A modified silk fibroin reinforced calcium silicate thermal insulation material and its preparation method

Abstract

The present invention belongs to the technical field of building materials, and discloses a modified silk fibroin reinforced calcium silicate thermal insulation material and a preparation method thereof. The present invention adopts a method of first dissolving and then mixing to rapidly mix a silk fibroin solution containing calcium chloride and a sodium silicate emulsion at a certain flow rate to obtain modified silk fibroin reinforced fibers; then adding the obtained fibers into a calcium silicate thermal insulation material to obtain a modified silk fibroin reinforced calcium silicate thermal insulation material. The process of the present invention is simple and easy to operate, has strong practicability, and is suitable for industrial popularization and application.

Description

Technical Field

[0001] The present invention belongs to the technical field of building materials, and particularly relates to a modified silk fibroin reinforced calcium silicate thermal insulation material and a preparation method thereof. Background Art

[0002] Calcium silicate thermal insulation materials are mainly composed of calcium and silicon materials, and by adding an appropriate amount of fibers, they are formed into lightweight thermal insulation materials through foaming and steam curing. They have excellent properties such as lightweight and high strength, waterproof and moisture-proof, and non-deformable, and have broad application prospects in the construction field.

[0003] Currently, calcium silicate thermal insulation materials generally have problems such as poor toughness and cracking, which severely limit the application of calcium silicate thermal insulation materials. Based on the above situation, the present invention proposes a modified silk fibroin reinforced calcium silicate thermal insulation material and a preparation method thereof. Summary of the Invention

[0004] Aiming at the problems and deficiencies existing in the prior art, the purpose of the present invention is to provide a modified silk fibroin reinforced calcium silicate thermal insulation material and a preparation method thereof.

[0005] Based on the above purpose, the present invention adopts the following technical solutions:

[0006] The first aspect of the present invention provides a preparation method of modified silk fibroin reinforced fibers, comprising the following steps:

[0007] 1) Dissolve silk fibroin in an alcohol solution of a soluble calcium salt to obtain a silk fibroin solution;

[0008] 2) Add a surfactant and an organic solvent to a soluble silicate solution and disperse evenly to obtain a silicate emulsion;

[0009] 3) Spray out the silk fibroin solution from a first nozzle, and at the same time spray out the silicate emulsion from a second nozzle close to the first nozzle. The silk fibroin solution sprayed out from the first nozzle and the silicate emulsion sprayed out from the second nozzle converge at the nozzle part and then are sprayed out to obtain a mixture;

[0010] 4) Disperse and heat the mixture for reaction, and after the reaction is completed, filter and collect the filtrate to obtain modified silk fibroin reinforced fibers.

[0011] Preferably, in step 1), the alcoholic solution of the soluble calcium salt is formed by mixing the soluble calcium salt, water and ethanol; further, the soluble calcium salt is calcium chloride or / and calcium nitrate. Preferably, in the alcoholic solution of the soluble calcium salt, the mass ratio of the soluble calcium salt, water and ethanol is 1∶(6 - 8)∶(2 - 4); further, when the alcoholic solution of the soluble calcium salt is the alcoholic solution of calcium chloride, the mass ratio of calcium chloride, water and ethanol in the alcoholic solution of calcium chloride is 1∶(6 - 8)∶(2 - 4).

[0012] Preferably, in step 1), the mass ratio of the silk fibroin to the soluble calcium salt is 1∶(1 - 2); further, when the soluble calcium salt is calcium chloride, the mass ratio of the silk fibroin to calcium chloride is 1∶(1 - 2).

[0013] Preferably, in step 1), the dissolution condition is heat treatment at 70 - 80°C. Further, after obtaining the silk fibroin solution, the temperature is kept constant to prevent the precipitation of silk fibroin in the solution.

[0014] Preferably, the mass ratio of the soluble calcium salt to the soluble silicate is 1∶(2 - 3).

[0015] Preferably, in step 2), the soluble silicate solution is an aqueous solution of the soluble silicate; further, the soluble silicate is sodium silicate or / and potassium silicate. Preferably, the mass fraction of the soluble silicate in the soluble silicate solution is 20% - 25%; further, when the soluble silicate is sodium silicate, the mass fraction of sodium silicate in the sodium silicate solution is 20% - 25%.

[0016] Preferably, in step 2), the surfactant is cetyltrimethylammonium bromide or / and sodium dodecylbenzenesulfonate; the mass ratio of the surfactant to the soluble silicate is (0.75 - 2)∶1. Further, when the soluble silicate is sodium silicate, the mass ratio of the surfactant to sodium silicate is (0.75 - 2)∶1.

[0017] Preferably, in step 2), the organic solvent is a mixed solution of cyclohexane and n-butanol; the mass ratio of cyclohexane to n-butanol is (6 - 15)∶(0.5 - 1). Further, the mass ratio of cyclohexane to the soluble silicate is (6 - 15)∶1, and the mass ratio of n-butanol to the soluble silicate is (0.5 - 1)∶1; when the soluble silicate is sodium silicate, the mass ratio of cyclohexane to sodium silicate is (6 - 15)∶1, and the mass ratio of n-butanol to sodium silicate is (0.5 - 1)∶1.

