Polyphenylene sulfide composite material with low dielectric constant and preparation method thereof

Abstract

The invention discloses a preparation method of a polyphenylene sulfide composite material with a low dielectric constant. The preparation method comprises the following steps: S1, uniformly mixing and stirring 50-60 parts by mass of trifluoromethyl functionalized polyphenylene sulfide, 3-5 parts by mass of functionalized cage type polyhedral oligomeric silsesquioxane, 1-5 parts by mass of a compatilizer and 0.2-0.5 part by mass of an antioxidant; and S2, mixing the materials mixed and stirred in the step S1 with 25-35 parts by mass of glass fibers, melting, extruding and granulating to obtain the polyphenylene sulfide composite material with the low dielectric constant. The preparation method comprises the following steps: firstly, introducing trifluoromethyl into a PPS molecular chain through a simple process to prepare functionalized polyphenylene sulfide, and then adding functionalized cage type polyhedral oligomeric silsesquioxane, glass fibers, a compatilizer and an antioxidant to prepare the polyphenylene sulfide composite material with a low dielectric constant, so as to meet the requirements of the fields of 5G and the like on high performance of materials.

Description

Technical Field

[0001] This invention relates to the field of polymer materials, specifically to a low dielectric constant polyphenylene sulfide (PPS) composite material and its preparation method. Background Art

[0002] Polyphenylene sulfide (PPS), as a high-performance specialty engineering plastic, possesses outstanding characteristics such as high temperature resistance, corrosion resistance, self-flame retardancy, and good electrical properties, making it widely used in numerous fields such as electronics, aerospace, and more. However, with the rapid development of technology, especially the rise of 5G communication technology, more stringent requirements have been placed on the dielectric properties of materials. The relatively high dielectric constant (Dk) of traditional PPS materials (approximately 3.0-4.0) can significantly affect high-frequency electromagnetic signals, limiting its application in fields such as 5G where signal transmission quality requirements are extremely high.

[0003] Currently, the main methods for reducing the dielectric constant of polyphenylene sulfide (PPS) resins include physical modification, chemical modification, and composite modification. Physical modification involves blending PPS with low-dielectric-constant fillers (such as SiO2 and BN), which is simple to operate but suffers from poor filler dispersibility and decreased mechanical properties. Chemical modification typically involves introducing nonpolar groups such as fluorine atoms and alkyl segments into the PPS molecular chain to optimize the molecular chain structure and reduce molecular packing density, but it also suffers from decreased mechanical properties. Composite modification involves introducing large-volume or microporous structures, which is more difficult to implement. Obtaining a low dielectric constant requires the material to have loose packing, low polarity, or air gaps in its structure, while high mechanical properties depend on dense crystallinity, high polarity, and defect-free molecular arrangement. These two factors are mutually restrictive in structural design. Therefore, when developing a PPS composite material with a low dielectric constant, it is of great significance to ensure the material's mechanical properties through appropriate preparation methods. Summary of the Invention

[0004] In view of the above-mentioned deficiencies of the prior art, the purpose of this invention is to provide a low dielectric constant polyphenylene sulfide composite material and its preparation method. First, a functionalized polyphenylene sulfide is prepared by introducing trifluoromethyl groups into the PPS molecular chain through a simple process. Then, functionalized cage-like polyhedral oligomeric silsesquioxane, glass fiber, compatibilizer, and antioxidant are added to prepare a polyphenylene sulfide composite material with a low dielectric constant, so as to meet the high performance requirements of materials in fields such as 5G.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] A method for preparing a low dielectric constant polyphenylene sulfide composite material includes the following steps:

[0007] S1. Mix 50-60 parts of trifluoromethyl functionalized polyphenylene sulfide, 3-5 parts of functionalized cage-type polyhedral oligomeric silsesquioxane, 1-5 parts of compatibilizer, and 0.2-0.5 parts of antioxidant according to the following mass ratios and stir evenly.

[0008] S2. Mix the materials from S1 with 25-35 parts by mass of glass fiber, melt extrude and granulate to obtain a low dielectric constant polyphenylene sulfide composite material.

[0009] Furthermore, the process of mixing and stirring the substances in S1 is to add them to a mixer and stir at a speed of 300-500 r / min for 10-30 min.

