A polymer building material and a method for reuse

Abstract

The present invention discloses a polymer building material and a method for reuse. The polymer lunar building material comprises the following raw materials: 100-300 parts of a high molecular polymer and 700-1000 parts of soil. For large-scale exploration and resource development of extraterrestrial celestial bodies such as the moon and Mars, a permanent or semi-permanent habitat is required as a basis. However, traditional cement cannot be used due to problems such as cost and manufacturing conditions. Therefore, a building material preparation method that can be processed, used, and recycled in extreme environments is needed to meet the requirements of sustainable planetary surface construction. The present invention realizes the consolidation of soil particles by the polymer through compaction and heating, can form relatively high strength in a short time, and can be reused by re-compacting and heating after grinding. The present invention provides a building material preparation method that can be processed, used, and recycled in harsh environments, and can help solve the infrastructure problems faced by extraterrestrial exploration.

Description

Technical Field

[0001] The present invention belongs to the field of building materials, and particularly relates to a polymer building material and a method for its reuse. Background Art

[0002] For large-scale exploration and resource development of extraterrestrial celestial bodies such as the Moon and Mars, a permanent or semi-permanent habitat is required as a basis. However, directly transporting building materials from the Earth has problems of excessively high costs and low efficiency. Therefore, it is necessary to utilize the surface resources of celestial bodies as basic materials to reduce construction costs. The most economical one is the in-situ use of soil. By sintering, cementing and other methods, the soil is shaped and solidified to prepare a functional building material, which can be used to protect the safety of personnel and equipment. However, most extraterrestrial planets and satellites have harsh surface environments, and the atmospheric thickness, radiation intensity, and temperature conditions have strict requirements on the preparation method and service performance of building materials. Traditional cement concrete and geopolymer concrete technologies cannot adapt to extreme environmental conditions and require a large amount of water resources; while the molten consolidation technology of soil needs to heat the soil to more than a thousand degrees, and this continuous high-energy output is difficult to achieve in the initial exploration. Therefore, there is currently a need for a building material preparation method that can be processed, used, and recycled in extreme environments to meet the needs of sustainable planetary surface construction. Summary of the Invention

[0003] The present invention provides a reusable polymer building material, which can consolidate soil in a short time, generate strength, and can be recycled according to actual needs, effectively saving construction costs and meeting the needs of repair and demolition.

[0004] To achieve the above object, the present invention provides a polymer building material, and the polymer lunar surface building material comprises the following raw materials in parts by weight: 100 - 300 parts of a high molecular polymer, and 700 - 1000 parts of soil, wherein the high molecular polymer is a solid powder thermoplastic high molecular polymer.

[0005] Further, the particle size of the high molecular polymer is less than 75 μm; the melting point is higher than 230 °C; the decomposition temperature is at least 50 °C higher than the melting point; the embrittlement temperature is lower than -180 °C, and the radiation tolerance value is not less than 10^3 Gy.

[0006] Further, the particle size of the soil material is 0.01 μm - 1 mm, and the median particle size is 51 - 138 μm.

[0007] Further, the preparation method of the polymer building material comprises the following steps:

[0008] S101. Mix the high molecular polymer and the soil in proportion and stir well to obtain a mixed powder;

[0009] S102. Place the mixed powder in a mold and compact it to obtain a dense material;

[0010] S103. Heat the dense material after demolding;

[0011] S104. Let the dense material cool naturally after heating to obtain a polymer building material.

[0012] Furthermore, the heating temperature in S103 is the melting point of the polymer, and the holding time is not less than 30 minutes.

[0013] Furthermore, the compaction condition in S102 is to use a press to compact at a constant loading speed of not less than 5 kN / s, and the compaction density of the dense material in S102 is not less than 1.7 g / cm 3 .

