Heat-resistant light wallboard and preparation method thereof

Abstract

The invention discloses a heat-resistant light wallboard and a preparation method thereof, and relates to the technical field of building wallboards. The hollow microspheres with uniform and stable wall thickness are prepared by copolymerizing supporting macromolecules of polystyrene and zirconium hydroxide, so that the mechanical property and high temperature resistance of the light wallboard are improved, and then the hollow microspheres are blended with nano boron carbide, calcium magnesium aluminate cement and phosphate cement to form a system with a complete structure, so that the mechanical property of the wallboard is further improved, and the light wallboard has a good application prospect. Then, low-porosity foam is prepared by adopting a carbon dioxide foaming process, calcium ions and magnesium ions in the cement are subjected to mineralization reaction with carbon dioxide to form calcite, so that the curing effect is achieved, the strength and the high-temperature-resistant effect of the wallboard are improved, then, hollow microspheres are calcined and hardened, phosphate can be used as a high-temperature adhesive, and the wallboard can be well cured. Pores in a matrix are filled with the boron carbide, so that the mechanical property and the high-temperature-resistant effect of the wallboard are improved.

Description

Technical Field

[0001] This invention relates to the field of building wall panel technology, specifically to a heat-resistant lightweight wall panel and its preparation method. Background Technology

[0002] Fires are characterized by their suddenness and destructiveness, and are among the most frequent, destructive, and harmful natural disasters in my country. In my country, the direct economic losses caused by fires are enormous, especially when building fires break out, posing a significant threat to the lives and property of surrounding residents. Furthermore, numerous fire phenomena demonstrate that radiative heat transfer is the primary method of heat transfer during the spread and diffusion of large-scale fires. Studies indicate that when the diameter of the fire source is greater than 0.3 meters, approximately 30% of the heat energy released by the fire is radiated into the surrounding environment. Since this thermal radiation mainly originates from the electromagnetic radiation of surrounding materials, no other transfer medium is needed for subsequent heat transfer, enabling long-distance heat transfer. Moreover, within a short period of heating, the surface temperature of adjacent buildings can rise to 550°C. While cement-based materials are non-combustible and do not produce smoke or toxic gases during fires (at high temperatures), the physical and chemical changes that occur within the cement-based materials themselves at high temperatures cause severe structural damage, reducing their durability and safety, and posing a significant hazard. The damage to cement-based materials at high temperatures is affected by many factors, including the material's own properties, heating conditions, and load conditions. Summary of the Invention

[0003] The purpose of this invention is to provide a heat-resistant lightweight wall panel and its preparation method to solve the problems existing in the prior art.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a heat-resistant lightweight wall panel, comprising the following preparation steps: (1) Mix zirconium hydroxide and 10wt% hydrochloric acid aqueous solution evenly, add polystyrene solution, and mix evenly to obtain polymer solution; (2) Mix polyvinyl alcohol and deionized water, heat to 60~90℃, stir at 50rpm for 20~50min, add calcium chloride, then deionized water as the inner phase and polymer solution as the intermediate phase, add it through a syringe, heat to 40~70℃ in an oxygen atmosphere, stir at 20~60rpm for 2~6h, then cool to 20~30℃ and solidify for 30~60h, then filter, take the solid, remove the inner aqueous phase at 40~60℃, and obtain hollow microspheres; (3) Mix hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate and deionized water, stir slowly for 20~50s, stir quickly for 80~200s, add sodium bicarbonate and aluminum nitrate, continue to stir quickly for 8~15s, then pour into a mold to form, demold, cure, and calcined to obtain heat-resistant lightweight wall panel.

[0005] Furthermore, the preparation method of the polystyrene solution in step (1) is as follows: polystyrene and 10wt% hydrochloric acid aqueous solution are mixed at a mass ratio of 2:25.

[0006] Furthermore, in step (1), the mass ratio of zirconium hydroxide, 10wt% hydrochloric acid aqueous solution, and polystyrene solution is 3~10:80:80.

[0007] Furthermore, in step (2), the mass ratio of polyvinyl alcohol, deionized water, and calcium chloride is 2:100:1.

[0008] Furthermore, the slow stirring rate in step (3) is 30~60 rpm.

[0009] Furthermore, the rapid stirring rate in step (3) is 1200~1400 rpm.

[0010] Furthermore, the maintenance time described in step (3) is 1 to 7 days.

[0011] Furthermore, the calcination temperature in step (3) is 500~900℃ and the time is 2~4h.

