A weather resistant, corrosion resistant, long lasting geotextile composition suitable for cold regions

Abstract

The present application relates to the field of polymer compound composition and its preparation method, and discloses a weather-resistant and corrosion-resistant long-acting geotextile composition suitable for cold regions, which comprises the following steps: providing a polymer matrix containing an interface pinning agent; injecting the interface pinning agent into the polymer matrix melt in an extruder and carrying out high-shear blending to form a composition melt; and extruding the composition melt into a shape and carrying out dynamic sonophoresis annealing treatment. Through the preparation method, the composition amorphous region forms a stable glass body with reduced free volume cavities, and the interface pinning agent is simultaneously migrated to the interface of the residual micro-cavities and bound to water molecules, so that the occurrence of micro-ice wedge effect is inhibited, and the unification of low-temperature flexibility and freeze-thaw damage resistance is realized.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of weather-resistant corrosion-resistant long-acting geotextile composition suitable for cold regions, belong to the composition of high molecular compound and its preparation method technical field. BACKGROUND

[0002] The current technical route commonly used for preparing long-acting weather-resistant materials for geotechnical engineering, especially in cold regions, is to select a polyolefin or elastomer blend with a low glass transition temperature as the matrix, and to use a rapid cooling process after melt blending to ensure the flexibility of the material at extremely low temperatures. However, this commonly used preparation method has an inherent technical constraint: the conventional rapid air cooling or water cooling quenching process, while ensuring the amorphous structure required for the flexibility of the solidified material, also inevitably freezes a large number of thermodynamically non-equilibrium free volume cavities between the polymer chains.

[0003] This approach, which relies on chemical additives, is particularly common in the field of related weather-resistant materials. Its protective mechanism is based on the release or surface coating of active substances, rather than fundamental improvements to the physical structure of the material matrix. For example, Chinese patent CN110591545A discloses a high-weather-resistant and corrosion-resistant polyurethane coating and its preparation method. The technical idea of this scheme is to wrap nano-copper stearate copolymer in epoxy resin and use light-sensitive resin to slowly release active substances in response to ultraviolet light to achieve corrosion resistance and weather resistance. However, this method is essentially a surface coating solution, and its protective function relies on the continuous release of chemical additives. For geotextile compositions, this approach does not address the physical defect of free volume cavities formed in the matrix material during conventional quenching processes. Therefore, it cannot fundamentally prevent the microscopic ice wedge damage caused by the accumulation of water molecules after repeated freeze-thaw cycles. These cavities do not appear as defects in the early stages of material service, but water molecules will penetrate and accumulate in them through diffusion during the soil burial and water vapor contact in cold regions for several years. When the temperature drops below freezing, these cavities become nucleation points for microscopic ice crystals. The stress generated by the volume expansion of water when it freezes, combined with repeated freeze-thaw cycles, leads to the accumulation of this microscopic ice wedge damage, ultimately causing microcracks in the material and leading to premature failure of its physical properties.

[0004] Therefore, how to innovate from the preparation method level, while maintaining a high amorphous content to ensure low-temperature flexibility, to change the thermodynamic state and physical structure of this amorphous state, eliminate the free volume nucleation points inside it caused by conventional processes, and thus avoid the microscopic ice wedge effect of the composition, is the technical problem to be solved by the present application. SUMMARY

[0005] This invention provides a weather-resistant and corrosion-resistant long-lasting geotextile composition suitable for cold regions. Its main purpose is to solve the problem of how to innovate the preparation method, and fundamentally change the thermodynamic state and physical structure of the amorphous state while maintaining a high amorphous content in the composition to ensure low-temperature flexibility. This eliminates the free volume nucleation points solidified by conventional processes, thereby avoiding the problem of microscopic ice wedge effect in the composition.

[0006] To achieve the above objectives, the present invention provides a weather-resistant and corrosion-resistant long-lasting geotextile composition suitable for cold regions, which is prepared by the following method, the method comprising:

[0007] Step 101: Provide a polymer matrix and an interface pinning agent, wherein the interface pinning agent is an amphiphilic copolymer comprising a nonpolar segment compatible with the polymer matrix and a polar segment for pinning the microcavity interface;

[0008] Step 102: In the extruder, the polymer matrix is ​​melted at the front section of the extruder to form a matrix melt;

[0009] Step 103: After the matrix melt is formed, an interface pinning agent is added to the matrix melt in the middle or rear section of the extruder.

[0010] Step 104 involves melting and blending the matrix melt containing the interfacial pinning agent through a high-shear section of an extruder to form a polymer composition melt.

[0011] Step 105: Extruding the polymer composition melt into an extrudate;

[0012] Step 106 involves subjecting the extrudate to dynamic sono-induced annealing, which includes: applying mechanical vibration to the extrudate during controlled cooling from a temperature above its glass transition temperature to a temperature below its glass transition temperature; wherein the melt blending in steps 102 to 104 provides a uniform physical condition for the migration of the interface pinning agent in step 106; and the controlled cooling and mechanical vibration in the dynamic sono-induced annealing process synergistically: promote the relaxation of amorphous segments in the polymer matrix to form a stable glass with reduced free volume cavities; promote the migration of the interface pinning agent to the residual microcavity interface in the stable glass, and utilize polar segments to bind water molecules at this interface to form non-frozen bound water and inhibit ice crystal nucleation.

[0013] Preferably, the polymer matrix is ​​a blend of ethylene propylene diene monomer (EPDM) rubber and linear low-density polyethylene (LLDPE), wherein the ethylene content of the EPDM rubber is 55% to 70%, and the melt index of the LLDPE is 190. 0.8 g / 10 min to 2.2 g / 10 min under a load of 2.16 kg; the interfacial pinning agent is a maleic anhydride grafted ethylene propylene diene rubber copolymer having a maleic anhydride grafting rate of 0.5% to 1.5%.

[0014] Preferably, the mechanical vibration in step 106 is a subsonic wave vibration or a low frequency ultrasonic wave vibration, and the frequency of the mechanical vibration is in the range of 10 kHz to 30 kHz.

[0015] Preferably, the controlled cooling in step 106 is a slow cooling process, and the cooling rate is lower than 10 / second to ensure that the amorphous zone segments of the polymer matrix have a relaxation time.

[0016] Preferably, in step 106, an electrostatic field is applied to the extrudate simultaneously with the mechanical vibration, and the electrostatic field is used to cooperate with the mechanical vibration to drive the interfacial pinning agent to migrate and enrich to the outer surface of the extrudate, thereby forming a chemical protective layer on the outer surface of the extrudate.

[0017] Preferably, in step 101, a low surface energy corrosion resistant polymer which is thermodynamically incompatible with the polymer matrix is provided in addition to the interfacial pinning agent; and in step 106, the mechanical vibration is used to simultaneously accelerate the migration of the low surface energy corrosion resistant polymer to the outer surface of the extrudate to form a chemically inert layer on the outer surface of the extrudate.

[0018] Preferably, the low surface energy corrosion resistant polymer is a fluorine-containing polymer or a polysiloxane.

[0019] Preferably, the method further comprises: step 801, in step 106, monitoring an operating parameter of the device for applying the mechanical vibration in real time, which is related to the acoustic impedance of the extrudate; step 802, based on the time variation characteristic of the operating parameter, characterizing that the glass transition of the extrudate has been completed; and step 803, based on the characterization result, adaptively regulating the rate of the controlled cooling or stopping the application of the mechanical vibration.

[0020] Preferably, the operating parameter is the driving power required to maintain a constant amplitude of the mechanical vibration ; and the time variation characteristic in step 802 is that the time derivative of the driving power satisfies , wherein is a preset power change rate threshold value which characterizes the occurrence of the glass transition.

[0021] ​Preferably, step 106 further comprises: monitoring an electrical operating parameter related to energy coupling efficiency of the device for applying mechanical vibration in real time; and dynamically adjusting the driving frequency of the mechanical vibration to lock the driving frequency on the system resonance frequency of the extrudate and the device based on the monitoring result of the electrical operating parameter.

[0022] Compared with the prior art, the application has the following beneficial effects:

[0023] 1. By applying specific mechanical vibration in the controlled cooling process, time and energy required for relaxation and rearrangement of amorphous zone segments of the polymer matrix are provided, prompting the composition to form a thermodynamically more balanced dense structure, i.e. a stable glass body, which itself physically reduces the free volume cavities available for water molecules to aggregate in the conventional quenching process; at the same time, the dynamic process also drives the pre-set interfacial pinning agent in the composition to migrate and enrich to any residual micro-cavity interface, and its polar segment then binds the first infiltrated water molecules, achieving physical occupation while inhibiting ice crystal nucleation points from a mechanism, so that the composition has built-in protection against physical damage of micro-ice wedge effect on the internal structure while maintaining low-temperature flexibility.

[0024] 2. By separating the plasticization of the polymer matrix and the addition of the interfacial pinning agent in time in the extruder, and using the high viscosity of the matrix melt to provide dispersion resistance for the subsequent high shear section, near-molecular level dispersion of the interfacial pinning agent in the matrix is achieved; this micro-homogeneity achieved in the melt blending stage provides the necessary physical premise for the global effective migration and high-efficiency pinning of the pinning agent in the subsequent dynamic acoustic annealing step, avoiding weak points or short board effects caused by local non-uniformity of the material, and ensuring the consistency of the overall freeze-thaw fatigue resistance of the final composition product.

[0025] 3. The static electric field is applied synchronously in the process window of dynamic acoustic annealing, which takes advantage of the high migration ability of the interfacial pinning agent given by the acoustic wave vibration, and through the directional driving force of the electric field, realizes the functional reuse of the single chemical component, i.e. the interfacial pinning agent; that is, while the acoustic field drives part of the pinning agent to complete the internal micro-cavity pinning, the electric field cooperatively drives another part of the pinning agent to enrich to the outer surface of the extrudate, and forms an inherent chemical shielding surface rich in polar functional groups in the cooling and solidification, so that the composition material obtains the ability to resist physical ice wedge internally, and at the same time obtains the chemical corrosion protection ability to external acid, alkali and salt media. BRIEF DESCRIPTION OF DRAWINGS

[0026] Fig. 1 Process flow chart of the dynamic acoustic annealing and closed-loop control preparation process of the application;

[0027] Fig. 2A graph showing the influence of cooling rate on the density of free volume cavities and freeze-thaw resistance of the composition of the present application;

[0028] Fig. 3 A use case diagram showing the functional requirements of the composition of the present application for application in cold regions. DETAILED DESCRIPTION

[0029] To enable those skilled in the art to understand the technical solutions of the present application, the present application will be further described in detail below, and it should be understood that the present application is not limited to the specific solutions described below, and various changes or improvements made by those skilled in the art without creative labor shall fall within the scope of protection of the present application.

[0030] The weather-resistant and corrosion-resistant long-acting geotextile composition suitable for cold regions and its preparation method provided by the present application, the core of which is a complete process system composed of raw material selection, melt blending and dynamic post-treatment, which prepares a micro-uniform polymer composition melt by melt high-shear blending of the high polymer matrix and the interface pinning agent in time sequence, extrudes the melt into a geotextile form, and immediately applies a dynamic acoustic annealing treatment to it, which, through the synergy of thermodynamic path and mechanical energy field, reduces the free volume cavities introduced by the conventional process from the micro-physical structure while maintaining the low-temperature flexibility of the composition, and inhibits the ice crystal nucleation point, thereby obtaining a geotextile composition with long-term protection capability against micro-ice wedge effect; in a specific solution, the preparation method performs step 101, i.e. providing a high polymer matrix and an interface pinning agent; the high polymer matrix is a polymer blend with a low glass transition temperature, which provides the basis for the low-temperature flexibility of the final product, and one preferred embodiment is that the matrix is a blend of ethylene-propylene-diene rubber and linear low-density polyethylene, to ensure the amorphous content and processing fluidity inside the matrix, the ethylene content of the ethylene-propylene-diene rubber is controlled in the range of 55% to 70%, and the linear low-density polyethylene is controlled in the range of 0.910g / cm3 to 0.930g / cm3, and the melt index under the load of 2.16kg is selected in the range of 0.8g / 10min to 2.2g / 10min; the interface pinning agent is a key chemical component for subsequent microstructure regulation, which is an amphiphilic copolymer containing non-polar segments for compatibility with the high polymer matrix and polar segments for pinning the interface of micro-cavities, in this solution, a maleic anhydride grafted ethylene-propylene-diene rubber copolymer is preferably used, the non-polar ethylene-propylene-diene rubber backbone ensures compatibility with the matrix, and the grafted maleic anhydride groups serve as polar segments required for subsequent pinning of water molecules; to ensure the effectiveness of the pinning function while avoiding self-aggregation caused by excessive introduction, the maleic anhydride grafting rate is limited in the range of 0.5% to 1.5%.

[0031] ​After the raw materials are prepared, the system performs a time-sequential separation melt blending process, which is usually completed in a twin-screw extruder with multiple feeding ports and functional sections; step 102 is performed, only the high-molecular matrix is added in the front section of the extruder, i.e. the first feeding zone, and the matrix is fully melt-plasticized in this section through the conveying and shearing action of the screw to form a continuous and stable matrix melt; after the matrix melt has been stably formed, step 103 is performed, the interfacial pinning agent is added to the high-viscosity matrix melt through a side feeding port in the middle or rear section of the extruder; then, step 104 is performed, the matrix melt with the interfacial pinning agent immediately flows through the high-shear section in the extruder downstream of the side feeding port, which is composed of a specific combination of kneading blocks, in this section, the high-viscosity matrix melt provides the necessary shear stress for the effective dispersion of the interfacial pinning agent, so that it is fully sheared and uniformly dispersed in the matrix, thereby forming a micro-uniform high-molecular composite melt; this time-sequential separation and in-melt high-shear dispersion achieved through steps 102 to 104 ensures the near-molecular level distribution of the interfacial pinning agent in the matrix, which constitutes a physical prerequisite for the global effective migration of the pinning agent in subsequent step 106; the uniform composite melt then performs step 105, i.e. it is extruded into an extrudate in the form of a geotextile blanket through the extruder head; the extrudate is not subjected to conventional rapid water cooling or air cooling treatment, but is immediately introduced into a dynamic acoustic annealing treatment zone to perform step 106; the core of dynamic acoustic annealing treatment is the synergistic effect of two physical means, first, the extrudate is subjected to controlled cooling, which slowly and controllably cools it from a temperature higher than its glass transition temperature to a temperature lower than its , the controlled cooling is preferably a slow cooling process, and the cooling rate is controlled to be lower than 10 / second to ensure that the amorphous region segments of the high-molecular matrix have sufficient relaxation time; second, specific mechanical vibration is applied to the extrudate throughout the controlled cooling process, which is preferably subsonic wave vibration or low-frequency ultrasonic vibration with a frequency in a specific range, such as 10 kHz to 30 kHz, the vibration provides additional energy required to overcome the energy barrier for chain segment relaxation.

[0032] The synergistic effect of controlled cooling and mechanical vibration simultaneously induces two microstructure evolutions inside the polymer composition: Action I, which enables the polymer matrix amorphous zone segments to obtain sufficient energy and time to rearrange and relax, thus collapsing most of the high-energy state free volume cavities that would be frozen in the conventional quenching process, forming a stable glass body with higher density, lower energy, and thermodynamically closer to equilibrium, which physically reduces the main place where micro-ice wedge effect occurs; Action II, which simultaneously enhances the migration ability of the uniformly dispersed interfacial pinning agent molecules, allowing them to preferentially migrate and pin to the interface of the few remaining micro-cavities that cannot be completely eliminated due to structural relaxation. When water molecules penetrate, the polar segments of the interfacial pinning agent bind these water molecules at the interface through hydrogen bonds and other forces, forming non-freezing bound water with extremely low freezing point or even not freezing. This dual effect of physical occupation and chemical binding effectively inhibits the possibility of subsequent free water nucleation and crystallization at this location, thus achieving the unity of low-temperature flexibility and freeze-thaw resistance of the composition; To further enhance the multi-dimensional protection performance of the composition, the preparation method of the present application can also include one or more synergistic enhancement steps; In one scheme, to impart chemical resistance to the outer surface of the composition, during the execution of step 106, an additional static electric field is applied to the extrudate while the mechanical vibration is applied, which takes advantage of the enhanced migration ability of the interfacial pinning agent by sound wave vibration and applies a directional driving force to the polar segments of the interfacial pinning agent, synergistically driving a portion of the interfacial pinning agent to migrate and accumulate on the outer surface of the extrudate. As the material cools and solidifies, a chemical protective layer rich in polar functional groups is formed on the outer surface of the extrudate.

[0033] In another scheme, to achieve surface chemical inert shielding, in step 101, in addition to providing a polymer matrix and an interfacial pinning agent, a low-surface-energy corrosion-resistant polymer that is thermodynamically incompatible with the polymer matrix is also provided, such as a fluorine-containing polymer or a polysiloxane; accordingly, when step 106 is subsequently executed, the applied mechanical vibration is given a dual function: one, to achieve matrix relaxation and interfacial pinning agent pinning; two, the vibration energy is also used to accelerate the phase separation and migration rate of the low-surface-energy corrosion-resistant polymer in the viscous melt, allowing it to efficiently migrate and accumulate on the surface of the extrudate within the time window of controlled cooling, thus forming a physically anchored chemical inert layer on the outer surface of the extrudate; In addition, to ensure the consistency and stability of step 106, the core process in industrial production, the method can also introduce closed-loop control logic; In one scheme, the method also includes steps 801 to 803; that is, in step 106, the device itself of the ultrasonic transducer used to apply mechanical vibration is used to monitor one of its operating parameters related to the acoustic impedance of the extrudate in real time; A specific example is to monitor the driving power required to maintain a constant amplitude of mechanical vibration Because the modulus of acoustic impedance increases sharply when a material undergoes a glass transition, leading to... Accordingly, in step 802, the system analyzes the time-varying characteristics of operating parameters online, for example, when the drive power is detected. time derivative Meets a preset power change rate threshold (Right now When the extrudate has completed its dynamic glass transition, the system adaptively adjusts the process parameters based on the characterization results in step 803, immediately stopping the application of mechanical vibration or switching to a rapid cooling stage, thereby avoiding open-loop control deviations caused by material batch fluctuations. In another optimization scheme, to ensure that acoustic energy is always coupled to the material interior with the highest efficiency, step 106 also includes: real-time monitoring of electrical operating parameters of the device used to apply mechanical vibration, such as load current or phase angle, which are related to energy coupling efficiency; and based on the monitoring results of electrical operating parameters, dynamically adjusting the driving frequency of mechanical vibration through control logic such as a phase-locked loop, so that the driving frequency always automatically tracks and locks onto the system resonant frequency of the extrudate and the device.

[0034] Example 1: In a major infrastructure project in a high-altitude permafrost region, such as a high-altitude railway subgrade or oil pipeline foundation, the engineering requirements dictate that the geotextile composition used must withstand temperatures as low as -40°C for a service life of several decades. Extreme low temperatures and hundreds of freeze-thaw cycles per year; geotextiles prepared using conventional melt blending and rapid air-cooling processes, although their initial glass transition temperature... The low-temperature flexibility exhibited can meet the acceptance criteria, but after 3-5 years of actual service, due to the cumulative damage from the microscopic ice wedge effect, its physical properties will begin to deteriorate irreversibly, leading to premature failure. This is a technical problem in this field. To address this challenge, a preparation method as defined in the aforementioned specific embodiments is adopted. The core of this method lies in the synergy of two key stages: the sequential separation and in-melt high-shear blending in steps 102 to 104 and the dynamic sonic annealing in step 106. In the melt blending stage, the plasticization of the polymer matrix and the addition of the interface pinning agent are sequentially separated in the extruder, and the high viscosity of the matrix melt itself is used to provide dispersion resistance for the subsequent high-shear section. This allows the interface pinning agent to form a microscopically uniform distribution in the matrix before entering step 106, which constitutes the physical prerequisite for subsequent interface pinning.

[0035] When the microscopically uniform extrudate enters the dynamic sonic annealing section of step 106, this approach differs from the conventional quenching process; at this stage, below 10... The controlled slow cooling process at 5 °C / s provides time for the amorphous region segments of the polymer matrix to relax and rearrange, and the simultaneously applied 20 kHz mechanical vibration provides energy for the segments to overcome the energy barrier; the synergy of the two methods promotes the relaxation of the amorphous region segments, forming a stable glassy structure with reduced free volume cavities, and also promotes the migration of the uniformly dispersed interfacial pinning agent to the interface of any residual microcavity; the long-acting protection mechanism of the geotextile composition prepared by the above method under the working conditions in the aforementioned permafrost regions is as follows: when external water molecules penetrate into the material interior by diffusion, the physical cavities available for their aggregation have been reduced due to the formation of the stable glassy body; and for the water molecules that penetrate into the interface of the residual microcavity, the polar segments of the interfacial pinning agent pre-enriched therein bind them to form non-frozen bound water with a reduced freezing point; through the synergistic mechanism of physical cavity reduction and interfacial pinning bound water, the conditions for the occurrence of micro-ice wedge effect are inhibited.

[0036] Example 2: This example is used to objectively verify the synergy of the key process steps in the preparation method of the application and the key components in the composition for resisting the micro-ice wedge effect when the geotextile composition is used in cold regions; test setup: prepare the sample group (S1) of the application and four control groups (CA, CB, CC, CD); raw material specifications: the polymer matrix is prepared by pre-mixing 60 parts by weight of ethylene propylene rubber (EPDM, ethylene content 65%) and 30 parts by weight of linear low density polyethylene (LLDPE, melt index 1.0 g / 10 min, density 0.92 g / cm3) according to GB / T 3682-2018 standard under a load of 190 C); interfacial pinning agent is maleic anhydride grafted ethylene propylene rubber copolymer (EPDM-g-MAH) with a maleic anhydride grafting rate of 1.0 wt%; equipment specifications: blending equipment: one co-rotating twin-screw extruder with a length-diameter ratio L / D of 40:1, a side feeding port is set at L / D=18, and a high-shear kneading component is configured in the L / D=20-30 section, the temperature control accuracy of each zone is ±1 C; post-processing equipment (application): dynamic acoustic annealing device, composed of a calender roll, a 20 kHz low-frequency ultrasonic vibration system, and a speed-controlled cooling air cooling module, the cooling rate can be controlled at 5 C / s; post-processing equipment (control): conventional quenching device, a 20 C circulating water tank can achieve a cooling rate of more than 50 C / s.

