Creep resistant ultra-high molecular weight polyethylene composite and method of making same

Abstract

This invention discloses a creep-resistant ultra-high molecular weight polyethylene (UHMWPE) composite material and its preparation method. The composite material is obtained by hot pressing of UHMWPE powder, a crosslinking agent, and modified calcium sulfate whiskers. The crosslinking agent is 1,3,5-triacryloylhexahydro-triazine. Before hot pressing, the crosslinking agent is uniformly coated on the surface of the UHMWPE particles. During hot pressing, a crosslinking reaction is initiated in the particle boundary region, forming an interfacial crosslinking network. The modified calcium sulfate whiskers are obtained by surface modification of calcium sulfate whiskers with a silane coupling agent. The interfacial crosslinking network and the whisker bridging structure together constitute a multi-scale synergistic reinforcement network. This invention is the first to introduce calcium sulfate whiskers into the TAF interfacial crosslinked UHMWPE system, achieving an organic integration of chemical crosslinking and physical reinforcement. Tests show that at 70°C... o C. Under a stress of 1 MPa for 30 minutes, the creep elongation of the composite material of the present invention is as low as 0.47%, which is 55.2% lower than that of unmodified UHMWPE. The Vicat softening point reaches 140.2℃ and the tensile strength reaches 36.5 MPa.

Description

Technical Field

[0001] This invention relates to the field of polymer composite materials technology, and in particular to a creep-resistant ultra-high molecular weight polyethylene composite material and its preparation method. Background Technology

[0002] Ultra-high molecular weight polyethylene (UHMWPE) fiber is the third generation of high-performance fibers following carbon fiber and aramid fiber. It possesses advantages such as high specific strength, high specific modulus, excellent impact resistance, chemical corrosion resistance, and low density, making it widely used in military bulletproofing, aerospace, marine engineering, and medical devices. However, UHMWPE has a linear molecular chain structure with only weak van der Waals forces between molecules. Under long-term stress, molecular chain slippage easily occurs, leading to severe creep deformation and poor dimensional stability, especially at high temperatures. This severely limits its application in fields with stringent requirements for dimensional stability, such as deep-sea mooring cables and high-temperature structural components.

[0003] To improve the creep resistance of UHMWPE, researchers both domestically and internationally have developed various modification methods, mainly including: filler modification (such as adding carbon nanotubes, graphene, silica, etc.), chemical crosslinking modification (such as peroxide crosslinking, silane crosslinking), irradiation crosslinking modification (such as gamma rays, electron beams, ultraviolet light), and branching modification. In recent years, interfacial crosslinking strategies have received widespread attention.

[0004] Jing et al. (Ind. Eng. Chem. Res. 2025, 64, 12500-12511) disclosed a method using trimethylolpropane triacrylate (TMPTMA) as a crosslinking agent. This method involves mixing the crosslinking agent at room temperature to coat the surface of UHMWPE particles, followed by hot pressing to form a micron-scale interfacial crosslinked framework. This method significantly reduces the amount of crosslinking agent used (0.5%) while preserving the highly crystalline structure within the particles, enabling the material to withstand temperatures up to 70°C. o The tensile strength of C increased by 67.1%, and the creep resistance increased by 40.2%. However, TMPTMA has an adipose chain structure, and the cross-linked network it forms is a flexible network, so there is still room for improvement in its ability to inhibit molecular chain slippage.

[0005] Chinese invention patent CN202011219644.1 discloses a high-modulus, creep-resistant ultra-high molecular weight polyethylene fiber and its preparation method. This method involves adding a UV photosensitizer, a crosslinking agent, and a silane coupling agent to the spinning raw material, and initiating crosslinking through UV irradiation. This method requires UV equipment and a photosensitizer, is complex, and the crosslinking reaction is difficult to control, easily leading to fiber surface oxidation and a decline in mechanical properties. Chinese invention patent CN201110096019.7 discloses a calcium sulfate whisker-modified UHMWPE composite material, but it only uses a single physical filler and lacks the synergistic effect of a chemical crosslinking network, resulting in limited improvement in creep resistance. Furthermore, calcium sulfate whiskers (CSW), as a widely available and inexpensive reinforcing material, have been used to modify thermoplastics such as polypropylene and polyphenylene sulfide (e.g., CN202311227572.9, CN 201110107335), but there are no reports of its combined application with TAF interfacial crosslinking technology for creep-resistant modification of UHMWPE. Summary of the Invention

[0006] The purpose of this invention is to provide a creep-resistant ultra-high molecular weight polyethylene composite material and its preparation method, so as to solve the problems of decreased crystallinity caused by crosslinking modification, limited reinforcement effect of single filler modification, and insufficient improvement of creep resistance in the prior art.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A creep-resistant ultra-high molecular weight polyethylene composite material is prepared by hot pressing of ultra-high molecular weight polyethylene powder, crosslinking agent, and modified calcium sulfate whiskers.

[0009] The crosslinking agent is 1,3,5-triacryloylhexahydro-triazine (TAF), and its structural formula is as follows:

[0010]

[0011] The crosslinking agent is uniformly coated on the surface of ultra-high molecular weight polyethylene particles before hot pressing. During hot pressing, a crosslinking reaction is initiated in the particle boundary region to form an interfacial crosslinking network.

[0012] The modified calcium sulfate whiskers are obtained by surface modification of calcium sulfate whiskers with silane coupling agent, and their surface has functional groups that can participate in cross-linking reaction; during the hot pressing process, the modified calcium sulfate whiskers cross the particle boundary, and their surface functional groups chemically bond with the interface cross-linking network to form a bridging structure, which is uniformly distributed in the matrix and the interfacial gap to form a micron-scale physical reinforcement skeleton.

[0013] The interfacial cross-linking network and the whisker bridging structure together constitute a multi-scale synergistic reinforcement network.

[0014] This invention also provides a method for preparing creep-resistant ultra-high molecular weight polyethylene composite material, comprising the following steps:

[0015] Step 1: Preparation of modified calcium sulfate whiskers: Add calcium sulfate whiskers and silane coupling agent KH-570 to anhydrous ethanol at a mass ratio of 100:1-100:5, and ultrasonically disperse for 30-60 minutes, followed by 60-80 minutes. o C. Stir the reaction for 2-4 hours, filter, wash, and vacuum dry to obtain modified calcium sulfate whiskers;

[0016] Step 2, Interface Coating and Mixing: Mix TAF, thermal initiator and ultra-high molecular weight polyethylene powder in proportion, stir at room temperature for 3-5 minutes to make the crosslinking agent uniformly coat the surface of polyethylene particles.

[0017] Step 3, Multi-scale composite: Mix the modified calcium sulfate whiskers obtained in Step 1 with the mixture from Step 2 until homogeneous;

[0018] Step 4, Hot pressing: Place the mixture obtained in step 3 into a mold and heat at 200-220°C. o C. Hot-press at 8-12 MPa for 15-25 min, and then cool to obtain the composite material.

[0019] Preferably, based on 100 parts by weight of ultra-high molecular weight polyethylene powder, the amounts of each component are as follows: 0.3-0.8 parts of crosslinking agent, 0.5-3.0 parts of modified calcium sulfate whiskers, 0.1-0.3 parts of thermal initiator, and 0.05-0.2 parts of coupling agent.

[0020] Preferably, the viscosity-average molecular weight of the ultra-high molecular weight polyethylene is 3 million to 10 million, more preferably 3.5 million to 4.5 million.

[0021] Preferably, the calcium sulfate whiskers have a diameter of 1-4 μm, a length of 50-200 μm, and an aspect ratio of 20-100.

[0022] Preferably, in step 2, the thermal initiator is di-tert-butyl peroxide (DTBP), dicumyl peroxide (DCP), or a combination thereof.

[0023] Preferably, the ratio of the modified calcium sulfate whiskers to the crosslinking agent is 1:0.5-1:2.

