High-temperature-resistant PE composite material and preparation method thereof
By compounding heat-resistant polyethylene resin and modified nano-spherical alumina into PE material to form a dynamic cross-linked network, the problem of insufficient heat resistance of PE material is solved, and the stability and toughness of the material are balanced under high temperature environment.
Patent Information
- Application Number
- CN202610053082.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-01-15
- Publication Date
- 2026-03-06
AI Technical Summary
Existing PE materials have poor heat resistance, and improving heat resistance often comes at the expense of processability, toughness, or recyclability.
A composite of polyethylene resin and heat-resistant polyethylene resin was used, and modified nano-spherical alumina was added. By grafting polybutadiene segments and borate ester groups onto the surface of the nano-spherical alumina, a dynamic cross-linking network was formed, which enhanced the thermal stability and mechanical properties of the material.
It significantly improves the high-temperature resistance of the material while maintaining good overall performance, such as toughness and mechanical properties, making it suitable for high-temperature environments.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of engineering plastics technology, and in particular to a high-temperature resistant PE composite material and its preparation method. Background Technology
[0002] Polyethylene (PE) has excellent chemical stability, good electrical insulation, outstanding low-temperature resistance, and excellent processing performance. It is one of the most widely produced and used polymer materials, and is widely used in various fields including packaging, agriculture, construction, cables, and automotive parts.
[0003] Polyethylene (PE) is a semi-crystalline polyolefin material with a linear saturated hydrocarbon molecular chain and weak intermolecular forces. While this unique structure endows it with good flexibility and low-temperature resilience, it also results in insufficient heat resistance and a low heat distortion temperature. With industrial development, many fields have placed higher demands on the heat resistance of polymer materials, such as automotive engine compartment parts and high-temperature cable insulation layers. These fields require materials to maintain stable performance over long periods at higher temperatures. Therefore, developing a high-temperature resistant PE material is of great significance for expanding the application range of PE and meeting market demands.
[0004] Currently, the main ways to improve the heat resistance of PE materials include crosslinking modification and inorganic filler filling. Crosslinking modification mainly involves radiation crosslinking or chemical crosslinking to form a three-dimensional network structure of PE molecular chains, thereby improving the heat resistance of the material. However, this method is complex and the material is difficult to recycle. Using high heat-resistant inorganic fillers such as talc and mica to improve the thermal stability of composite materials can easily lead to an increase in material density and a decrease in toughness. Furthermore, poor bonding between the filler and the matrix interface can result in a significant decrease in the mechanical properties of the material.
[0005] Therefore, while existing technologies improve the heat resistance of PE, they often sacrifice its processability, toughness, or recyclability, and the modification effect is limited. Therefore, developing a PE material that can significantly improve high-temperature resistance while maintaining good overall performance is of great significance. Summary of the Invention
[0006] This invention provides a high-temperature resistant PE composite material and its preparation method, which can solve the problems of poor high-temperature resistance and difficulty in achieving both mechanical properties in existing PE materials.
[0007] In a first aspect, the present invention provides a high-temperature resistant PE composite material, comprising the following raw materials in parts by weight: 80-90 parts of polyethylene resin; 10-20 parts of heat-resistant polyethylene resin; Modified nano-spherical alumina, 6-10 parts; Lubricant 0.5 to 2 parts; Antioxidant 0.5 to 2 parts; The surface of the modified nano-spherical alumina is grafted with polybutadiene segments and borate ester groups.
[0008] Preferably, the polyethylene resin includes high-density polyethylene resin and linear low-density polyethylene resin in a mass ratio of (60-70):(10-20).
[0009] Preferably, the lubricant includes one or more combinations of stearamide, ethylene bis-stearamide, polyethylene wax, and calcium stearate.
[0010] Preferably, the antioxidant includes one or more combinations of antioxidant 1010, antioxidant 1076, antioxidant 1330, antioxidant 168 and antioxidant DLTP.
