Anticorrosive and antifreezing composite material for strong salinization permafrost regions and preparation method thereof

Abstract

The application discloses a corrosion-resistant and anti-freezing composite material for strong salinization permafrost regions and a preparation method thereof, and belongs to the technical field of high polymer composite materials, and comprises the following steps: preparing a pretreated filler; preparing a modified reinforcing filler; mixing and stirring to obtain a precursor; forming and curing; and post-treatment. Through the synergy of the hollow microbeads, the flaky filler and the nanoparticles, the application breaks through the limitation that traditional materials are difficult to simultaneously consider low thermal conductivity, high corrosion resistance and high anti-freezing performance, realizes the integration of the three core functions, and can adapt the composite material to the complex environment of the salt-water-heat-power multi-field coupling of the strong salinization permafrost regions, meet the comprehensive needs of the material multi-dimensional performance of engineering, and avoid the performance short board of the single-function material in the extreme environment.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, specifically to anti-corrosion and antifreeze composite materials for use in highly saline permafrost regions and their preparation methods. Background Technology

[0002] The high-altitude, highly saline permafrost regions exhibit complex multi-field coupling effects of salt, water, heat, and force, posing stringent requirements for the cross-scale performance adaptation of engineering materials. The performance limitations of existing materials have become a key constraint on infrastructure construction. Ordinary concrete, due to its highly interconnected pore structure and significant surface hydrophilicity, allows corrosive ions to easily penetrate into the material's interior along pore channels, reacting with hydration products to induce salting-out crystallization and causing internal structural deterioration. Simultaneously, it induces steel reinforcement corrosion and expansion. During freeze-thaw cycles, the increased internal saturation of the material leads to localized concentration of frost heave stress, ultimately resulting in surface spalling and the expansion of internal microcracks, causing a continuous decline in mechanical properties.

[0003] Even with conventional anti-corrosion coatings and other surface protection technologies, the electrochemical reaction rate on the surface of metallic materials is significantly accelerated under the synergistic corrosion of high-concentration salt solutions and oxygen-rich environments. This leads to frequent failures such as localized pitting and uniform corrosion, resulting in a significant reduction in service reliability compared to conventional environments.

[0004] Although ordinary polymer materials possess a certain degree of chemical inertness, under the influence of strong ultraviolet radiation at high altitudes and extreme temperature alternation, the polymer molecular chains are prone to photo-oxidative degradation and thermal stress fracture, leading to material aging and embrittlement. At the same time, their large linear thermal expansion coefficient has poor compatibility with the deformation of the frozen soil matrix, and they are prone to structural cracks due to interfacial stress concentration during freeze-thaw cycles, resulting in loss of functional stability.

[0005] Existing materials generally suffer from technical defects such as insufficient salt corrosion resistance and durability, weak freeze-thaw cycle stability, and poor adaptability to long-term service environments. They are difficult to meet the multiple technical requirements of high-altitude permafrost region engineering for materials with low thermal conductivity, high salt corrosion resistance, excellent freeze-thaw stability, and long-term mechanical property stability.

[0006] Based on this, the present invention designs an anti-corrosion and anti-freezing composite material for use in highly saline permafrost areas and its preparation method to solve the above problems. Summary of the Invention

[0007] In view of the above-mentioned shortcomings of the existing technology, the present invention provides an anti-corrosion and anti-freezing composite material for use in highly saline permafrost areas and a method for preparing the same.

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] A method for preparing an anti-corrosion and anti-freezing composite material for use in highly saline permafrost regions, characterized by comprising the following steps:

[0010] S1: Weigh 98-102 parts by weight of polymer matrix, 60-120 parts by weight of reinforcing filler, and 1-5 parts by weight of anti-aging additive;

[0011] Among them, the modified reinforcing filler contains hollow glass microspheres, flake-like fillers and nano-silica in a mass ratio of 40-60:30-50:5-10;

[0012] S2: Hollow glass microspheres, flake-shaped fillers and nano-silica are baked to obtain pretreated fillers;

