A fly ash geopolymer thermal insulation material containing thermoplastic phenol formaldehyde resin and a preparation method thereof

Abstract

The application discloses a fly ash geopolymer thermal insulation material containing thermoplastic phenolic resin and a preparation method thereof. By adding thermoplastic phenolic resin powder in the process of preparing the fly ash geopolymer, the phenolic resin is solidified and forms a cross-linked network structure at 80 DEG C constant temperature solidification, so that the porosity of the geopolymer is increased and the neck diameter of the ink bottle hole is reduced. The high porosity increases the heat transfer path and reduces the cross-sectional area of heat transfer, and the reduction of the ink bottle hole neck diameter reduces the heat exchange of the gas in the pore. The overall thermal conductivity of the geopolymer is reduced, and thus the thermal insulation performance is enhanced, so that the thermal insulation problem in the building field can be solved. The disclosed geopolymer is green, low in cost and simple in manufacturing process, and the stable and fire-resistant phenolic resin is combined with the solid waste fly ash, so that the porosity is increased under the guarantee of the compressive strength. The solid waste reuse is promoted, the carbon emission is reduced, the thermal insulation performance is improved, and the application is suitable for promotion and application.

Description

Technical Field

[0001] The invention relates to the technical field of engineering materials and discloses a high-porosity foamed fly ash geopolymer, in particular to a fly ash geopolymer insulation material containing thermoplastic phenolic resin and a preparation method thereof. Background Art

[0002] Portland cement (OPC) is the most widely used building material in the world. However, in recent years, the carbon emissions associated with Portland cement have attracted considerable attention. Compared to OPC, geopolymers are increasingly attracting attention as a binder material with lower carbon emissions. Geopolymers are inorganic aluminosilicates derived from solid aluminosilicates rich in active silica and alumina (mostly from solid waste such as fly ash, coal gangue, and blast furnace slag) through polymerization in an alkaline solution.

[0003] In addition, giving geopolymers thermal insulation properties has always been a hot area of ​​research in building materials. The key problem to be solved by the present invention is to develop geopolymers using solid waste and to improve the thermal insulation properties of geopolymers. This will provide a thermal insulation building material with lower carbon emissions for the engineering construction field and realize the recycling of solid waste. Compared with conventional thermal insulation materials (such as polyurethane), geopolymers have superior fire resistance. Secondly, geopolymers themselves have certain mesopores (2 to 50nm) and micropores (<2nm), with a porosity of 25% to 30%, which is generated by water evaporation during constant temperature curing. However, the porosity caused by water evaporation in the geopolymer system is not enough to produce thermal insulation properties comparable to conventional thermal insulation materials. Therefore, it is necessary to find a modified substance that can increase the porosity of geopolymers.

[0004] Phenolic resin is an organic material derived from the polycondensation of phenol-formaldehyde or its derivatives. It exhibits excellent heat resistance and is widely used in construction, military, industrial, agricultural, architectural, aerospace, and other fields. Phenolic resin forms a cross-linked porous network structure after curing at high temperatures (above 80°C). However, the impact of phenolic resin on geopolymers as thermal insulation materials has not been explored. Summary of the Invention

[0005] In view of this, the present application provides a fly ash geopolymer insulation material containing thermoplastic phenolic resin, which increases the porosity of the geopolymer and reduces the neck diameter of the ink bottle hole by curing the thermoplastic phenolic resin at 80°C. The high porosity will increase the heat transfer path and reduce the cross-sectional area of ​​heat transfer, while reducing the neck diameter of the ink bottle hole can reduce the heat exchange of the gas in the pores. The overall thermal conductivity of the geopolymer is reduced and the thermal insulation performance is enhanced, which can solve the insulation problem in the construction field.

[0006] Specifically, phenolic resin, after forming a porous three-dimensional cross-linked network, can introduce pores into fly ash-based geopolymers, increasing their porosity. This is because the thermal conductivity of air is much lower than that of solid materials. Furthermore, the introduction of pores reduces the cross-sectional area for heat conduction. The tortuous structure created by the pores also increases the heat transfer path through the solid, ultimately reducing the driving force for heat flow through the solid material (i.e., the temperature gradient). Furthermore, the addition of phenolic resin can optimize the pore size distribution and pore morphology of the geopolymer.