[0010] The mixing in S2 involves adding the material from S1 into the hopper of a twin-screw extruder and adding the glass fiber into the side feed port of the twin-screw extruder. During the mixing, melt extrusion, and granulation process in S2, the temperature of the feeding section of the twin-screw extruder is 250-290℃, the temperature of the plasticizing and shearing section is 275-315℃, the die temperature is 295-335℃, and the screw speed of the twin-screw extruder is 240-260 r / min.

[0011] Furthermore, the preparation method of the trifluoromethyl-functionalized polyphenylene sulfide includes the following steps:

[0012] SP1. Add 252.2 mol of N-methyl-2-pyrrolidone, 3.90 mol of sodium sulfide polyhydrate containing Na2S, 2.3 mol of hydroxyl-containing reaction stabilizer, and 21.27 mol of auxiliary agent to the high-pressure reactor in the following order: heat up and dehydrate under nitrogen protection.

[0013] SP2. Add 48 mol of p-dichlorobenzene, 2.2 mol of p-halotrifluorotoluene, and 49.4 mol of N-methyl-2-pyrrolidone to the high-pressure reactor in the following order: heat to 220°C, hold for 2 hours, then heat to 265°C and hold for 3 hours.

[0014] SP3. After the high-pressure reactor is cooled to 150°C, the contents are centrifuged. The solid material obtained after centrifugation is thoroughly washed with demineralized water. The washed material is then vacuum dried to obtain trifluoromethyl functionalized polyphenylene sulfide.

[0015] Furthermore, the polyhydrate sodium sulfide can be one or more of sodium sulfide trihydrate, sodium sulfide pentahydrate, and sodium sulfide nonahydrate;

[0016] The antioxidant is one or more of antioxidant 1010, antioxidant 168, antioxidant 445, antioxidant BHT, and antioxidant 1076.

[0017] Furthermore, the reaction stabilizer is one or more of sodium hydroxide, potassium hydroxide, barium hydroxide, and calcium hydroxide.

[0018] Furthermore, the auxiliary agent is one or more of sodium carbonate, sodium acetate, lithium chloride, lithium acetate, and lithium bromide.

[0019] Furthermore, the p-halotrifluorotoluene is one or more of p-chlorotrifluorotoluene, p-bromotrifluorotoluene, and p-iodotrifluorotoluene.

[0020] Further, the cage-shaped polyhedral oligomeric silsesquioxane (POSS) is one or more of octaphenyl polyhedral oligomeric silsesquioxane (OP-POSS), octachloropropyl polyhedral oligomeric silsesquioxane (OCP-POSS), and octaphenylaminopropyl polyhedral oligomeric silsesquioxane (octaphenylaminopropyl polyhedral oligomeric silsesquioxane).

[0021] Further, the compatibilizer is 4-(2,5-dimethyl-1H-pyrrole)benzenethiol, and its preparation method includes the following steps:

[0022] SJ1. Under a nitrogen atmosphere, 1,4-dibromobenzene, potassium thioacetate, and CuI are added to dry DMF.

[0023] SJ3, heat to 100-12℃, stir and react for 12 hours;

[0024] SJ4. Cool to room temperature, pour the reaction solution into ice water, extract with ethyl acetate, wash with saturated brine, dry with anhydrous sodium sulfate, remove the solvent by rotary evaporation under reduced pressure, and purify to obtain 1-bromo-4-(thioacetoxy)benzene.

[0025] SJ5. Under a N2 atmosphere, 1-bromo-4-(thioacetoxy)benzene, 2,5-dimethyl-1H-pyrrole, K2CO3, CuI and Phen are added to dry toluene.

[0026] SJ6, heat to 110℃ and stir for 24 hours;

[0027] SJ7, cooled to room temperature, quenched the reaction with saturated ammonium chloride solution, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, removed the solvent by rotary evaporation under reduced pressure, and purified to obtain 4-(2,5-dimethyl-1H-pyrrolo-1-yl)phenylthioacetic acid ester;

[0028] SJ8. Dissolve [4-(thioacetoxy)phenyl]-2,5-dimethyl-1H-pyrrole in a methanol / water mixed solvent;

[0029] SJ9, add KOH, heat to 40℃, and stir to react for 1 hour;

[0030] SJ0, after the reaction is complete, acidify the reaction solution with dilute hydrochloric acid to pH≈5-6;

[0031] SJ11 was extracted with dichloromethane, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was removed by rotary evaporation under reduced pressure to obtain 4-(2,5-dimethyl-1H-pyrrole)benzylthiol.