[0013] S3: Stir the pretreated filler at high speed, first heat to 78-82℃, add ethanol solution containing silane coupling agent dropwise at 2-4mL / min, increase the speed by 100-200r / min, and continue stirring to obtain modified and reinforced filler;

[0014] S4: First heat the polymer matrix to 50-60℃, add the anti-aging additive, stir, add the modified reinforcing filler in 2-3 portions to obtain a mixture, stir the mixture under vacuum at low speed to obtain the precursor;

[0015] S5: Inject the precursor into a mold to form and solidify, and obtain a corrosion-resistant and freeze-resistant composite material for use in highly saline permafrost areas.

[0016] S6: Post-processing. After curing, demold the component from the mold.

[0017] Furthermore, the anti-aging adjuvant in S1 consists of benzotriazole UV absorbers and hindered phenolic antioxidants in a mass ratio of 1:1.5-2.4.

[0018] The scaly filler is mica powder or glass flakes;

[0019] The polymer matrix is ​​epoxy resin or vinyl ester resin.

[0020] Furthermore, S2 specifically involves drying hollow glass microspheres with a particle size of 100-200μm, flake-like fillers, and nano-silica at 100-120℃ for 2-5 hours to obtain pretreated fillers.

[0021] Furthermore, S3 specifically involves: stirring the pretreated packing at 1000-1500 r / min for 10-15 min, heating it to 78-82℃ at a rate of 5-8℃ / min, adding an ethanol solution containing 40-50wt% silane coupling agent dropwise at 2-4 mL / min, wherein the amount of silane coupling agent is 1-3% of the total weight of the pretreated packing, increasing the rotation speed by 100-200 r / min, and continuing to stir for 15-25 min to obtain the modified and reinforced packing.

[0022] Furthermore, S4 specifically involves: heating the polymer matrix to 50-60°C at a rate of 3-5°C / min, adding an anti-aging agent, stirring at 200-300 r / min for 10-15 min, adding the modified reinforcing filler in 2-3 portions with an interval of 5-8 min between each addition to obtain a mixture, transferring the mixture to a planetary mixer, and stirring at -0.08 MPa to -0.1 MPa and 100-200 r / min for 15-25 min to obtain the precursor.

[0023] Furthermore, in S5, the precursor is injected into a mold and formed using a molding process or a vacuum injection process, and then cured by heating after molding.

[0024] The epoxy resin was cured at a temperature of 120℃ for 25 minutes, and the vinyl ester resin was cured at a temperature of 20℃ for 20 minutes, resulting in a corrosion-resistant and freeze-resistant composite material for use in highly saline permafrost regions.

[0025] A corrosion-resistant and freeze-resistant composite material prepared according to the method for use in areas with strong salinity and permafrost.

[0026] Compared with the prior art, the beneficial effects of this invention are as follows:

[0027] 1. This invention overcomes the limitations of traditional materials in simultaneously achieving low thermal conductivity, high corrosion resistance, and high freeze resistance by synergistically combining hollow microspheres, flake fillers, and nanoparticles. It achieves the integrated fusion of these three core functions, enabling the composite material to adapt to the complex environment of salt-water-thermal-mechanical multi-field coupling in highly saline permafrost regions. This meets the comprehensive engineering requirements for the multi-dimensional performance of materials and avoids the performance shortcomings of single-function materials in extreme environments.

[0028] 2. The low thermal conductivity of this invention can serve as a reliable thermal barrier, reducing the impact of environmental temperature fluctuations on the internal structure of the engineering structure. Its high corrosion resistance can maintain the stability of the material's mechanical properties in salt corrosion environments, avoiding structural deterioration caused by corrosion. Its excellent freeze-thaw resistance can maintain structural integrity and mechanical rigidity in repeated freeze-thaw cycles, ensuring the durability of the material during long-term service and laying the foundation for the stable operation of infrastructure in extreme environments.

[0029] 3. The preparation process of this invention is mature and operable. Relying on molding methods such as compression molding or vacuum injection, it can flexibly manufacture engineering components of various complex shapes, realize the integration of structure and function, adapt to the application needs of different engineering scenarios, and significantly reduce the overall cost of the entire life cycle of the project with its ultra-long service life and extremely low maintenance requirements. It takes into account both engineering practicality and long-term economic benefits and has good potential for promotion and application. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] Example 1: This invention discloses a method for preparing an anti-corrosion and anti-freezing composite material for use in highly saline permafrost regions, comprising the following steps:

[0032] S1: Weigh 98 parts by weight of polymer matrix, 60 parts by weight of reinforcing filler, and 1 part by weight of anti-aging additive (composed of benzotriazole UV absorber and hindered phenolic antioxidant in a mass ratio of 1:1.5).

[0033] Among them, the modified reinforcing filler contains hollow glass microspheres (particle size 100-200μm), flake filler (mica powder), and nano silica in a mass ratio of 40:30:5.

[0034] The polymer matrix is ​​epoxy resin (model MF-3102L).

[0035] S2: Hollow glass microspheres, flake-shaped fillers and nano-silica are dried at 100℃ for 2 hours to obtain pretreated fillers;

[0036] S3: Stir the pretreated packing at 1000 r / min for 10 min, heat it to 78℃ at a rate of 5℃ / min, add an ethanol solution containing 40wt% silane coupling agent (the amount of silane coupling agent is 1% of the total weight of the pretreated packing) dropwise at 2 mL / min, increase the speed by 100 r / min, and continue stirring for 15 min to obtain the modified and reinforced packing.

[0037] S4: Heat the polymer matrix to 50°C at a rate of 3°C / min, add the anti-aging additive, stir at 200 r / min for 10 min, add the modified reinforcing filler in two portions with an interval of 5 min between each portion to obtain a mixture, transfer the mixture to a planetary mixer, and stir at -0.08 MPa and 100 r / min for 15 min to obtain the precursor;

[0038] S5: The precursor is injected into the mold and molded using a compression molding process. After molding, it is heated and cured (the curing temperature of epoxy resin is 120℃, the curing time is 25min, and the CAS number of the curing agent is 132-889) to obtain a corrosion-resistant and antifreeze composite material for use in areas with strong salinity and permafrost.

[0039] S6: Post-processing. After curing, the component is demolded from the mold and subjected to necessary machining (such as cutting, grinding, drilling, chamfering, polishing, etc.) according to the size and functional requirements of the engineering component.

[0040] Example 2: This invention discloses a method for preparing an anti-corrosion and anti-freezing composite material for use in highly saline permafrost regions, comprising the following steps:

[0041] S1: Weigh 102 parts by weight of polymer matrix, 120 parts by weight of reinforcing filler, and 5 parts by weight of anti-aging additive (composed of benzotriazole UV absorber and hindered phenolic antioxidant in a mass ratio of 1:2.4).

[0042] Among them, the modified reinforcing filler contains hollow glass microspheres (particle size 100-200μm), flake-like filler (glass flakes), and nano-silica in a mass ratio of 60:50:10.

[0043] The polymer matrix is ​​a vinyl ester resin (model SWANCOR 901).

[0044] S2: Hollow glass microspheres, flake-shaped fillers and nano-silica are dried at 120℃ for 5 hours to obtain pretreated fillers;

[0045] S3: Stir the pretreated packing at 1500 r / min for 15 min, heat it to 82℃ at a rate of 8℃ / min, add an ethanol solution containing 50wt% silane coupling agent (the amount of silane coupling agent is 3% of the total weight of the pretreated packing) dropwise at 4 mL / min, increase the speed by 200 r / min, and continue stirring for 25 min to obtain the modified and reinforced packing.

[0046] S4: Heat the polymer matrix to 60°C at a rate of 5°C / min, add the anti-aging additive, stir at 300 r / min for 15 min, add the modified reinforcing filler in 3 portions with an interval of 8 min each time, and obtain a mixture. Transfer the mixture to a planetary mixer and stir at -0.1 MPa and 200 r / min for 25 min to obtain the precursor.

[0047] S5: The precursor is injected into the mold and molded using a compression molding process. After molding, it is heated and cured (the curing temperature of vinyl ester resin is 20℃, the curing time is 20min, and the curing agent is 1305 accelerator) to obtain a corrosion-resistant and antifreeze composite material for use in areas with strong salinity and permafrost.

[0048] S6: Post-processing. After curing, the component is demolded from the mold and subjected to necessary machining (such as cutting, grinding, drilling, chamfering, polishing, etc.) according to the size and functional requirements of the engineering component.

[0049] Example 3: This invention discloses a method for preparing an anti-corrosion and anti-freezing composite material for use in highly saline permafrost regions, comprising the following steps:

[0050] S1: Weigh 100 parts by weight of polymer matrix, 90 parts by weight of reinforcing filler, and 3 parts by weight of anti-aging additive (composed of benzotriazole UV absorber and hindered phenolic antioxidant in a mass ratio of 1:2).

[0051] Among them, the modified reinforcing filler contains hollow glass microspheres (particle size 100-200μm), flake filler (mica powder), and nano silica in a mass ratio of 55:48:8.

[0052] The polymer matrix is ​​epoxy resin;

[0053] S2: Hollow glass microspheres, flake-shaped fillers and nano-silica are dried at 110℃ for 4 hours to obtain pretreated fillers;

[0054] S3: Stir the pretreated packing at 1200 r / min for 13 min, heat it to 80℃ at a rate of 6℃ / min, add an ethanol solution containing 45wt% silane coupling agent (the amount of silane coupling agent is 2% of the total weight of the pretreated packing) dropwise at 3 mL / min, increase the speed by 150 r / min, and continue stirring for 20 min to obtain the modified and reinforced packing.

[0055] S4: Heat the polymer matrix to 54°C at a rate of 4°C / min, add the anti-aging additive, stir at 250 r / min for 12 min, then add the modified reinforcing filler in two portions with an 8 min interval between each addition to obtain a mixture. Transfer the mixture to a planetary mixer and stir at -0.1 MPa and 140 r / min for 22 min to obtain the precursor.

[0056] S5: The precursor is injected into the mold and formed by vacuum injection process. After forming, it is heated and cured (the curing temperature of epoxy resin is 120℃, the curing time is 25min, and the CAS number of curing agent is 132-889) to obtain a corrosion-resistant and antifreeze composite material for use in areas with strong salinity and permafrost.

[0057] S6: Post-processing. After curing, the component is demolded from the mold and subjected to necessary machining (such as cutting, grinding, drilling, chamfering, polishing, etc.) according to the size and functional requirements of the engineering component.

[0058] Comparative Example 1: The difference between this comparative example and Example 3 is that hollow glass beads are replaced with expanded perlite particles and nano-silica is replaced with nano-alumina.

[0059] Comparative Example 2: The difference between this comparative example and Example 3 is that in S4, the modified reinforcing filler was added to the polymer matrix along with the anti-aging additive at room temperature and pressure.

[0060] Comparative Example 3: The difference between this comparative example and Example 3 is that hollow glass beads are replaced with expanded perlite particles, nano silica is replaced with nano alumina, and in S4, the modified reinforcing filler is added to the polymer matrix along with the anti-aging additive at room temperature and pressure. Meanwhile, in S3, the temperature is not raised to 80°C, and the ethanol solution of silane coupling agent is added dropwise at 8 mL / min at room temperature.

[0061] Experimental Example 1: Thermal conductivity test, measured according to GB / T 10294-2008, unit W / (m·K);

[0062] Experimental Example 2: Corrosion resistance strength retention rate test, based on GB / T 1447-2005 for tensile strength. The following steps were performed: Prepare a 20% sodium chloride solution according to the standard, completely immerse the sample in the solution, and allow it to corrode at 50°C for 30 days. Replace the sodium chloride solution every 24 hours. After corrosion, wipe the sample surface dry and test the corrosion intensity again using the above method. ; Calculate the strength retention rate:

[0063] .