[0007] Phenolic resin can directionally increase pore diameters in the 1-20 μm range. According to the Knudsen effect (Equations 1 and 2), smaller pores have lower thermal conductivity. Hydrogen peroxide, a common foaming agent for geopolymers, reacts violently, forming pores larger than 1000 μm. The thermoplastic phenolic resin used in the present invention can generate pores in the 1-20 μm range, which are smaller than those generated by hydrogen peroxide. This results in lower thermal conductivity and improved thermal insulation performance.

[0008]

[0009]

[0010] Furthermore, the addition of phenolic resin can reduce the diameter of the ink bottle pores within the geopolymer. As a binder, phenolic resin exhibits excellent compatibility with fly ash geopolymer. Microscopically, it can adhere to the neck of the ink bottle pore, effectively reducing its diameter and improving the closure of the pore. The size of the opening in the ink bottle pore affects the heat conduction of gas between the pore and the throat. Improving the closure of the ink bottle pore promotes gas accumulation and inhibits gas migration. As the opening narrows, the gas within the pore is less likely to exchange heat with the gas outside, thus improving the thermal insulation performance of the geopolymer.

[0011] It should also be noted that the silicon-aluminum molar ratio of the fly ash used must be known before production. The corresponding alkaline activator is then prepared based on this ratio to achieve an overall silicon-aluminum molar ratio of 1.9 after mixing. Because the alkaline activator must be prepared based on the chemical composition of the fly ash, a mixed powder of solid analytically pure sodium silicate and sodium hydroxide was used as the alkaline activator.

[0012] In order to achieve the above object, the present invention adopts the following technical solutions:

[0013] The first technical purpose of the present invention is to provide a fly ash geopolymer insulation material containing thermoplastic phenolic resin, which is mainly prepared from the following substances in parts by weight:

[0014] 90-110 parts of fly ash, 50-70 parts of water, 5-10 parts of thermoplastic phenolic resin, and 25-30 parts of alkali activator.

[0015] Optionally, the fly ash geopolymer insulation material containing thermoplastic phenolic resin is mainly prepared from the following substances in parts by weight:

[0016] 100 parts of fly ash, 50 parts of water, 5-10 parts of thermoplastic phenolic resin, and 26.5 parts of alkali activator.

[0017] It should be noted that the fly ash geopolymer insulation material prepared by the present invention has a solid-liquid ratio of 2, a silicon-aluminum molar ratio of 1.9, and a constant temperature curing temperature of 80°C.

[0018] Optionally, the alkaline activator is a mixed powder of sodium hydroxide and sodium silicate, and the molar ratio (modulus) of SiO2 to Na2O in the mixed powder is 1.4; wherein, the sodium hydroxide is an analytically pure powder, accounting for 25.6% of the mass of the mixed powder; the sodium silicate is an analytically pure powder, and its modulus (molar ratio of SiO2 to Na2O) is 2.8, accounting for 74.4% of the mass of the mixed powder.

[0019] Optionally, the thermoplastic phenolic resin is a white to light yellow powder with a particle size of 1 μm to 10 μm, a free phenol content of ≤4.5%, a hexamethylenetetramine content of 0%, and a 180 mesh pass rate of ≥99.5%.

[0020] The second technical purpose of the present invention is to provide a method for preparing the above-mentioned fly ash geopolymer insulation material containing thermoplastic phenolic resin, the method specifically comprising the following steps:

[0021] S1: Add sodium hydroxide to water at room temperature, let it stand to room temperature after it is completely dissolved, and then heat it in a water bath at 50°C and remove it. Then, add sodium silicate to the water in a ratio of 1 to 2 parts to prevent the sodium silicate powder from agglomerating into lumps, and stir with a glass rod until the sodium silicate is completely dissolved to obtain an alkaline activator solution.

[0022] S2: The alkaline activator solution described in S1 is allowed to stand to room temperature, and then fly ash is slowly added to form a geopolymer slurry, which is stirred on a disperser at a speed of 400 r / min for 4 to 6 minutes.