[0012] Furthermore, the mass ratio of the hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, deionized water, sodium bicarbonate, and aluminum nitrate in step (3) is 5~15:1~3:100~200:20~50:0.35:60~100:1~2.5:0.8~1.6.

[0013] Furthermore, the porosity of the heat-resistant lightweight wall panel described in step (3) is 30-60%.

[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: The wall panel of the present invention is made by mixing hollow microspheres, nano boron carbide, calcium magnesium aluminate cement and phosphate cement, and then foaming and calcining it to achieve heat resistance and high strength.

[0015] First, hollow microspheres are prepared by copolymerizing polystyrene and zirconium hydroxide. Under oxygen-heat treatment, the micro-adjustment between supporting polymers in polystyrene is promoted, and the microspheres undergo oxidative cross-linking with zirconium hydroxide. This results in uniform wall thickness, good concentricity, and stability of the bilayer spherical polymer, thereby improving the mechanical properties of the lightweight wall panel. Furthermore, zirconium oxide has strong high-temperature resistance and poor thermal conductivity, which can enhance the high-temperature resistance of the matrix by slowing down heat transfer. Next, the microspheres are blended with nano-boron carbide, calcium magnesium aluminate cement, and phosphate cement. Zirconium hydroxide enhances the bonding force between the components of the matrix through its surface hydroxyl groups. In addition, nano-boron carbide induces calcium and aluminum ions in cement particles to form more hydrates through the "nano-induced hydration effect," thus forming a complete structural system and further improving the mechanical properties of the wall panel.

[0016] Secondly, low-porosity foam is produced using a carbon dioxide foaming process. Calcium and magnesium ions and their hydration products in cement can undergo a mineralization reaction with carbon dioxide, sealing them in the cement-based material as inorganic carbonates. A certain distance exists between the foam cells. A small amount of carbon dioxide inside the cells reacts with the hydration products around the pore walls through a carbonation reaction, forming calcite, thus providing a curing effect and strengthening the pore wall structure. This further enhances the strength and high-temperature resistance of the wall panel. Next, calcination treatment is performed to remove some hydroxyl groups from zirconium hydroxide, thereby hardening the hollow microspheres and enhancing the mechanical properties of the wall panel. Phosphate acts as a high-temperature adhesive, and during this process, boron carbide is oxidized to boron oxide, accompanied by a certain volume expansion and weight gain. Both fill the pores in the matrix caused by the loss of water molecules, making the matrix microstructure denser, thus enhancing the mechanical properties and high-temperature resistance of the wall panel. Detailed Implementation

[0017] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0018] To more clearly illustrate the method provided by the present invention, the following embodiments are provided in detail. The test methods for various indicators of the heat-resistant lightweight wall panels produced in the following embodiments are as follows: High temperature resistance: The fire resistance limit of the same size examples and comparative examples was tested according to GB50016.

[0019] Mechanical properties: The flexural strength of the same size examples and comparative examples was tested according to GB / T11969.

[0020] Example 1; (1) Polystyrene and 10wt% hydrochloric acid aqueous solution were mixed at a mass ratio of 2:25 to obtain a polystyrene solution; zirconium hydroxide and 10wt% hydrochloric acid aqueous solution were mixed evenly, and then added to the polystyrene solution and mixed evenly to obtain a polymer solution; the mass ratio of zirconium hydroxide, 10wt% hydrochloric acid aqueous solution and polystyrene solution was 3:80:80. (2) Mix polyvinyl alcohol and deionized water, heat to 60°C, stir at 50 rpm for 20 min, add calcium chloride, and then add deionized water as the inner phase and polymer solution as the intermediate phase through a syringe. Under an oxygen atmosphere, heat to 40°C, stir at 20 rpm for 2 h, then cool to 20°C and solidify for 30 h. Then, filter, take the solid, and remove the inner aqueous phase at 40°C to obtain hollow microspheres; the mass ratio of polyvinyl alcohol, deionized water and calcium chloride is 2:100:1. (3) Hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, and deionized water are mixed and stirred at 30 rpm for 20 s and 1200 rpm for 80 s. Sodium bicarbonate and aluminum nitrate are added and stirred rapidly for another 8 s. The mixture is then poured into a mold, demolded, cured for 1 day, and calcined at 500℃ for 2 h to obtain a heat-resistant lightweight wall panel with a porosity of 30%. The mass ratio of hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, deionized water, sodium bicarbonate, and aluminum nitrate is 5:1:100:20:0.35:60:1:0.8.