[0032] A low dielectric constant polyphenylene sulfide composite material, characterized in that it is prepared according to any of the above-mentioned methods for preparing low dielectric constant polyphenylene sulfide composite materials.

[0033] Because of the adoption of the above technical solution, the present invention has the following advantages:

[0034] 1. This invention successfully prepared trifluoromethyl-functionalized polyphenylene sulfide through simple chemical modification. The introduction of trifluoromethyl groups reduced the molecular packing density and the intermolecular interactions, thereby effectively reducing the dielectric constant of the resin itself.

[0035] 2. This invention uses cage-shaped polyhedral oligomeric silsesquioxane, which utilizes its special hollow cage structure with nanoscale cavities inside, which is equivalent to introducing a large number of "micro air bubbles" inside the material. Since the dielectric constant Dk and dielectric loss Df of air are both at their lowest values ​​(Dk=1, Df≈0), the introduction of air significantly reduces the dielectric constant of the composite material.

[0036] 3. The present invention uses 4-(2,5-dimethyl-1H-pyrrole)benzenethiol as a compatibilizer, which can significantly enhance the adhesion between PPS-CF3 and glass fiber. The pyrrole derivative helps to bind with glass fiber, while the functionalized thiol group is beneficial to bind with PPS-CF3.

[0037] 4. The composite material prepared by this invention has excellent mechanical properties while reducing the dielectric constant.

[0038] Other advantages, objectives and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination or study, or may be learned from the practice of the invention. Detailed Implementation

[0039] The present invention will be further described below with reference to the embodiments.

[0040] Example 1:

[0041] In a 50L high-pressure reactor, 25.00 kg of N-methyl-2-pyrrolidone (NMP), 8.53 kg of sodium sulfide polyhydrate (containing 3.90 mol of Na2S), 0.09 kg of sodium hydroxide, and 0.90 kg of lithium chloride were added sequentially, and the mixture was heated to remove water under N2 protection.

[0042] Then, 7.05 kg of p-dichlorobenzene (p-DCB), 0.40 kg of p-chlorotrifluorotoluene, and 4.90 kg of N-methyl-2-pyrrolidone (NMP) were added sequentially. The mixture was heated to 220 °C and held at that temperature for 2 hours. The temperature was then further increased to 265 °C and held at that temperature for 3 hours. After cooling to 150 °C, the mixture was centrifuged, the solid was collected, thoroughly washed with deionized water, and dried under vacuum to obtain trifluoromethyl-functionalized polyphenylene sulfide.

[0043] 58 kg of trifluoromethyl functionalized polyphenylene sulfide, 3.5 kg of octaphenylaminopropyl polyhedral oligomeric silsesquioxane, 3.0 kg of 4-(2,5-dimethyl-1H-pyrrolithyl)benzenethiol, and 0.45 kg of antioxidant 1010 were sequentially added to a mixer and stirred at 450 r / min for 25 min. The specific preparation method of 4-(2,5-dimethyl-1H-pyrrole)benzenethiol includes the following steps: SJ1, under N2 atmosphere, 1,4-dibromobenzene, potassium thioacetate, and CuI are added to dry DMF; SJ3, the mixture is heated to 100-12℃ and stirred for 12 hours; SJ4, the mixture is cooled to room temperature, poured into ice water, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent is removed by rotary evaporation under reduced pressure to obtain 1-bromo-4-(thioacetoxy)benzene; SJ5, under N2 atmosphere, 1-bromo-4-(thioacetoxy)benzene, 2,5-dimethyl-1H-pyrrole, K2CO3, CuI, and Phen are added to dry toluene; SJ6, the mixture is heated to 110℃ and stirred for 24 hours. Hours; SJ7, Cool to room temperature, quench the reaction with saturated ammonium chloride solution, extract with ethyl acetate, wash with saturated brine, dry with anhydrous sodium sulfate, remove solvent by rotary evaporation under reduced pressure, and purify to obtain 4-(2,5-dimethyl-1H-pyrrolo-1-yl)phenylthioacetate; SJ8, Dissolve [4-(thioacetoxy)phenyl]-2,5-dimethyl-1H-pyrrolo in methanol / water mixed solvent; SJ9, Add KOH, heat to 40℃, and stir for 1 hour; SJ0, After the reaction is complete, acidify the reaction solution with dilute hydrochloric acid to pH≈5-6; SJ11, Extract with dichloromethane, wash with saturated brine, dry with anhydrous sodium sulfate, remove solvent by rotary evaporation under reduced pressure, and purify to obtain 4-(2,5-dimethyl-1H-pyrrolo)benzylthiol.

