High-density polyethylene material with high hydrogen barrier property as well as preparation method and application of high-density polyethylene material

Abstract

The invention relates to the technical field of materials, and discloses a high-density polyethylene material with high hydrogen barrier property as well as a preparation method and application thereof, and the high-density polyethylene material comprises the following components in parts by weight: 100 parts of high-density polyethylene and 1-5 parts of ionic liquid; the hydrogen permeability coefficient of the high-density polyethylene material is less than or equal to 6.246 * 10 <-16 > mol.m / (m < 2 >. S.Pa) under the conditions of 10 MPa and 7 DEG C; the hydrogen permeability coefficient of the high-density polyethylene material is smaller than or equal to 6.447 * 10 <-16 > mol.m / (m < 2 >. S.Pa) under the conditions of 70 MPa and 20 DEG C. According to the technical scheme provided by the invention, the hydrogen barrier capability of the high-density polyethylene can be improved on the premise that the original performance of the high-density polyethylene is not sacrificed.

Description

Technical Field

[0001] The present application relates to the field of material technology, and in particular to a high-density polyethylene material with high hydrogen barrier properties, a preparation method thereof, and an application thereof. Background Art

[0002] High-density polyethylene (HDPE) performs poorly as a hydrogen barrier, primarily due to its non-polar linear and semi-crystalline structure, which results in high hydrogen permeability. While existing technologies, such as nanomaterial fillers or blending with high-barrier polymers, can improve barrier properties, they often compromise mechanical and thermal processing properties, and face challenges such as poor dispersibility and incompatibility.

[0003] To solve this technical problem, it is necessary to improve the hydrogen barrier capability of HDPE without sacrificing its original performance, especially for the storage, transportation and safety requirements in the field of hydrogen energy. Summary of the Invention

[0004] The present application provides a high-density polyethylene material with high hydrogen barrier performance, and a preparation method and application thereof, which achieves the technical effect of improving its hydrogen barrier capability without sacrificing the original performance of high-density polyethylene.

[0005] In order to achieve the above objectives, the main technical solutions adopted in this application include: In a first aspect, the present invention provides a high-density polyethylene material with high hydrogen barrier performance, comprising, by weight, 100 parts of high-density polyethylene and 1-5 parts of an ionic liquid; the high-density polyethylene material has a hydrogen permeability coefficient of less than or equal to 6.246×10 -16 mol·m / (m 2 ·s·Pa); the hydrogen permeability coefficient of the high-density polyethylene material under the conditions of 70MPa and 20°C is less than or equal to 6.447×10 -16 mol·m / (m 2 ·s·Pa).

[0006] This embodiment effectively improves the hydrogen barrier performance of high-density polyethylene by adding an appropriate amount of ionic liquid to it. Within the addition range of 1 to 5 parts, the ionic liquid can optimize the microstructure of high-density polyethylene, enhance the interaction between molecules, and significantly reduce the hydrogen permeability coefficient. Under the conditions of 10MPa, 7℃ and 70MPa, 20℃, the hydrogen permeability coefficient of high-density polyethylene material is less than or equal to 6.246×10 -16 mol·m / (m 2 ·s·Pa) and 6.447×10 -16 mol·m / (m 2·s·Pa), demonstrating excellent hydrogen barrier properties. However, the addition level of ionic liquids needs to be strictly controlled. Below 1 part is insignificant improvement in barrier properties, while exceeding 5 parts may disrupt the microstructure of the HDPE material, further impacting its mechanical and thermal processing properties. By precisely controlling the addition level of ionic liquids, hydrogen barrier properties can be improved while maintaining the mechanical and thermal processing properties of the HDPE material, achieving an optimal balance of performance.

[0007] In one embodiment, the elastic modulus of the high-density polyethylene material is ≥1179.68 MPa, the yield strength is ≥19.90 MPa, the tensile strength is ≥20.79 MPa, and the maximum elongation is ≥402.34%.

[0008] The high-density polyethylene material of this embodiment has excellent mechanical properties, such as elastic modulus ≥1179.68MPa, yield strength ≥19.90MPa, tensile strength ≥20.79MPa, and maximum elongation ≥402.34%, which significantly improves its barrier performance to hydrogen while maintaining mechanical stability. These properties ensure that the high-density polyethylene material is not easily deformed or cracked when subjected to external pressure, dynamic loads, or impact, thereby effectively reducing the possibility of hydrogen penetration. In addition, the improvement of these mechanical properties also ensures that the high-density polyethylene material can maintain good shape stability and ductility during thermal processing, meeting the requirements for processing accuracy and material reliability during the manufacturing process.

[0009] In one embodiment, the high-density polyethylene material has a melting onset temperature ≥123.15°C, a melting peak temperature ≥133.99°C, and a melting end temperature ≥143.40°C.

[0010] This example optimizes the high-density polyethylene material's melting onset temperature (≥123.15°C), peak melting temperature (≥133.99°C), and melting end temperature (≥143.40°C) to improve hydrogen barrier properties while maintaining its mechanical properties and thermal processing performance. A higher melting temperature helps increase the material's crystallinity, thereby enhancing the close arrangement of molecules and, in turn, improving its hydrogen barrier properties. Furthermore, a higher melting temperature ensures the material's stability during thermal processing, providing a wider temperature window and avoiding performance degradation due to improper processing. Therefore, properly controlling the melting temperature can ensure high hydrogen barrier properties while maintaining the material's strength, rigidity, and good processing characteristics, ensuring its stability in high-performance applications.

[0011] In one embodiment, the PE grade of the high-density polyethylene is above PE80.

[0012] This embodiment uses high-density polyethylene of PE80 or above, which can significantly improve the hydrogen barrier performance of high-density polyethylene materials while maintaining their excellent mechanical properties and thermal processing properties. High-density polyethylene of PE80 or above has a more regular microstructure and molecular chain arrangement, which makes it show higher density and lower hydrogen permeability in terms of hydrogen barrier. In addition, the compressive strength and impact resistance of materials above PE80 are stronger, and they can withstand higher internal pressures during long-term use, maintain structural stability, and avoid performance degradation due to external impact or aging. By combining with ionic liquids, the hydrogen barrier effect can be further improved without affecting its mechanical properties and thermal processing properties, ensuring the long life and high reliability of high-density polyethylene materials in practical applications. Therefore, the use of high-density polyethylene of PE80 or above can achieve the best balance between hydrogen barrier performance and the comprehensive performance of high-density polyethylene materials.

[0013] In one embodiment, the PE grade of the high-density polyethylene is selected from PE80 or PE100.

[0014] This embodiment uses high-density polyethylene of PE80 or PE100, which can significantly improve the barrier performance to hydrogen while maintaining excellent mechanical properties and thermal processing properties. Since the molecular chain arrangement of PE80 and PE100 is more regular and the microstructure is denser, the diffusion of hydrogen is effectively hindered, thereby improving the barrier effect of hydrogen. In addition, these materials can still maintain good mechanical properties such as tensile strength and impact resistance under high temperature and high pressure conditions, and their thermal processing performance is also guaranteed, ensuring that they can be easily molded and processed in practical applications. After combining with ionic liquids, PE80 and PE100 further optimize the crystallization behavior and molecular chain arrangement, enhancing the hydrogen barrier effect without affecting the mechanical properties and thermal stability of the material. Therefore, the use of PE80 or PE100 not only improves the hydrogen barrier performance, but also ensures the stability and reliability of the material in long-term use, and is suitable for hydrogen storage containers, seals, hydrogen pipelines and other fields.