[0011] By adopting the above technical solution, the high-temperature resistant PE composite material of the present invention is made by compounding polyethylene resin and heat-resistant polyethylene resin. The heat-resistant polyethylene resin is a non-crosslinked polyolefin material obtained by copolymerizing ethylene and octene. It can introduce a molecular chain structure with higher thermal stability into the resin matrix. After melt processing, it can form a dense and strong physical entanglement network. When the material is heated, the enhanced network structure can effectively resist the movement and slippage of molecular chains, support the overall structure, delay the softening and deformation of the material, thereby broadening the service temperature of the material and enhancing its high-temperature resistance.
[0012] Furthermore, the polyethylene resin used in this invention is a blend of high-density polyethylene (HDPE) and linear low-density polyethylene (LDPE). HDPE has a higher heat distortion temperature and strength, serving as the main resin skeleton. The insertion of LDPE can encapsulate and bridge the rigid crystalline regions of HDPE, providing good flexibility to the material. This also ensures that the material can effectively transfer and disperse stress under external forces when modified nano-spherical alumina is subsequently introduced, thus greatly improving the material's impact resistance. Therefore, by using HDPE and LDPE as the base matrix and introducing heat-resistant polyethylene resin as the key reinforcing phase, a heat-resistant physical network and support points are formed, thereby improving the thermal stability of the resin matrix itself.
[0013] Furthermore, modified nano-spherical alumina is added to the high-temperature resistant PE composite material. Nano-spherical alumina itself possesses high thermal stability, maintaining structural stability even at high temperatures. When uniformly dispersed in the resin matrix, it forms a rigid physical barrier that hinders the thermal movement of polymer molecular chains. Simultaneously, the particles added in this invention are spherical nanoparticles, which can more effectively bear loads, increasing the heat distortion temperature while minimizing stress concentration. Therefore, while improving rigidity, it significantly reduces the impact of filler particles on toughness, facilitating uniform stress transmission and improving the material's mechanical properties.
[0014] The modified nano-spherical alumina surface is also grafted with polybutadiene segments and borate ester groups. On the one hand, the borate ester bonds act as bridging bonds, enabling the grafting of polybutadiene segments onto the nano-spherical alumina surface. The molecular structure of polybutadiene segments is similar to that of polyethylene resin, resulting in good interfacial compatibility between the modified nano-spherical alumina and the matrix resin. The modified nano-spherical alumina can be uniformly dispersed in the matrix resin. Furthermore, the steric hindrance effect of the polybutadiene segments effectively prevents the potential agglomeration of the modified nano-spherical alumina. Without the addition of additional compatibilizers, the uniform dispersion of the modified nano-spherical alumina in the matrix can be ensured, reducing the problem of easy precipitation of small molecules such as compatibilizers.
[0015] On the other hand, the borate ester bond itself, as a dynamic covalent bond, can further form dynamic cross-linking points with the polymer chains of the resin through the entanglement of polybutadiene segments and matrix resin molecular segments. This results in a semi-interpenetrating dynamic cross-linked network of rigid nanoparticles and flexible dynamic covalent bonds. When the temperature rises, the constructed network structure can effectively restrict the slippage and large-size movement of polymer chains, maintaining the structural stability of the material at higher temperatures and significantly improving its long-term heat resistance. Furthermore, the dynamic characteristics of the borate ester group enable the material to dissipate energy through reversible bond recombination when facing high-temperature localized stress concentrations, maintaining good high-temperature resistance while improving the material's impact toughness.
[0016] Preferably, the raw materials for modified nano-spherical alumina include borate nano-spherical alumina and a modifier in a mass ratio of 1:(1 to 1.5); The modifiers include hydroxyl-terminated polybutadiene and isosorbide in a mass ratio of 1:(0.1 to 0.3).
[0017] Preferably, the modified nano-spherical alumina is prepared according to the following method: Pretreatment of nano-spherical alumina: Disperse nano-spherical alumina in an alcohol solvent, raise the temperature to 70-75℃, add an aminosilane coupling agent, reflux for 20-24 h, and then wash and dry to obtain pretreated nano-spherical alumina; Preparation of borate nanosphere alumina: Pretreated nanosphere alumina was dispersed in a solvent, carboxyphenylboronic acid was added, and after stirring and dispersing, buffer solution was added. The mixture was stirred and reacted at room temperature for 20-24 hours. Finally, the borate nanosphere alumina was obtained by centrifugation, washing and drying. Preparation of modified nano-spherical alumina: The temperature of the hydroxyl-terminated polybutadiene solution was raised to 100-110℃, and boronized nano-spherical alumina was added. The mixture was stirred under vacuum for 1-2 hours. After centrifugation, washing and drying, the mixture was added to isosorbide solution and stirred at 40-60℃ for 6-8 hours. Finally, the modified nano-spherical alumina was obtained after centrifugation, washing and drying.
[0018] Preferably, the mass ratio of aminosilane coupling agent to nano-spherical alumina is (0.1-0.2):100.
[0019] More preferably, the aminosilane coupling agent includes one or more combinations of 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane and 3-aminopropylmethyldiethoxysilane.
[0020] More preferably, the particle size of the nano-spherical alumina is 150–300 nm.
[0021] Preferably, the carboxyphenylboronic acid includes one or more combinations of 3-carboxyphenylboronic acid, 4-carboxyphenylboronic acid, 2-carboxyphenylboronic acid and 3,5-dicarboxyphenylboronic acid.
[0022] Preferably, the mass ratio of pretreated nano-spherical alumina to carboxyphenylboronic acid is 1:(1.8-2).
[0023] By adopting the above technical solution, the nano-spherical alumina is first pretreated. The silanol groups generated by the hydrolysis of an aminosilane coupling agent are then introduced onto the surface of the nano-spherical alumina with amino groups. Further, in a buffer solution, the carboxyl groups react with the amino groups on the surface of the pretreated nano-spherical alumina to form amide bonds, thereby grafting phenylboronic acid groups onto the surface of the nano-spherical alumina. Finally, a modification reaction is carried out. Specifically, the highly reactive boric acid groups undergo an esterification reaction with the hydroxyl groups in terminally hydroxyl polybutadiene under heating conditions, thus initially grafting polybutadiene segments onto the surface of the nano-spherical alumina particles. Then, isosorbide is added, which has high reactivity with the boric acid groups. Its cis-diol structure can react with the boric acid groups to form stable cyclic borate ester groups, allowing the nano-spherical alumina particles to simultaneously connect flexible polybutadiene segments and rigid isosorbide units.
[0024] The modified nano-spherical alumina obtained in the end contains polybutadiene segments that can improve the interfacial compatibility with the matrix resin. It can achieve deep entanglement and interdiffusion with the molecular chains of polyethylene resin, thereby achieving uniform and highly dispersed nano-spherical alumina in the matrix resin. Furthermore, the flexible interfacial layer formed can effectively transfer stress and improve the toughness of the material.
[0025] The introduction of isosorbide can, on the one hand, form stable borate ester groups, which can enhance the hydrolysis resistance and thermal stability of the borate ester groups. Under heat, these groups can undergo dynamic recombination, dissipating heat stress, maintaining the integrity of the material structure, and improving the material's heat resistance and stability. On the other hand, its rigid structure can provide rigid support, increasing the modulus of the interfacial layer, thereby enhancing the material's heat distortion temperature and resistance to deformation. Finally, a high-temperature resistant PE composite material with excellent high-temperature resistance and a balance of rigidity and toughness is obtained.
[0026] Secondly, the present invention provides a method for preparing a high-temperature resistant PE composite material, which includes the following process steps: S1. Weigh the raw materials according to the corresponding mass proportions and mix them evenly to obtain the premix; S2. The premixed material is melted and plasticized at 180-220℃ and then extruded and granulated to obtain a high-temperature resistant PE composite material.
[0027] The beneficial effects of this invention are: 1. The high-temperature resistant PE composite material of the present invention is made by compounding polyethylene resin and heat-resistant polyethylene resin. The heat-resistant polyethylene resin can introduce a molecular chain structure with higher thermal stability into the resin matrix, which can effectively resist the movement and slippage of molecular chains and delay the softening and deformation of the material. The polyethylene resin is obtained by compounding high-density polyethylene resin and linear low-density polyethylene resin. While providing a rigid heat-resistant skeleton, it also introduces flexible molecular chain segments, which can effectively transfer and disperse stress and improve the comprehensive mechanical properties of the composite material.
[0028] 2. The high-temperature resistant PE composite material of this invention incorporates modified nano-spherical alumina. The spherical structure allows for more effective load bearing, increasing the material's heat distortion temperature and minimizing stress concentration. The modified nano-spherical alumina surface is grafted with polybutadiene segments and borate ester groups, effectively improving the interfacial compatibility between the nanoparticles and the matrix material. This achieves uniform and highly dispersed nano-spherical alumina in the matrix resin. Furthermore, the entanglement of the polybutadiene segments with the matrix resin molecular segments introduces dynamic crosslinking points. This allows for energy dissipation through reversible bond recombination when facing high-temperature localized stress concentrations, maintaining good high-temperature resistance while improving the material's impact toughness. Detailed Implementation
[0029] The specific embodiments of the present invention will be described in detail below, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.
[0030] Preparation Example 1: A modified nano-spherical alumina was prepared according to the following method: Pretreatment of nano-spherical alumina: 100g of nano-spherical alumina (average particle size of 200nm) was dispersed in 40mL of methanol, the temperature was raised to 70℃, 0.15mL of 3-aminopropyltrimethoxysilane was added, the mixture was refluxed for 20h, and then washed and dried to obtain pretreated nano-spherical alumina. Preparation of borate-treated nanosphere alumina: 10g of the pretreated nanosphere alumina obtained above was dispersed in 100mL of dimethyl sulfoxide, 20g of 3-carboxyphenylboronic acid was added, and after stirring and dispersing, 180mg of buffer solution was added, wherein the buffer solution was EDC / NHS buffer solution with a mass ratio of 1:2. The reaction was stirred at room temperature for 24h, and finally the borate-treated nanosphere alumina was obtained by centrifugation, washing and drying. Preparation of modified nano-spherical alumina: A 2 g / mL solution of terminal hydroxyl polybutadiene (using toluene as solvent) was heated to 100 °C, and 10 g of the above-oboxidized nano-spherical alumina was added. The mixture was stirred under vacuum for 1 h, centrifuged, washed, and dried, and then added to a 0.2 g / mL isosorbide solution (using N,N-dimethylformamide as solvent). The mixture was stirred at 50 °C for 7 h, and finally centrifuged, washed, and dried to obtain the modified nano-spherical alumina. The amount of terminal hydroxyl polybutadiene (average number average molecular weight of 4150) added was 10 g, and the amount of isosorbide added was 2 g.
[0031] Preparation Example 2: A modified nano-spherical alumina was prepared according to the following method: Pretreatment of nano-spherical alumina: 100g of nano-spherical alumina (average particle size of 200nm) was dispersed in 40mL of methanol, the temperature was raised to 70℃, 0.1mL of 3-aminopropyltrimethoxysilane was added, the mixture was refluxed for 20h, and then washed and dried to obtain pretreated nano-spherical alumina. Preparation of borate-treated nanosphere alumina: 10g of the pretreated nanosphere alumina obtained above was dispersed in 100mL of dimethyl sulfoxide, 18g of 3-carboxyphenylboronic acid was added, and after stirring and dispersing, 180mg of buffer solution was added, wherein the buffer solution was EDC / NHS buffer solution with a mass ratio of 1:2. The reaction was stirred at room temperature for 24h, and finally the borate-treated nanosphere alumina was obtained by centrifugation, washing and drying. Preparation of modified nano-spherical alumina: A 2 g / mL solution of terminal hydroxyl polybutadiene (using toluene as solvent) was heated to 100 °C, and 10 g of the above-oboxidized nano-spherical alumina was added. The mixture was stirred under vacuum for 1 h, centrifuged, washed, and dried, and then added to a 0.2 g / mL solution of isosorbide (using N,N-dimethylformamide as solvent). The mixture was stirred at 50 °C for 7 h, and finally centrifuged, washed, and dried to obtain the modified nano-spherical alumina. The amount of terminal hydroxyl polybutadiene (average number average molecular weight of 4150) added was 9 g, and the amount of isosorbide added was 1 g.