[0014] Further, the polymer building material also includes a reuse method, and the reuse method includes the following steps:

[0015] S201. Grind the recycled polymer building material thoroughly to make recycled powder;

[0016] S202. Place the recycled powder in a mold and compact the recycled powder to obtain a dense recycled material;

[0017] S203. Heat the dense recycled material after demolding;

[0018] S204. Let the dense recycled material cool naturally after heating to obtain a polymer building material with a certain strength.

[0019] Furthermore, the heating temperature in S203 is the melting point of the polymer, and the holding time is not less than 30 minutes.

[0020] Furthermore, the compaction condition is to use a press to compact at a constant loading speed of not less than 5 kN / s.

[0021] Furthermore, the compaction density of the dense recycled material in S202 is not less than 1.7 g / cm 3 .

[0022] The present invention provides a polymer building material, which utilizes the characteristic that thermoplastic high molecular polymers can be repeatedly melted and consolidated, realizes the reuse of building materials, and achieves a breakthrough in the in-situ resource building material recycling scheme on extraterrestrial bodies. The thermoplastic high molecular polymer adopted in the present invention has a relatively high molecular weight, a stable molecular structure, good weather resistance to vacuum, high and low temperatures, and strong radiation, high chemical stability, and does not react with other substances. After reaching the melting point, the polymer changes from a solid to a viscous melt, and after the temperature decreases, the melt recrystallizes and transforms into a solid, which can achieve segmented or local consolidation and has high operability. In addition, during the preparation of the building material of the present invention, simple compaction can be used for shaping. The compaction operation can reduce the gap between soil particles and polymer particles, make the material dense, and help the molten polymer and soil particles to be fully mixed and bonded into blocks. When recycling and reusing are required, the grinding into powder operation can fully break the consolidated polymer and soil, and ensure the volume stability of the test block during the melting and consolidation process when used again.

[0023] In summary, the polymer building material and its reuse method of the present invention can cope with the extreme environments on the surfaces of extraterrestrial planets and satellites, and have broad prospects for engineering applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present specification or the prior art, the following will briefly introduce the drawings required to be used in the embodiments. By referring to the drawings, the features and advantages of the present invention will be more clearly understood. The drawings are schematic and should not be construed as limiting the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0025] Figure 1 It is a flow chart for the preparation and reuse of the polymer building material in this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0026] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention. Unless otherwise specified, the technical means adopted in the embodiments are conventional reagents, methods, and equipment well known to those skilled in the art.

[0027] The embodiment of the present invention discloses a polymer building material, which includes the following raw materials in parts by weight: 100 - 300 parts of high molecular polymer, and 700 - 1000 parts of soil.

[0028] Specifically, the raw materials used in the embodiments of the present invention are as follows:

[0029] The soil material is simulated lunar soil: the chemical composition is shown in Table 1, with a density of 1.51 g / cm 3 , and the median particle size is 88 μm.

[0030] Table 1 Chemical composition of simulated lunar soil (wt%)

[0031]

[0032] The high molecular polymer: tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer (PFA), with a median particle size of 8.5 μm, and the molecular structural formula is as follows:

[0033]

[0034] Among them, R is perfluoropropyl, with a molecular formula of -CF2CF2CF3 and a mass fraction of 4.0%. The melting point of PFA is 310 °C, and the initial decomposition temperature is 490 °C. The long-term use temperature range is -250~260 °C, and the radiation tolerance value is 10^3 Gy. The high molecular polymer of the present invention can also use fluoropolymers such as PTFE and FEP. The radiation tolerance value (the maximum radiation dose that can be tolerated) of the fluoropolymer is about 1×10 3 Gy, and the average dose of lunar surface particle radiation is 1.32×10 -5 Gy / h. Lunar surface radiation will not cause aging of the fluoropolymer. The above-mentioned fluoropolymers can be used in the temperature range of -250~260 °C for a long time

[0035] To further illustrate the effects of the solutions of the present invention, Examples 1-12 and Comparative Examples 1-6 are listed below.