[0021] Example 2; (1) Polystyrene and 10wt% hydrochloric acid aqueous solution were mixed at a mass ratio of 2:25 to obtain a polystyrene solution; zirconium hydroxide and 10wt% hydrochloric acid aqueous solution were mixed evenly, and then added to the polystyrene solution and mixed evenly to obtain a polymer solution; the mass ratio of zirconium hydroxide, 10wt% hydrochloric acid aqueous solution and polystyrene solution was 7:80:80. (2) Mix polyvinyl alcohol and deionized water, heat to 75°C, stir at 50 rpm for 35 min, add calcium chloride, and then add deionized water as the inner phase and polymer solution as the intermediate phase through a syringe. Under an oxygen atmosphere, heat to 55°C, stir at 40 rpm for 4 h, then cool to 25°C and solidify for 48 h. Then, filter, take the solid, and remove the inner aqueous phase at 50°C to obtain hollow microspheres; the mass ratio of polyvinyl alcohol, deionized water and calcium chloride is 2:100:1. (3) Hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, and deionized water are mixed and stirred at 45 rpm for 35 s and 1300 rpm for 140 s. Sodium bicarbonate and aluminum nitrate are added and stirred rapidly for 12 s. The mixture is then poured into a mold, demolded, and cured for 4 days. After calcination at 700℃ for 3 h, a heat-resistant lightweight wall panel with a porosity of 40% is obtained. The mass ratio of hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, deionized water, sodium bicarbonate, and aluminum nitrate is 10:2:150:33:0.35:80:1.9:1.2.

[0022] Example 3; (1) Polystyrene and 10wt% hydrochloric acid aqueous solution were mixed at a mass ratio of 2:25 to obtain a polystyrene solution; zirconium hydroxide and 10wt% hydrochloric acid aqueous solution were mixed evenly, and then added to the polystyrene solution and mixed evenly to obtain a polymer solution; the mass ratio of zirconium hydroxide, 10wt% hydrochloric acid aqueous solution and polystyrene solution was 10:80:80. (2) Mix polyvinyl alcohol and deionized water, heat to 90°C, stir at 50 rpm for 50 min, add calcium chloride, and then add deionized water as the inner phase and polymer solution as the intermediate phase through a syringe. Under an oxygen atmosphere, heat to 70°C, stir at 60 rpm for 6 h, then cool to 30°C and solidify for 60 h. Then, filter, take the solid, and remove the inner aqueous phase at 60°C to obtain hollow microspheres; the mass ratio of polyvinyl alcohol, deionized water and calcium chloride is 2:100:1. (3) Hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, and deionized water are mixed and stirred at 60 rpm for 50 s and 1400 rpm for 200 s. Sodium bicarbonate and aluminum nitrate are added and stirred rapidly for 15 s. The mixture is then poured into a mold, demolded, and cured for 7 days. After calcination at 900℃ for 4 h, a heat-resistant lightweight wall panel with a porosity of 60% is obtained. The mass ratio of hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, deionized water, sodium bicarbonate, and aluminum nitrate is 15:3:200:50:0.35:100:2.5:1.6.

[0023] Comparative Example 1; The difference between Comparative Example 1 and Example 2 is that step (2) is different. Step (2) is changed to: mixing polyvinyl alcohol and deionized water, heating to 75°C, stirring at 50 rpm for 35 min, adding calcium chloride, and then adding the polymer solution. Under an oxygen atmosphere, heating to 55°C, stirring at 40 rpm for 4 h, then cooling to 25°C, curing for 48 h, then filtering, taking the solid, drying at 50°C, and obtaining microspheres; the mass ratio of polyvinyl alcohol, deionized water, and calcium chloride is 2:100:1; the remaining steps are the same as in Example 2.

[0024] Comparative Example 2; The difference between Comparative Example 2 and Example 2 is that steps (1) and (2) are different, and step (3) is changed to: mixing nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, and deionized water, stirring at 45 rpm for 35 s, stirring at 1300 rpm for 140 s, adding sodium bicarbonate and aluminum nitrate, continuing to stir rapidly for 12 s, then pouring into a mold to form, demolding, curing for 4 days, and calcining at 700℃ for 3 h to obtain a heat-resistant lightweight wall panel with a porosity of 40%; the mass ratio of nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, deionized water, sodium bicarbonate, and aluminum nitrate is 2:150:33:0.35:80:1.9:1.2; the remaining steps are the same as in Example 2.