[0018] Preferably, in step 2), the dispersion method is ultrasonic dispersion.

[0019] Preferably, in step 3), the spraying speed of the silk fibroin solution from the first nozzle is 2-8 m / s; the spraying speed of the silicate emulsion from the second nozzle is the same as that of the first nozzle; the silk fibroin solution sprayed from the first nozzle and the silicate emulsion sprayed from the second nozzle are combined at the nozzle part to obtain a mixture, and the spraying speed of the mixture from the nozzle part is not less than 1.2 times, preferably 1.2-1.5 times, of the spraying speed of the first nozzle or / and the second nozzle.

[0020] Preferably, in step 4), the dispersion treatment method is ultrasonic treatment; the heating treatment is specifically: water bath heating at 120-140 °C; the heating reaction time is 12 h or more.

[0021] Preferably, in step 4), the filtrate collected after filtration further includes washing and drying treatments; the solvent used for the washing treatment is ethanol; the drying treatment method is drying.

[0022] As an alternative, the first nozzle and the second nozzle, as the branch ports of the Y-type mixing device, are respectively connected to the nozzle part located on the main trunk, and the nozzle part sprays the mixture from the third nozzle (mixing nozzle) of the nozzle part. Further, in order to make the spraying speed of the third nozzle of the nozzle part greater than that of the first nozzle or / and the second nozzle, the diameter of the third nozzle can be reduced or an opening can be made on the side wall of the nozzle part and compressed air can be introduced to spray the compressed air into the silk fibroin solution sprayed from the first nozzle and the silicate emulsion sprayed from the second nozzle, and at the same time, the silk fibroin solution and the silicate emulsion are brought into contact and mixed by using the compressed air.

[0023] The second aspect of the present invention provides a modified silk fibroin reinforced fiber prepared by the preparation method described in the first aspect above.

[0024] The third aspect of the present invention provides an application of the modified silk fibroin reinforced fiber described in the second aspect above in a calcium silicate thermal insulation material.

[0025] The fourth aspect of the present invention provides a calcium silicate thermal insulation material reinforced with modified silk fibroin fiber, which comprises the following components in parts by mass: 80 parts of quartz sand powder, 30-50 parts of carbide slag powder, 10-20 parts of cement, 5-8 parts of zeolite powder, 3-5 parts of fine sink beads, 3-5 parts of modified silk fibroin reinforced fiber, 40-60 parts of water, 1-2 parts of foaming agent, 3-5 parts of calcium stearate; the modified silk fibroin reinforced fiber is the modified silk fibroin reinforced fiber described in the second aspect above.

[0026] Preferably, the quartz sand powder, carbide slag powder, cement, zeolite powder, and fine cenospheres all have good grindability. Therefore, they need to be mixed before use and then ground to obtain a mixed powder. The specific surface area of the mixed powder is 500 - 700 m 2 / kg.

[0027] Preferably, the specific surface area of the quartz sand powder is 300 - 500 m 2 / kg.

[0028] Preferably, the fine cenospheres are active spherical particles with a density greater than that of water, extracted from raw fly ash.

[0029] Preferably, the foaming agent is at least one of hydrogen peroxide foaming agent, rosin resin foaming agent, or protein foaming agent.

[0030] The fifth aspect of the present invention provides a preparation method of the modified silk fibroin reinforced fiber calcium silicate thermal insulation material described in the fourth aspect above, including the following steps:

[0031] (1) Weigh each component according to the ratio of the modified silk fibroin reinforced fiber calcium silicate thermal insulation material described in the fourth aspect above;

[0032] (2) Grind the quartz sand powder, carbide slag powder, cement, zeolite powder, fine cenospheres, and modified silk fibroin reinforced fiber to obtain a mixed powder; then add water to the mixed powder and stir evenly to obtain a mixed slurry;

[0033] (3) Add the foaming agent and calcium stearate to the mixed slurry and stir to obtain a foam slurry;

[0034] (4) Press the foam slurry into shape, and after curing, obtain a green body; perform steam curing on the green body to obtain the modified silk fibroin reinforced fiber calcium silicate thermal insulation material.

[0035] Preferably, in step (2), the grinding treatment is carried out by a ball mill; the specific surface area of the mixed powder after the grinding treatment is 500 - 700 m 2 / kg.

[0036] Preferably, in step (3), the stirring treatment conditions are: the stirring speed ≥ 400 r / min, and the stirring time ≥ 3 min. Further, the foaming agent and calcium stearate are fully dissolved during the stirring treatment.

[0037] Preferably, in step (4), the pressing conditions are: maintaining for 2 - 4 h under a pressure condition of 1.2 - 1.5 MPa.

