A modified polyphenylene sulfide and a preparation method and application thereof

Abstract

The present application relates to the technical field of modified polymer materials, in particular to a modified polyphenylene sulfide and a preparation method thereof.The present application provides a modified polyphenylene sulfide, which comprises, in terms of weight fractions, 40-60 parts of polyphenylene sulfide resin, 5-10 parts of glass fiber, 6-15 parts of modified graphene, 3-9 parts of silane coupling agent, 20-30 parts of silicon carbide coated with fluorine-containing compounds, and 12-18 parts of medical stone; wherein the modified graphene has amino groups and / or carboxyl groups grafted on the surface thereof.The present application simultaneously introduces glass fiber, modified graphene, silicon carbide coated with fluorine-containing compounds and medical stone into a polyphenylene sulfide matrix, and through the cooperation of the above-mentioned additives, the obtained modified polyphenylene sulfide has high tensile strength, high toughness, high wear resistance and good heat dissipation performance, thereby greatly widening the application field of polyphenylene sulfide.

Description

Technical Field

[0001] This invention relates to the field of modified polymer materials technology, specifically to a modified polyphenylene sulfide, its preparation method, and its applications. Background Technology

[0002] Polyphenylene sulfide (PPS) is a high-performance specialty engineering plastic with alternating benzene rings and sulfur atoms in its molecular chain. This unique structure endows PPS with excellent chemical stability, high-temperature resistance, and mechanical properties, making it widely used in the automotive industry, electronics industry, military and defense, and medical equipment. However, traditional PPS also suffers from poor toughness, insufficient wear resistance, and poor heat dissipation, which limits its further applications.

[0003] Currently, there are studies on improving the wear resistance and thermal conductivity of PPS by adding carbon fiber, graphene, and molybdenum disulfide, but the toughness of the resulting PPS still needs to be improved. Other studies have improved the interfacial bonding between glass fiber and PPS by modifying glass fiber, thereby better improving the mechanical properties of PPS, and improved the wear resistance of PPS by adding graphene and molybdenum disulfide. However, these studies have not mentioned the improvement of PPS toughness, and the introduction of inorganic molybdenum disulfide particles may also lead to phase separation inside PPS, so it is still impossible to obtain PPS with excellent comprehensive performance. Summary of the Invention

[0004] In view of this, the present invention provides a modified polyphenylene sulfide, its preparation method and application. The modified polyphenylene sulfide has the characteristics of high toughness, strong wear resistance and high heat dissipation capacity, and also has good mechanical properties, with excellent comprehensive performance.

[0005] To solve the above technical problems, the first aspect of the present invention provides a modified polyphenylene sulfide, comprising, by weight parts: 40-60 parts of polyphenylene sulfide resin, 5-10 parts of glass fiber, 6-15 parts of modified graphene, 3-9 parts of silane coupling agent, 20-30 parts of silicon carbide coated with fluorine-containing compounds, and 12-18 parts of maifanite; wherein the modified graphene has amino and / or carboxyl groups grafted onto its surface.

[0006] During their research, the inventors discovered that adding unmodified graphene to the polyphenylene sulfide (PPS) resin matrix, while exhibiting good thermal conductivity, reduces the toughness of PPS. Therefore, the inventors grafted amino and / or carboxyl functional groups onto the graphene surface, creating hydrogen bonds within or between the graphene molecules. This resulted in a three-dimensional network structure within the PPS matrix, enhancing its toughness and impact resistance. In addition to introducing modified graphene, this invention also added fluorinated silicon carbide and maifanite to the matrix. The fluorinated silicon carbide is coated with a fluorinated polymer, which further promotes compatibility between the silicon carbide and PPS. The addition of maifanite increases the hardness of the PPS matrix, thereby improving its wear resistance.