[0044] The mixed material was transferred to the feeding hopper of a twin-screw extruder, and 33 kg of glass fiber was added through the side feed port. Melt extrusion granulation was then performed to obtain granular low-dielectric-constant polyphenylene sulfide composite material. The process parameters were: feeding section 270°C, plasticizing and shearing section 295°C, die head 315°C, and screw speed 250 r / min.

[0045] Comparative Example 1:

[0046] 58 kg of conventional polyphenylene sulfide, 3.5 kg of octaphenylaminopropyl polyhedral oligomeric silsesquioxane, 3.0 kg of 4-(2,5-dimethyl-1H-pyrrolithyl)benzenethiol, and 0.45 kg of antioxidant 1010 were added sequentially to a mixer and stirred at 450 r / min for 25 min.

[0047] The mixed material was transferred to the feeding hopper of a twin-screw extruder, and 33 kg of glass fiber was added through the side feed port. Melt extrusion granulation was then performed to obtain granular low-dielectric-constant polyphenylene sulfide composite material. The process parameters were: feeding section 270°C, plasticizing and shearing section 295°C, die head 315°C, and screw speed 250 r / min.

[0048] Comparative Example 2:

[0049] 58 kg of trifluoromethyl functionalized polyphenylene sulfide, 3.0 kg of 4-(2,5-dimethyl-1H-pyrrolidinyl)benzylthiol, and 0.45 kg of antioxidant 1010 were sequentially added to a mixer and stirred at 450 r / min for 25 min.

[0050] The mixed material was transferred to the feeding hopper of a twin-screw extruder, and 33 kg of glass fiber was added through the side feed port. Melt extrusion granulation was then performed to obtain granular low-dielectric-constant polyphenylene sulfide composite material. The process parameters were: feeding section 270°C, plasticizing and shearing section 295°C, die head 315°C, and screw speed 250 r / min.

[0051] Comparative Example 3:

[0052] 58 kg of trifluoromethyl functionalized polyphenylene sulfide, 3.5 kg of octaphenylaminopropyl polyhedral oligomeric silsesquioxane, and 0.45 kg of antioxidant 1010 were sequentially added to a mixer and stirred at 450 r / min for 25 min.

[0053] The mixed material was transferred to the feeding hopper of a twin-screw extruder, and 33 kg of glass fiber was added through the side feed port. Melt extrusion granulation was then performed to obtain granular low-dielectric-constant polyphenylene sulfide composite material. The process parameters were: feeding section 270°C, plasticizing and shearing section 295°C, die head 315°C, and screw speed 250 r / min.

[0054] The polyphenylene sulfide samples prepared in Example 1 and Comparative Examples 1-3 were used to make standard samples. The tensile strength, dielectric constant, dielectric loss and notched impact strength of the samples were tested. The test results are shown in Table 1.

[0055] Table 1. Performance Test Results

[0056]

[0057]

[0058] As can be directly seen from Table 1, the low dielectric constant polyphenylene sulfide composite material prepared in Example 1 has a dielectric constant as low as 2.5 and a node loss as low as 0.0027, which is significantly lower than the dielectric constant and dielectric loss of polyphenylene sulfide in Comparative Examples 1 and 2. At the same time, its physical properties (tensile strength and notched impact strength) are at a high level. That is, the low dielectric constant polyphenylene sulfide composite material prepared in Example 1 not only meets the minimum dielectric constant and dielectric loss requirements, but also has excellent mechanical properties.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a low dielectric constant polyphenylene sulfide composite material, characterized in that, Includes the following steps: S1. Mix 50-60 parts of trifluoromethyl functionalized polyphenylene sulfide, 3-5 parts of functionalized cage-type polyhedral oligomeric silsesquioxane, 1-5 parts of compatibilizer, and 0.2-0.5 parts of antioxidant according to the following mass ratios and stir evenly. S2. Mix the materials from S1 with 25-35 parts by mass of glass fiber, melt extrude and granulate to obtain a low dielectric constant polyphenylene sulfide composite material.