[0038] Preferably, in step (4), the curing conditions are: heat preservation for 8 - 12 h under a temperature condition of 60 - 80 °C.

[0039] Preferably, in step (4), the steam curing treatment conditions are as follows: the hydration reaction is carried out in saturated steam with a pressure of 1.0 - 1.2 MPa and a temperature of 160 - 180 °C; the steam curing treatment time is 12 - 16 h.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0041] (1) The present invention first adopts the method of dissolving first and then mixing, and rapidly mixes the silk fibroin solution containing calcium chloride and the sodium silicate emulsion through a Y-shaped mixing device at a certain flow rate, prompting the calcium chloride in the silk fibroin to react rapidly with sodium silicate to generate nano-calcium silicate, while precipitating silk fibroin, so that the generated nano-calcium silicate just adheres to the precipitated silk fibroin, obtaining a modified silk fibroin reinforced fiber with a large amount of nano-calcium silicate attached, and further obtaining an in-situ fiber reinforcement effect. The present invention also adds the modified silk fibroin reinforced fiber prepared above to the preparation of calcium silicate boards. Moreover, due to the presence of a large amount of nano-calcium silicate on the fiber, these nano-calcium silicate further serve as nucleating substances, reducing the nucleation potential barrier of cement hydration and promoting the formation of hydrated calcium silicate on the fiber surface. Furthermore, the fiber and the calcium silicate product form a whole. At the same time, relying on the high toughness and high strength of the silk fibroin fiber itself, the flexural strength and crack resistance of the calcium silicate thermal insulation material are improved. In one of the embodiments, the calcium silicate thermal insulation material prepared with the modified silk fibroin reinforced fiber prepared by the present invention has a flexural strength of 0.58 MPa, a compressive strength of 1.43 MPa, and a thermal conductivity of 0.084 W / m·k.

[0042] (2) The sodium silicate emulsion prepared by the present invention is an oil-in-water sodium silicate solution particle wrapped by a surfactant. When it meets the silk fibroin solution containing calcium chloride, the ethanol in the silk fibroin solution can be miscible with the oil component in the oil-in-water sodium silicate solution particle, thereby releasing sodium silicate and rapidly reacting with calcium chloride in the silk fibroin solution to generate nano-calcium silicate. At the same time, due to the above changes in the system in the silk fibroin solution, silk fibroin will precipitate, so that the generated nano-calcium silicate just adheres to the precipitated silk fibroin, and then a modified silk fibroin reinforced fiber is obtained. Finally, reacting the fiber under high-temperature water bath conditions can further promote the growth of nano-calcium silicate on the silk fibroin surface and improve the overall activity of the fiber.

[0043] (3) The present invention can also control the fineness of the generated nanofibers through a spinning pump, and thus calcium silicate thermal insulation materials with different mechanical and thermal insulation properties can be obtained; the present invention also adds fine sink beads in the preparation of calcium silicate thermal insulation materials. The fine sink beads can increase the slipperiness of the slurry, reduce its forming difficulty, promote the uniform distribution of slurry particles, and reduce the adverse effect of increasing the viscosity of the slurry after adding fibers. Therefore, the process of the present invention is simple and easy to operate, has strong practicability, and is suitable for industrial promotion and application.

[0044] Other advantages, objectives and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be learned from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following specification. Brief Description of the Drawings

[0045] Figure 1 It is a schematic structural diagram of an embodiment of the Y-shaped mixing device used in the preparation of the modified silk fibroin reinforced fiber of the present invention. Detailed Embodiments

[0046] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below through embodiments in conjunction with the drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0047] It should be noted that, without conflict, the embodiments in the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0048] The silk fibroin used in the present invention is obtained by degumming silk with the sodium carbonate degumming method.

[0049] (I) Preparation of Modified Silk Fibroin Reinforced Fiber

[0050] Example 1-1

[0051] This example provides a modified silk fibroin reinforced fiber, and its preparation method includes the following steps:

[0052] 1) Add 1 part by mass of silk fibroin to 11 parts by mass of calcium chloride alcohol solution, heat to 75 °C to form a mixed solution A, and keep it at a constant temperature; the calcium chloride alcohol solution is formed by mixing CaCl2, H2O and C2H5OH with a mass ratio of 1:8:2.

[0053] 2) Dissolve 2.8 parts by mass of sodium silicate in 10 parts by mass of water, stir to dissolve to obtain a sodium silicate aqueous solution; add 3 parts by mass of cetyltrimethylammonium bromide, 25 parts by mass of cyclohexane and 2.5 parts by mass of n-butanol to the sodium silicate aqueous solution, and disperse and mix evenly by ultrasonic to form a sodium silicate emulsion B.