[0007] The modified polyphenylene sulfide provided by this invention utilizes glass fiber to enhance mechanical properties. A coupling agent enables modified graphene, fluorinated silicon carbide, and maifanite to achieve good "fusion" with the polyphenylene sulfide matrix, ensuring that the modified graphene, maifanite, and fluorinated silicon carbide play their respective roles. At the same time, there is a synergistic effect between the modified graphene and the fluorinated silicon carbide to promote heat transfer, thereby obtaining a modified polyphenylene sulfide with high toughness, strong wear resistance, and good heat dissipation performance.

[0008] Among them, modified graphene and fluorinated silicon carbide synergistically enhance heat transfer, achieving a thermal conductivity effect of 1+1>2. The synergistic mechanism between the two can be explained as follows: First, graphene sheets can span multiple interfaces between fluorinated silicon carbide particles and polymers, directly connecting the heat source and the heat dissipation end, reducing phonon scattering; Second, the fluorinated polymer thin layer on the silicon carbide surface can form a tight contact with graphene through π-π stacking or hydrogen bonding, reducing interfacial thermal resistance; Third, the hydrophobicity of graphene and its good compatibility with fluorinated polymers (such as PTFE) reduce phonon scattering caused by interfacial defects; Finally, silicon carbide particles have good thermal conductivity and can act as "nodes" in the graphene network, supplementing longitudinal heat conduction, thereby achieving a thermal conductivity effect of 1+1>2.

[0009] Preferably, the modified polyphenylene sulfide comprises, by weight, 48-52 parts of polyphenylene sulfide resin, 7-9 parts of glass fiber, 8-12 parts of modified graphene, 5-7 parts of silane coupling agent, 23-28 parts of silicon carbide coated with fluorine-containing compounds, and 14-16 parts of maifanite; wherein the modified graphene surface is grafted with amino and / or carboxyl groups.

[0010] More preferably, the modified polyphenylene sulfide comprises, by weight, 50 parts of polyphenylene sulfide resin, 8 parts of glass fiber, 10 parts of modified graphene, 6 parts of silane coupling agent, 25 parts of silicon carbide coated with fluorine-containing compounds, and 15 parts of maifanite; wherein the modified graphene is grafted with amino and / or carboxyl groups on its surface.

[0011] Preferably, the modified polyphenylene sulfide further includes 0.5 to 2 parts of antioxidant.

[0012] Preferably, the modified graphene is obtained by reacting graphene with p-aminobenzoic acid. The p-aminobenzoic acid molecule itself contains a benzene ring, as well as amino and carboxyl groups. Using it to modify graphene allows for the grafting of hydroxyl and / or carboxyl groups onto the graphene surface. Furthermore, the presence of the benzene ring improves the compatibility between the modified graphene and the polyphenylene sulfide matrix, preventing phase separation and ensuring that the three-dimensional network structure formed by the modified graphene enhances the toughness of the polyphenylene sulfide.

[0013] Preferably, the modified graphene is prepared according to the following steps: dispersing graphene in ethanol, adding p-aminobenzoic acid and reacting under stirring for 1-2 hours, controlling the pH to be 2.5-4 during the reaction, then separating the solid and liquid, drying the solid, to obtain the modified graphene.

[0014] More preferably, the modified graphene is prepared according to the following steps: graphene is dispersed in ethanol, and p-aminobenzoic acid is added at a mass ratio of 1:1 to 2. During the reaction, the pH is controlled at 2.5 to 4, and the reaction is carried out under stirring for 1 to 2 hours. Then, solid-liquid separation is performed to remove unreacted p-aminobenzoic acid and ethanol, and the solid is dried at 60 to 80°C to obtain the modified graphene.

[0015] Preferably, the silicon carbide coated with fluorine-containing compounds is prepared by the following steps: dispersing silicon carbide in a fluorine-containing polymer emulsion, stirring and dispersing for 20-30 minutes, then separating the solid and liquid and drying the obtained solid to obtain the silicon carbide coated with fluorine-containing compounds.

[0016] More preferably, the silicon carbide coated with fluorine-containing compounds is prepared by the following steps: dispersing silicon carbide in a fluorine-containing polymer emulsion at a mass ratio of 1:0.5 to 1, stirring and dispersing for 20 to 25 minutes, then separating the solid and liquid and drying the obtained solid to obtain the silicon carbide coated with fluorine-containing compounds.