2. The method for preparing low dielectric constant polyphenylene sulfide composite material according to claim 1, characterized in that, The substances in S1 are mixed and stirred evenly by adding them to a mixer and stirring at a speed of 300-500 r / min for 10-30 min. The mixing in S2 involves adding the material from S1 into the hopper of a twin-screw extruder and adding the glass fiber into the side feed port of the twin-screw extruder. During the mixing, melt extrusion, and granulation process in S2, the temperature of the feeding section of the twin-screw extruder is 250-290℃, the temperature of the plasticizing and shearing section is 275-315℃, the die temperature is 295-335℃, and the screw speed of the twin-screw extruder is 240-260 r / min.

3. The method for preparing low dielectric constant polyphenylene sulfide composite material according to claim 1, characterized in that, The preparation method of the trifluoromethyl functionalized polyphenylene sulfide includes the following steps: SP1. Add 252.2 mol of N-methyl-2-pyrrolidone, 3.90 mol of sodium sulfide polyhydrate containing Na2S, 2.3 mol of hydroxyl-containing reaction stabilizer and 21.27 mol of auxiliary agent to the high-pressure reactor in the following order: heat up and dehydrate under nitrogen protection. SP2. Add 48 mol of p-dichlorobenzene, 2.2 mol of p-halotrifluorotoluene, and 49.4 mol of N-methyl-2-pyrrolidone to the high-pressure reactor in the following order: heat to 220°C, hold for 2 hours, then heat to 265°C and hold for 3 hours. SP3. After the high-pressure reactor is cooled to 150°C, the contents are centrifuged. The solid material obtained after centrifugation is thoroughly washed with demineralized water. The washed material is then vacuum dried to obtain trifluoromethyl functionalized polyphenylene sulfide.

4. The method for preparing low dielectric constant polyphenylene sulfide composite material according to claim 3, characterized in that, The sodium sulfide polyhydrate may be one or more of sodium sulfide trihydrate, sodium sulfide pentahydrate, and sodium sulfide nonahydrate; The antioxidant is one or more of antioxidant 1010, antioxidant 168, antioxidant 445, antioxidant BHT, and antioxidant 1076.

5. The method for preparing low dielectric constant polyphenylene sulfide composite material according to claim 3, characterized in that, The reaction stabilizer is one or more of sodium hydroxide, potassium hydroxide, barium hydroxide, and calcium hydroxide.

6. The method for preparing low dielectric constant polyphenylene sulfide composite material according to claim 3, characterized in that, The additive is one or more of sodium carbonate, sodium acetate, lithium chloride, lithium acetate, and lithium bromide.

7. The method for preparing low dielectric constant polyphenylene sulfide composite material according to claim 3, characterized in that, The p-halotrifluorotoluene is one or more of p-chlorotrifluorotoluene, p-bromotrifluorotoluene, and p-iodinetrifluorotoluene.

8. The method for preparing low dielectric constant polyphenylene sulfide composite material according to claim 1, characterized in that, The cage-type polyhedral oligomeric silsesquioxane (POSS) is one or more of octaphenyl polyhedral oligomeric silsesquioxane (OP-POSS), octachloropropyl polyhedral oligomeric silsesquioxane (OCP-POSS), and octaphenylaminopropyl polyhedral oligomeric silsesquioxane (octaphenylaminopropyl polyhedral oligomeric silsesquioxane).

9. The method for preparing low dielectric constant polyphenylene sulfide composite material according to claim 1, characterized in that, The compatibilizer is 4-(2,5-dimethyl-1H-pyrrole)benzenethiol, and its preparation method includes the following steps: SJ1. