellulose aerogel fibers, compared with Example 6, the difference is that the content of hemihydrate gypsum in step (2) is changed to 20% of the cellulose solid content. Except for the above differences, other operations are the same and will not be elaborated here.
[0101] Please refer to Figure 1 , Figure 1 , which is a flowchart for preparing gypsum / aerogel fibers provided in Examples 2-3 of the present invention. The preparation process includes two aspects: wet spinning and atmospheric drying. During the wet spinning process, hemihydrate gypsum undergoes a hydration reaction when encountering water to form a dihydrate gypsum crystal network, which combines with the cellulose network to form hemihydrate gypsum / cellulose hydrogel fibers. After the replacement treatment of the hemihydrate gypsum / cellulose hydrogel fibers, gypsum / cellulose aerogel fibers are formed through the atmospheric drying method.
[0102] Please refer to Figure 2 , Figure 2 , which is a morphological diagram of three spinning solutions prepared in Examples 1-3 of the present invention. Among them, (a) is a cellulose solution without adding hemihydrate gypsum, (b) is a cellulose solution with 10% of the cellulose solid content of hemihydrate gypsum added, and (c) is a cellulose solution with 20% of the cellulose solid content of hemihydrate gypsum added. It can be seen that hemihydrate gypsum has excellent dispersibility and stability in the cellulose solution. Adding hemihydrate gypsum to the cellulose solution will not affect the formation of the spinning solution and can improve the processing performance.
[0103] Please refer to Figure 3 , Figure 3Shear rheological test diagrams of three kinds of spinning solutions prepared in Examples 1-3 of the present invention. Among them, (a) is the frequency sweep diagram of the cellulose solution without adding hemihydrate gypsum, (b) is the frequency sweep diagram of the cellulose solution with 10% of hemihydrate gypsum based on the solid content of cellulose added, (c) is the frequency sweep diagram of the cellulose solution with 20% of hemihydrate gypsum based on the solid content of cellulose added, and (d) is the strain rate-viscosity diagram of the three spinning solutions. It can be seen that all three spinning solutions exhibit shear thinning behavior where the viscosity decreases with the increase of the shear rate, indicating that all three spinning dope have pseudoplasticity and are beneficial for processing such as coating and injection. Among them, the viscosity of the spinning solution with 20% hemihydrate gypsum added is the highest, and the viscosity of the spinning solution without adding hemihydrate gypsum is the lowest. Although the increase in the content of hemihydrate gypsum increases the frictional resistance and viscosity in the spinning dope, it still maintains the shear thinning characteristics, indicating that the spinning solution with hemihydrate gypsum added has high zero-shear viscosity and shear thinning behavior, which is beneficial for spinning.
[0104] Please refer to Figure 4 , Figure 4 is the scanning electron microscope image of the gypsum / cellulose aerogel fiber prepared in Example 2 of the present invention. It can be seen that after adding hemihydrate gypsum, the gypsum / cellulose aerogel fiber prepared by the normal temperature drying method has a complete morphology and a complete pore structure.
[0105] Please refer to Figure 5 , Figure 5 is the Micro-CT visualization image of the gypsum / aerogel fiber prepared in Example 2 of the present invention. Through the hydration reaction of hemihydrate gypsum, a self-supporting hard skeleton of dihydrate gypsum combined with a continuous cellulose skeleton is obtained. As further confirmed by 3D X-ray tomography, in the cellulose aerogel fiber mediated by calcium sulfate hydrate, cellulose and calcium sulfate hydrate can spontaneously generate an isotropic 3D interconnected structure. The two phases are interconnected and supported to form an interpenetrating double network architecture.
[0106] Please refer to Figure 6 , Figure 6 is the mechanical property diagram of the cellulose aerogel fiber prepared in Examples 1-3, 6-8 of the present invention. It can be seen that without adding hemihydrate gypsum, the mechanical properties of the cellulose aerogel fiber prepared by the atmospheric pressure drying method are equivalent to those of the cellulose aerogel fiber prepared by the supercritical carbon dioxide method. However, after adding hemihydrate gypsum, the toughness of the gypsum / cellulose aerogel fiber prepared by the atmospheric pressure drying method is significantly enhanced, and its mechanical properties are better than those of the cellulose aerogel fiber prepared by supercritical carbon dioxide drying.
[0107] The above are only the preferred embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present invention.
Claims
1. A method for preparing gypsum / cellulose aerogel fiber, characterized in that: The steps include: dispersing hemihydrate gypsum in dimethyl sulfoxide solution to obtain a hemihydrate gypsum / DMSO dispersion; Adding an ionic liquid to the hemihydrate gypsum / DMSO dispersion and stirring to obtain a hemihydrate gypsum / DMSO / ionic liquid mixed solution; dissolving cellulose cotton pulp in the hemihydrate gypsum / DMSO / ionic liquid mixed solution to obtain a hemihydrate gypsum cellulose spinning stock solution; The semi-hydrated gypsum cellulose spinning stock solution is squeezed into a coagulation bath, and after coagulation and forming, the semi-hydrated gypsum / cellulose hydrogel fiber is obtained; The semi-hydrated gypsum / cellulose hydrogel fibers are subjected to a replacement treatment and then naturally dried to obtain gypsum / cellulose aerogel fibers.
2. The method for preparing gypsum / cellulose aerogel fiber according to claim 1, characterized in that: The cellulose cotton pulp is the fragments of cellulose cotton paper pulp after being crushed.
3. The method for preparing gypsum / cellulose aerogel fiber according to claim 2, characterized in that: The polymerization degree of the cellulose cotton pulp is 400-800, and the length of the fragments is 0.1-0.5 mm.
4. The method for preparing gypsum / cellulose aerogel fiber according to claim 1, characterized in that: The cellulose cotton pulp is dissolved in the semi-hydrated gypsum / DMSO / ionic liquid mixed solution to obtain the semi-hydrated gypsum cellulose spinning stock solution, wherein the mass fraction of the semi-hydrated gypsum is 5-80% of the solid content of the cellulose.
5. The method for preparing gypsum / cellulose aerogel fiber according to claim 1, characterized in that: The ionic liquid is added to the gypsum / DMSO dispersion, and stirred to obtain a hemihydrate gypsum / DMSO / ionic liquid mixed solution, wherein the ratio of ionic liquid to dimethyl sulfoxide is 1:
4.
6. The method for preparing gypsum / cellulose aerogel fiber according to claim 1, characterized in that: The ionic liquid is one of 1-ethyl-3-methylimidazolium acetate, 1-allyl-3-methylimidazolium chloride, 1-allyl-3-methylimidazolium acetate and 1-butyl-3-methylimidazolium acetate.
7. The method for preparing gypsum / cellulose aerogel fiber according to claim 1, characterized in that: The cellulose cotton pulp is dissolved in the semi-hydrated gypsum / DMSO / ionic liquid mixed solution to obtain the semi-hydrated gypsum cellulose spinning stock solution, the dissolution temperature is 75-80° C., and the dissolution time is 2-12 hours.
8. The method for preparing gypsum / cellulose aerogel fiber according to claim 1, characterized in that: In the replacement process, the number of replacements is 6, and each time lasts 30 minutes.
9. The method for preparing gypsum / cellulose aerogel fiber according to claim 1, characterized in that: The natural drying time is 1 to 2 hours.
10. A gypsum / cellulose aerogel fiber, characterized in that: The aerogel fiber is prepared by the method for preparing the gypsum / cellulose aerogel fiber according to any one of claims 1 to 9.