[0032] Preparation Example 3: A modified nano-spherical alumina was prepared according to the following method: Pretreatment of nano-spherical alumina: 100g of nano-spherical alumina (average particle size of 200nm) was dispersed in 40mL of methanol, the temperature was raised to 70℃, 0.2mL of 3-aminopropyltrimethoxysilane was added, the mixture was refluxed for 20h, and then washed and dried to obtain pretreated nano-spherical alumina. Preparation of borate-treated nanosphere alumina: 10g of the pretreated nanosphere alumina obtained above was dispersed in 100mL of dimethyl sulfoxide, 20g of 3-carboxyphenylboronic acid was added, and after stirring and dispersing, 180mg of buffer solution was added, wherein the buffer solution was EDC / NHS buffer solution with a mass ratio of 1:2. The reaction was stirred at room temperature for 24h, and finally the borate-treated nanosphere alumina was obtained by centrifugation, washing and drying. Preparation of modified nano-spherical alumina: A 2 g / mL solution of terminal hydroxyl polybutadiene (using toluene as solvent) was heated to 100 °C, and 10 g of the borate nano-spherical alumina obtained above was added. The mixture was stirred under vacuum for 1 h, centrifuged, washed, and dried, and then added to a 0.2 g / mL solution of isosorbide (using N,N-dimethylformamide as solvent). The mixture was stirred at 50 °C for 7 h, and finally centrifuged, washed, and dried to obtain the modified nano-spherical alumina. The amount of terminal hydroxyl polybutadiene (average number average molecular weight of 4150) added was 11.5 g, and the amount of isosorbide added was 3.5 g.
[0033] Preparation Example 4: A modified nano-spherical alumina was prepared according to the following method: Pretreatment of nano-spherical alumina: 100g of nano-spherical alumina (average particle size of 200nm) was dispersed in 40mL of methanol, the temperature was raised to 70℃, 0.2mL of 3-aminopropyltrimethoxysilane was added, the mixture was refluxed for 20h, and then washed and dried to obtain pretreated nano-spherical alumina. Preparation of borate-treated nanosphere alumina: 10g of the pretreated nanosphere alumina obtained above was dispersed in 100mL of dimethyl sulfoxide, 20g of 3-carboxyphenylboronic acid was added, and after stirring and dispersing, 180mg of buffer solution was added, wherein the buffer solution was EDC / NHS buffer solution with a mass ratio of 1:2. The reaction was stirred at room temperature for 24h, and finally the borate-treated nanosphere alumina was obtained by centrifugation, washing and drying. Preparation of modified nano-spherical alumina: The temperature of a 2 g / mL hydroxyl-terminated polybutadiene solution (using toluene as solvent) was raised to 100 °C, and 10 g of the above-oborated nano-spherical alumina was added. The mixture was stirred under vacuum for 1 h, and finally centrifuged, washed and dried to obtain modified nano-spherical alumina. The amount of hydroxyl-terminated polybutadiene (average number average molecular weight of 4150) added was 10 g.
[0034] Preparation Example 5: A modified nano-spherical alumina, which differs from Preparation Example 1 only in that the amount of hydroxyl-terminated polybutadiene added is 8g and the amount of isosorbide added is 4g.
[0035] Preparation Example 6, a modified nanosphere alumina, differs from Preparation Example 1 only in that the amount of hydroxyl-terminated polybutadiene added is 4.2 g and the amount of isosorbide added is 0.8 g.
[0036] Preparation Example 7, a modified nanosphere alumina, differs from Preparation Example 1 only in that the amount of hydroxyl-terminated polybutadiene added is 16.5 g and the amount of isosorbide added is 3.5 g.