[0023] S3: The geopolymer slurry described in S2 is removed from the disperser. In order to uniformly disperse the phenolic resin in the geopolymer slurry, the thermoplastic phenolic resin is added to the geopolymer slurry in a ratio of 0.25 to 0.5 parts. Each time the thermoplastic phenolic resin is added to the geopolymer slurry, it is necessary to stir it on the disperser at a speed of 400 r / min for 1 to 2 minutes; after all the thermoplastic phenolic resin is added to the slurry, stir it on the disperser at 400 r / min for 2 to 4 minutes to obtain slurry II.

[0024] S4: Pour the slurry II described in S3 into a plastic mold, cure it in a constant temperature box at 80°C for 24 hours, demould it, and cure it at room temperature for 28 days.

[0025] It can be seen from the above technical solution that, compared with the prior art, the present invention provides a fly ash geopolymer insulation material containing thermoplastic phenolic resin and a preparation method thereof, which has the following excellent effects:

[0026] The present invention adds thermoplastic phenolic resin powder to the production of a fly ash-based geopolymer. The phenolic resin solidifies at a constant temperature of 80°C, forming a cross-linked network structure. This increases the porosity of the geopolymer and reduces the diameter of the ink bottle neck. High porosity increases the heat transfer path and reduces the cross-sectional area for heat transfer, while reducing the diameter of the ink bottle neck reduces heat exchange within the pores. This reduces the overall thermal conductivity of the geopolymer and enhances its thermal insulation properties, addressing insulation issues in the construction industry. The geopolymer disclosed in this invention is environmentally friendly, low-cost, and has a simple production process. It innovatively combines the stable refractory phenolic resin with a solid waste-based fly ash matrix, increasing porosity while maintaining compressive strength. This approach promotes solid waste reuse and reduces carbon emissions while also improving thermal insulation performance, making it suitable for widespread application. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] To clearly illustrate the technical solutions in the examples of the present invention, the following briefly introduces the drawings required in the embodiments or descriptions of the prior art. It should be noted that the drawings in the descriptions are only embodiments of the present invention and are provided so that those skilled in the art or of ordinary skill in the art can derive other drawings based on the provided drawings without inventive effort.

[0028] Figure 1 The present invention discloses a process flow chart for preparing the fly ash geopolymer thermal insulation material containing thermoplastic phenolic resin.

[0029] Figure 2 This is the computed tomography image of Comparative Example 1.

[0030] Figure 3 This is a computed tomography image of Example 3.

[0031] Figure 4 This is a schematic diagram of the scanning electron microscope of the sample obtained by curing at room temperature for 28 days in comparative example 1.

[0032] Figure 5 This is a schematic diagram of a scanning electron microscope of the sample obtained by curing at room temperature for 28 days in Example 3.

[0033] Figure 6 Schematic diagram of the mercury injection-mercury removal curve of the sample obtained by curing at room temperature for 28 days in Comparative Example 1.

[0034] Figure 7 This is a schematic diagram of the mercury intrusion-mercury depressurization curve of the sample obtained by curing at room temperature for 28 days in Example 3.

[0035] Figure 8 This is the pore size distribution diagram of the sample obtained by oxidation at room temperature for 28 days in Comparative Example 1.

[0036] Figure 9 This is the pore size distribution diagram of the sample obtained by curing at room temperature for 28 days in Example 3. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions disclosed in the present invention in conjunction with the embodiments of the present invention and the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0038] The embodiment of the invention discloses a method for preparing a fly ash geopolymer thermal insulation material containing thermoplastic phenolic resin.

[0039] In order to better understand the present invention, the present invention is further specifically described below through the following specific embodiments, but it should not be understood as limiting the present invention. Some non-essential improvements and adjustments made by technicians in this field based on the above invention content are also considered to fall within the scope of protection of the present invention.

[0040] Example 1

[0041] (1) The high-porosity foamed fly ash geopolymer prepared in Example 1 has the following physical properties: a solid-liquid mass ratio of 2; and a silicon-aluminum molar ratio of 1.9.

[0042] (2) The high-porosity foamed fly ash geopolymer prepared in Example 1 comprises the following components in parts by weight: 100 parts of fly ash, 50 parts of water, 5 parts of thermoplastic phenolic resin, and 26.5 parts of alkali activator.