[0015] In one embodiment, the ionic liquid comprises a cation and an anion; wherein the cation is selected from an imidazolium cation; and the anion is selected from at least one of acetate and diethylphosphate.

[0016] This embodiment can effectively improve the barrier performance of high-density polyethylene to hydrogen by introducing an ionic liquid containing imidazolium cations and anions such as acetate and diethylphosphate, while maintaining its mechanical properties and thermal processing properties. The cations and anions in the ionic liquid interact with the high-density polyethylene molecular chains, promote the orderly arrangement of the molecular chains, and form a denser microstructure. The denser structure reduces pores and defects, thereby effectively reducing the diffusion rate of hydrogen and improving the barrier performance of hydrogen. In addition, since anions such as imidazolium cations and acetate have low reactivity with high-density polyethylene, they interact with high-density polyethylene through physical mixing and interface regulation, avoiding chemical degradation and maintaining its mechanical properties and thermal stability. Therefore, the high-density polyethylene material not only provides a reliable hydrogen barrier effect, but also can maintain good mechanical strength and thermal processing properties under high temperature and high pressure conditions.

[0017] In one embodiment, the ionic liquid is selected from 1-ethyl-3-methylimidazolium acetate or 1-ethyl-3-methylimidazolium diethyl phosphate; the purity of the 1-ethyl-3-methylimidazolium acetate or the 1-ethyl-3-methylimidazolium diethyl phosphate is ≥97%.

[0018] This embodiment introduces 1-ethyl-3-methylimidazolium acetate or 1-ethyl-3-methylimidazolium diethyl phosphate with a purity of ≥97% as an ionic liquid, which can effectively improve the hydrogen barrier performance of high-density polyethylene while maintaining its mechanical properties and thermal processing properties. These ionic liquids are evenly dispersed in polyethylene, promote the orderly arrangement of molecular chains, form a dense microstructure, increase the diffusion resistance of hydrogen molecules, and thus improve the hydrogen barrier effect. The interaction between imidazole cations and polyethylene molecular chains further enhances the crystallinity and structural density of the molecular chains, while ensuring that the mechanical and thermal stability of high-density polyethylene are not destroyed. Overall, the addition of ionic liquids not only improves the hydrogen barrier performance, but also ensures the excellent performance of high-density polyethylene materials under high temperature and high pressure environments.

[0019] In a second aspect, an embodiment of the present application provides a method for preparing the above-mentioned high-density polyethylene material, the preparation method comprising: stirring high-density polyethylene to obtain stirred high-density polyethylene; mixing the stirred high-density polyethylene with an ionic liquid to obtain a premix; and hot pressing and cold pressing the premix to obtain the high-density polyethylene material.

[0020] This embodiment can effectively improve the hydrogen barrier performance of high-density polyethylene materials while maintaining their mechanical properties and thermal processing properties through the careful design of process steps such as stirring of high-density polyethylene, ionic liquid mixing, hot pressing and cold pressing. The stirring process makes the high-density polyethylene particles evenly dispersed, enhances its fluidity, and provides a good foundation for subsequent mixing. After mixing the ionic liquid with the stirred high-density polyethylene, the ionic liquid can be evenly dispersed in the high-density polyethylene to form a dense microstructure, effectively increasing the diffusion resistance of hydrogen and improving the hydrogen barrier effect. The combination of hot pressing and cold pressing ensures the uniformity, dimensional stability and excellent mechanical properties of the material. Ultimately, through the optimization of this series of processes, the high-density polyethylene material obtained maintains excellent mechanical and thermal processing properties while improving the hydrogen barrier performance, meeting the high performance requirements in practical applications.

[0021] In one embodiment, the stirring conditions are: at a temperature of 140-200°C, the stirring time is 10-15 minutes, and the stirring speed is 30-60 rpm; the mixing conditions are: at a temperature of 140-200°C, the stirring and mixing time is 10-20 minutes, and the stirring and mixing speed is 30-60 rpm; the hot pressing conditions are: the hot pressing pressure is 15-20 MPa, the temperature is 140-200°C, and the hot pressing time is 15-30 minutes; the cold pressing and shaping conditions are: the cold pressing pressure is 15-20 MPa, the temperature is 10-40°C, and the cold pressing and shaping time is 20-40 minutes.

[0022] In a third aspect, an embodiment of the present application provides an industrial-scale amplification process, which includes: granulating, molding, cooling and shaping the high-density polyethylene material described above or the high-density polyethylene material prepared by the above-mentioned preparation method to obtain an industrial-scale amplified high-density polyethylene material.

[0023] This embodiment uses a carefully designed high-density polyethylene preparation process, including stirring, ionic liquid mixing, hot pressing and cold pressing to effectively improve its hydrogen barrier performance while maintaining excellent mechanical properties and thermal processing properties. During the industrial scale expansion process, the high-density polyethylene material is first melt-extruded through a granulation device to ensure the uniformity of the material. Then, the particles are formed (such as injection molding, extrusion molding, compression molding, blow molding, thermoforming, rotational molding, etc.), and the temperature, pressure and injection speed are strictly controlled to ensure that the high-density polyethylene material fully fills the mold and the molding quality meets the requirements. Finally, the cooling and shaping process ensures the dimensional accuracy and surface quality of the high-density polyethylene material, thereby maintaining its consistency and reliability. Through the optimization of this series of processes, not only the hydrogen barrier effect is improved, but also the application performance of the high-density polyethylene material in hydrogen storage containers, seals, hydrogen pipelines and other fields is ensured, providing an efficient hydrogen energy storage and transportation solution.

[0024] In one embodiment, the granulation temperature is 150-160°C; the molding temperature is 200°C.

[0025] In a fourth aspect, an embodiment of the present application provides an application of a high-density polyethylene material. The high-density polyethylene material described above or the high-density polyethylene material prepared by the preparation method described above is applied to hydrogen storage and transportation containers, pipelines, pipe joints or fuel cell hydrogen seals. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific implementation or the description of the prior art.

[0027] Figure 1 The scanning electron microscope images of Example 1 and Comparative Example 1 provided in this application; Figure 2 The infrared spectrum of Example 1 provided in this application; Figure 3 The infrared spectrum of Example 2 provided in this application; Figure 4 The infrared spectrum of Example 3 provided in this application; Figure 5 The infrared spectrum of Comparative Example 1 provided in this application; Figure 6 The DSC curve diagram of Example 1 provided in this application; Figure 7 The DSC curve diagram of Comparative Example 1 provided in this application; Figure 8 TG and DTG curves of Example 1 provided in this application; Figure 9 TG and DTG curves of Comparative Example 1 provided in this application. DETAILED DESCRIPTION

[0028] To make the purpose, technical solutions, and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0029] High-density polyethylene (HDPE) is a material widely used in gas pipelines, containers, packaging materials, and fuel-related engineering due to its excellent mechanical properties, corrosion resistance, good processability, and low cost. Despite its superior performance in a variety of applications, HDPE suffers from significant deficiencies in its hydrogen barrier properties. HDPE is a non-polar linear polymer with highly flexible chains and weak interchain forces. Its microstructure is characterized by interweaving of crystalline and amorphous regions, resulting in a high hydrogen permeability. This makes it unable to meet the stringent gas barrier requirements of applications such as hydrogen storage and transportation and fuel cell housings.

[0030] The permeation of hydrogen in HDPE follows a "dissolution-diffusion" mechanism: hydrogen molecules first physically adsorb on the polyethylene surface and dissolve in the amorphous regions. They then diffuse through the free volume between the polymer segments, ultimately escaping through the other side. Due to HDPE's semicrystalline structure, hydrogen primarily diffuses along the amorphous regions, while the crystalline regions, with their tightly packed segments, form a physical barrier.

[0031] Existing approaches to improving the gas barrier properties of polyethylene (such as HDPE) primarily include filling with nanomaterials (e.g., nano-montmorillonite and graphene oxide), blending with high-barrier polymers (e.g., EVOH and PA), or constructing dense composite layers. However, these approaches are generally plagued by challenges stemming from differences in the physical and chemical properties of the materials and challenges in process implementation. For example, when filling HDPE with nano-montmorillonite, the nanomaterials, due to their large surface area and high surface energy, tend to agglomerate, making uniform dispersion difficult to achieve using conventional physical blending processes. Microscopic defects formed by filler aggregation can serve as pathways for gas permeation, reducing the gas barrier effect. Furthermore, polyethylene is a hydrophobic, non-polar polymer, while nano-inorganic fillers are often highly hydrophilic. This polarity difference results in poor interfacial compatibility, making ideal interfacial bonding difficult, leading to debonding and voids, and thus weakening barrier and mechanical properties. Furthermore, the added nanomaterials can form a physical network between polymer chains, hindering their motion and reducing the melt flow index (MFI). This can negatively impact flow properties and molding quality during thermal processing, such as injection molding, extrusion, and blow molding. When HDPE is blended with polar high-barrier polymers (such as EVOH and PA), phase separation easily occurs due to their poor polarity, resulting in an uneven material structure and the formation of micropores, which affects gas barrier and mechanical properties. Even using compatibilizers to improve dispersion and interface properties can lead to complex processes, increased costs, and potential new mobility or stability issues. Furthermore, when HDPE and EVOH are blended, multiple melting peaks often occur or the melting-crystallization temperature range narrows, leading to localized overheating, decomposition, or inadequate crystallization, narrowing the processing window and requiring stricter temperature control.

[0032] Furthermore, existing technologies often lead to a decrease in the mechanical and thermal processing properties of the material. For example, the addition of nanofillers and high-barrier polymers often reduces the melt flow index (MFI) of HDPE, thereby affecting thermal processing techniques such as injection molding and extrusion. More importantly, while some technologies attempt to improve hydrogen barrier properties through surface modification or the addition of high-performance composite materials, these methods suffer from complex processes, high costs, and unstable modification results, making them difficult to meet the high demands of fields such as hydrogen energy.

[0033] In summary, how to improve the barrier properties of high-density polyethylene to hydrogen while maintaining its mechanical properties and thermal processing properties is a technical problem that needs to be solved at present.

[0034] In order to solve the above technical problems, according to an embodiment of the present application, a high-density polyethylene material with high hydrogen barrier performance is provided, which comprises 100 parts of high-density polyethylene and 1-5 parts of ionic liquid in parts by weight; the high-density polyethylene material has a hydrogen permeability coefficient of less than or equal to 6.246×10 -16 mol·m / (m2 ·s·Pa); the hydrogen permeability coefficient of the high-density polyethylene material under the conditions of 70MPa and 20°C is less than or equal to 6.447×10 - 16 mol·m / (m 2 ·s·Pa).

[0035] Specifically, high-density polyethylene (HDPE), as a matrix material, exhibits excellent mechanical properties, chemical resistance, and processability. Ionic liquids are liquids composed of cations and anions that are liquid at or near room temperature. As additives, ionic liquids are used to enhance the hydrogen barrier properties of HDPE. The addition of ionic liquids can alter the microstructure of HDPE, thereby affecting its gas barrier properties. Furthermore, the amount of ionic liquid added is controlled between 1 and 5 parts, aiming to enhance the hydrogen barrier properties while ensuring stable processability and mechanical properties. When the ionic liquid addition amount is less than 1 part, the ionic liquid is unevenly distributed in the HDPE, resulting in insufficient interface regulation and chain segment alignment induction, making it difficult to form an effective hydrogen diffusion barrier structure, and the barrier properties are not significantly improved. When the ionic liquid addition amount exceeds 5 parts, the excess ionic liquid aggregates in the HDPE, disrupting the material's microstructure and increasing intercrystalline interfacial defects. This can even affect the HDPE's melt processability and thermal stability, leading to a decrease in mechanical properties. To this end, by precisely controlling the amount of ionic liquid added, it is possible to improve the hydrogen barrier performance while maintaining the stability of the processability and mechanical properties of the high-density polyethylene material, thereby optimizing the overall performance.

[0036] This embodiment effectively improves the hydrogen barrier performance of high-density polyethylene by adding an appropriate amount of ionic liquid to it. Within the addition range of 1 to 5 parts, the ionic liquid can optimize the microstructure of high-density polyethylene, enhance the interaction between molecules, and significantly reduce the hydrogen permeability coefficient. Under the conditions of 10MPa, 7℃ and 70MPa, 20℃, the hydrogen permeability coefficient of high-density polyethylene material is less than or equal to 6.246×10 -16 mol·m / (m 2 ·s·Pa) and 6.447×10 -16 mol·m / (m 2 ·s·Pa), demonstrating excellent hydrogen barrier properties. However, the addition level of ionic liquids needs to be strictly controlled. Below 1 part is insignificant improvement in barrier properties, while exceeding 5 parts may disrupt the microstructure of the HDPE material, further impacting its mechanical and thermal processing properties. By precisely controlling the addition level of ionic liquids, hydrogen barrier properties can be improved while maintaining the mechanical and thermal processing properties of the HDPE material, achieving an optimal balance of performance.

[0037] In one embodiment, the elastic modulus of the high-density polyethylene material is ≥1179.68 MPa, the yield strength is ≥19.90 MPa, the tensile strength is ≥20.79 MPa, and the maximum elongation is ≥402.34%.

[0038] Specifically, elastic modulus is an important indicator of material rigidity, referring to the ease with which a material undergoes elastic deformation under load. For high-density polyethylene (HDPE), an elastic modulus ≥1179.68 MPa indicates high rigidity. Even when subjected to significant external forces, its shape and dimensions remain minimally deformed, maintaining their original shape. This property is crucial for applications requiring precise dimensional control and long-term load bearing, such as pipes and structural components. It also enables HDPE to remain stable under high loads and resist deformation. Yield strength is the critical stress at which a material begins to permanently deform under load. For HDPE, a yield strength ≥19.90 MPa indicates that it can withstand significant external forces without permanent deformation. Specifically, when loads are below this threshold, HDPE will return to its original shape; however, when loads exceed this threshold, it enters a plastic deformation phase. This allows HDPE to maintain its performance under prolonged loads or impacts, particularly in applications requiring durability and long-term stability. Tensile strength refers to the maximum stress a material can withstand under a tensile load. A high-density polyethylene material with a tensile strength ≥20.79MPa means it can withstand high tensile forces without breaking during stretching. Higher tensile strength helps increase the service life of high-density polyethylene materials and reduces the risk of fracture due to excessive tensile stress. Elongation is the maximum degree of deformation of a material when stretched, indicating the maximum deformation ratio the material can withstand during stretching. A high-density polyethylene material with a maximum elongation ≥402.34% indicates very good ductility and the ability to significantly elongate when subjected to tensile force without immediately breaking. This feature allows high-density polyethylene materials to absorb more energy when subjected to impact or dynamic loads, thereby reducing the risk of brittle fracture.