[0017] Preferably, the fluorinated polymer emulsion is selected from polytetrafluoroethylene emulsion or perfluoropolyether emulsion. Polytetrafluoroethylene emulsion or perfluoropolyether emulsion allows silicon carbide to be well compatible with the polyphenylene sulfide matrix.

[0018] Preferably, the glass fiber has an average length of 300–800 μm and an average diameter of 10–13 μm; the maifanite has a particle size of 10–50 μm.

[0019] More preferably, the glass fiber has an average length of 500-800 μm and an average diameter of 40-50 μm; the maifanite has a particle size of 30-50 μm.

[0020] Glass fiber is a high-performance inorganic non-metallic material with good insulation and heat resistance, but it is brittle and has poor wear resistance. Combining it with modified graphene can simultaneously improve the mechanical properties and toughness of polyphenylene sulfide (PPS). Maifan stone, whose main component is aluminosilicate, provides a more robust "framework" for the PPS matrix through its porous structure. After melting, PPS fills the pores of the maifan stone, tightly bonding it to the PPS matrix and thus improving the wear resistance of PPS.

[0021] A second aspect of the present invention provides a method for preparing modified polyphenylene sulfide, comprising the following steps: heating and melting the polyphenylene sulfide resin according to a designed ratio, adding a silane coupling agent and silicon carbide coated with a fluorine-containing compound and stirring evenly to obtain a first mixture; mixing the modified graphene, glass fiber and maifanite evenly to obtain a second mixture; and granulating the first mixture and the second mixture by extruding them through a twin-screw extruder to obtain the modified polyphenylene sulfide.

[0022] Preferably, the temperature of the twin-screw extruder is 250–280°C and the rotation speed is 300–400 r / min.

[0023] More preferably, the temperature of the twin-screw extruder is 260-270°C and the rotation speed is 380 r / min.

[0024] A third aspect of the present invention provides the application of the above-described modified polyphenylene sulfide or prepared according to the above-described method in the fields of electronic devices, fire protection equipment and household appliances.

[0025] The beneficial effects of this invention are as follows: This invention introduces glass fiber, modified graphene, silicon carbide coated with fluorine-containing compounds, and maifanite into the polyphenylene sulfide matrix. Through the combination of the above-mentioned additives, the modified polyphenylene sulfide obtained has high toughness, high wear resistance, and good heat dissipation performance, which greatly expands the application field of polyphenylene sulfide. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0027] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the meaning consistent with their meaning in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined.

[0028] Although various methods for modifying polyphenylene sulfide (PPS) exist, many have certain drawbacks, often resulting in performance improvements at the expense of other aspects, failing to achieve modified PPS with excellent overall performance. Therefore, this invention provides a modified PPS that exhibits high toughness, strong wear resistance, and high heat dissipation capacity, while also possessing good mechanical properties, demonstrating excellent overall performance.

[0029] Unless otherwise specified, all raw materials and equipment used in the following examples and comparative examples are commercially available products. The antioxidant used is antioxidant 1010.

[0030] Example 1

[0031] This embodiment provides a modified polyphenylene sulfide, comprising, by weight: 50 parts of polyphenylene sulfide resin, 8 parts of glass fiber (average length 500-600 μm, average diameter 10-13 μm), 10 parts of modified graphene, 6 parts of KH570 silane coupling agent, 25 parts of silicon carbide coated with fluorine-containing compounds, 15 parts of maifanite (particle size 30-50 μm), and 1 part of antioxidant; wherein, the modified graphene surface is grafted with amino and / or carboxyl groups.

[0032] The modified polyphenylene sulfide was prepared by the following method:

[0033] According to the above design formula, polyphenylene sulfide resin is heated and melted, silane coupling agent KH570 and silicon carbide coated with fluorine-containing compounds are added and stirred evenly to obtain the first mixture; modified graphene, glass fiber and maifan stone are mixed evenly to obtain the second mixture; the first mixture and the second mixture are extruded and granulated through a twin-screw extruder, wherein the temperature of the twin-screw extruder is 250-280℃ and the rotation speed is 380r / min.