[0024] Preferably, in step 4, the hot-pressing temperature is 210°C. o C, pressure 10 MPa, time 20 min.

[0025] This invention further provides an application of ultra-high molecular weight polyethylene composite material obtained by the above preparation method in high-temperature structural components and deep-sea mooring cables.

[0026] By employing the above technical solution—combining TAF interfacial crosslinking technology with a rigid triazine ring structure with modified calcium sulfate whisker physical reinforcement technology—a multi-scale dual-network structure of "rigid chemical crosslinking network and micron-scale physical reinforcement framework" can be formed. This structure not only inhibits molecular chain slippage at the micron scale through the TAF crosslinking network but also bears stress at the micron scale through the high-modulus framework of calcium sulfate whiskers. Furthermore, KH-570 surface modification achieves chemical bonding between the whiskers and the crosslinking network, resulting in a synergistic effect of "1+1>2". This invention is the first to introduce calcium sulfate whiskers into the TAF interfacial crosslinked UHMWPE system, realizing the organic integration of chemical crosslinking and physical reinforcement. Tests show that at 70... o C. Under a stress of 1 MPa for 30 minutes, the creep elongation of the composite material of this invention is as low as 0.47%, which is 55.2% lower than that of unmodified UHMWPE. The Vicat softening point reaches 140.2℃, and the tensile strength reaches 36.5 MPa. The method of this invention is simple and low in cost, and is applicable to high-temperature structural components, deep-sea mooring cables, and other fields.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. First construction of a multi-scale dual-network structure: This invention introduces calcium sulfate whiskers into the TAF interface crosslinked UHMWPE system for the first time, and constructs a multi-scale dual-network structure of "rigid chemical crosslinking network (micrometer scale) and micrometer physical reinforcement framework", realizing the organic integration of chemical crosslinking and physical reinforcement at the micrometer scale.

[0029] 2. Significant synergistic effect: The interfacial crosslinking of calcium sulfate whiskers and TAF produces a synergistic effect. The creep elongation of the composite material of this invention (0.47%) is reduced by 27.7% compared with TAF alone (0.65%), and by 55.2% compared with the unmodified sample (1.05%).

[0030] 3. Excellent comprehensive mechanical properties: The tensile strength of the composite material of this invention reaches 36.5 MPa, which is 81.6% higher than that of the unmodified sample; the flexural modulus reaches 1320 MPa, which is 94.1% higher than that of the unmodified sample; and the elongation at break is maintained at 325%, which significantly improves the strength while maintaining good toughness.

[0031] 4. High crystallinity retention: Since cross-linking only occurs at the particle interface, the highly crystalline structure inside the particles is retained, with a crystallinity of 63.5%, which is close to that of the unmodified sample (63.8%) and far higher than that of the traditional melt cross-linked sample (53.8%).

[0032] 5. Significantly improved heat resistance: The Vicat softening point reached 140.2℃, an increase of 11.7℃ compared to the unmodified sample. o C, compared to TAF alone, shows a 2.4% increase in interfacial crosslinking.o C.

[0033] 6. Simple process and low cost: This invention only requires hot pressing after mixing at room temperature, without the need for special equipment such as ultraviolet irradiation or supercritical CO2. Calcium sulfate whiskers are inexpensive and suitable for large-scale industrial production. Attached Figure Description

[0034] Figure 1 Different samples of the present invention at 70 o C. Comparison of creep elongation rates under 1 MPa stress for 30 min (bar chart);

[0035] Figure 2 This is a scanning electron microscope image (×5000x) of the cross-section of the sample in Example 2 of the present invention.