[0039] The high-density polyethylene material of this embodiment has excellent mechanical properties, such as elastic modulus ≥1179.68MPa, yield strength ≥19.90MPa, tensile strength ≥20.79MPa, and maximum elongation ≥402.34%, which significantly improves its barrier performance to hydrogen while maintaining mechanical stability. These properties ensure that the high-density polyethylene material is not easily deformed or cracked when subjected to external pressure, dynamic loads, or impact, thereby effectively reducing the possibility of hydrogen penetration. In addition, the improvement of these mechanical properties also ensures that the high-density polyethylene material can maintain good shape stability and ductility during thermal processing, meeting the requirements for processing accuracy and material reliability during the manufacturing process.

[0040] In one embodiment, the high-density polyethylene material has a melting onset temperature ≥123.15°C, a melting peak temperature ≥133.99°C, and a melting end temperature ≥143.40°C.

[0041] Specifically, a melting onset temperature ≥123.15°C indicates that the HDPE material must be heated to at least 123.15°C to melt during processing (such as injection molding and extrusion). A higher melting onset temperature also indicates that the HDPE material has good thermal stability at lower temperatures and is less likely to melt prematurely in high-temperature environments. A melting peak temperature ≥133.99°C indicates that the HDPE material requires a higher amount of heat to fully melt during the melting process, which may affect processing energy consumption. A higher melting peak temperature may also indicate that the HDPE material has a higher degree of crystallinity, which is generally associated with the strength and rigidity of the HDPE material. A melting end temperature ≥143.40°C provides a wider temperature window for HDPE processing, helping to optimize processing conditions and ensure the flow and uniformity of the HDPE material during processing. A higher melting end temperature also indicates the potential of HDPE for high-temperature applications, such as structural materials or thermoplastic composites in high-temperature environments.

[0042] This embodiment optimizes the melting onset temperature (≥123.15°C), melting peak temperature (≥133.99°C), and melting end temperature (≥143.40°C) of the high-density polyethylene material, thereby improving the hydrogen barrier performance while maintaining its mechanical properties and thermal processing properties. A higher melting temperature helps to increase the crystallinity of the material, thereby enhancing the close arrangement between molecules, and thus improving its barrier properties to hydrogen. In addition, a higher melting temperature also ensures the stability of the material during thermal processing, provides a wider temperature window, and avoids performance degradation due to improper processing. Therefore, reasonable control of the melting temperature can maintain the strength, rigidity, and good processing characteristics of the material while ensuring high hydrogen barrier performance, ensuring its stability in high-performance applications. In one embodiment, the PE grade of the high-density polyethylene is above PE80.

[0043] Specifically, PE grades are classified based on performance indicators such as the material's long-term hydrostatic strength. These grades reflect the material's mechanical properties and durability under specific conditions. For example, PE80 indicates that the material can withstand a long-term hydrostatic strength of 8.0 MPa under specified conditions; PE100 indicates a long-term hydrostatic strength of 10.0 MPa. Higher grades indicate the material's ability to withstand higher pressures over long-term use, resulting in better mechanical properties and durability. High-density polyethylene (HDPE) is selected from materials with a PE grade of 80 or higher. These materials offer higher compressive strength, allowing them to withstand higher internal pressures, and better impact resistance, maintaining structural integrity under external impacts and reducing the risk of pipe rupture. Furthermore, materials with a PE grade of 80 or higher maintain stable performance over long-term use, making them less susceptible to aging and performance degradation. This helps extend the life of piping systems and reduce maintenance costs. HDPE grades of PE80 or higher have a more regular microstructure, with more ordered molecular chain arrangement. This regular structure creates a denser matrix, which effectively hinders the diffusion of hydrogen molecules. When combined with ionic liquids, PE80 and higher grades interact better with the ionic liquid, forming a more effective hydrogen diffusion barrier. The more even distribution of the ionic liquid within these high-PE grades allows for more effective manipulation of the crystallization behavior and molecular chain arrangement of the HDPE, further enhancing its hydrogen barrier properties. Therefore, the selection of high-density polyethylene (HDPE) grades above PE80 ensures superior mechanical properties, durability, and hydrogen barrier performance. These high-PE grades offer increased compressive strength, improved impact resistance, and long-term stability, enabling them to synergize with the ionic liquid to form a denser microstructure, effectively hindering the diffusion of hydrogen molecules.

[0044] This embodiment uses high-density polyethylene of PE80 or above, which can significantly improve the hydrogen barrier performance of high-density polyethylene materials while maintaining their excellent mechanical properties and thermal processing properties. High-density polyethylene of PE80 or above has a more regular microstructure and molecular chain arrangement, which makes it show higher density and lower hydrogen permeability in terms of hydrogen barrier. In addition, the compressive strength and impact resistance of materials above PE80 are stronger, and they can withstand higher internal pressures during long-term use, maintain structural stability, and avoid performance degradation due to external impact or aging. By combining with ionic liquids, the hydrogen barrier effect can be further improved without affecting its mechanical properties and thermal processing properties, ensuring the long life and high reliability of high-density polyethylene materials in practical applications. Therefore, the use of high-density polyethylene of PE80 or above can achieve the best balance between hydrogen barrier performance and the comprehensive performance of high-density polyethylene materials.

[0045] In one embodiment, the PE grade of the high-density polyethylene is selected from PE80 or PE100.

[0046] Specifically, the molecular chains of PE80 and PE100 are more regularly arranged and their microstructures are denser, which helps to form a more effective hydrogen diffusion barrier structure. When combined with ionic liquids, PE80 and PE100 can better interact with the ionic liquids, forming a more uniform distribution. Ionic liquids in these materials can more effectively regulate the crystallization behavior and molecular chain arrangement of high-density polyethylene, further improving hydrogen barrier properties. The use of PE80 or PE100 not only improves hydrogen barrier properties, but also maintains the mechanical properties and thermal stability of the material. This means that in practical applications, this material can maintain good performance under high pressure and temperature conditions, and is suitable for use in fields such as hydrogen storage containers, seals, and hydrogen pipelines.

[0047] This embodiment uses high-density polyethylene of PE80 or PE100, which can significantly improve the barrier performance to hydrogen while maintaining excellent mechanical properties and thermal processing properties. Since the molecular chain arrangement of PE80 and PE100 is more regular and the microstructure is denser, the diffusion of hydrogen is effectively hindered, thereby improving the barrier effect of hydrogen. In addition, these materials can still maintain good mechanical properties such as tensile strength and impact resistance under high temperature and high pressure conditions, and their thermal processing performance is also guaranteed, ensuring that they can be easily molded and processed in practical applications. After combining with ionic liquids, PE80 and PE100 further optimize the crystallization behavior and molecular chain arrangement, enhancing the hydrogen barrier effect without affecting the mechanical properties and thermal stability of the material. Therefore, the use of PE80 or PE100 not only improves the hydrogen barrier performance, but also ensures the stability and reliability of the material in long-term use, and is suitable for hydrogen storage containers, seals, hydrogen pipelines and other fields.

[0048] In one embodiment, the ionic liquid comprises a cation and an anion; wherein the cation is selected from an imidazolium cation; and the anion is selected from at least one of acetate and diethylphosphate.

[0049] Specifically, the introduction of ionic liquids can regulate the crystallization behavior of high-density polyethylene (HDPE). There is an interaction between the cations and anions in the ionic liquid and the HDPE molecular chains. This interaction can promote the orderly arrangement of the HDPE molecular chains and form a denser microstructure. A denser microstructure means that the pores and defects inside the HDPE are reduced, which effectively hinders the diffusion of hydrogen molecules and significantly reduces the hydrogen permeability coefficient. Ionic liquids containing imidazolium cations, acetate groups, and diethyl phosphate groups have low reactivity with HDPE and mainly interact through physical mixing and interfacial regulation. This physical mixing and interfacial regulation does not destroy the original structure of HDPE, but rather hinders the diffusion of hydrogen by forming tiny "obstacles" in the HDPE matrix. This minimal reactivity maintains the original structure of HDPE, avoids chemical degradation, and ensures that the intrinsic properties of the material are not affected.

[0050] This embodiment can effectively improve the barrier performance of high-density polyethylene to hydrogen by introducing an ionic liquid containing imidazolium cations and anions such as acetate and diethylphosphate, while maintaining its mechanical properties and thermal processing properties. The cations and anions in the ionic liquid interact with the high-density polyethylene molecular chains, promote the orderly arrangement of the molecular chains, and form a denser microstructure. The denser structure reduces pores and defects, thereby effectively reducing the diffusion rate of hydrogen and improving the barrier performance of hydrogen. In addition, since anions such as imidazolium cations and acetate have low reactivity with high-density polyethylene, they interact with high-density polyethylene through physical mixing and interface regulation, avoiding chemical degradation and maintaining its mechanical properties and thermal stability. Therefore, the high-density polyethylene material not only provides a reliable hydrogen barrier effect, but also can maintain good mechanical strength and thermal processing properties under high temperature and high pressure conditions.

[0051] In one embodiment, the ionic liquid is selected from 1-ethyl-3-methylimidazolium acetate or 1-ethyl-3-methylimidazolium diethyl phosphate; the purity of the 1-ethyl-3-methylimidazolium acetate or the 1-ethyl-3-methylimidazolium diethyl phosphate is ≥97%.

[0052] Specifically, 1-ethyl-3-methylimidazole acetate or 1-ethyl-3-methylimidazole diethyl phosphate has low volatility and high thermal stability, which makes it difficult to volatilize or decompose during processing and use, and can be stably present in high-density polyethylene. And it has good dispersibility and can be evenly distributed in high-density polyethylene, promoting the orderly arrangement of high-density polyethylene molecular chains, forming a denser microstructure. A denser microstructure means that the pores and defects inside the high-density polyethylene are reduced, thereby effectively hindering the diffusion of hydrogen molecules. These ionic liquids can guide the arrangement of high-density polyethylene molecular chains, making them more regular. For example, the nitrogen atoms of the imidazole cations can form weak electrostatic interactions with the polar groups on the high-density polyethylene molecular chains, promoting the orderly arrangement of the molecular chains. The presence of ionic liquids can also make it easier for high-density polyethylene molecular chains to enter an ordered crystalline state, thereby forming a denser crystalline structure.

[0053] This embodiment introduces 1-ethyl-3-methylimidazolium acetate or 1-ethyl-3-methylimidazolium diethyl phosphate with a purity of ≥97% as an ionic liquid, which can effectively improve the hydrogen barrier performance of high-density polyethylene while maintaining its mechanical properties and thermal processing properties. These ionic liquids are evenly dispersed in polyethylene, promote the orderly arrangement of molecular chains, form a dense microstructure, increase the diffusion resistance of hydrogen molecules, and thus improve the hydrogen barrier effect. The interaction between imidazole cations and polyethylene molecular chains further enhances the crystallinity and structural density of the molecular chains, while ensuring that the mechanical and thermal stability of high-density polyethylene are not destroyed. Overall, the addition of ionic liquids not only improves the hydrogen barrier performance, but also ensures the excellent performance of high-density polyethylene materials under high temperature and high pressure environments.

[0054] An embodiment of the present application provides a method for preparing the above-mentioned high-density polyethylene material, which comprises: stirring high-density polyethylene to obtain stirred high-density polyethylene; mixing the stirred high-density polyethylene with an ionic liquid to obtain a premix; and hot pressing and cold pressing the premix to obtain the high-density polyethylene material.

[0055] Specifically, by stirring, high-density polyethylene particles or powder are fully dispersed, and their uniformity and fluidity are improved, so that the stirred high-density polyethylene has better fluidity and uniformity. The stirred high-density polyethylene is mixed with the ionic liquid in proportion. The mixing equipment can be a twin-screw extruder, a high-speed mixer or a kneader. During the mixing process, the ionic liquid can be uniformly dispersed in the high-density polyethylene to form a premix by controlling the temperature and stirring speed. By hot pressing, the premix is ​​melted and formed at high temperature. During the hot pressing process, the high-density polyethylene melts and flows, and the ionic liquid is uniformly dispersed in the molten high-density polyethylene to form a uniform high-density polyethylene material. By cold pressing, the high-density polyethylene material after hot pressing is shaped during the cooling process, ensuring the dimensional stability and mechanical properties of the high-density polyethylene material.

[0056] This embodiment can effectively improve the hydrogen barrier performance of high-density polyethylene materials while maintaining their mechanical properties and thermal processing properties through the careful design of process steps such as stirring of high-density polyethylene, ionic liquid mixing, hot pressing and cold pressing. The stirring process makes the high-density polyethylene particles evenly dispersed, enhances its fluidity, and provides a good foundation for subsequent mixing. After mixing the ionic liquid with the stirred high-density polyethylene, the ionic liquid can be evenly dispersed in the high-density polyethylene to form a dense microstructure, effectively increasing the diffusion resistance of hydrogen and improving the hydrogen barrier effect. The combination of hot pressing and cold pressing ensures the uniformity, dimensional stability and excellent mechanical properties of the material. Ultimately, through the optimization of this series of processes, the high-density polyethylene material obtained maintains excellent mechanical and thermal processing properties while improving the hydrogen barrier performance, meeting the high performance requirements in practical applications.

[0057] In one embodiment, the stirring conditions are: at a temperature of 140-200°C, the stirring time is 10-15 minutes, and the stirring speed is 30-60 rpm; the mixing conditions are: at a temperature of 140-200°C, the stirring and mixing time is 10-20 minutes, and the stirring and mixing speed is 30-60 rpm; the hot pressing conditions are: the hot pressing pressure is 15-20 MPa, the temperature is 140-200°C, and the hot pressing time is 15-30 minutes; the cold pressing and shaping conditions are: the cold pressing pressure is 15-20 MPa, the temperature is 10-40°C, and the cold pressing and shaping time is 20-40 minutes.

[0058] An embodiment of the present application provides an industrial scale-up process, which includes: granulating, molding, cooling and shaping the high-density polyethylene material described above or the high-density polyethylene material prepared by the preparation method described above to obtain an industrial scale-up high-density polyethylene material.