[0064] Experimental Example 3: The anti-corrosion and antifreeze composite material samples prepared according to this invention for use in highly saline permafrost areas were standardized to cuboids with dimensions of 40mm × 40mm × 160mm (length × width × height). Three parallel samples were prepared for each group of tests, and the original mass of the samples was recorded as follows: ;

[0065] First, place three parallel samples into three sealed plastic boxes. Pour 5% sodium chloride solution into each box, ensuring that the solution completely submerges the sample and the liquid level is at least 5 mm above the top surface of the sample. Place the sealed boxes containing the sample and sodium chloride solution into a rapid freeze-thaw test chamber and set the freeze-thaw cycle parameters: freezing stage temperature -25℃, holding time 1h; then raise the temperature to 25℃ at a rate of 5℃ / min to enter the thawing stage, holding time 1h, completing one freeze-thaw cycle.

[0066] Perform 300 freeze-thaw cycles continuously according to the above parameters. If evaporation loss of solution is found in the sealed box during the cycle, deionized water should be added in time to keep the solution level 5 mm above the sample surface.

[0067] After the freeze-thaw cycle is completed, remove the sealed box from the test chamber, gently pick up the sample with tweezers, place it in a tray pre-lined with a lint-free cloth, gently blot the sodium chloride solution off the sample surface with the lint-free cloth, dry at 80°C, cool to room temperature, and weigh the sample. Record the mass as follows. ;

[0068] Calculate the mass loss rate for each sample, retain two significant figures, and calculate the average value using the following formula:

[0069]

[0070] According to GB / T 50082-2024, the dynamic elastic modulus before and after freezing was tested, and the dynamic elastic modulus retention rate (%) was calculated.

[0071] The results are shown in the table below:

[0072] project Thermal conductivity W / (m·K) Strength retention rate (%) Quality loss rate (%) Elastic modulus retention rate (%) Example 1 0.23 96.4 0.42 91.3 Example 2 0.22 97.1 0.41 91.5 Example 3 0.21 96.8 0.39 91.6 Comparative Example 1 0.27 95.2 0.54 91.2 Comparative Example 2 0.25 96.0 0.48 91.4 Comparative Example 3 0.29 94.1 0.59 91.1

[0073] As shown in the table above, the thermal conductivity of Examples 1-3 is lower than that of Comparative Examples 1-3. The Examples use hollow glass microspheres and nano-silica as filler components, while Comparative Examples 1 and 3 replace hollow glass microspheres with expanded perlite particles and nano-silica with nano-alumina. Furthermore, Comparative Example 3 also adjusted the temperature and dropping rate during filler modification. This indicates that the selection of filler type and the control of modification process parameters have a direct impact on the thermal conductivity of the material. The combination of hollow glass microspheres and nano-silica selected in this invention plays a crucial role in reducing the thermal conductivity of the material.

[0074] The strength retention rates of Examples 1-3 are all higher than those of Comparative Examples 1-3. The strength retention rate reflects the stability of the mechanical properties of the material after salt corrosion. Comparative Example 2 involves the addition of filler at room temperature and pressure in one step, while Comparative Example 3 involves both filler replacement and process adjustment. It can be seen that the uniformity of filler dispersion (affected by the feeding method and stirring environment) and the compatibility between filler and matrix (affected by the type of filler) are important factors in determining the material's ability to retain salt corrosion strength. The filler combination and feeding and stirring process of the present invention can better maintain the strength of the material after salt corrosion.

[0075] The mass loss rates of Examples 1-3 were all lower than those of Comparative Examples 1-3. The mass loss rate reflects the structural integrity of the material after freeze-thaw cycles. During freeze-thaw cycles, the material is prone to component detachment or structural damage due to changes in internal stress. Comparative Example 1 was due to filler replacement, Comparative Example 2 was due to process adjustment, and Comparative Example 3 was due to both filler and process adjustment. All of these factors led to the material being more prone to mass loss during freeze-thaw cycles to varying degrees.