[0036] Figure 3 These are X-ray diffraction patterns of different samples from this invention;

[0037] Figure 4 These are DSC melt curves of different samples from this invention;

[0038] Figure 5 This is a bar chart comparing the Vicat softening points of different samples from this invention. Detailed Implementation

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the scope of protection of the present invention. The embodiments described in this invention are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0040] 1.1 Experimental materials:

[0041] Table 1:

[0042]

[0043] 1.2 Modification treatment of calcium sulfate whiskers

[0044] Add 100 parts by weight of calcium sulfate whiskers and 3 parts by weight of KH-570 to 500 parts by weight of anhydrous ethanol, and ultrasonically disperse for 45 minutes. o Stir the reaction at C for 3 h, filter, wash three times with anhydrous ethanol, and then... o Vacuum drying at C for 12 h yields modified calcium sulfate whiskers, which are then set aside for later use.

[0045] 1.3 Sample Preparation

[0046] Blank sample: Place 100 parts of UHMWPE powder in a mold and heat at 210°C. o C. Hot-press at 10 MPa for 20 min, then allow to cool naturally.

[0047] Comparative Example A (CSW only): UHMWPE powder (100 parts), modified calcium sulfate whiskers (2 parts), and antioxidant 1010 (0.2 parts) were mixed evenly and heated at 210 °C. o C. Hot-press at 10 MPa for 20 min.

[0048] Comparative Example B (TAF interfacial crosslinking only): UHMWPE powder (100 parts), TAF (0.5 parts), and DTBP (0.2 parts) were mixed and stirred at room temperature for 3 min to ensure the crosslinking agent was uniformly coated on the particle surface. The mixture was then stirred at 210 °C. o C. Hot-press at 10 MPa for 20 min.

[0049] Comparative Example C (CSW conventional melt crosslinking): UHMWPE powder (100 parts), TAF (0.5 parts), DTBP (0.2 parts), and modified calcium sulfate whiskers (2 parts) were mixed in an internal mixer at 160°C. o C. Mix at 60 rpm for 10 minutes, then at 210 rpm. o C. Hot-press at 10 MPa for 20 min.

[0050] Comparative Example D (TAF conventional melt crosslinking, without CSW): UHMWPE powder (100 parts), TAF (0.5 parts), and DTBP (0.2 parts) were mixed in an internal mixer at 160°C. o C. Mix at 60 rpm for 10 minutes, then at 210 rpm. o C. Hot-press at 10 MPa for 20 min.

[0051] Example 1 (TAF interfacial crosslinking with CSW 1.0 part): UHMWPE powder (100 parts), TAF (0.5 parts), and DTBP (0.2 parts) were mixed and stirred at room temperature for 3 min. Modified calcium sulfate whiskers (1.0 part) were added and mixed evenly. The mixture was then stirred at 210 °C. o C. Hot-press at 10 MPa for 20 min.

[0052] Example 2 (TAF interfacial crosslinking and CSW 2.0 parts): Same as Example 1, except that the amount of modified calcium sulfate whiskers was changed to 2.0 parts.

[0053] Example 3 (TAF interfacial crosslinking and CSW 3.0 parts): Same as Example 1, except that the amount of modified calcium sulfate whiskers was changed to 3.0 parts.

[0054] Example 4 (TAF 0.3 parts and CSW 1.5 parts): TAF 0.3 parts, DTBP 0.12 parts, modified calcium sulfate whiskers 1.5 parts, the rest is the same as in Example 1.

[0055] Example 5 (0.8 parts TAF and 1.5 parts CSW): 0.8 parts TAF, 0.32 parts DTBP, 1.5 parts modified calcium sulfate whiskers, and the rest are the same as in Example 1.

[0056] 1.4 Test Methods

[0057] 1.41 Gel Content Test

[0058] Referencing GB / T 18474-2001 standard, the sample was cut into thin slices, wrapped in a 120-mesh stainless steel mesh, and extracted in xylene at 150℃ for 8 hours (with a small amount of antioxidant added). After extraction, the sample was washed three times with ethanol. o Dry at C for 6 h until constant weight. Gel content = (mass after extraction / mass before extraction) × 100%.