[0054] 3) Adopt Figure 1The Y-shaped mixing device shown blends the mixed solution A and the sodium silicate emulsion B. Specifically: A metering pump is used to quantitatively, continuously, and evenly extrude the mixed solution A from the fine-hole extrusion outlet 1 of the spinneret at a speed of 4 m / s. At the same time, a metering pump is used to extrude the sodium silicate emulsion B from another fine-hole extrusion outlet 2 at a speed of 4 m / s. The mixed solution A and the sodium silicate emulsion B simultaneously flow into the nozzle part not exceeding 10 cm through the extrusion outlets 1 and 2, form a mixed liquid in the nozzle part, and then the mixed liquid is extruded from the fine-hole extrusion outlet 3 of the nozzle part at a speed of 6 m / s by means of introducing compressed air or reducing the diameter of the extrusion outlet 3.

[0055] 4) The mixed liquid ejected from the fine-hole extrusion outlet 3 is ultrasonically dispersed and then reacts for 15 h under the condition of a 130 °C water bath. The filtered product collected by filtration is washed with ethanol and dried to obtain the modified silk fibroin reinforced fiber.

[0056] Examples 1-2

[0057] This example provides a modified silk fibroin reinforced fiber, and its preparation method includes the following steps:

[0058] 1) Add 1 part by mass of silk fibroin to 11 parts by mass of calcium chloride alcohol solution, heat to 80 °C to form a mixed solution A, and keep it at a constant temperature; the calcium chloride alcohol solution is formed by mixing CaCl2, H2O, and C2H5OH with a mass ratio of 1:8:2.

[0059] 2) Dissolve 2.5 parts by mass of sodium silicate in 10 parts by mass of water, stir and dissolve to obtain a sodium silicate aqueous solution; add 3 parts by mass of cetyltrimethylammonium bromide, 30 parts by mass of cyclohexane, and 2 parts by mass of n-butanol to the sodium silicate aqueous solution, and ultrasonically disperse and mix evenly to form a sodium silicate emulsion B.

[0060] 3) Use Figure 1 The Y-shaped mixing device shown blends the mixed solution A and the sodium silicate emulsion B. Specifically: A metering pump is used to quantitatively, continuously, and evenly extrude the mixed solution A from the fine-hole extrusion outlet 1 of the spinneret at a speed of 2 m / s. At the same time, a metering pump is used to extrude the sodium silicate emulsion B from another fine-hole extrusion outlet 2 at a speed of 2 m / s. The mixed solution A and the sodium silicate emulsion B simultaneously flow into the nozzle part not exceeding 10 cm through the extrusion outlets 1 and 2, form a mixed liquid in the nozzle part, and then the mixed liquid is extruded from the fine-hole extrusion outlet 3 of the nozzle part at a speed of 3 m / s by means of introducing compressed air or reducing the diameter of the extrusion outlet 3.

[0061] 4) The mixed liquid ejected from the fine-hole extrusion outlet 3 is ultrasonically dispersed and then reacts for 12 h under the condition of a 140 °C water bath. The filtered product collected by filtration is washed with ethanol and dried to obtain the modified silk fibroin reinforced fiber.

[0062] Examples 1 - 3

[0063] This example provides a modified silk fibroin reinforced fiber, and its preparation method includes the following steps:

[0064] 1) Add 1 part by mass of silk fibroin to 11 parts by mass of calcium chloride alcohol solution, heat to 70 °C to form a mixed solution A, and keep it at a constant temperature; the calcium chloride alcohol solution is formed by mixing CaCl2, H2O, and C2H5OH with a mass ratio of 1:8:2.

[0065] 2) Dissolve 3 parts by mass of sodium silicate in 10 parts by mass of water, stir to dissolve to obtain a sodium silicate aqueous solution; add 3 parts by mass of sodium dodecylbenzenesulfonate, 20 parts by mass of cyclohexane, and 3 parts by mass of n - butanol to the sodium silicate aqueous solution, and disperse and mix evenly by ultrasonic treatment to form a sodium silicate emulsion B.

[0066] 3) Use the Figure 1 shown Y - type mixing device to blend the mixed solution A and the sodium silicate emulsion B. Specifically: use a spinning pump (metering pump) to quantitatively, continuously, and evenly extrude the mixed solution A from the fine - hole extrusion port 1 of the spinneret at a speed of 8 m / s, and at the same time use a metering pump to extrude the sodium silicate emulsion B from another fine - hole extrusion port 2 at a speed of 8 m / s. The mixed solution A and the sodium silicate emulsion B simultaneously flow into the nozzle part not exceeding 10 cm through the extrusion ports 1 and 2, form a mixed liquid in the nozzle part, and then use the method of introducing compressed air or reducing the diameter of the extrusion port 3 to extrude the mixed liquid from the fine - hole extrusion port 3 of the nozzle part at a speed of 10 m / s.

[0067] 4) After ultrasonic dispersion of the mixed liquid extruded from the fine - hole extrusion port 3, react it under the condition of a water bath at 120 °C for 16 h. The filtered and collected filtrate is washed with ethanol and dried to obtain the modified silk fibroin reinforced fiber.

[0068] Comparative Example 1 - 1

[0069] The content of a modified silk fibroin reinforced fiber is basically the same as that of Example 1 - 1, and the difference is that: in step 4), the mixed liquid after ultrasonic dispersion reacts under the condition of a water bath at 100 °C for 15 h.

[0070] Comparative Example 1 - 2

[0071] The content of a modified silk fibroin reinforced fiber is basically the same as that of Example 1 - 1, and the difference is that: in step 4), the mixed liquid after ultrasonic dispersion reacts under the condition of a water bath at 160 °C for 15 h.

[0072] Comparative Example 1 - 3

[0073] The content of a modified silk fibroin reinforced fiber is basically the same as that of Example 1-1, except that: in step 4), the mixed solution after ultrasonic dispersion reacts for 10 h under the condition of a water bath at 130 °C (the reaction is incomplete).

[0074] Comparative Example 1-4

[0075] This example provides a modified silk fibroin reinforced fiber, and its preparation method includes the following steps:

[0076] 1) Add 1 part by mass of silk fibroin to 4 parts by mass of ethanol and dissolve it at 75 °C to form a silk fibroin solution A, and keep it at a constant temperature.

[0077] 2) Dissolve 2.8 parts by mass of sodium silicate in 10 parts by mass of water, stir and dissolve it to obtain an aqueous sodium silicate solution; add 3 parts by mass of cetyltrimethylammonium bromide, 25 parts by mass of cyclohexane and 2.5 parts by mass of n-butanol to the aqueous sodium silicate solution, and disperse and mix them evenly by ultrasonic treatment to form a sodium silicate emulsion B.

[0078] 3) Mix CaCl2, H2O and C2H5OH with a mass ratio of 1:8:2 to obtain a calcium chloride alcohol solution C.

[0079] 4) Mix the sodium silicate emulsion B and the calcium chloride alcohol solution C, disperse them evenly by ultrasonic treatment, and carry out a hydrothermal reaction at 130 °C under the condition of a water bath for 24 h to obtain an emulsion D;

[0080] 5) Use Figure 1 the Y-shaped mixing device shown to blend the silk fibroin solution A and the emulsion D. Specifically: use a spinning pump (metering pump) to quantitatively, continuously and evenly extrude the silk fibroin solution A from the fine hole extrusion port 1 of the spinneret at a speed of 4 m / s, and at the same time use a metering pump to extrude the emulsion D from another fine hole extrusion port 2 at a speed of 4 m / s. The silk fibroin solution A and the emulsion D flow into the nozzle part not exceeding 10 cm through the extrusion ports 1 and 2 at the same time, form a mixed solution in the nozzle part, and then use the method of introducing compressed air or reducing the diameter of the extrusion port 3 to extrude the mixed solution from the fine hole extrusion port 3 of the nozzle part at a speed of 6 m / s.

[0081] 6) After ultrasonic dispersion of the mixed solution extruded from the fine hole extrusion port 3, react it for 15 h under the condition of a water bath at 130 °C, and filter the collected filtrate, wash it with ethanol and dry it to obtain a modified silk fibroin reinforced fiber.

[0082] Comparative Example 1-5

[0083] The content of a modified silk fibroin reinforced fiber is basically the same as that of Example 1-1, except that: in step 3), the mixed solution A and the sodium silicate emulsion B are directly mixed and then extruded from the fine hole extrusion port 3 of the nozzle part at a speed of 6 m / s.

[0084] (2) Preparation of modified silk fibroin reinforced fiber calcium silicate thermal insulation material

[0085] Example 2-1

[0086] A modified silk fibroin reinforced fiber calcium silicate thermal insulation material, comprising the following components in parts by mass: 80 parts of quartz sand powder (purchased from a sand mining factory, obtained after cleaning and grinding, with a specific surface area of 400 m 2 / kg), 40 parts of carbide slag powder (slag waste generated from carbide production of acetylene, obtained after drying and grinding), 15 parts of PO.42.5 cement, 7 parts of zeolite powder (zeolite purchased from a building materials market, obtained after grinding), 4 parts of fine cenospheres (fly ash raw ash purchased from a thermal power plant, obtained after screening), 4 parts of modified silk fibroin reinforced fiber, 50 parts of water, 1 part of foaming agent (protein-based foaming agent), 3 parts of calcium stearate; the modified silk fibroin reinforced fiber is the modified silk fibroin reinforced fiber prepared in the above Example 1-1.

[0087] The preparation method of the above-mentioned modified silk fibroin reinforced fiber calcium silicate thermal insulation material comprises the following steps:

[0088] (1) Pour the quartz sand powder, carbide slag powder, cement, zeolite powder, fine cenospheres, and modified silk fibroin reinforced fiber into a ball mill for grinding treatment to obtain a mixed powder with a specific surface area of 600 m 2 / kg; then add water to the mixed powder and stir evenly to obtain a mixed slurry;

[0089] (2) Add the protein-based foaming agent and calcium stearate to the mixed slurry and stir to dissolve, control the stirring speed at 600 r / min, and the stirring time at 4 min to obtain a foam slurry;

[0090] (3) Pour the foam slurry into a mold, press it at 1.3 MPa for 3 h, cure it at 70 °C for 10 h after molding to obtain a green body; steam-cure the green body in saturated steam at 1.1 MPa and 170 °C for 14 h, and slowly cool it to room temperature after taking it out to obtain the modified silk fibroin reinforced fiber calcium silicate thermal insulation material.

[0091] Example 2-2

[0092] A modified silk fibroin reinforced fiber calcium silicate thermal insulation material, comprising the following components in parts by mass: 80 parts of quartz sand powder (purchased from a sand mining factory, obtained after cleaning and grinding, with a specific surface area of 300 m 250 parts of calcium carbide slag powder (calcium carbide waste residue generated from the production of acetylene from calcium carbide, obtained by drying and grinding), 10 parts of PO.42.5 cement, 8 parts of zeolite powder (zeolite purchased from the building materials market and obtained by grinding), 3 parts of fine cenospheres (fly ash raw ash purchased from a thermal power plant and obtained by screening), 5 parts of modified silk fibroin reinforcing fiber, 60 parts of water, 2 parts of foaming agent (rosin resin-based foaming agent), 3 parts of calcium stearate; the modified silk fibroin reinforcing fiber is the modified silk fibroin reinforcing fiber prepared in the above Examples 1-2.

[0093] The preparation method of the above-mentioned calcium silicate thermal insulation material with modified silk fibroin reinforcing fiber comprises the following steps:

[0094] (1) Pour quartz sand powder, calcium carbide slag powder, cement, zeolite powder, fine cenospheres, and modified silk fibroin reinforcing fiber into a ball mill for grinding treatment to obtain a mixed powder with a specific surface area of 500 m 2 / kg; then add water to the mixed powder and stir evenly to obtain a mixed slurry;

[0095] (2) Add rosin resin-based foaming agent and calcium stearate to the mixed slurry and stir to dissolve, control the stirring speed at 400 r / min, and stir for 5 min to obtain a foam slurry;

[0096] (3) Pour the foam slurry into a mold, press it at 1.2 MPa for 4 h, cure it at 60 °C for 12 h after forming to obtain a green body; steam-cure the green body in saturated steam at 1.0 MPa and 180 °C for 12 h, and slowly cool it to room temperature after taking it out to obtain the calcium silicate thermal insulation material with modified silk fibroin reinforcing fiber.

[0097] Examples 2-3

[0098] A calcium silicate thermal insulation material with modified silk fibroin reinforcing fiber, comprising the following components in parts by mass: 80 parts of quartz sand powder (purchased from a sand mining factory, obtained after cleaning and grinding, with a specific surface area of 500 m 2 / kg), 30 parts of calcium carbide slag powder (calcium carbide waste residue generated from the production of acetylene from calcium carbide, obtained by drying and grinding), 20 parts of PO.42.5 cement, 5 parts of zeolite powder (zeolite purchased from the building materials market and obtained by grinding), 5 parts of fine cenospheres (fly ash raw ash purchased from a thermal power plant and obtained by screening), 3 parts of modified silk fibroin reinforcing fiber, 40 parts of water, 2 parts of foaming agent (hydrogen peroxide with a concentration of 27.5%), 5 parts of calcium stearate; the modified silk fibroin reinforcing fiber is the modified silk fibroin reinforcing fiber prepared in the above Examples 1-3.

[0099] The preparation method of the above-mentioned calcium silicate thermal insulation material with modified silk fibroin reinforcing fiber comprises the following steps:

[0100] (1) Pour quartz sand powder, carbide slag powder, cement, zeolite powder, fine sink beads, and modified silk fibroin reinforced fibers into a ball mill for grinding to obtain a mixed powder with a specific surface area of 700 m 2 / kg; then add water to the mixed powder and stir evenly to obtain a mixed slurry;

[0101] (2) Add hydrogen peroxide and calcium stearate to the mixed slurry and stir to dissolve, control the stirring speed at 500 r / min, and the stirring time at 3 min to obtain a foamed slurry;

[0102] (3) Pour the foamed slurry into a mold, press it under the condition of 1.5 MPa for 2 h, cure it at 80 °C for 8 h after forming to obtain a green body; steam-cure the green body in saturated steam at 1.2 MPa and 160 °C for 16 h, and slowly cool it to room temperature after taking it out to obtain a modified silk fibroin reinforced fiber calcium silicate thermal insulation material.

[0103] Comparative Example 2-1

[0104] The content of a modified silk fibroin reinforced fiber calcium silicate thermal insulation material is basically the same as that of Example 2-1, and the difference is that: the modified silk fibroin reinforced fiber is the modified silk fibroin reinforced fiber prepared in the above Comparative Example 1-1.