[0036] The preparation methods of Examples 1~9 and Comparative Example 6 are as follows:

[0037] S101. Mix PFA and simulated lunar soil according to the mass ratio and stir well to obtain a mixed powder;

[0038] S102. Place the mixed powder in a mold and use a press to compact the mixed powder at a constant loading speed of 5 kN / s to obtain a dense material with a predetermined compaction density;

[0039] S103. Heat the demolded dense material in a muffle furnace (atmospheric pressure) and a vacuum heating furnace (low vacuum degree, air pressure 50 Pa) respectively: heat it to 320 °C at a rate of 10 °C / min and keep it warm for 1 hour.

[0040] S104. After the dense material is heated, it is naturally cooled to obtain a polymer building material with a certain strength.

[0041] The preparation methods of Examples 10 to 12 and Comparative Examples 1 to 2 are as follows:

[0042] S201. Thoroughly grind the recycled polymer building materials to make recycled powders with a specific fineness.

[0043] S202. Place the recycled powders in a mold, and use a press to compact the recycled powders at a constant loading rate of not less than 5 kN / s to obtain a dense recycled material with a predetermined compaction density.

[0044] S203. Heat the demolded dense recycled materials in a muffle furnace (atmospheric pressure) and a vacuum heating furnace (air pressure 50 Pa) respectively: heat up to 320 °C at a rate of 10 °C / min and hold for 1 hour.

[0045] S204. After the dense recycled materials are heated, let them cool naturally to obtain polymer building materials with a certain strength.

[0046] The preparation methods of Comparative Examples 3 to 5 are as follows:

[0047] S301. Mix portland cement and simulated lunar soil in a mass ratio and stir thoroughly to obtain mixed powders.

[0048] S302. Place the mixed powders in a mold, and use a press to compact the mixed powders at a constant loading rate of 5 kN / s to obtain a dense material with a predetermined compaction density.

[0049] S303. Place the demolded dense material in a 40 °C constant temperature water bath curing box for 28 days to obtain portland cement building materials with a certain strength.

[0050] The components and compaction densities of Examples 1 - 12 and Comparative Examples 1 - 6 are as follows:

[0051] Example 1. A polymer building material, with the raw material components in parts by weight, 50 parts of PFA, 950 parts of simulated lunar soil, and a compaction density of 1.72 g / cm 3 .

[0052] Example 2. A polymer building material, with the raw material components in parts by weight, 50 parts of PFA, 950 parts of simulated lunar soil, and a compaction density of 2.04 g / cm 3 .

[0053] Example 3. A polymer building material, with the raw material components in parts by weight, 50 parts of PFA, 950 parts of simulated lunar soil, and a compaction density of 2.36 g / cm 3 .

[0054] Example 4 A polymer building material, the components of the raw materials are in parts by weight, 100 parts of PFA, 900 parts of simulated lunar soil, and the compaction density is 1.72 g / cm 3 .

[0055] Example 5 A polymer building material, the components of the raw materials are in parts by weight, 100 parts of PFA, 900 parts of simulated lunar soil, and the compaction density is 2.04 g / cm 3 .

[0056] Example 6 A polymer building material, the components of the raw materials are in parts by weight, 100 parts of PFA, 900 parts of simulated lunar soil, and the compaction density is 2.36 g / cm 3 .

[0057] Example 7 A polymer building material, the components of the raw materials are in parts by weight, 200 parts of PFA, 800 parts of simulated lunar soil, and the compaction density is 1.72 g / cm 3 .

[0058] Example 8 A polymer building material, the components of the raw materials are in parts by weight, 200 parts of PFA, 800 parts of simulated lunar soil, and the compaction density is 2.04 g / cm 3 .

[0059] Example 9 A polymer building material, the components of the raw materials are in parts by weight, 200 parts of PFA, 800 parts of simulated lunar soil, and the compaction density is 2.36 g / cm 3 .