[0059] 1.42 Differential Scanning Calorimetry (DSC)

[0060] A NETZSCH DSC 204 F1 differential scanning calorimeter was used in an N2 atmosphere at a heating rate of 10°C. o C / min, temperature range: room temperature - 200°C o C. Crystallinity X c = (ΔH m / ΔH m 0 ) × 100%, where ΔHm 0 = 293 J / g.

[0061] 1.43 X-ray diffraction analysis (XRD)

[0062] An X'Pert PRO MPD X-ray diffractometer was used, with Cu Kα radiation, tube voltage of 40 kV, tube current of 40 mA, scanning range of 2θ = 5°–40°, and scanning rate of 1 ° / min. The grain size was calculated according to the Scherrer formula: L = Kλ / (βcosθ).

[0063] 1.44 Vicat softening point test

[0064] Referencing GB / T 1633-2000 standard. An HDT / V-3116 Vicat heat distortion temperature tester was used, with a heating rate of 120°C. o C / h, load 10 N, sample size 10 mm × 10 mm × 4 mm.

[0065] 1.45 Creep Performance Test

[0066] A NETZSCH DMA 303 Eplexor dynamic thermomechanical analyzer was used, in three-point bending mode, under constant stress of 1 MPa and temperature of 70°C. o C, Test time 30 min. Creep elongation ε = (ΔL / L0) × 100%.

[0067] 1.46 Mechanical Property Testing

[0068] Refer to GB / T 1040.2-2022 standard. A universal testing machine was used, with a tensile speed of 50 mm / min, a dumbbell-shaped specimen, and a test temperature of 23±2℃. o C.

[0069] 1.47 Scanning electron microscopy (SEM) observation

[0070] A ZEISS Gemini SEM 300 scanning electron microscope with an accelerating voltage of 10 kV was used. The samples were subjected to liquid nitrogen embrittlement followed by gold sputtering, and the fracture morphology was observed.

[0071] 1.5 Experimental Results

[0072] 1.51 Gel content and crystallization properties

[0073] Table 2. Gel content and crystallization properties of each sample

[0074]

[0075] As shown in Table 2, the gel content of Comparative Example B (TAF interfacial crosslinking) (84.2%) was significantly higher than that of Comparative Example D (TAF conventional melt crosslinking, 46.3%), demonstrating that the interfacial crosslinking process has higher crosslinking efficiency. The gel content of Examples 1-5 (85.3-89.1%) was further higher than that of Comparative Example B, indicating that the addition of calcium sulfate whiskers promoted the crosslinking reaction. The crystallinity of Example 2 (63.2%) was close to that of the blank sample (63.8%), and much higher than that of the conventional melt crosslinking sample (Comparative Example D only 53.8%), demonstrating that the interfacial crosslinking and whisker reinforcement strategy preserved the highly crystalline structure inside UHMWPE to the maximum extent.

[0076] 1.52 Vicat softening point and creep properties

[0077] Table 3. Vicat softening point and creep properties of each sample

[0078]

[0079] As shown in Table 3, Example 2 (2.0 parts of CSW) exhibited the best creep performance, with a creep elongation of only 0.47% after 30 minutes, a reduction of 55.2% compared to the blank sample and 27.7% compared to Comparative Example B (TAF single interfacial crosslinking). The Vicat softening point reached 140.2°C. o C, an increase of 11.7 compared to the blank sample. o C, an increase of 2.4 compared to comparative example B. o C. When the amount of CSW was increased to 3.0 parts (Example 3), the creep performance decreased slightly, mainly due to the agglomeration of excessive whiskers, forming stress concentration points.

[0080] 1.53 Mechanical properties

[0081] Table 4 Mechanical properties of each sample

[0082]

[0083] As shown in Table 4, the tensile strength of Example 2 reached 36.5 MPa, which is 81.6% higher than that of the blank sample and 9.9% higher than that of Comparative Example B (33.2 MPa); the flexural modulus reached 1320 MPa, which is 94.1% higher than that of the blank sample and 15.8% higher than that of Comparative Example B (1140 MPa). At the same time, the elongation at break remained at 325%, which is much higher than that of the traditional melt crosslinked sample (Comparative Example D is only 142%), indicating that the present invention maintains good toughness while significantly improving strength.