[0105] Comparative Example 2-2

[0106] The content of a modified silk fibroin reinforced fiber calcium silicate thermal insulation material is basically the same as that of Example 2-1, and the difference is that: the modified silk fibroin reinforced fiber is the modified silk fibroin reinforced fiber prepared in the above Comparative Example 1-2.

[0107] Comparative Example 2-3

[0108] The content of a modified silk fibroin reinforced fiber calcium silicate thermal insulation material is basically the same as that of Example 2-1, and the difference is that: the modified silk fibroin reinforced fiber is the modified silk fibroin reinforced fiber prepared in the above Comparative Example 1-3.

[0109] Comparative Example 2-4

[0110] The content of a modified silk fibroin reinforced fiber calcium silicate thermal insulation material is basically the same as that of Example 2-1, and the difference is that: the modified silk fibroin reinforced fiber is the modified silk fibroin reinforced fiber prepared in the above Comparative Example 1-4.

[0111] Comparative Example 2-5

[0112] The content of a modified silk fibroin reinforced calcium silicate thermal insulation material is basically the same as that of Example 2-1, and the difference lies in that: the modified silk fibroin reinforced fiber is the modified silk fibroin reinforced fiber prepared in the above Comparative Examples 1-5.

[0113] Comparative Example 2-6

[0114] The content of a modified silk fibroin reinforced calcium silicate thermal insulation material is basically the same as that of Example 2-1, and the difference lies in that: the modified silk fibroin reinforced fiber is replaced with unmodified silk fibroin.

[0115] Taking the calcium silicate thermal insulation materials prepared in Examples 2-1 to 2-3 and Comparative Examples 2-1 to 2-6 of the present invention as samples, the flexural strength and compressive strength of the samples were tested according to the methods specified in GB / T 50081-2019, the density of the samples was tested according to the methods specified in GB / T 7019-2014, the dry shrinkage rate of the samples was tested according to the methods specified in JC / T564.1-2008, the thermal conductivity of the samples was tested according to the methods specified in GB / T 10294-2008, and the number of cracks generated in the samples was observed and counted at the same time. The results are shown in Table 1 below.

[0116] Table 1 Performance test data of calcium silicate thermal insulation material samples prepared under different conditions

[0117]

[0118] As can be seen from Table 1, by comparing Example 2-1 and Comparative Example 2-6, it can be seen that compared with unmodified silk fibroin, the addition of the modified silk fibroin reinforced fiber prepared by the present invention can significantly improve the flexural strength, compressive strength and crack resistance of the calcium silicate thermal insulation material, reduce the thermal conductivity and improve the thermal insulation performance, indicating that the addition of the modified silk fibroin reinforced fiber of the present invention is more conducive to the combination of silk fibroin and calcium silicate board particle raw materials, and thus is more conducive to improving the material strength.

[0119] By comparing Example 2-1 and Comparative Example 2-5, it can be seen that the calcium silicate thermal insulation material prepared with silk fibroin treated by mixing first and then spraying has poor flexural strength, compressive strength and crack resistance, and also has a higher thermal conductivity, indicating that the premature mixing of the mixed solution A containing silk fibroin and the sodium silicate emulsion B without pressure extrusion is not conducive to the formation of the modified silk fibroin reinforced fiber.

[0120] It can be seen from the comparison between Example 2-1 and Comparative Examples 2-1 to 2-3 that during the preparation of the modified silk fibroin reinforced fiber, if the heat treatment temperature of the mixed solution is too high or too low, it is not conducive to the formation of the modified silk fibroin reinforced fiber; if the heat treatment time is too short, the modification of silk fibroin is insufficient, resulting in the inability to obtain calcium silicate thermal insulation materials with more obvious enhancement effects in flexural strength, compressive strength, crack resistance and thermal conductivity.

[0121] It can be seen from the comparison between Example 2-1 and Comparative Example 2-4 that the effect of compounding calcium chloride alcohol solution and sodium silicate emulsion is not as good as that of compounding with silk fibroin solution. This is because nano calcium silicate can be formed after compounding calcium chloride alcohol solution and sodium silicate emulsion. Although silk fibroin reinforced fiber can also be obtained by mixing nano calcium silicate and silk fibroin solution, it cannot achieve the in-situ reinforcement effect. Therefore, the calcium silicate thermal insulation material prepared with it is also inferior to the calcium silicate thermal insulation material obtained after the optimized preparation method of the present invention.

[0122] In summary, the present invention effectively overcomes the deficiencies in the prior art and has high industrial utilization value. The role of the above embodiments is to illustrate the substantial content of the present invention, but does not limit the protection scope of the present invention. Those of ordinary skill in the art should understand that the technical solution of the present invention can be modified or equivalently replaced without departing from the essence and protection scope of the technical solution of the present invention.