[0025] Comparative Example 3; The difference between Comparative Example 3 and Example 2 is that step (3) is different. Step (3) is changed to: mixing hollow microspheres, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, and deionized water, stirring at 45 rpm for 35 s, stirring at 1300 rpm for 140 s, adding sodium bicarbonate and aluminum nitrate, continuing to stir rapidly for 12 s, then pouring into a mold to form, demolding, curing for 4 days, and calcining at 700℃ for 3 h to obtain a heat-resistant lightweight wall panel with a porosity of 40%; the mass ratio of the hollow microspheres, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, deionized water, sodium bicarbonate, and aluminum nitrate is 10:150:33:0.35:80:1.9:1.2; the remaining steps are the same as in Example 2.

[0026] Comparative Example 4; The difference between Comparative Example 4 and Example 2 is that step (3) is different. Step (3) is changed to: mixing hollow microspheres, nano boron carbide, phosphate cement, aluminum stearate, and deionized water, stirring at 45 rpm for 35 s, stirring at 1300 rpm for 140 s, adding sodium bicarbonate and aluminum nitrate, continuing to stir rapidly for 12 s, then pouring into a mold to form, demolding, curing for 4 days, and calcining at 700℃ for 3 hours to obtain a heat-resistant lightweight wall panel with a porosity of 40%; the mass ratio of hollow microspheres, nano boron carbide, phosphate cement, aluminum stearate, deionized water, sodium bicarbonate, and aluminum nitrate is 10:2:183:0.35:80:1.9:1.2; the remaining steps are the same as in Example 2.

[0027] Comparative Example 5; The difference between Comparative Example 5 and Example 2 is that step (3) is different. Step (3) is changed to: mixing hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, aluminum stearate, and deionized water, stirring at 45 rpm for 35 s, stirring at 1300 rpm for 140 s, adding sodium bicarbonate and aluminum nitrate, continuing to stir rapidly for 12 s, then pouring into a mold to form, demolding, curing for 4 days, and calcining at 700℃ for 3 h to obtain a heat-resistant lightweight wall panel with a porosity of 40%; the mass ratio of hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, aluminum stearate, deionized water, sodium bicarbonate, and aluminum nitrate is 10:2:183:0.35:80:1.9:1.2; the remaining steps are the same as in Example 2.

[0028] Comparative Example 6; The difference between Comparative Example 6 and Example 2 is that step (3) is different. Step (3) is changed to: mixing hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, and deionized water, stirring at 45 rpm for 35 s, stirring at 1300 rpm for 140 s, adding sodium dodecyl sulfate, continuing to stir rapidly for 12 s, then pouring into a mold to form, demolding, curing for 4 days, and calcining at 700℃ for 3 h to obtain a heat-resistant lightweight wall panel with a porosity of 40%; the mass ratio of hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, deionized water, and sodium dodecyl sulfate is 10:2:150:33:0.35:80:3; the remaining steps are the same as in Example 2.

[0029] Comparative Example 7; The difference between Comparative Example 7 and Example 2 is that step (3) is different. Step (3) is changed to: mixing hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, and deionized water, stirring at 45 rpm for 35 s, stirring at 1300 rpm for 140 s, adding sodium bicarbonate and aluminum nitrate, continuing to stir rapidly for 12 s, then pouring into a mold to form, demolding, curing for 4 days, and calcining at 700℃ for 3 h to obtain a heat-resistant lightweight wall panel with a porosity of 80%; the mass ratio of hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, deionized water, sodium bicarbonate, and aluminum nitrate is 10:2:150:33:0.35:80:2.9:2.5; the remaining steps are the same as in Example 2.

[0030] Comparative Example 8; The difference between Comparative Example 8 and Example 2 is that step (3) is different. Step (3) is changed to: mixing hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, and deionized water, stirring at 45 rpm for 35 s, stirring at 1300 rpm for 140 s, adding sodium bicarbonate and aluminum nitrate, continuing to stir rapidly for 12 s, then pouring into a mold to form, demolding, curing for 4 days, and obtaining a heat-resistant lightweight wall panel with a porosity of 40%; the mass ratio of hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, deionized water, sodium bicarbonate, and aluminum nitrate is 10:2:150:33:0.35:80:1.9:1.2; the remaining steps are the same as in Example 2.

[0031] Example of effect Table 1 below shows the performance analysis results of the heat-resistant lightweight wall panels of Examples 1 to 3 and Comparative Examples 1 to 8 of the present invention.