[0034] The modified graphene used was prepared according to the following steps: 100g of graphene was dispersed in 1000mL of ethanol, 150g of p-aminobenzoic acid (mass ratio 1:1.5) was added, and the mixture was reacted with stirring for 1.5h. During the reaction, the pH was controlled at 2.5-4. After filtration, the solid was dried at 80℃ to obtain the modified graphene. The fluorinated silicon carbide was prepared according to the following steps: 200g of silicon carbide was dispersed in 150g of polytetrafluoroethylene emulsion at a mass ratio of 1:0.75, and the mixture was stirred and dispersed for 25min. After filtration, the solid was dried at 60℃ to obtain the fluorinated silicon carbide.

[0035] Example 2

[0036] This embodiment provides a modified polyphenylene sulfide, comprising, by weight: 42 parts of polyphenylene sulfide resin, 6 parts of glass fiber (average length 300-500 μm, average diameter 10-13 μm), 8 parts of modified graphene, 4 parts of KH570 silane coupling agent, 20 parts of silicon carbide coated with fluorine-containing compounds, 12 parts of maifanite (particle size 30-50 μm), and 0.6 parts of antioxidant; wherein, the modified graphene surface is grafted with amino and / or carboxyl groups.

[0037] The modified polyphenylene sulfide was prepared by the following method:

[0038] According to the above design formula, polyphenylene sulfide resin is heated and melted, silane coupling agent KH570 and silicon carbide coated with fluorine-containing compounds are added and stirred evenly to obtain the first mixture; modified graphene, glass fiber and maifan stone are mixed evenly to obtain the second mixture; the first mixture and the second mixture are extruded and granulated through a twin-screw extruder, wherein the temperature of the twin-screw extruder is 260-280℃ and the speed is 320r / min.

[0039] The modified graphene used was prepared according to the following steps: 100g of graphene was dispersed in 1000mL of ethanol, 100g of p-aminobenzoic acid (mass ratio 1:1) was added, and the mixture was reacted with stirring for 1h. During the reaction, the pH was controlled at 2.5-4. After filtration, the solid was dried at 80℃ to obtain the modified graphene. The fluorinated silicon carbide was prepared according to the following steps: 200g of silicon carbide was dispersed in 100g of polytetrafluoroethylene emulsion at a mass ratio of 1:0.5, stirred and dispersed for 20min, then filtered and the resulting solid was dried at 60℃ to obtain the fluorinated silicon carbide.

[0040] Example 3

[0041] This embodiment provides a modified polyphenylene sulfide, comprising, by weight: 60 parts of polyphenylene sulfide resin, 10 parts of glass fiber (average length 500-800 μm, average diameter 40-50 μm), 15 parts of modified graphene, 8 parts of silane coupling agent KH570, 28 parts of silicon carbide coated with fluorine-containing compounds, 18 parts of maifanite (particle size 10-30 μm), and 2 parts of antioxidant; wherein, the modified graphene surface is grafted with amino and / or carboxyl groups.

[0042] The modified polyphenylene sulfide was prepared by the following method:

[0043] According to the above design formula, polyphenylene sulfide resin is heated and melted, silane coupling agent KH570 and silicon carbide coated with fluorine-containing compounds are added and stirred evenly to obtain the first mixture; modified graphene, glass fiber and maifan stone are mixed evenly to obtain the second mixture; the first mixture and the second mixture are extruded and granulated through a twin-screw extruder, wherein the temperature of the twin-screw extruder is 270-280℃ and the speed is 390r / min.

[0044] The modified graphene used was prepared according to the following steps: 100g of graphene was dispersed in 1000mL of ethanol, 200g of p-aminobenzoic acid (mass ratio 1:2) was added, and the mixture was reacted with stirring for 2h. During the reaction, the pH was controlled at 2.5-4. After filtration, the solid was dried at 80℃ to obtain the modified graphene. The fluorinated silicon carbide was prepared according to the following steps: 200g of silicon carbide was dispersed in 200g of perfluoropolyether emulsion at a mass ratio of 1:1, and the mixture was stirred and dispersed for 30min. After filtration, the solid was dried at 60℃ to obtain the fluorinated silicon carbide.

[0045] Comparative Example 1

[0046] This comparative example provides a modified polyphenylene sulfide with a formulation composition similar to that of Example 1, the only difference being the absence of modified graphene. The remaining formulation and preparation method are the same as those of Example 1 and will not be repeated here.

[0047] Comparative Example 2

[0048] This comparative example provides a modified polyphenylene sulfide with a formulation similar to that of Example 1, except that silicon carbide coated with fluorine-containing compounds is not added. The rest of the formulation and preparation method are the same as those of Example 1 and will not be repeated here.

[0049] Comparative Example 3

[0050] This comparative example provides a modified polyphenylene sulfide with a formulation composition similar to that of Example 1, the only difference being the absence of maifanite. The remaining formulation and preparation method are the same as those of Example 1 and will not be repeated here.

[0051] Comparative Example 4

[0052] This comparative example provides a modified polyphenylene sulfide with a formulation composition similar to that of Example 1. The only difference is that the modified graphene used is modified with an equal amount of lysine instead of para-aminobenzoic acid. The rest of the formulation and preparation method are the same as those of Example 1 and will not be repeated here.

[0053] Comparative Example 5

[0054] This comparative example provides a modified polyphenylene sulfide with a formulation composition similar to that of Example 1. The only difference is that the modified graphene is replaced with an equal amount of ordinary graphene. The rest of the formulation and preparation method are the same as those of Example 1 and will not be repeated here.

[0055] Comparative Example 6

[0056] This comparative example provides a modified polyphenylene sulfide with a formulation similar to that of Example 1. The only difference is that the silicon carbide used is not fluorinated, i.e., silicon carbide is added directly. The rest of the formulation and preparation method are the same as those of Example 1, and will not be repeated here.

[0057] Comparative Example 7

[0058] This comparative example provides a modified polyphenylene sulfide with a formulation similar to that of Example 1, except that maifanite is replaced with an equal amount of molybdenum disulfide. The rest of the formulation and preparation method are the same as those of Example 1 and will not be repeated here.

[0059] Test Example

[0060] The modified polyphenylene sulfide materials obtained in Examples 1-3 and Comparative Examples 1-7 were processed and cut into sample shapes that matched the test standards. Three parallel samples were prepared for each group of samples. The tensile strength (GB / T1040.1-2018), impact strength (GB / T 1043.1-2008), abrasion resistance (GB / T 3960-2016), and thermal conductivity (GB / T 22588-2008) of each sample were tested. The average value was finally calculated, and the results are shown in Table 1.

[0061] Table 1

[0062]

[0063]