[0084] 1.54 Synergistic Effect Analysis

[0085] Table 5 Calculation of Synergistic Efficiency Index

[0086]

[0087] As shown in Table 5, the effect of CSW alone decreased by 8.6%; the effect of TAF interfacial crosslinking alone decreased by 38.1%; the theoretical superposition effect decreased by 46.7%; and the actual synergistic effect of the four components decreased by 55.2%. The above results indicate that there is a significant synergistic effect between CSW and TAF interfacial crosslinking, rather than a simple superposition.

[0088] Among them, such as Figure 1 As shown: different samples at 70 o C. Bar chart comparing creep elongation rates under 1 MPa stress for 30 min. Horizontal axis: 1-blank sample, 2-comparative example A, 3-comparative example B, 4-comparative example C, 5-Example 1, 6-Example 2. Vertical axis: creep elongation rate (%). Data are shown in Table 3.

[0089] like Figure 2 As shown: Scanning electron microscope (SEM) image (×5000x) of a cross-section of the sample from Example 2. Figure 2It can be seen that the micron-sized TAF cross-linked framework and the micro-nano-sized calcium sulfate whiskers are interwoven and distributed; the whiskers are oriented along the stress direction and span the gaps in the cross-linked network to form a "bridging" effect; the whiskers are tightly bonded to the matrix interface without debonding, proving that the KH-570 coupling treatment significantly enhances the interfacial bonding strength; the internal crystalline region maintains a complete lamellar structure, confirming the protective effect of interfacial cross-linking on the internal crystalline structure.

[0090] like Figure 3 The figure shows the X-ray diffraction patterns of different samples. The figure displays the XRD curves of the blank sample, Comparative Example B, and Example 2. The (110) and (200) crystal plane diffraction peaks are located at 2θ = 21.6° and 23.8°, respectively. The peak intensity of Example 2 is slightly closer to that of the blank sample and higher than that of Comparative Example B.

[0091] like Figure 4 The figure shows the DSC melting curves of different samples. The graph displays the melting peaks of the blank sample, Comparative Example B, and Example 2. The melting temperature of Example 2 is 140.3 °C. o C) and the peak area is close to that of the blank sample.

[0092] like Figure 5 The chart shows a comparison of the Vicat softening points of different samples. The vertical axis represents the Vicat softening point (VPC). o C).

[0093] The difference between this invention and the closest prior art is that:

[0094] Table 6:

[0095]

[0096] In summary, the inventiveness of this invention is embodied in the following ways:

[0097] (1) For the first time, calcium sulfate whiskers were introduced into the TAF interfacial crosslinking system: Although calcium sulfate whiskers have been used for HDPE modification in the prior art, they have never been used for TAF interfacial crosslinking UHMWPE system. This invention found that there is a significant synergistic effect between CSW and TAF interfacial crosslinking (synergistic effect index 1.18).

[0098] (2) A multi-scale dual-network structure was constructed: Unlike existing single cross-linking network or single filler filling technology, this invention realizes the organic integration of chemical cross-linking and physical reinforcement at the micro-nano scale, forming a composite reinforcement system that runs through and interweaves.

[0099] (3) Enhanced interfacial chemical bonding: The surface of CSW is modified by KH-570 to form an organic coating layer on its surface, which not only improves the dispersibility, but also introduces functional groups that can participate in the reaction on the surface of CSW, forming chemical bonds with the TAF crosslinking network, significantly enhancing the interfacial bonding strength.

[0100] (4) Breakthrough in technical bias: Those skilled in the art usually believe that adding rigid fillers will reduce the toughness of materials. This invention protects the internal flexible crystalline region through the interface crosslinking process. At the same time, the orientation arrangement of CSW whiskers and the interface bonding of KH-570 avoid stress concentration, thus achieving a simultaneous improvement in strength and toughness.