Claims

1. A preparation method of a modified silk fibroin reinforced fiber, characterized in that, It includes the following steps: 1) Dissolve silk fibroin in an alcohol solution of a soluble calcium salt to obtain a silk fibroin solution; 2) Add a surfactant and an organic solvent to a soluble silicate solution and disperse evenly to obtain a silicate emulsion; 3) Spray out the silk fibroin solution from the first spray outlet, and at the same time spray out the silicate emulsion from the second spray outlet close to the first spray outlet. The silk fibroin solution sprayed out from the first spray outlet and the silicate emulsion sprayed out from the second spray outlet converge at the nozzle part and then are sprayed out to obtain a mixture; 4) Disperse and process the mixture and then heat it for reaction. After the reaction ends, filter and collect the filtrate to obtain modified silk fibroin reinforced fibers; The heat treatment is specifically: water bath heating at 120 - 140 °C.

2. The preparation method of the modified silk fibroin reinforced fiber according to claim 1, characterized in that, The mass ratio of the silk fibroin to the soluble calcium salt is 1∶(1 - 2); The mass ratio of the soluble calcium salt to the soluble silicate is 1∶(2 - 3).

3. The preparation method of the modified silk fibroin reinforced fiber according to claim 1 or 2, characterized in that, The alcohol solution of the soluble calcium salt is composed of a soluble calcium salt, water and ethanol; The soluble silicate solution is an aqueous solution of a soluble silicate; The mass ratio of the surfactant to the soluble silicate is (0.75 - 2)∶1; The organic solvent is a mixed solution of cyclohexane and n-butanol.

4. The preparation method of the modified silk fibroin reinforced fiber according to claim 3, characterized in that, In the alcohol solution of the soluble calcium salt, the mass ratio of the soluble calcium salt, water and ethanol is 1∶(6 - 8)∶(2 - 4); The soluble calcium salt is calcium chloride or / and calcium nitrate; The surfactant is cetyltrimethylammonium bromide or / and sodium dodecylbenzenesulfonate; The mass ratio of cyclohexane to the soluble silicate is (6 - 15)∶1; The mass ratio of n-butanol to the soluble silicate is (0.5 - 1)∶1; The mass fraction of the soluble silicate in the soluble silicate solution is 20% - 25%; The soluble silicate is sodium silicate or / and potassium silicate; In step 4), the heating reaction time is 12 h or more.

5. The preparation method of the modified silk fibroin reinforced fiber according to claim 1 or 2 or 4, characterized in that, The spraying speed of the silk fibroin solution from the first spray outlet is 2 - 8 m / s; The spraying speed of the silicate emulsion from the second spray outlet is the same as the spraying speed of the first spray outlet; The silk fibroin solution sprayed out from the first spray outlet and the silicate emulsion sprayed out from the second spray outlet converge at the nozzle part to obtain a mixed solution, and the spraying speed of the mixed solution from the nozzle part is not less than 1.2 times the spraying speed of the first spray outlet or the second spray outlet.

6. Modified silk fibroin reinforced fibers prepared by the preparation method according to any one of claims 1 - 5.

7. Application of the modified silk fibroin reinforced fibers according to claim 6 in calcium silicate thermal insulation materials.

8. A modified silk fibroin reinforced calcium silicate fiber thermal insulation material, characterized in that, It includes components in the following mass parts: 80 parts of quartz sand powder, 30 - 50 parts of carbide slag powder, 10 - 20 parts of cement, 5 - 8 parts of zeolite powder, 3 - 5 parts of fine sink beads, 3 - 5 parts of modified silk fibroin reinforced fibers, 40 - 60 parts of water, 1 - 2 parts of foaming agent, 3 - 5 parts of calcium stearate; The modified silk fibroin reinforced fibers are the modified silk fibroin reinforced fibers according to claim 6.

9. The preparation method of the modified silk fibroin reinforced fiber calcium silicate thermal insulation material according to claim 8, characterized in that, It includes the following steps: (1) Weigh each component according to the ratio of the modified silk fibroin reinforced fiber calcium silicate thermal insulation material described in claim 8; (2) Grind quartz sand powder, carbide slag powder, cement, zeolite powder, fine sink beads, and modified silk fibroin reinforced fibers to obtain a mixed powder; then add water to the mixed powder and stir evenly to obtain a mixed slurry; (3) Add a foaming agent and calcium stearate to the mixed slurry and stir to obtain a foam slurry; (4) Press the foam slurry into shape and cure to obtain a green body; steam-cure the green body to obtain a calcium silicate thermal insulation material reinforced with modified silk fibroin fibers.

10. The preparation method of the modified silk fibroin reinforced fiber calcium silicate thermal insulation material according to claim 9, characterized in that, In step (2), the specific surface area of the mixed powder is 500 - 700 m 2 / kg; in step (4), the pressure for pressing and forming is 1.2 - 1.5 MPa; the curing conditions are: heat preservation for 8 - 12 h under the temperature condition of 60 - 80 °C; the conditions for steam curing treatment are: carry out the hydration reaction in saturated steam with a pressure of 1.0 - 1.2 MPa and a temperature of 160 - 180 °C.

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