[0059] Specifically, the prepared high-density polyethylene (HDPE) material is placed in a pelletizing machine, such as a twin-screw or single-screw extruder. Heating and shearing the material melt and extrude it to form uniform pellets. The pellets are then molded using various methods, including injection molding, extrusion molding, compression molding, blow molding, thermoforming, and rotational molding. For example, in injection molding, the pellets are placed in the hopper of the injection molding machine and heated to melt them. The molten material is then injected into a mold, where it is forced to fill every corner of the mold under high pressure. During the injection molding process, parameters such as temperature, pressure, and injection speed must be controlled to ensure molding quality. After injection molding, the product remains in the mold and is cooled using a cooling system (such as water or air). The cooling time typically varies depending on the thickness and shape of the product, ranging from tens of seconds to several minutes. After cooling is complete, the mold is opened and the resulting industrial-scale HDPE material is removed. This industrial-scale process, through the steps of pelletizing, injection molding, and cooling to finalize the shape, transforms laboratory or small-scale HDPE production into products suitable for large-scale industrial applications. This process ensures material uniformity and consistency, improves the dimensional accuracy and surface quality of finished products, and meets the material quality and production efficiency requirements of industrial production. This material has a wide range of applications in hydrogen storage containers, seals, hydrogen pipelines, and other industrial products, providing a new solution for the storage and transportation of hydrogen energy.

[0060] This embodiment uses a carefully designed high-density polyethylene preparation process, including stirring, ionic liquid mixing, hot pressing and cold pressing to effectively improve its hydrogen barrier performance while maintaining excellent mechanical properties and thermal processing properties. During industrial-scale amplification, the high-density polyethylene material is first melt-extruded through a granulation device to ensure the uniformity of the material. Next, the particles are formed, and the temperature, pressure and injection speed are strictly controlled to ensure that the high-density polyethylene material fully fills the mold and the molding quality meets the requirements. Finally, the cooling and shaping process ensures the dimensional accuracy and surface quality of the high-density polyethylene material, thereby maintaining its consistency and reliability. Through the optimization of this series of processes, not only the hydrogen barrier effect is improved, but also the application performance of the high-density polyethylene material in hydrogen storage containers, seals, hydrogen pipelines and other fields is ensured, providing an efficient hydrogen energy storage and transportation solution.

[0061] In one embodiment, the granulation temperature is 150-160°C; the molding temperature is 200°C.

[0062] An embodiment of the present application provides an application of a high-density polyethylene material. The high-density polyethylene material described above or the high-density polyethylene material prepared by the preparation method described above is applied to hydrogen storage and transportation containers, pipelines, pipe joints or fuel cell hydrogen seals.

[0063] Specifically, in hydrogen storage and transportation container applications, high-density polyethylene (HDPE) can contain other fillers or additives, such as glass fiber and carbon fiber, to further enhance the material's mechanical properties and durability. Furthermore, it can be combined with other materials (such as metals) to form a multilayer structure to enhance the overall performance and safety of the container.

[0064] In pipeline applications, HDPE can be compounded with other materials (such as rubber) to form a multilayer structure to enhance the sealing performance and corrosion resistance of the pipeline. In addition, other additives such as antioxidants and UV absorbers can be included to improve the weather resistance and service life of the pipeline.

[0065] In pipe fitting applications, HDPE can contain other fillers or additives, such as sealants and lubricants, to further enhance the sealing and durability of the fitting. Furthermore, it can be combined with other materials (such as metal) to form a multilayer structure to enhance the overall performance and safety of the fitting.

[0066] In fuel cell hydrogen seal applications, HDPE can contain additives such as sealants and antioxidants to further enhance the seal's sealing performance and durability. Furthermore, it can be compounded with other materials (such as rubber) to form a multilayer structure to enhance the seal's overall performance and reliability.

[0067] This high-density polyethylene material and its preparation method have broad application prospects in the field of hydrogen storage and transportation. By adding ionic liquids, the hydrogen barrier properties of the high-density polyethylene material are significantly improved, while maintaining good mechanical properties and thermal stability. In addition, by including other fillers or additives, and compounding with other materials to form a multilayer structure, the performance of the high-density polyethylene material can be further improved to meet the strict material performance requirements of hydrogen storage and transportation containers, pipelines, pipe joints, and fuel cell hydrogen seals. The application of this high-density polyethylene material provides a new solution for the storage and transportation of hydrogen energy, which has important practical significance and broad development prospects.

[0068] This example significantly enhances the hydrogen barrier properties of high-density polyethylene (HDPE) by optimizing its preparation process, specifically by adding ionic liquids, fillers, and additives, while maintaining excellent mechanical and thermal processing properties. These improvements enhance the safety and service life of HDPE in applications such as hydrogen storage and transportation containers, pipelines, pipe joints, and fuel cell hydrogen seals.

[0069] In order to better explain the present application and facilitate understanding, the present application is described in detail below through specific embodiments. The raw materials used in the examples and comparative examples, unless otherwise specified, are all disclosed in the prior art, for example, can be directly purchased or prepared according to the preparation methods disclosed in the prior art, and the parts are all parts by weight.

[0070] Example 1 The high-density polyethylene material with high hydrogen barrier performance in this embodiment is made from the following raw materials: The preparation method of high-density polyethylene material with high hydrogen barrier performance is as follows: Step S1, stirring high-density polyethylene PE100 at a temperature of 200° C. for 10 minutes at a stirring speed of 40 rpm to obtain stirred high-density polyethylene; Step S2, introducing ionic liquid 1-ethyl-3-methylimidazolium acetate into the stirred high-density polyethylene, and continuing to stir and mix at a temperature of 200° C. and a stirring and mixing speed of 40 rpm for 20 minutes to obtain a premix; Step S3, placing the premix into a mold and hot pressing it at a pressure of 17 MPa, a temperature of 200° C., and a compression time of 20 min; Step S4, cold pressing the product obtained in step S3, with a cold pressing pressure of 17 MPa, a temperature of 20° C., and a cold pressing time of 40 min, and demolding to obtain a high-density polyethylene material.

[0071] Example 2 The high-density polyethylene material with high hydrogen barrier performance in this embodiment is made from the following raw materials: The preparation method of high-density polyethylene material with high hydrogen barrier performance is as follows: Step S1, stirring high-density polyethylene PE100 at a temperature of 200° C. for 12 minutes at a stirring speed of 30 rpm to obtain stirred high-density polyethylene; Step S2, introducing ionic liquid 1-ethyl-3-methylimidazolium acetate into the stirred high-density polyethylene, and continuing to stir and mix at a temperature of 200° C. and a stirring and mixing speed of 30 rpm for 15 minutes to obtain a premix; Step S3, placing the premix into a mold for hot pressing at a pressure of 15 MPa, a temperature of 180° C., and a compression time of 20 min; Step S4, cold pressing the product obtained in step S3, with a cold pressing pressure of 15 MPa, a temperature of 10° C., and a cold pressing time of 20 min, and demolding to obtain a high-density polyethylene material.

[0072] Example 3 The high-density polyethylene material with high hydrogen barrier performance in this embodiment is made from the following raw materials: The preparation method of high-density polyethylene material with high hydrogen barrier performance is as follows: Step S1, stirring high-density polyethylene PE100 at a temperature of 140° C. and a stirring speed of 60 rpm for 14 minutes to obtain stirred high-density polyethylene; Step S2, introducing ionic liquid 1-ethyl-3-methylimidazolium acetate into the stirred high-density polyethylene, and continuing to stir and mix at a temperature of 140° C. and a stirring and mixing speed of 60 rpm for 10 minutes to obtain a premix; Step S3, placing the premix into a mold for hot pressing at a pressure of 20 MPa, a temperature of 200° C., and a compression time of 20 min; Step S4, cold pressing the product obtained in step S3, with a cold pressing pressure of 20 MPa, a temperature of 30° C., and a cold pressing time of 30 min, and demolding to obtain a high-density polyethylene material.