[0037] ​Sample group preparation process: sample group S1 of the present application: the complete method of the present application was adopted; 90 parts by weight of the polymer matrix was added from the main feeding port of the twin-screw extruder, and 10 parts by weight of the interfacial pinning agent was added from the side feeding port at L / D = 18 (steps 102-103); the temperature of each zone of the extruder was set to 170 -180 -190 -190 -185 , and the screw rotation speed was set to 200 rpm, so that the material passed through the high shear section (step 104); after the extrudate was formed into a 2 mm thick sheet (step 105), it was immediately introduced into a dynamic acoustic annealing device, and cooled to 40 at a controlled cooling rate of 5 / second under 20 kHz mechanical vibration (step 106); control group A (CA, conventional quenching): steps 102-105 were the same as S1; step 106 was replaced by: after the extrudate was formed, it was immediately introduced into a 20 circulating water tank for conventional quenching, and the cooling rate was greater than 50 / second; control group B (CB, lack of pinning agent): steps 102-106 were the same as S1, but in step 103, the weight of the interfacial pinning agent added from the side feeding port was 0; control group C (CC, lack of mechanical vibration): steps 102-105 were the same as S1; step 106 was the same as S1, but the 20 kHz mechanical vibration system of the dynamic acoustic annealing device was turned off, and only controlled cooling at a rate of 5 / second was performed; control group D (CD, conventional blending): step 106 was the same as S1; but steps 102-104 were replaced by: after 90 parts by weight of the matrix and 10 parts by weight of the pinning agent were dry premixed in a high-speed mixer, they were all added to the extruder from the main feeding port, and the other process parameters of the extruder were the same as S1; test method and data: the sheets of the above-mentioned S1, CA, CB, CC, and CD sample groups were all prepared into standard tensile sample strips; all the sample strips were soaked in 20 water for 24 hours, frozen in a-40 environment for 8 hours, then taken out and thawed in 20 water for 16 hours, which was counted as one freeze-thaw cycle; after 0, 50, 100, and 200 freeze-thaw cycles, respectively, sample strips were taken from each sample group and immediately placed in a-40 environmental test chamber, and their tensile elongation at break (%) was tested according to the GB / T1040.2-2006 standard, which was used to represent the toughness retention ability of the material at low temperature, and the lower the value, the more serious the embrittlement of the material, i.e. the worse the resistance to micro ice wedge effect; the-40 tensile elongation at break (%) test results of each sample group after different freeze-thaw cycle times are shown in Table 1.

[0038] Table 1: -40C tensile elongation retention (%) of each sample group after different freeze-thaw cycles (F-T) Table 1: -40C tensile elongation retention (%) of each sample group after different freeze-thaw cycles (F-T)

[0039]

[0040] Test result analysis: see Table 1, the control group A (conventional quenching) experienced a rapid decrease in elongation at break after freeze-thaw cycles, and dropped to 55.4% after 200 cycles, which had been embrittled, which was due to the quenching process freezing a large number of free volume cavities in the amorphous region, forming the nucleation point of the microscopic ice wedge effect; the control group B (without NCA) showed that even if the dynamic acoustic annealing process step 106 was used, the retention rate of the elongation at break (24.4%) was still lower than that of the sample group of the present application, which confirmed the necessity of the interface pinning agent step 101, that is, the residual microcavity in the stable glass body formed after the relaxation of the amorphous region chain segment still needs to be pinned and bound by the interface pinning agent to inhibit ice crystal nucleation; the control group C without vibration, the performance retention rate of 42.1% of slow cooling was worse than that of the sample group of the present application, but better than that of the control group A, which showed that the thermodynamic control in the slow cooling step 106 alone was not enough to make the chain segment in the high viscosity melt fully relaxed, and the mechanical control in the mechanical vibration step 106 had to be applied to form a stable glass body with higher density; the performance retention rate of the control group D was 21.2% which was also attenuated, which showed that the micro-uniformity of the interface pinning agent was the premise of the subsequent pinning mechanism to take effect, verifying the necessity of the time sequence separation and the melt internal high shear blending process in steps 102 to 104; the sample group (S1) of the present application still had a tensile elongation retention rate of 97.4% after 200 freeze-thaw cycles, and its test results were different from all the control groups; the test data objectively confirmed that only the specific combination of the high molecular matrix and the interface pinning agent with the specific melt blending process time sequence separation and high shear and the specific post-processing process dynamic acoustic annealing could be combined to form the stable glass body with reduced free volume cavities and the non-frozen bound water pinned to the interface of the residual microcavity in the composition through synergistic effect, thereby maintaining the low temperature flexibility of the material while making it have long-term protection ability against the microscopic ice wedge effect. Test result analysis: see Table 1, the control group A (conventional quenching) experienced a rapid decrease in elongation at break after freeze-thaw cycles, and dropped to 55.4% after 200 cycles, which had been embrittled, which was due to the quenching process freezing a large number of free volume cavities in the amorphous region, forming the nucleation point of the microscopic ice wedge effect; the control group B (without NCA) showed that even if the dynamic acoustic annealing process step 106 was used, the retention rate of the elongation at break (24.4%) was still lower than that of the sample group of the present application, which confirmed the necessity of the interface pinning agent step 101, that is, the residual microcavity in the stable glass body formed after the relaxation of the amorphous region chain segment still needs to be pinned and bound by the interface pinning agent to inhibit ice crystal nucleation; the control group C without vibration, the performance retention rate of 42.1% of slow cooling was worse than that of the sample group of the present application, but better than that of the control group A, which showed that the thermodynamic control in the slow cooling step 106 alone was not enough to make the chain segment in the high viscosity melt fully relaxed, and the mechanical control in the mechanical vibration step 106 had to be applied to form a stable glass body with higher density; the performance retention rate of the control group D was 21.2% which was also attenuated, which showed that the micro-uniformity of the interface pinning agent was the premise of the subsequent pinning mechanism to take effect, verifying the necessity of the time sequence separation and the melt internal high shear blending process in steps 102 to 104; the sample group (S1) of the present application still had a tensile elongation retention rate of 97.4% after 200 freeze-thaw cycles, and its test results were different from all the control groups; the test data objectively confirmed that only the specific combination of the high molecular matrix and the interface pinning agent with the specific melt blending process time sequence separation and high shear and the specific post-processing process dynamic acoustic annealing could be combined to form the stable glass body with reduced free volume cavities and the non-frozen bound water pinned to the interface of the residual microcavity in the composition through synergistic effect, thereby maintaining the low temperature flexibility of the material while making it have long-term protection ability against the microscopic ice wedge effect.