[0043] (3) The alkaline activator used in Example 1 is a mixed powder of sodium hydroxide and sodium silicate, including 19.7 parts of sodium silicate and 6.8 parts of sodium hydroxide; wherein the sodium hydroxide is an analytically pure powder, and the molar ratio (modulus) of SiO2 to Na2O in the mixed powder is 1.4; the sodium hydroxide is an analytically pure powder, accounting for 25.6% of the mass of the mixed powder; and the sodium silicate is an analytically pure powder, whose modulus (molar ratio of SiO2 to Na2O) is 2.8, accounting for 74.4% of the mass of the mixed powder.

[0044] (4) The thermoplastic phenolic resin used in Example 1 is white to light yellow powder, particle size 1-10 μm, free phenol ≤4.5%, urotropine 0%, 180 mesh passing rate ≥99.5%.

[0045] (5) After the preparation of the materials, sodium hydroxide is added to water at room temperature, and after complete dissolution, it is left to stand at room temperature. It is removed from the water bath after heating at 50°C, and then sodium silicate is added to the water in a ratio of 1.5 parts to prevent the sodium silicate from coagulating into a block. At the same time, a glass rod is used to stir until the sodium silicate is completely dissolved, and an alkali activator solution is prepared.

[0046] (6) The alkali activator solution prepared in step (5) is left to stand at room temperature, and then fly ash is slowly added to prepare a geopolymer slurry. The slurry is stirred on a disperser at a speed of 400 r / min for 6 minutes.

[0047] (7) The geopolymer slurry prepared in step (6) is removed from the disperser. In order to uniformly disperse the phenolic resin in the geopolymer slurry, thermoplastic phenolic resin is added to the geopolymer slurry in a ratio of 0.4 parts. After each addition of thermoplastic phenolic resin to the geopolymer slurry, it is stirred on the disperser at a speed of 400 r / min for 2 minutes. After all the thermoplastic phenolic resin is added to the slurry, it is stirred on the disperser at a speed of 400 r / min for 4 minutes to prepare slurry II.

[0048] (8) The slurry II prepared in step (7) is poured into a plastic mold and cured at 80°C in a constant temperature oven for 24 hours. After demolding, it is removed and cured at room temperature for 28 days. The sample is subjected to thermal conductivity detection, scanning electron microscope analysis and mercury injection method analysis.

[0049] Example 2

[0050] (1) The high-porosity foamed fly ash geopolymer prepared in Example 2 has the following physical properties: solid-liquid ratio is 2; silicon-aluminum molar ratio is 1.9.

[0051] (2) The high-porosity foamed fly ash geopolymer prepared in Example 2 includes the following components by weight fraction: fly ash 100 parts, water 50 parts, thermoplastic phenolic resin 7.5 parts, alkali activator 26.5 parts.

[0052] (3) The alkali activator used in Example 2 is a mixture of sodium hydroxide and sodium silicate powder, including sodium silicate 19.7 parts and sodium hydroxide 6.8 parts; and the molar ratio (modulus) of SiO2 to Na2O in the mixture is 1.4; wherein the sodium hydroxide is an analytical pure powder, accounting for 25.6% of the mass of the mixture. The sodium silicate is an analytical pure powder, with a modulus (molar ratio of SiO2 to Na2O) of 2.8, accounting for 74.4% of the mass of the mixture.

[0053] (4) The thermoplastic phenolic resin used in Example 2 is a white to light yellow powder with a particle size of 1 μm to 10 μm, free phenol ≤ 4.5%, hexamethylenetetramine 0%, and a 180 mesh pass rate ≥ 99.5%.

[0054] (5) After the materials are prepared, sodium hydroxide is added to water at room temperature. After it is completely dissolved, it is allowed to stand at room temperature. It is then heated in a water bath at 50°C and removed. Then, sodium silicate is added to the water in a ratio of 1.5 parts to prevent the sodium silicate powder from agglomerating. At the same time, it is stirred with a glass rod until the sodium silicate is completely dissolved to obtain an alkaline activator solution.

[0055] (6) The alkaline activator solution prepared in step (5) was allowed to stand at room temperature, and then fly ash was slowly added to prepare a geopolymer slurry, which was stirred at a speed of 400 r / min on a disperser for 6 minutes.