[0073] Example 4 The high-density polyethylene material with high hydrogen barrier performance in this embodiment is made from the following raw materials: The preparation method of high-density polyethylene material with high hydrogen barrier performance is as follows: Step S1, stirring high-density polyethylene PE80 at a temperature of 200° C. for 15 minutes at a stirring speed of 50 rpm to obtain stirred high-density polyethylene; Step S2, introducing ionic liquid 1-ethyl-3-methylimidazolium diethyl phosphate into the stirred high-density polyethylene, and continuing to stir and mix at a temperature of 200° C. and a stirring and mixing speed of 50 rpm for 20 minutes to obtain a premix; Step S3: placing the premix into a mold and hot pressing the premix at a pressure of 18 MPa, a temperature of 140° C., and a compression time of 20 min. Step S4, cold pressing the product obtained in step S3, with a cold pressing pressure of 18 MPa, a temperature of 40° C., and a cold pressing time of 40 min, and demolding to obtain a high-density polyethylene material.

[0074] Comparative Example 1 The same as Example 1, except that the ionic liquid 1-ethyl-3-methylimidazolium acetate was not added.

[0075] Comparative Example 2 The same as Example 3, except that the ionic liquid 1-ethyl-3-methylimidazolium acetate was not added.

[0076] Comparative Example 3 The same as Example 4, except that the ionic liquid 1-ethyl-3-methylimidazolium diethyl phosphate was not added.

[0077] Comparative Example 4 The same as Example 1, except that 8 parts of ionic liquid 1-ethyl-3-methylimidazolium acetate were added.

[0078] Comparative Example 5 The same as Example 1, the only difference is that in the formula of Example 1, 2 parts of maleic anhydride are additionally added.

[0079] The microstructure analysis of Example 1 and Comparative Example 1 is carried out as shown in the following figure. Figure 1 These are scanning electron microscope images of Example 1 and Comparative Example 1 provided in this application. Figure 1 (a) is the sample of Comparative Example 1, which has obvious particles and defects on its surface and a relatively loose microstructure. This may be due to the fact that the arrangement of the high-density polyethylene molecular chains is not regular enough, and there are many gaps and micropores. Figure 1 Sample (b) in Figure 1 shows the sample from Example 1. After adding the ionic liquid, the sample surface became smoother and denser, with significantly fewer defects and particles. This indicates that the introduction of the ionic liquid effectively promoted the orderly arrangement of the HDPE molecular chains and improved the interactions between the chains, thereby creating a denser and more uniform microstructure. The voids and micropores within the material are the primary pathways for gas molecules to diffuse. After adding the ionic liquid, the HDPE material's microstructure became denser, with significantly fewer voids and micropores. The diffusion path for hydrogen molecules was extended, and the diffusion resistance increased, significantly reducing the hydrogen permeability coefficient and improving the material's gas barrier properties.

[0080] The infrared spectrum test of the above examples 1 to 3 and comparative example 1 is carried out. Figure 2 This is the infrared spectrum of Example 1 provided in this application. Figure 3 This is the infrared spectrum of Example 2 provided in this application. Figure 4 This is the infrared spectrum of Example 3 provided in this application. Figure 5 This is the infrared spectrum of Comparative Example 1 provided in this application. Figure 2 、 Figure 3 、 Figure 4 and Figure 5It is shown that Examples 1-3 and Comparative Example 1 are basically consistent in the position and intensity of the main characteristic absorption peaks, indicating that the introduction of ionic liquids has not changed the chemical structure of high-density polyethylene. No new absorption peaks appear in the infrared spectra of Examples 1-3, and no obvious displacement or disappearance of the original characteristic peaks is observed, indicating that no new chemical bonds are formed between the ionic liquid and the high-density polyethylene. This means that the interaction between the ionic liquid and the high-density polyethylene is mainly physical mixing and interface regulation, rather than chemical reaction. Since no chemical bonding reaction occurs, the main chain structure and chemical configuration of the high-density polyethylene are maintained, so its intrinsic properties such as chemical stability, corrosion resistance and thermal stability are not affected.

[0081] The above Example 1 and Comparative Example 1 were subjected to DSC and TGA tests. Figure 6 、 Figure 8 The DSC and TG / DTG curves of Example 1 provided in this application. Figure 7 、 Figure 9 The DSC and TG / DTG curves of Comparative Example 1 provided in this application. Figure 6 The melting onset temperature, peak temperature and end temperature of Example 1 did not change much, indicating that the ionic liquid did not significantly change the crystal structure of high-density polyethylene. The crystallinity increased from 72.63% to 77.61%, indicating that the ionic liquid promoted the orderly arrangement of high-density polyethylene molecular chains and enhanced the crystallization ability, which is consistent with the Figure 1 This is consistent with the dense structure observed in (b). Figure 8 Example 1 and Figure 9 The TG curves of Comparative Example 1 are essentially identical, indicating very similar thermogravimetric behavior. The DTG peak positions of Example 1 and Comparative Example 1 are consistent, indicating no shift in the temperature of maximum thermogravimetric loss rate and no change in the thermal decomposition mechanism. Furthermore, the thermal stability remains unchanged, demonstrating that the ionic liquid is stable at high temperatures and does not induce premature degradation.

[0082] The above Examples 1-4 and Comparative Examples 1-5 were subjected to hydrogen permeation tests according to standard methods. The hydrogen permeation performance test results of the above samples are shown in Table 1: Table 1 Hydrogen permeability test results As can be seen from Table 1, according to the comparison of Comparative Example 1 and Example 1, Comparative Example 2 and Example 3, and Comparative Example 3 and Example 4, the hydrogen permeability coefficient of Example 1 with the addition of an appropriate amount of ionic liquid is significantly lower than that of Comparative Example 1 without the addition of ionic liquid, the hydrogen permeability coefficient of Example 3 with the addition of an appropriate amount of ionic liquid is significantly lower than that of Comparative Example 2 without the addition of ionic liquid, and the hydrogen permeability coefficient of Example 4 with the addition of an appropriate amount of ionic liquid is significantly lower than that of Comparative Example 3 without the addition of ionic liquid, indicating that the introduction of the ionic liquid effectively hinders the diffusion of hydrogen molecules and improves the hydrogen barrier performance of the material.

[0083] A comparison between Comparative Example 4 and Example 1 shows that the amount of ionic liquid added in Comparative Example 4 reaches 8 parts, exceeding the preferred range (1-5 parts), resulting in an increase in the hydrogen permeability coefficient instead of a decrease. This indicates that the excess ionic liquid may agglomerate, form defects, or phase separate in the matrix, destroying the dense structure of the material and reducing the hydrogen barrier performance.

[0084] According to the comparison between Comparative Example 5 and Example 1, 2 parts of maleic anhydride were added to Example 1, and the hydrogen permeability coefficient increased from 4.484×10 -16 mol·m / (m 2 ·s·Pa) increased to 6.069×10 -16 mol·m / (m 2 ·s·Pa), indicating that the addition of maleic anhydride did not further improve the hydrogen barrier performance, but may have interfered with the interface structure between the ionic liquid and the high-density polyethylene matrix, weakening the barrier effect.

[0085] In summary, the examples are always better than the comparative examples, indicating that ionic liquids can effectively improve the hydrogen barrier performance under different conditions.