[0041] Example 3: This example is used to compare the difference in freeze-thaw cycle resistance between inventive sample S1 and comparative example CE1 which uses a conventional flexibility aid instead of the interfacial pinning agent; the preparation of inventive sample S1 is the same as in Example 2, i.e. using 90 parts by weight of the high molecular matrix and 10 parts by weight of the interfacial pinning agent which is EPDM-g-MAH with a grafting rate of 1.0 wt% of maleic anhydride; the high molecular matrix used in comparative example CE1 is the same as in S1, but the 10 parts by weight of the interfacial pinning agent is replaced by 10 parts by weight of a conventional polyolefin elastomer POE which is a metallocene-catalyzed ethylene-octene copolymer with a density of 0.870 g / cm3and a melt index of 1.1 g / 10 min under a load of 2.16 kg at 190 °C, and which does not contain polar functional groups, which is a well-known aid for improving the low-temperature flexibility of polyolefins in the art; the preparation process of sample S1 uses the complete preparation process of Example 2, i.e. the sequential separation and melt internal high-shear blending of steps 102 to 104, and the dynamic sonically-induced annealing of step 106, which annealing process includes 20 kHz mechanical vibration and controlled cooling at 5 °C / s; the preparation process of comparative example CE1 uses the same preparation process as S1, i.e. 90 parts by weight of the high molecular matrix is added from the main port, 10 parts by weight of POE is added from the side feeding port, and the same high-shear blending is carried out in the same extruder temperature and rotation speed of 200 rpm, and the extrudate is also subjected to the dynamic sonically-induced annealing of step 106, which annealing process also includes 20 kHz mechanical vibration and controlled cooling at 5 °C / s; the freeze-thaw cycle test method is the same as in Example 2, and the test standards for the tensile elongation at break (in %) are also the same; the test results of the tensile elongation at break (in %) of samples S1 and CE1 after different freeze-thaw cycle times are shown in Table 2.

[0042] Table 2: Comparison table of freeze-thaw cycle resistance of samples S1 and CE1

[0043]

[0044] ​​​​​Referring to Table 2, the comparative example CE1, due to the addition of the conventional softener POE, initially exhibited a low-temperature flexibility of 453.0% after 0 freeze-thaw cycles, which is at the same level as the 452.5% of the sample group of the present invention. However, after 200 freeze-thaw cycles, the low-temperature elongation at break of CE1 was only 88.7%, and the retention rate dropped to 19.6%, indicating embrittlement failure. Its failure data is similar to that of the control group CB in Example 2, which lacked the interfacial pinning agent, at 24.4%. This data shows that by replacing the interfacial pinning agent of the present invention with the polyolefin elastomer POE used to improve flexibility, even with the application of... The same dynamic sono-annealing process, namely step 106, was applied, but the composition still could not resist freeze-thaw damage. This is attributed to the use of the conventional flexibility aid POE, which does not possess the amphiphilic copolymer structure of an interface pinning agent. Physically, it cannot migrate to the residual microcavity interface during dynamic sono-annealing, nor can it bind water molecules at the interface through polar segments to inhibit ice crystal nucleation. This result confirms that the synergistic combination of the interface pinning agent and the dynamic sono-annealing process used in this invention is a specific technical solution to solve the microscopic ice wedge effect in the prior art, and cannot be replaced by conventional additives used in the art to improve apparent flexibility.

[0045] Example 4: This example combines Figs. 1 to 3 This describes a weather-resistant and corrosion-resistant long-lasting geotextile composition suitable for cold regions, such as... Fig. 1 As shown, the method begins by providing a polymer matrix, such as EPDM and LLDPE, and an interface pinning agent, such as a maleic anhydride graft copolymer. These two raw materials undergo a time-separation and in-melt high-shear blending step, namely steps 102-104, to form a homogeneous composition melt. This composition melt is then extruded, namely step 105, to form a geotextile extrudate. The extrudate is then introduced into a core dynamic sono-induced annealing treatment step, namely step 106. This step is characterized by the synergistic effect of controlled cooling and mechanical vibration. Furthermore, during the execution of step 106, the resonant frequency is dynamically locked by monitoring electrical parameters, and the process is adaptively controlled by monitoring operating parameters, such as controlling the cooling rate. Finally, the product treated in step 106 is a long-lasting geotextile composition that forms a stable glassy state and suppresses the microscopic ice wedge effect.

[0046] like Fig. 2 As shown, the horizontal axis represents the cooling rate, and the range shown is from 1... / second to 50 / second, the left ordinate represents the elongation retention rate (%) after 200 freeze-thaw cycles, and the right ordinate represents the relative value of the free volume cavity density. The curve showing the elongation retention rate (%) after 200 freeze-thaw cycles, represented by the solid line, indicates that, as shown in Figure 1... / second, 5 / second or 10 At a low cooling rate of 20 m / s, the retention rate is close to 100%, while as the cooling rate increases to 20 m / s... / second and 50 / second, the retention rate drops sharply. Meanwhile, the relative value curve of free volume cavity density, shown by the dashed line, exhibits the opposite trend: extremely low density at low cooling rates and increasing density at high cooling rates. The correspondence between the two curves reveals that lower cooling rates result in lower free volume cavity density, thus achieving a higher freeze-thaw resistance retention rate. Fig. 3 As shown, it illustrates the application objectives of the system represented by the dashed box. On the one hand, the system is challenged by the cold regional environment represented by the octagonal box. On the other hand, the civil engineer, represented by the human figure, puts forward clear functional requirements for the system. These requirements, namely the use cases included in the system, are specifically represented by the three elliptical boxes: resistance to micro ice wedge effects and freeze-thaw damage, resistance to chemical corrosion, and maintenance of low-temperature flexibility.

[0047] Example 5: This example provides a standardized engineering procedure for calibrating key control parameters in step 106 of the dynamic sono-induced annealing process, in order to address the potential impact of batch fluctuations in the raw materials of the polymer matrix or interface pinning agent on the actual glass transition temperature of the material. The calibration procedure addresses the industrial production problem of acoustic impedance drift. Using a dynamic acoustic annealing calibration device equipped with online monitoring and control functions, an offline calibration test is performed on a reference batch of geotextile composition with the same formulation and preparation process as sample group S1 in Example 2. This calibration device, in addition to possessing the 20kHz low-frequency ultrasonic vibration system of Example 2, has a controller capable of monitoring drive power. In addition to performing frequency sweeping and speed control cooling modules, it also integrates a module for synchronously measuring the extrudate storage modulus. A non-contact dynamic mechanical analysis (DMA) probe was used as a reference standard; the calibration procedure included the following steps: introducing the product from extrusion step 105 into the calibration equipment and maintaining its temperature at 100°C. A higher than its The high elastic state temperature; at this temperature, the speed-controlled cooling is turned off, and the ultrasonic vibration system is started, with its driving frequency scanning in the range of 18.0kHz to 22.0kHz, while monitoring the driving power. The system will The peak frequency of 20.1 kHz was identified as the initial system resonant frequency of the material in this state. ,Should The value is used as the starting tracking point for the resonant lock-in logic in subsequent step 106; the system initiates the complete calibration cooling procedure: the speed control cooling module is started and set to 5. / second, simultaneously activating the ultrasonic vibration system to operate at a frequency of In automatic resonant frequency tracking and locking mode starting from 100; Throughout the initial cooling process, the system control unit synchronously recorded two data streams at 100ms intervals: 1. Drive power from the vibration system controller. 2. Reference energy storage modulus from the DMA probe .

[0048] After cooling is complete, the recorded data is analyzed: (Referring to the energy storage modulus) On the curve, the point at which the slope reaches its maximum, i.e., the point of fastest modulus growth, is identified and designated as the reference point for the dynamic glass transition of the material. In driving power On the curve, extract The power value at the same moment, and the power value near that point. Time derivative in seconds The calculated specific power change rate value of 12.5 W / s was determined as the preset power change rate threshold for production line control. The output of this calibration procedure is the initial system resonant frequency. and preset power change rate threshold This information is written into the controllers of all dynamic acoustic annealing equipment on the production line; in subsequent continuous production, the equipment can perform resonant frequency locking simply by monitoring its own electrical parameters, without relying on expensive and complex DMA probes. The system determines the conditions and accurately indicates in real time that the extrudate has completed the glass transition, thereby adaptively adjusting the cooling rate or stopping mechanical vibration, ensuring that even if there are fluctuations in raw material batches, the quality of the prepared stable glass remains highly consistent.

[0049] Example 6: This example is used to verify the implementation methods and effects of two different technical approaches for forming a chemical protective layer on the surface of a geotextile composition. Sample preparation: Base sample (S1): using the same raw material specifications and preparation process as the sample (S1) of the present invention in Example 2; Sample S2: based on the formulation of S1 (90 parts by weight of polymer matrix and 10 parts by weight of interface pinning agent), an additional 2 parts by weight of a low surface energy corrosion-resistant polymer is added, specifically a hydroxyl-terminated polydimethylsiloxane (PDMS), which has a surface energy of 25... viscosity of 1000 mPa s; the PDMS was added together with the high polymer matrix from the main feed port in step 102; the rest of the preparation process, including steps 102-106 (sequential blending and dynamic sonophoresis), was exactly the same as S1; sample group S3: the formulation was exactly the same as S1, 90 parts by weight of the high polymer matrix and 10 parts by weight of the interfacial pinning agent; during the execution of the dynamic sonophoresis in step 106 of S1, an electrostatic field was applied synchronously; the electrostatic field was realized by setting a corona discharge electrode between the compression roller and the grounded cooling roller of the dynamic sonophoresis device, a direct current high voltage of 15 kV was applied to the extrudate to make its surface charged; surface property and corrosion resistance test: to verify the formation of the surface chemical protective layer, the water contact angle test (according to GB / T30693-2014) was performed on the extrudate (upper surface) of sample groups S1, S2 and S3; to verify the actual effect of the protective layer, another sample group was taken, and the tensile strength retention rate (%) was tested according to the GB / T1690-2010 standard after being immersed in a 5% (mass fraction) hydrochloric acid (HCl) solution for 7 days, and then being taken out, washed and dried.

[0050] Table 3: Comparison of surface properties and corrosion resistance of sample groups S1, S2 and S3

[0051]

[0052] The test results are shown in Table 3. The water contact angle of sample group S2 was 105.2°, showing strong hydrophobicity, which confirmed that the low surface energy polysiloxane (PDMS) had successfully migrated and enriched on the surface of the extrudate during the dynamic sonophoresis in step 106, driven by mechanical vibration acceleration and thermodynamic incompatibility, forming a chemically inert layer. Correspondingly, the strength retention rate (97.3%) after HCl corrosion was improved compared with S1 (88.1%). The water contact angle of sample group S3 was 35.8°, showing strong hydrophilicity, which was different from S1 (60.5°) and S2 (105.2°). The result confirmed that the electrostatic field applied in step 106 used the electrophoretic effect of the polar groups (maleic anhydride) in the interfacial pinning agent (EPDM-g-MAH) molecules to irreversibly drive and enrich them on the outer surface of the extrudate, forming a chemical protective layer rich in polar functional groups. Correspondingly, the strength retention rate (96.5%) after HCl corrosion was also improved compared with S1.

[0053] It is obvious to those skilled in the art that the present application is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or essential characteristics of the present application.

[0054] ​Finally, it should be noted that the above examples are merely intended to illustrate the technical solutions of the present application and not to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A weather-resistant and corrosion-resistant long-lasting geotextile composition suitable for cold regions, characterized in that, The composition is prepared by the following method, the method comprising: Step 101: Provide a polymer matrix and an interface pinning agent, wherein the interface pinning agent is an amphiphilic copolymer comprising a nonpolar segment compatible with the polymer matrix and a polar segment for pinning the microcavity interface; Step 102: In the extruder, the polymer matrix is ​​melted at the front section of the extruder to form a matrix melt; Step 103: After the matrix melt is formed, an interface pinning agent is added to the matrix melt in the middle or rear section of the extruder. Step 104 involves melting and blending the matrix melt containing the interfacial pinning agent through a high-shear section of an extruder to form a polymer composition melt. Step 105: Extruding the polymer composition melt into an extrudate; Step 106 involves subjecting the extrudate to dynamic sono-induced annealing, which includes: applying mechanical vibration to the extrudate during controlled cooling from a temperature above its glass transition temperature to a temperature below its glass transition temperature; wherein the melt blending in steps 102 to 104 provides a uniform physical prerequisite for the migration of the interfacial pinning agent in step 106; and the controlled cooling and mechanical vibration in the dynamic sono-induced annealing process synergistically: promote the relaxation of amorphous segments in the polymer matrix to form a stable glass with reduced free volume cavities; promote the migration of the interfacial pinning agent to the residual microcavity interface in the stable glass, and utilize polar segments to bind water molecules at this interface to form non-frozen bound water and inhibit ice crystal nucleation; Furthermore, the polymer matrix is ​​a blend of ethylene propylene diene monomer (EPDM) rubber and linear low-density polyethylene (LLDPE), wherein the ethylene content of EPDM rubber is 55% to 70%, and the melt index of the LLDPE is 190. The concentration at a load of 2.16 kg ranged from 0.8 g / 10 min to 2.2 g / 10 min; the interfacial pinning agent was a maleic anhydride-grafted EPDM rubber copolymer with a maleic anhydride grafting rate of 0.5% to 1.5%. The mechanical vibration in step 106 is subacoustic vibration or low-frequency ultrasonic vibration, and the frequency of the mechanical vibration is in the range of 10kHz to 30kHz. The controlled cooling in step 106 is a slow cooling process with a cooling rate of less than 10. / Second.

2. The weather-resistant and corrosion-resistant long-lasting geotextile composition suitable for cold regions according to claim 1, characterized in that, In step 106, while applying mechanical vibration to the extrudate, an electrostatic field is also applied to the extrudate; the electrostatic field is used to coordinate with the mechanical vibration to drive the interfacial pinning agent to migrate to and accumulate on the outer surface of the extrudate, thereby forming a chemical protective layer on the outer surface of the extrudate.

3. The weather-resistant and corrosion-resistant long-lasting geotextile composition suitable for cold regions according to claim 1, characterized in that, In step 101, in addition to the polymer matrix and the interface pinning agent, a low surface energy corrosion-resistant polymer that is thermodynamically incompatible with the polymer matrix is ​​also provided; and in step 106, mechanical vibration is used to simultaneously accelerate the migration of the low surface energy corrosion-resistant polymer to the outer surface of the extrudate, so as to form a chemically inert layer on the outer surface of the extrudate.

4. The weather-resistant and corrosion-resistant long-lasting geotextile composition suitable for cold regions according to claim 3, characterized in that, The low surface energy corrosion-resistant polymer is a fluoropolymer or a polysiloxane.

5. The weather-resistant and corrosion-resistant long-lasting geotextile composition suitable for cold regions according to claim 1, characterized in that, The method further includes: step 801, in step 106, real-time monitoring of an operating parameter of the device for applying mechanical vibration that is related to the acoustic impedance of the extrudate; step 802, characterizing that the extrudate has completed the glass transition based on the time variation characteristics of the operating parameter; and step 803, adaptively adjusting the rate of controlled cooling or stopping the application of mechanical vibration based on the characterization results.

6. The weather-resistant and corrosion-resistant long-lasting geotextile composition suitable for cold regions according to claim 5, characterized in that, The operating parameters are the drive power required to maintain a constant amplitude of mechanical vibration. The time variation characteristic in step 802 is the driving power. time derivative satisfy ,in, This is a preset power change rate threshold that characterizes the occurrence of the glass transition.

7. The weather-resistant and corrosion-resistant long-lasting geotextile composition suitable for cold regions according to claim 1, characterized in that, Step 106 further includes: real-time monitoring of electrical operating parameters of the device used to apply mechanical vibration, which are related to energy coupling efficiency; and dynamically adjusting the driving frequency of the mechanical vibration based on the monitoring results of the electrical operating parameters.

Images