[0101] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Those skilled in the art will readily understand and grasp the concepts, and various improvements and modifications can be made without departing from the principles of the invention. Therefore, modifications or improvements made without departing from the spirit of the invention should also be considered within the scope of protection of the invention.

Claims

1. A creep-resistant ultra-high molecular weight polyethylene composite material, characterized in that, It is prepared by hot pressing of ultra-high molecular weight polyethylene powder, crosslinking agent and modified calcium sulfate whiskers: The crosslinking agent is 1,3,5-triacryloylhexahydro-triazine (TAF), and its structural formula is as follows: The crosslinking agent is uniformly coated on the surface of ultra-high molecular weight polyethylene particles before hot pressing. During hot pressing, a crosslinking reaction is initiated in the particle boundary region to form an interfacial crosslinking network. The modified calcium sulfate whiskers are obtained by surface modification of calcium sulfate whiskers with silane coupling agent, and their surface has functional groups that can participate in cross-linking reaction. During hot pressing, the modified calcium sulfate whiskers cross the particle boundary, and their surface functional groups chemically bond with the interfacial cross-linking network to form a bridging structure, which is uniformly distributed in the matrix and interfacial gaps to form a micron-scale physical reinforcement skeleton. The interfacial cross-linking network and the whisker bridging structure together constitute a multi-scale synergistic reinforcement network.

2. The method for preparing a creep-resistant ultra-high molecular weight polyethylene composite material according to claim 1, characterized in that, Includes the following steps: Step 1: Preparation of modified calcium sulfate whiskers: Add calcium sulfate whiskers and silane coupling agent to anhydrous ethanol at a mass ratio of 100:1-100:5, and ultrasonically disperse for 30-60 minutes, followed by 60-80 minutes of further dispersion. o C. Stir the reaction for 2-4 hours, filter, wash, and vacuum dry to obtain modified calcium sulfate whiskers; Step 2, Interface Coating and Mixing: Mix TAF, thermal initiator and ultra-high molecular weight polyethylene powder in proportion, stir at room temperature for 3-5 minutes to make the crosslinking agent uniformly coat the surface of polyethylene particles. Step 3, Multi-scale composite: Mix the modified calcium sulfate whiskers obtained in Step 1 with the mixture from Step 2 until homogeneous; Step 4, Hot pressing: Place the mixture obtained in step 3 into a mold and heat at 200-220°C. o C. Hot-press at 8-12 MPa for 15-25 min, and then cool to obtain the composite material.

3. The method for preparing a creep-resistant ultra-high molecular weight polyethylene composite material according to claim 2, characterized in that, Based on 100 parts by weight of ultra-high molecular weight polyethylene powder, the amounts of each component are as follows: crosslinking agent 0.3-0.8 parts, modified calcium sulfate whiskers 0.5-3.0 parts, thermal initiator 0.1-0.3 parts, coupling agent 0.05-0.2 parts.

4. The method for preparing a creep-resistant ultra-high molecular weight polyethylene composite material according to claim 2, characterized in that, The viscosity-average molecular weight of the ultra-high molecular weight polyethylene is 3 million to 10 million.

5. The method for preparing a creep-resistant ultra-high molecular weight polyethylene composite material according to claim 2, characterized in that, The calcium sulfate whiskers have a diameter of 1-4 μm, a length of 50-200 μm, and an aspect ratio of 20-100.

6. The method for preparing a creep-resistant ultra-high molecular weight polyethylene composite material according to claim 2, characterized in that, In step 2, the thermal initiator is di-tert-butyl peroxide (DTBP), dicumyl peroxide (DCP), or a combination thereof.

7. The method for preparing a creep-resistant ultra-high molecular weight polyethylene composite material according to claim 2, characterized in that, The ratio of the modified calcium sulfate whiskers to the crosslinking agent is 1:0.5-1:

2.

8. The application of an ultra-high molecular weight polyethylene composite material obtained by the preparation method according to any one of claims 2-7 in high-temperature structural components and deep-sea mooring cables.

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