[0032] Table 1

[0033] A comparison of the experimental data from the examples and comparative examples in Table 1 reveals that the present invention utilizes hollow microspheres prepared by copolymerizing polystyrene and zirconium hydroxide. Under oxygen-heat treatment, this promotes fine-tuning between the supporting polymers in the polystyrene and oxidative crosslinking with zirconium hydroxide, resulting in uniform wall thickness, good concentricity, and stability of the bilayer spherical polymer, thereby improving the mechanical properties of the lightweight wall panel. Furthermore, zirconium oxide slows down heat transfer, enhancing the high-temperature resistance of the matrix. Subsequently, when blended with nano-boron carbide, calcium magnesium aluminate cement, and phosphate cement, zirconium hydroxide, through its surface hydroxyl groups, enhances the bonding force between the matrix components. Moreover, nano-boron carbide induces the formation of more hydrates from calcium and aluminum ions in the cement particles through the "nano-induced hydration effect," further improving the mechanical properties of the wall panel. Low-porosity foam is produced using a carbon dioxide foaming process. Calcium and magnesium ions and their hydration products in cement can undergo mineralization reactions with carbon dioxide, and there is a certain distance between the foam pores. A small amount of carbon dioxide inside the pores reacts with the hydration products around the pore walls through a carbonization reaction to form calcite, thus creating a curing effect and strengthening the pore wall structure. This further enhances the strength and high-temperature resistance of the wall panel. Subsequently, calcination treatment is carried out to remove some of the hydroxyl groups on zirconium hydroxide, thereby hardening the hollow microspheres and enhancing the mechanical properties of the wall panel. Phosphate can act as a high-temperature adhesive, and during this process, boron carbide is oxidized to generate boron oxide. Both of these components together fill the pores in the matrix caused by the loss of water molecules and make the microstructure of the matrix denser, thereby enhancing the mechanical properties and high-temperature resistance of the wall panel.

[0034] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No markings in the claims should be construed as limiting the scope of the claims.

Claims

1. A method for preparing a heat-resistant lightweight wall panel, characterized in that, The preparation steps include the following: (1) Mix zirconium hydroxide and 10wt% hydrochloric acid aqueous solution evenly, add polystyrene solution, and mix evenly to obtain polymer solution; (2) Mix polyvinyl alcohol and deionized water, heat to 60~90℃, stir at 50rpm for 20~50min, add calcium chloride, then deionized water as the inner phase and polymer solution as the intermediate phase, add it through a syringe, heat to 40~70℃ in an oxygen atmosphere, stir at 20~60rpm for 2~6h, then cool to 20~30℃ and solidify for 30~60h, then filter, take the solid, remove the inner aqueous phase at 40~60℃, and obtain hollow microspheres; (3) Mix hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate and deionized water, stir slowly for 20~50s, stir quickly for 80~200s, add sodium bicarbonate and aluminum nitrate, continue to stir quickly for 8~15s, then pour into a mold to form, demold, cure, and calcined to obtain heat-resistant lightweight wall panel.

2. The method for preparing a heat-resistant lightweight wall panel according to claim 1, characterized in that, The preparation method of the polystyrene solution in step (1) is as follows: polystyrene and 10wt% hydrochloric acid aqueous solution are mixed at a mass ratio of 2:

25.

3. The method for preparing a heat-resistant lightweight wall panel according to claim 1, characterized in that, The mass ratio of zirconium hydroxide, 10wt% hydrochloric acid aqueous solution, and polystyrene solution in step (1) is 3~10:80:

80.

4. The method for preparing a heat-resistant lightweight wall panel according to claim 1, characterized in that, The mass ratio of polyvinyl alcohol, deionized water, and calcium chloride in step (2) is 2:100:

1.

5. The method for preparing a heat-resistant lightweight wall panel according to claim 1, characterized in that, The slow stirring rate in step (3) is 30~60 rpm.

6. The method for preparing a heat-resistant lightweight wall panel according to claim 1, characterized in that, The rapid stirring speed in step (3) is 1200~1400 rpm.

7. The method for preparing a heat-resistant lightweight wall panel according to claim 1, characterized in that, The maintenance period described in step (3) is 1 to 7 days.

8. The method for preparing a heat-resistant lightweight wall panel according to claim 1, characterized in that, The calcination temperature in step (3) is 500~900℃ and the time is 2~4h.

9. The method for preparing a heat-resistant lightweight wall panel according to claim 1, characterized in that, The mass ratio of hollow microspheres, nano boron carbide, calcium magnesium aluminate cement, phosphate cement, aluminum stearate, deionized water, sodium bicarbonate and aluminum nitrate in step (3) is 5~15:1~3:100~200:20~50:0.35:60~100:1~2.5:0.8~1.

6.

10. The method for preparing a heat-resistant lightweight wall panel according to claim 1, characterized in that, The porosity of the heat-resistant lightweight wall panel in step (3) is 30-60%.

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