[0056] (7) The geopolymer slurry prepared in step (6) is removed from the disperser. In order to uniformly disperse the phenolic resin in the geopolymer slurry, the thermoplastic phenolic resin is added to the geopolymer slurry in a ratio of 0.4 parts. Each time the thermoplastic phenolic resin is added to the geopolymer slurry, it is stirred at a speed of 400 r / min for 2 minutes on the disperser. After all the thermoplastic phenolic resin is added to the slurry, it is stirred at 400 r / min for 4 minutes on the disperser to obtain slurry II.

[0057] (8) Pour the slurry II prepared in step (7) into a plastic mold and cure it in a thermostat at 80°C for 24 hours. After demolding, the mold is removed and cured at room temperature for 28 days. The sample is subjected to thermal conductivity testing, scanning electron microscopy analysis, and mercury intrusion analysis.

[0058] Example 3

[0059] (1) The high-porosity foamed fly ash geopolymer prepared in Example 3 has the following physical properties: a solid-liquid mass ratio of 2; and a silicon-aluminum molar ratio of 1.9.

[0060] (2) The high-porosity foamed fly ash geopolymer prepared in Example 3 comprises the following components in parts by weight: 100 parts of fly ash, 50 parts of water, 10 parts of thermoplastic phenolic resin, and 26.5 parts of alkali activator.

[0061] (3) The alkaline activator used in Example 3 is a mixed powder of sodium hydroxide and sodium silicate, including 19.7 parts of sodium silicate and 6.8 parts of sodium hydroxide; and the molar ratio (modulus) of SiO2 to Na2O in the mixed powder is 1.4; wherein the sodium hydroxide is an analytically pure powder, accounting for 25.6% of the mass of the mixed powder; and the sodium silicate is an analytically pure powder, whose modulus (molar ratio of SiO2 to Na2O) is 2.8, accounting for 74.4% of the mass of the mixed powder.

[0062] (4) The thermoplastic phenolic resin used in Example 3 is a white to light yellow powder with a particle size of 1 μm to 10 μm, free phenol ≤ 4.5%, hexamethylenetetramine 0%, and a 180 mesh pass rate ≥ 99.5%.

[0063] (5) After the materials are prepared, sodium hydroxide is added to water at room temperature. After it is completely dissolved, it is allowed to stand at room temperature. It is then heated in a water bath at 50°C and removed. Then, sodium silicate is added to the water in a ratio of 1.5 parts to prevent the sodium silicate powder from agglomerating. At the same time, it is stirred with a glass rod until the sodium silicate is completely dissolved to obtain an alkaline activator solution.

[0064] (6) The alkaline activator solution prepared in step (5) was allowed to stand at room temperature, and then fly ash was slowly added to prepare a geopolymer slurry, which was stirred at a speed of 400 r / min on a disperser for 6 minutes.

[0065] (7) The geopolymer slurry prepared in step (6) is removed from the disperser. In order to uniformly disperse the phenolic resin in the geopolymer slurry, the thermoplastic phenolic resin is added to the geopolymer slurry in a ratio of 0.4 parts. Each time the thermoplastic phenolic resin is added to the geopolymer slurry, it is stirred at a speed of 400 r / min for 2 minutes on the disperser. After all the thermoplastic phenolic resin is added to the slurry, it is stirred at 400 r / min for 4 minutes on the disperser to obtain slurry II.

[0066] (8) Pour the slurry II prepared in step (7) into a plastic mold and cure it in a thermostat at 80°C for 24 hours. After demolding, the mold is removed and cured at room temperature for 28 days. The sample is subjected to thermal conductivity testing, computed tomography analysis, scanning electron microscopy analysis, computed tomography analysis, and mercury intrusion porosimetry analysis.

[0067] Comparative Example 1

[0068] (1) The high-porosity foamed fly ash geopolymer prepared in Comparative Example 1 has the following physical properties: solid-liquid ratio of 2; silicon-aluminum molar ratio of 1.9.

[0069] (2) The high-porosity foamed fly ash geopolymer prepared in Comparative Example 1 comprises the following components in parts by weight: 100 parts of fly ash, 50 parts of water, 0 parts of thermoplastic phenolic resin, and 26.5 parts of alkali activator.