[0086] The above Examples 1-4 and Comparative Examples 1-5 were subjected to uniaxial tensile tests according to standard methods. The tensile mechanical properties test results of the above samples are shown in Table 2: Table 2 Tensile mechanical properties test results As can be seen from Table 2, according to the comparison between Comparative Example 1 and Example 1, Comparative Example 2 and Example 3, and Comparative Example 3 and Example 4, the mechanical properties (elastic modulus, yield strength, tensile strength, elongation) of the samples in the examples do not change much, indicating that the addition of an appropriate amount of ionic liquid has little effect on the mechanical properties of high-density polyethylene, and basically maintains the original mechanical properties of the material.

[0087] According to the comparison between Comparative Example 4 and Example 1, the amount of ionic liquid added in Comparative Example 4 reached 8 parts, which exceeded the preferred range (1-5 parts), resulting in a significant decrease in the elastic modulus, yield strength and tensile strength. This indicates that the excess ionic liquid may agglomerate, form defects or phase separate in the matrix, destroying the structural integrity of the material and reducing the mechanical properties.

[0088] Comparison of Comparative Example 5 and Example 1 reveals that, despite the addition of 2 parts of maleic anhydride to Example 1, the elastic modulus decreased from 1227.67 MPa to 1042.16 MPa, indicating that the addition of maleic anhydride reduced the material's rigidity. However, the yield strength and tensile strength did not change significantly, and the elongation decreased slightly, indicating that maleic anhydride has a limited effect on the material's overall mechanical properties, but does reduce its rigidity.

[0089] In summary, the mechanical properties of Examples 1-4 vary under different test conditions, but the influence of the addition of ionic liquid on the mechanical properties has a consistent trend, that is, an appropriate amount of addition has a small effect on the mechanical properties, while excessive addition will reduce the mechanical properties.

[0090] The above Examples 1-4 and Comparative Examples 1-5 were subjected to DSC tests according to the standard method. The DSC test results of the above samples are shown in Table 3: Table 3DSC test results As can be seen from Table 3, according to the comparison of Comparative Example 1 and Example 1, Comparative Example 2 and Example 3, and Comparative Example 3 and Example 4, the melting start temperature, peak temperature and end temperature of the samples in the examples do not change much, indicating that the appropriate addition of ionic liquid has little effect on the crystal structure and melting behavior of high-density polyethylene, and basically maintains the original thermal properties of high-density polyethylene.

[0091] According to the comparison between Comparative Example 4 and Example 1, the amount of ionic liquid added in Comparative Example 4 reached 8 parts, the melting start temperature and peak temperature increased slightly, and the melting end temperature decreased slightly, indicating that excessive ionic liquid may have a certain impact on the crystallization integrity of high-density polyethylene.

[0092] According to the comparison between Comparative Example 5 and Example 1, it can be seen that in Comparative Example 5, 2 parts of maleic anhydride are additionally added on the basis of Example 1, and the melting peak temperature and the termination temperature are significantly increased, indicating that the addition of maleic anhydride may have changed the crystal structure of high-density polyethylene, making its crystallization more perfect or forming a more stable crystal structure.

[0093] In summary, while the melting temperatures of Examples 1-4 varied under different test conditions, the effect of the ionic liquid on melting behavior remained consistent, indicating that a moderate addition had minimal impact. Therefore, the addition of the ionic liquid did not significantly alter the melting characteristics of the HDPE, ensuring the reliability of its thermal processing properties.

[0094] It should also be noted that the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, commodity, or apparatus that includes a series of elements includes not only those elements but also other elements not explicitly listed, or includes elements inherent to such process, method, commodity, or apparatus. In the absence of further limitations, an element defined by the phrase "comprises a ..." does not exclude the presence of other identical elements in the process, method, commodity, or apparatus that includes the element.

[0095] The foregoing is merely an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application should all be included within the scope of the claims of the present application.

[0096] Although the embodiments of the present application have been described with reference to the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present application, and such modifications and variations shall fall within the scope defined by the appended claims.

Claims

1. A high-density polyethylene material with high hydrogen barrier performance, characterized in that: In parts by weight, it comprises 100 parts of high-density polyethylene and 1-5 parts of ionic liquid; The hydrogen permeability coefficient of the high-density polyethylene material under the conditions of 10 MPa and 7°C is less than or equal to 6.246×10 - 16 mol·m / (m 2 ·s·Pa); The hydrogen permeability coefficient of the high-density polyethylene material under the conditions of 70 MPa and 20°C is less than or equal to 6.447×10 - 16 mol·m / (m 2 ·s·Pa).

2. The high-density polyethylene material according to claim 1, characterized in that The elastic modulus of the high-density polyethylene material is ≥1179.68 MPa, the yield strength is ≥19.90 MPa, the tensile strength is ≥20.79 MPa, and the maximum elongation is ≥402.34%.

3. The high-density polyethylene material according to claim 1, characterized in that The high-density polyethylene material has a melting start temperature of ≥123.15°C, a melting peak temperature of ≥133.99°C, and a melting end temperature of ≥143.40°C.

4. The high-density polyethylene material according to claim 1, characterized in that The PE grade of the high-density polyethylene is above PE80.

5. The high-density polyethylene material according to claim 4, characterized in that The PE grade of the high-density polyethylene is selected from PE80 or PE100.

6. The high-density polyethylene material according to claim 1, characterized in that The ionic liquid includes cations and anions; wherein, The cation is selected from imidazolium cations; The anion is selected from at least one of acetate and diethyl phosphate.

7. The high-density polyethylene material according to claim 6, characterized in that The ionic liquid is selected from 1-ethyl-3-methylimidazolium acetate or 1-ethyl-3-methylimidazolium diethyl phosphate; the purity of the 1-ethyl-3-methylimidazolium acetate or the 1-ethyl-3-methylimidazolium diethyl phosphate is ≥97%.

8. The method for preparing the high-density polyethylene material according to any one of claims 1 to 7, characterized in that: The preparation method comprises: The high-density polyethylene is stirred to obtain stirred high-density polyethylene; The stirred high-density polyethylene and ionic liquid are mixed to obtain a premix; The premix is ​​shaped by hot pressing and cold pressing to obtain the high-density polyethylene material.

9. The preparation method according to claim 8, characterized in that The stirring conditions are: at a temperature of 140-200°C, a stirring time of 10-15 minutes, and a stirring speed of 30-60 rpm; The mixing conditions are: at a temperature of 140-200°C, a stirring mixing time of 10-20 minutes, and a stirring mixing speed of 30-60 rpm; The hot pressing conditions are as follows: hot pressing pressure of 15-20 MPa, temperature of 140-200° C., and hot pressing time of 15-30 min; The cold pressing and shaping conditions are as follows: cold pressing pressure of 15-20 MPa, temperature of 10-40° C., and cold pressing and shaping time of 20-40 min.

10. An industrial scale-up process, characterized in that: The industrial scale-up process comprises: The high-density polyethylene material according to any one of claims 1 to 7 or the high-density polyethylene material prepared by the preparation method according to any one of claims 8 to 9 is granulated, formed, cooled and shaped to obtain an industrial-scale high-density polyethylene material.

11. The industrial scale-up process according to claim 10, characterized in that: The granulation temperature is 150-160°C; The molding temperature is 200°C.

12. An application of high-density polyethylene material, characterized in that: The high-density polyethylene material according to any one of claims 1 to 7 or the high-density polyethylene material prepared by the preparation method according to any one of claims 8 to 9 is used for hydrogen storage and transportation containers, pipelines, pipe joints or fuel cell hydrogen seals.

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