[0037] Preparation Example 8: A modified nano-spherical alumina was prepared according to the following method: Pretreatment of nano-spherical alumina: 100g of nano-spherical alumina (average particle size of 200nm) was dispersed in 40mL of methanol, the temperature was raised to 70℃, 0.15mL of 3-aminopropyltrimethoxysilane was added, the mixture was refluxed for 20h, and then washed and dried to obtain pretreated nano-spherical alumina. Preparation of borate-treated nanosphere alumina: 10g of the pretreated nanosphere alumina obtained above was dispersed in 100mL of dimethyl sulfoxide, 20g of 3-carboxyphenylboronic acid was added, and after stirring and dispersing, 180mg of buffer solution was added, wherein the buffer solution was EDC / NHS buffer solution with a mass ratio of 1:2. The reaction was stirred at room temperature for 24h, and finally the borate-treated nanosphere alumina was obtained by centrifugation, washing and drying. Preparation of modified nano-spherical alumina: 10g of the borate nano-spherical alumina obtained above was added to an isosorbide solution with a concentration of 0.2g / mL (using N,N-dimethylformamide as solvent), and stirred at 50℃ for 7h. Finally, after centrifugation, washing and drying, the modified nano-spherical alumina was obtained, wherein the amount of isosorbide added was 2g. Example
[0038] Example 1: A high-temperature resistant PE composite material was prepared according to the following process steps: S1. Weigh the raw materials according to the corresponding mass proportions. Specifically, weigh 80 parts of polyethylene resin, 20 parts of heat-resistant polyethylene resin (model DOWLEX™ 2388), 8 parts of the modified nano-spherical alumina prepared in Preparation Example 1, 1 part of stearamide and 1 part of antioxidant 1076. The polyethylene resin includes high-density polyethylene resin (model 2100J) and linear low-density polyethylene resin (model DFDA 7042) with a mass ratio of 70:10, and mix them evenly to obtain a premix. S2. The premixed material is melted and plasticized at 180-220℃ and then extruded and granulated to obtain a high-temperature resistant PE composite material.
[0039] Example 2: A high-temperature resistant PE composite material was prepared according to the following process steps: S1. Weigh the raw materials according to the corresponding mass proportions. Specifically, weigh 90 parts of polyethylene resin, 10 parts of heat-resistant polyethylene resin (model DOWLEX™ 2388), 10 parts of the modified nano-spherical alumina prepared in Preparation Example 1, 1 part of stearamide and 1 part of antioxidant 1076. The polyethylene resin includes high-density polyethylene resin (model 2100J) and linear low-density polyethylene resin (model DFDA 7042) with a mass ratio of 70:20, and mix them evenly to obtain a premix. S2. The premixed material is melted and plasticized at 180-220℃ and then extruded and granulated to obtain a high-temperature resistant PE composite material.
[0040] Example 3 is a high-temperature resistant PE composite material, which differs from Example 1 only in that the polyethylene resin includes high-density polyethylene resin and linear low-density polyethylene resin in a mass ratio of 60:20.
[0041] Example 4, a high-temperature resistant PE composite material, differs from Example 1 only in that the modified nano-spherical alumina prepared in Example 2 is replaced with an equal amount of the modified nano-spherical alumina prepared in Example 1.
[0042] Example 5, a high-temperature resistant PE composite material, differs from Example 1 only in that the modified nano-spherical alumina prepared in Example 3 is replaced with an equal amount of the modified nano-spherical alumina prepared in Example 1.
[0043] Example 6, a high-temperature resistant PE composite material, differs from Example 1 only in that the modified nano-spherical alumina prepared in Example 4 is replaced with an equal amount of the modified nano-spherical alumina prepared in Example 1.
[0044] Example 7, a high-temperature resistant PE composite material, differs from Example 1 only in that the modified nano-spherical alumina prepared in Example 5 is replaced with an equal amount of the modified nano-spherical alumina prepared in Example 1.
[0045] Example 8, a high-temperature resistant PE composite material, differs from Example 1 only in that the modified nano-spherical alumina prepared in Example 6 is replaced with an equal amount of the modified nano-spherical alumina prepared in Example 1.
[0046] Example 9, a high-temperature resistant PE composite material, differs from Example 1 only in that the modified nano-spherical alumina prepared in Example 7 is replaced with an equal amount of the modified nano-spherical alumina prepared in Example 1.
[0047] Comparative Example 1: A high-temperature resistant PE composite material was prepared according to the following process steps: S1. Weigh the raw materials according to the corresponding mass proportions. Specifically, weigh 100 parts of polyethylene resin, 8 parts of the modified nano-spherical alumina prepared in Preparation Example 1, 1 part of stearamide and 1 part of antioxidant 1076. The polyethylene resin includes high-density polyethylene resin (model 2100J) and linear low-density polyethylene resin (model DFDA 7042) with a mass ratio of 70:10, and mix them evenly to obtain a premix. S2. The premixed material is melted and plasticized at 180-220℃ and then extruded and granulated to obtain a high-temperature resistant PE composite material.
[0048] Comparative Example 2 is a high-temperature resistant PE composite material, which differs from Example 1 only in that the polyethylene resin is high-density polyethylene resin.
[0049] Comparative Example 3 is a high-temperature resistant PE composite material, which differs from Example 1 only in that the polyethylene resin includes high-density polyethylene resin and linear low-density polyethylene resin in a mass ratio of 50:30.
[0050] Comparative Example 4, a high-temperature resistant PE composite material, differs from Example 1 only in that the modified nano-spherical alumina prepared in Example 8 is replaced with an equal amount of the modified nano-spherical alumina prepared in Example 1.
[0051] Comparative Example 5 is a high-temperature resistant PE composite material, which differs from Example 1 only in that an equal amount of unmodified nano-spherical alumina is used to replace the modified nano-spherical alumina prepared in Preparation Example 1.
[0052] 1. Heat resistance test: The heat distortion temperature of the PE composite materials obtained in the examples and comparative examples was tested according to the relevant records in GB / T 1634.1-2025 "Determination of heat distortion temperature of plastics under load - Part 1: General test method". 2. Mechanical property testing: (1) Tensile property test: The tensile strength of the PE composite materials obtained in the examples and comparative examples was tested according to the relevant records in GB / T 1040.1-2018 "Determination of tensile properties of plastics - Part 1: General". (2) Impact resistance test: According to the relevant records in GB / T 1043.1-2008 "Determination of impact properties of simply supported plastic beams - Part 1: Non-instrumental impact test", the notched impact strength of the PE composite materials obtained in the examples and comparative examples was tested.
[0053] The results of the above experiments are shown in Table 1:
[0054] According to Table 1, and in conjunction with Examples 1, 6, and 7, it can be seen that the heat resistance and mechanical properties of Examples 6 and 7 are lower than those of Example 1. The reason for this is that the modified nano-spherical alumina in Example 6 did not contain isosorbide during the preparation process, resulting in poor stability of the borate ester groups, which are prone to hydrolysis and breakage. Therefore, during application, the grafted polybutadiene segments are easily detached from the surface of the nano-spherical alumina, reducing the interfacial force between the particles and the matrix resin, decreasing the stress transfer efficiency, and thus reducing both the high-temperature resistance and mechanical properties. In Example 7, excessive isosorbide was added, which caused excessive cross-linking on the surface of the nano-spherical alumina, increasing the rigidity of the interfacial layer, affecting the improvement of the material's toughness, leading to increased stress concentration and decreased impact strength.
[0055] Based on Examples 1, 8, 9 and Comparative Example 5, it can be seen that the performance of Examples 8, 9 and Comparative Example 5 is lower than that of Example 1. The reason is that in Example 8, the amount of modifier added was reduced, resulting in uneven surface modification, decreased compatibility between particles and matrix resin, and high surface energy in unmodified areas, which easily caused particle agglomeration. This not only prevented the construction of a penetrating heat-resistant network but also led to a decrease in the mechanical properties of the material. In Comparative Example 5, the nano-spherical alumina was not modified, so the performance decline was more obvious. In Example 9, the amount of modifier added was increased, which led to an increase in the rigidity of the modified layer and the presence of small free molecules, affecting the high-temperature resistance of the material.
[0056] Based on Example 1 and Comparative Examples 1 to 3, it can be seen that the various properties of Comparative Examples 1 to 3 are lower than those of Example 1. The reason is that Comparative Example 1 did not add heat-resistant polyethylene, so there was a lack of adjustment at the molecular level, and the high-temperature resistance decreased accordingly. Comparative Example 2 did not add linear low-density polyethylene, so the overall rigidity of the material increased, resulting in a significant decrease in impact strength. Comparative Example 3 added an excessive amount of linear low-density polyethylene, which not only affected the rigidity of the material, but also the large amount of flexible segments introduced led to a decrease in the high-temperature resistance of the material.
[0057] Combining Example 1 and Comparative Example 4, it can be seen that the various properties of Comparative Example 4 are lower than those of Example 1. The reason is that the modified nano-spherical alumina obtained in Comparative Example 4 does not have polybutadiene segments grafted onto its surface. As a result, the dispersibility of the nanoparticles in the system is greatly reduced, and they cannot be uniformly dispersed in the matrix resin. Moreover, they are difficult to form entanglement with the molecular chains of the matrix resin. The borate ester groups contained therein cannot play a regulating role in the polymer molecular chains, which leads to a decrease in the mechanical properties and high-temperature resistance of the material.
[0058] The above-disclosed embodiments are merely a few specific examples of the present invention. However, the embodiments of the present invention are not limited thereto, and any variations that can be conceived by those skilled in the art should fall within the protection scope of the present invention.
Claims
1. A high temperature resistant PE composite material, characterized in that, The raw materials include the following mass fractions: Polyethylene resin 80-90 parts; Heat-resistant polyethylene resin 10-20 parts; Modified nanometer spherical alumina 6-10 parts; Lubricant 0.5-2 parts; Antioxidant 0.5-2 parts; The modified nanometer spherical alumina has polybutadiene segments and borate groups grafted on the surface thereof.
2. The high temperature resistant PE composite material according to claim 1, characterized in that, The polyethylene resin includes high-density polyethylene resin and linear low-density polyethylene resin in a mass ratio of (60-70):(10-20).
3. The high temperature resistant PE composite material according to claim 1, characterized in that, The raw materials of the modified nanometer spherical alumina include boronated nanometer spherical alumina and a modifier in a mass ratio of 1:(1-1.5). The modifier includes hydroxyl-terminated polybutadiene and isosorbide in a mass ratio of 1:(0.1-0.3).
4. The high temperature resistant PE composite material according to claim 3, characterized in that, The modified nanometer spherical alumina is prepared by the following method: Pre-treatment of nanometer spherical alumina: disperse the nanometer spherical alumina in an alcohol solvent, raise the temperature to 70-75°C, add an amino silane coupling agent, reflux for 20-24 h, then wash and dry to obtain pre-treated nanometer spherical alumina; Preparation of boronated nanometer spherical alumina: disperse the pre-treated nanometer spherical alumina in a solvent, add carboxyphenylboronic acid, stir and disperse, then add a buffer solution, stir at room temperature for 20-24 h, and finally centrifuge, wash and dry to obtain boronated nanometer spherical alumina; Preparation of modified nanometer spherical alumina: raise the temperature of a hydroxyl-terminated polybutadiene solution to 100-110°C, add boronated nanometer spherical alumina, stir under vacuum for 1-2 h, centrifuge, wash and dry, then add to an isosorbide solution, stir at 40-60°C for 6-8 h, and finally centrifuge, wash and dry to obtain modified nanometer spherical alumina.
5. The high temperature resistant PE composite material according to claim 4, characterized in that, The mass ratio of the amino silane coupling agent to the nanometer spherical alumina is (0.1-0.2):
100.
6. The high temperature resistant PE composite material according to claim 4, characterized in that, The carboxyphenylboronic acid includes one or more of a combination of 3-carboxyphenylboronic acid, 4-carboxyphenylboronic acid, 2-carboxyphenylboronic acid and 3,5-dicarboxyphenylboronic acid.
7. The high temperature resistant PE composite material according to claim 4, characterized in that, The mass ratio of the pre-treated nanometer spherical alumina to the carboxyphenylboronic acid is 1:(1.8-2).
8. The high temperature resistant PE composite material of claim 1, wherein, The lubricant includes one or more of a combination of stearic acid amide, ethylene bis-stearamide, polyethylene wax and calcium stearate.
9. The high temperature resistant PE composite of claim 1, wherein, The antioxidant includes one or more of a combination of antioxidant 1010, antioxidant 1076, antioxidant 1330, antioxidant 168 and antioxidant DLTP.
10. A method for producing a high temperature resistant PE composite material, for producing the high temperature resistant PE composite material according to any one of claims 1 to 9, characterized in that, The process includes the following steps: S1. take the raw materials in corresponding mass fractions and mix uniformly to obtain a pre-mixture; S2. melt and plasticize the pre-mixture at 180-220°C, extrude and granulate to obtain a high-temperature-resistant PE composite material.