[0064] As shown in Table 1, the tensile strengths of Examples 1-3 and Comparative Examples 1-7 are comparable, but their impact resistance, abrasion resistance, and thermal conductivity differ significantly. Specifically, compared to Example 1, Comparative Example 1, which did not contain modified graphene, experienced a substantial decrease in impact strength to 6 kJ / m. 2The thermal conductivity of the modified polyphenylene sulfide (PPS) material decreased significantly, indicating that the addition of modified graphene in this invention can simultaneously improve the impact strength and thermal conductivity of the resulting PPS material. This is mainly because it can form a three-dimensional network structure within the PPS matrix, thereby improving toughness. Comparative Example 2, which did not contain fluorinated silicon carbide, also showed a significant decrease in thermal conductivity. This is because the absence of fluorinated silicon carbide prevents it from working synergistically with the modified graphene to dissipate heat, resulting in a significant decrease in the thermal conductivity of the modified PPS. This demonstrates that fluorinated silicon carbide and modified graphene synergistically promote heat transfer, achieving a thermal conductivity effect greater than the sum of its parts (1+1>2). Comparative Example 3, which did not contain maifanite, resulted in a significant decrease in the wear resistance of the obtained modified PPS. Comparative Example 4 replaced the modified graphene with lysine-modified graphene. Although its wear resistance and thermal conductivity did not change significantly, its toughness decreased significantly. This is because the lysine-modified graphene does not contain benzene rings on its surface, resulting in a large structural difference with the polyphenylene sulfide matrix and poor compatibility, thus failing to fully exert its toughness-enhancing effect. Comparative Example 5 replaced the modified graphene with ordinary graphene, which contains no or only a small amount of hydroxyl groups and no amino groups or benzene rings, therefore its toughness was even worse than that of Comparative Example 4. Comparative Example 6 used only silicon carbide without pre-fluorination. After the silicon carbide was filled into the polyphenylene sulfide matrix, it could not fully compatibility and contact with the matrix, and even phase separation occurred, resulting in the inability to fully exert its thermal conductivity. In Comparative Example 7, the wear resistance of the modified polyphenylene sulfide decreased significantly after molybdenum disulfide was used to replace maifanite. This is because molybdenum disulfide has almost no pores on its surface and inside, and cannot make close contact with the polyphenylene sulfide matrix. Therefore, its addition to the system has a limited effect on improving the wear resistance of polyphenylene sulfide.

[0065] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A modified polyphenylene sulfide, characterized in that, The product comprises, by weight parts: 40-60 parts polyphenylene sulfide resin, 5-10 parts glass fiber, 6-15 parts modified graphene, 3-9 parts silane coupling agent, 20-30 parts silicon carbide coated with fluorine-containing compounds, and 12-18 parts maifanite; the modified graphene is grafted with amino and / or carboxyl groups on its surface and is prepared according to the following steps: dispersing graphene in ethanol, adding p-aminobenzoic acid and reacting under stirring for 1-2 hours, controlling the pH at 2.5-4 during the reaction, then separating the solid and liquid, drying the solid to obtain the modified graphene; The silicon carbide coated with the fluorine-containing compound is prepared by the following steps: dispersing silicon carbide in a fluorine-containing polymer emulsion, stirring and dispersing for 20-30 minutes, then separating the solid and liquid and drying the obtained solid to obtain the silicon carbide coated with the fluorine-containing compound; the fluorine-containing polymer emulsion is selected from polytetrafluoroethylene emulsion or perfluoropolyether emulsion.

2. The modified polyphenylene sulfide according to claim 1, characterized in that, The composition, by weight, includes: 48-52 parts of polyphenylene sulfide resin, 7-9 parts of glass fiber, 8-12 parts of modified graphene, 5-7 parts of silane coupling agent, 23-28 parts of silicon carbide coated with fluorine-containing compounds, and 14-16 parts of maifanite; wherein the modified graphene has amino and / or carboxyl groups grafted onto its surface.

3. The modified polyphenylene sulfide as described in claim 1 or 2, characterized in that, The glass fiber has an average length of 300-800 μm and an average diameter of 35-50 μm; the maifanite has a particle size of 10-50 μm.

4. A method for preparing the modified polyphenylene sulfide according to any one of claims 1 to 3, characterized in that the step... include: According to the design ratio, the polyphenylene sulfide resin is heated and melted, and silane coupling agent and silicon carbide coated with fluorine-containing compounds are added and stirred evenly to obtain the first mixture; The modified graphene, glass fiber, and maifanite are mixed evenly to obtain a second mixture; The first mixture and the second mixture are extruded and granulated using a twin-screw extruder to obtain the modified polyphenylene sulfide.

5. The method for preparing modified polyphenylene sulfide as described in claim 4, characterized in that, The temperature of the twin-screw extruder is 250~280℃, and the rotation speed is 300~400r / min.

6. The application of the modified polyphenylene sulfide according to any one of claims 1 to 3 or the modified polyphenylene sulfide prepared according to the preparation method according to any one of claims 4 to 5 in the fields of electronic devices, fire protection equipment and household appliances.

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