[0070] (3) The alkaline activator used in Comparative Example 1 is a mixed powder of sodium hydroxide and sodium silicate, including 19.7 parts of sodium silicate and 6.8 parts of sodium hydroxide; and the molar ratio (modulus) of SiO2 to Na2O in the mixed powder is 1.4; the sodium hydroxide is an analytically pure powder, accounting for 25.6% of the mass of the mixed powder; the sodium silicate is an analytically pure powder, whose modulus is 2.8, accounting for 74.4% of the mass of the mixed powder.

[0071] (4) After the materials are prepared, sodium hydroxide is added to water at room temperature. After it is completely dissolved, it is allowed to stand at room temperature. It is then heated in a water bath at 50°C and removed. Then, sodium silicate is added to the water in a ratio of 1.5 parts to prevent the sodium silicate powder from agglomerating into lumps. At the same time, it is stirred with a glass rod until the sodium silicate is completely dissolved to obtain an alkaline activator solution.

[0072] (5) The alkaline activator solution prepared in step (4) was allowed to stand at room temperature, and then fly ash was slowly added to prepare a geopolymer slurry, and the slurry was prepared by stirring at a speed of 400 r / min on a disperser for 6 minutes.

[0073] (6) The slurry prepared in step (5) was poured into a plastic mold and cured in a thermostat at 80°C for 24 hours. After demolding, the mold was removed and cured at room temperature for 28 days. The sample was subjected to thermal conductivity testing, computed tomography analysis, scanning electron microscopy analysis, and mercury intrusion analysis.

[0074] Thermal conductivity test, using mercury intrusion method to analyze the porosity of the examples and comparative examples are shown below (Table 1):

[0075] Table 1 Porosity test of foamed fly ash geopolymer

[0076]

[0077] As shown in Table (1), since phenolic resin solidifies in an environment above 80°C and forms a porous cross-linked network structure, the porosity of fly ash geopolymer increases from 29.5% to 51.2%. Figure 2 、 Figure 3 The computer three-dimensional tomography images of Comparative Example 1 and Example 3 show that the pores of the fly ash geopolymer increased significantly after modification with thermoplastic phenolic resin. These increased pores increase the heat transfer path, reduce the heat transfer cross-sectional area, and reduce the thermal conductivity by filling with air, so that the thermal conductivity is reduced from 0.42 W / m·K to 0.17 W / m·K, which proves the good thermal insulation modification effect of phenolic resin.

[0078] In addition, the scanning electron microscope images of Comparative Example 1 and Example 3 are as follows: Figure 4 and Figure 5 As shown, it can be seen that the pore openness in comparative example 1 is better and the pore diameter is larger, while in example 3, due to the addition of phenolic resin, the pore openness is poor, which can effectively hinder gas convection and improve thermal insulation performance. Figure 6 and Figure 7It can be intuitively seen that the mercury injection and mercury extraction curves for both Comparative Example 1 and Example 3 do not overlap (known as hysteresis). This phenomenon is due to the presence of the ink bottle pore in the sample. The ink bottle pore consists of a neck and a pore, and the neck diameter is smaller than the pore diameter. During mercury extraction, the mercury in the neck is squeezed out first. Because the throat diameter is narrower than the pore, the throat hinders the extrusion of mercury in the pore before the throat's extrusion force is reached, resulting in a straight line segment in the extrusion curve. The hysteresis phenomenon in Example 3 significantly decreases with increasing the thermoplastic phenolic resin content. Compared with Comparative Example 1, the extrusion curve of the sample in Example 3 has a longer straight line segment. Furthermore, the descending section is steeper than that of Comparative Example 1. The fitting slope of the descending section of the mercury withdrawal curve for Comparative Example 1 is 0.049, while the fitting slope of the descending section of the mercury withdrawal curve for Example 3 is 0.219. This is because cavitation-controlled evaporation occurs within a narrow diameter range of the pore neck, and pore blockage also occurs, resulting in a steeper descending section of the mercury withdrawal curve and an increased slope. This indicates that the pore neck diameter of the sample in Example 3 is narrower. The narrowed pore diameter is more conducive to gas storage in the pores, reducing heat exchange and thus improving thermal insulation performance.