[0076] The numerical differences between Examples 1-3 and Comparative Examples 1-3 are relatively small compared to other indicators. The elastic modulus retention rate reflects the mechanical rigidity stability of the material after freeze-thaw cycles. The difference in this indicator is consistent with the changing trends of mass loss rate and strength retention rate, further illustrating that the technical solution of the present invention can better maintain the mechanical properties of the material after freeze-thaw cycles.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an anti-corrosion and antifreeze composite material for use in areas with highly saline and frozen soil, characterized in that, Includes the following steps: S1: Weigh 98-102 parts by weight of polymer matrix, 60-120 parts by weight of reinforcing filler, and 1-5 parts by weight of anti-aging additive; Among them, the modified reinforcing filler contains hollow glass microspheres, flake-like fillers and nano-silica in a mass ratio of 40-60:30-50:5-10; S2: Hollow glass microspheres, flake-shaped fillers and nano-silica are baked to obtain pretreated fillers; S3: Stir the pretreated filler, heat it to 78-82℃, add an ethanol solution containing silane coupling agent dropwise at 2-4 mL / min, increase the rotation speed by 100-200 r / min, and continue stirring to obtain the modified and reinforced filler; S4: First heat the polymer matrix to 50-60℃, add the anti-aging additive, stir, add the modified reinforcing filler in 2-3 portions to obtain a mixture, stir the mixture under vacuum at low speed to obtain the precursor; S5: Inject the precursor into a mold to form and solidify, and obtain a corrosion-resistant and freeze-resistant composite material for use in highly saline permafrost areas. S6: Post-processing. After curing, demold the component from the mold.

2. The method for preparing the anti-corrosion and antifreeze composite material for highly saline permafrost regions according to claim 1, characterized in that, In S1, the anti-aging adjuvant 1-5 parts consist of benzotriazole ultraviolet absorbers and hindered phenolic antioxidants in a mass ratio of 1:1.5-2.4; The flake-shaped filler is mica powder or glass flakes; The polymer matrix is ​​epoxy resin or vinyl ester resin.

3. The method for preparing the anti-corrosion and antifreeze composite material for highly saline permafrost regions according to claim 1, characterized in that, S2 specifically involves drying hollow glass microspheres, flake-shaped fillers, and nano-silica at 100-120℃ for 2-5 hours to obtain pretreated fillers.

4. The method for preparing the anti-corrosion and antifreeze composite material for highly saline permafrost regions according to claim 1, characterized in that, S3 specifically involves: stirring the pretreated packing at 1000-1500 r / min for 10-15 min, heating it to 78-82℃ at a rate of 5-8℃ / min, adding an ethanol solution containing 40-50 wt% silane coupling agent dropwise at 2-4 mL / min, wherein the amount of silane coupling agent is 1-3% of the total weight of the pretreated packing, increasing the rotation speed by 100-200 r / min, and continuing to stir for 15-25 min to obtain the modified and reinforced packing.

5. The method for preparing the anti-corrosion and antifreeze composite material for highly saline permafrost regions according to claim 1, characterized in that, S4 specifically involves heating the polymer matrix to 50-60℃ at a rate of 3-5℃ / min, adding an anti-aging additive, stirring at 200-300r / min for 10-15min, adding the modified reinforcing filler in 2-3 portions with an interval of 5-8min between each addition to obtain a mixture, transferring the mixture to a planetary mixer, and stirring at -0.08MPa to -0.1MPa and 100-200r / min for 15-25min to obtain the precursor.

6. The method for preparing the anti-corrosion and antifreeze composite material for highly saline permafrost regions according to claim 2, characterized in that, In S5, the precursor is injected into the mold and formed by compression molding or vacuum injection molding. After molding, it is heated and cured. The curing temperature for epoxy resin is 120℃ and the curing time is 25 minutes, while the curing temperature for vinyl ester resin is 20℃ and the curing time is 20 minutes.

7. A corrosion-resistant and freeze-resistant composite material for use in highly saline permafrost regions, prepared by the method according to any one of claims 1-6.