[0060] Example 10 Reuse of polymer building materials. The cured specimens of Example 2 were recycled, crushed and ground to a median particle size of 45 μm, and then compacted to a density of 2.04 g / cm 3

[0061] Example 11 Reuse of polymer building materials. The cured specimens of Example 5 were recycled, crushed and ground to a median particle size of 45 μm, and then compacted to a density of 2.04 g / cm 3 .

[0062] Example 12 Reuse of polymer building materials. The cured specimens of Example 8 were recycled, crushed and ground to a median particle size of 45 μm, and then compacted to a density of 2.04 g / cm 3 .

[0063] Comparative Example 1 Reuse of polymer building materials, which is different from Example 11 in that: the median particle size of the particles after crushing and grinding is 115 μm.

[0064] Comparative Example 2 Reuse of polymer building materials, different from Example 11 in that: the compaction density is 2.36 g / cm 3 .

[0065] Comparative Example 3 A cement-based building material, different from Example 2 in that: 50 parts of PFA are replaced by 50 parts of ordinary Portland cement.

[0066] Comparative Example 4 A cement-based building material, different from Example 5 in that: 100 parts of PFA are replaced by 100 parts of ordinary Portland cement.

[0067] Comparative Example 5 A cement-based building material, different from Example 8 in that: 200 parts of PFA are replaced by 200 parts of ordinary Portland cement.

[0068] Comparative Example 6 A polymer building material, different from Example 5 in that: the median particle size of the simulated lunar soil is 150 μm.

[0069] To illustrate Examples 1-12 and Comparative Examples 1-6 of the present invention, the obtained polymer building materials are now tested, and the specific test methods are as follows:

[0070] Taking the compressive strength as an index to measure the forming effect of polymer building materials, the loading speed is 0.1 kN / s.

[0071] The strength indexes of each example and comparative example are shown in Table 2. To simulate the lunar environment, normal pressure heating conditions and low vacuum heating conditions are now provided for comparison.

[0072] Table 2 Strength indexes of examples and comparative examples

[0073]

[0074] In the same example or comparative example, the low vacuum heating strength of polymer building materials is generally higher than the normal pressure heating strength. Molten PFA belongs to a viscoelastic fluid, and there are tiny spaces, i.e., free volumes, between molecules and between molecular chains inside the melt. The reduction of air pressure causes the space pressure to drop, the distance between macromolecules to increase, the range of chain segment movement to increase, the intermolecular force to decrease, the melt viscosity to decrease, and the fluidity to increase. Under the extrusion of simulated lunar soil particles, the PFA melt in low vacuum can flow in the gaps between lunar soil particles in a larger range, with higher cementation efficiency, and shows greater macroscopic strength after cooling and crystallization.

[0075] Examples 1 to 9 reflect the influence of PFA content and compaction density on the strength of building materials. The PFA content directly determines the amount of cementation; the compaction density determines the particle spacing, thereby affecting the cementation efficiency of molten PFA; improving the content and compaction density together determine the strength of polymer building materials.

[0076] Examples 10 to 12 illustrate the reuse effect of polymer building materials with different PFA dosages. Thanks to the thermoplastic properties of the polymer, the reshaped polymer building materials have considerable strength. However, the strength of each group does not reach the strength value of the first use, which is related to the volume shrinkage of the PFA material. During the first use, the volume shrinkage of loose PFA particles due to heat melting and reconsolidation reaches more than 50%. As the polymer building materials are reground, the redispersed PFA particles cannot reach the distribution density during the first use. Therefore, during the process of remelting and cooling, the cementing efficiency of PFA decreases.

[0077] Comparative Examples 1 and 2 can confirm that the crushing particle size and compaction density have a close influence on the reuse effect. Comparative Example 1 shows that the finer the crushing particle size during reuse, the higher the strength of the polymer building materials produced. Because the particles after the building materials are crushed are all combinations of PFA and simulated lunar soil. During the process of reheating, the melting of PFA causes the decomposition of the combination, and the lunar soil particles inside the combination are displaced or slide, forming damage inside the compacted body and reducing the density of the building materials. Comparative Example 2 shows that increasing the compaction density can effectively counteract this internal damage. A higher compaction density causes the particles to be squeezed together more tightly, resisting the damage caused by the decomposition of the combination during melting.

[0078] Comparative Examples 3 to 5 can demonstrate the advantages of polymer building materials over traditional cement building materials. Polymer building materials only need to be heated and cooled in a short time to form considerable strength, while traditional cement building materials need to be cured in an ideal environment for a long time. Under the condition of the same dosage, the strength of polymer building materials is higher than that of traditional cement building materials. The preparation process of polymer building materials does not require water to participate, and the strength formation process does not involve complex chemical reactions, and it has good tolerance to extreme environments. Traditional cement building materials need to ensure the normal progress of the hydration reaction and are intolerant to extreme environments.

[0079] Comparative Example 6 shows that the particle size of the simulated lunar soil is a key factor affecting the strength. The cementing effect of PFA on the simulated lunar soil with a coarse particle size is worse than that with a fine particle size because the difference in the void size between particles of different sizes affects the cementing efficiency of the PFA melt.

[0080] The polymer building materials and the reuse method described in the present invention can provide a practical solution to the construction problems in harsh environments.

[0081] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that after reading the specification of this application, they can still modify the specific implementation manners of the present invention or make equivalent replacements. However, these modifications or changes are all within the protection scope of the pending claims of the present invention application.

Claims

1. A method for reusing polymer building materials, characterized in that: The polymer building material comprises the following raw materials in parts by weight: 100 to 300 parts of a high molecular polymer and 700 to 1000 parts of soil. The high molecular polymer is a solid powdery thermoplastic high molecular polymer. The high molecular polymer is a tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer with a median particle size of 8.5 μm and a molecular structure as follows: ； Among them, R is perfluoropropyl, the molecular formula is -CF2CF2CF3, and the mass percentage is 4.0%; the melting point of PFA is 310℃, and the initial decomposition temperature is 490℃; The particle size of the high molecular polymer is less than 75 μm; the decomposition temperature is at least 50°C higher than the melting point; the brittle temperature is lower than -180°C, and the radiation tolerance value is not less than 10^3Gy; The soil material has a particle size of 0.01 μm to 1 mm, and a median particle size of 51 to 138 μm; the soil is simulated lunar soil; The preparation method of the polymer building material comprises the following steps: S101, mixing a high molecular polymer and soil in proportion and stirring thoroughly to obtain a mixed powder; S102, placing the mixed powder in a mold and compacting it to obtain a dense material; S103, heating the compacted material after demoulding; S104, after the compacted material is heated, it is naturally cooled to obtain a polymer building material; The compaction condition of S102 is to use a press to compact at a constant loading speed of not less than 5 kN / s, and the compaction density of the compacted material of S102 is not less than 1.7 g / cm 3 ; The method for reusing polymer building materials comprises the following steps: S201, fully grinding the recycled polymer building materials to produce recycled powder; S202, placing the recycled powder in a mold, and compacting the recycled powder to obtain a dense recycled material; S203, heating the compacted recycled material after demoulding; S204, after the compacted recycled material is heated, it is naturally cooled to obtain a polymer building material with a certain strength; the compaction condition is to use a press to compact at a constant loading speed of not less than 5 kN / s; The median particle size after grinding in the S201 is 45 μm.

2. A method for reusing polymer building materials according to claim 1, characterized in that: The heating temperature of S103 is the melting point of the polymer, and the insulation time is not less than 30 minutes.

3. The method for reusing polymer building materials according to claim 1, characterized in that: The heating temperature of S203 is the melting point of the polymer, and the insulation time is not less than 30 minutes.

4. The method for reusing a polymer building material according to claim 1, characterized in that: The compacted density of the S202 recycled material is not less than 1.7 g / cm 3 .

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