[0079] Furthermore, the pore size distribution of Comparative Example 1 and Example 3 is as follows Figure 8 and Figure 9 As shown, compared with Comparative Example 1, the pores with a pore size of 1 to 20 μm in Example 3 are significantly increased, as shown in FIG. Figure 8 and Figure 9 As shown in the dashed box, the porosity in the 1-20 μm range in Comparative Example 1 is 16.08%, while that in Example 3 is 42.25%. This is because thermoplastic phenolic resin forms a porous, cross-linked network structure at 80°C, with pores comparable in size to the particle size of the phenolic resin itself. These increased pores help improve the thermal insulation properties of fly ash geopolymers. Compared to hydrogen peroxide foaming agents, which can generate pores larger than 1000 μm, thermoplastic phenolic resin produces smaller pores and better insulation.

[0080] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the material amounts defined herein may be adjusted accordingly in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein, but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A fly ash geopolymer insulation material containing thermoplastic phenolic resin, characterized in that: According to parts by weight, it is mainly prepared from the following substances: 90-110 parts of fly ash, 50-70 parts of water, 5-10 parts of thermoplastic phenolic resin, 25-30 parts of alkali activator; The alkaline activator is a mixed powder of sodium hydroxide and sodium silicate, and the molar ratio (modulus) of SiO2 to Na2O in the mixed powder is 1.4; Wherein, the sodium hydroxide is analytically pure powder, accounting for 25.6% of the mass of the mixed powder; the sodium silicate is analytically pure powder, accounting for 74.4% of the mass of the mixed powder, and the molar ratio (modulus) of SiO2 to Na2O is 2.8; The thermoplastic phenolic resin is a white to light yellow powder with a particle size of 1 μm to 10 μm, a free phenol content of ≤4.5%, a hexamethylenetetramine content of 0%, and a 180 mesh pass rate of ≥99.5%; The preparation method of the fly ash geopolymer thermal insulation material containing thermoplastic phenolic resin specifically comprises the following steps: S1: Weigh the raw materials in proportion, dissolve sodium hydroxide in water and let it stand to room temperature, then heat it in a water bath to 50°C and add sodium silicate gradually to prevent caking, and stir to dissolve to prepare an alkaline activator solution; S2: slowly adding fly ash to the alkaline activator solution prepared in S1 and stirring to prepare slurry I; S3: adding thermoplastic phenolic resin gradually to the slurry I prepared in S2 while stirring, and stirring after the addition of the thermoplastic phenolic resin is completed to prepare slurry II; S4: pouring the slurry II prepared in S3 into a mold, curing at a constant temperature of 80° C. for 24 hours, then demoulding, and curing at room temperature for 28 days to obtain the fly ash geopolymer insulation material containing thermoplastic phenolic resin; The thermoplastic phenolic resin increases the porosity of the fly ash geopolymer insulation material and adheres to the pore size of the ink bottle hole, thereby reducing the pore size of the ink bottle hole; The fly ash geopolymer thermal insulation material containing thermoplastic phenolic resin has a porosity of 32.8%, 42.3% or 51.2%, and a thermal conductivity of 0.17 W / m·K, 0.26 W / m·K or 0.32 W / m·K.

2. The fly ash geopolymer insulation material containing thermoplastic phenolic resin according to claim 1, characterized in that: According to parts by weight, it is mainly prepared from the following substances: 100 parts of fly ash, 50 parts of water, 5-10 parts of thermoplastic phenolic resin, and 26.5 parts of alkali activator.

3. The fly ash geopolymer insulation material containing thermoplastic phenolic resin according to claim 1, characterized in that: The stirring speed in S2 is 400 r / min, and the stirring time is 4 to 6 min; the stirring speed in S3 is 400 r / min, and the stirring time is 1 to 2 min; and the stirring speed after the addition of the thermoplastic phenolic resin is 600 r / min, and the stirring time is 2 to 4 min.

4. The fly ash geopolymer insulation material containing thermoplastic phenolic resin according to claim 1 or 3, characterized in that: The sodium silicate in S1 is added in portions by weight in an amount of 1 to 2 parts, and the thermoplastic phenolic resin in S3 is added in portions by weight in an amount of 0.25 to 0.5 parts.

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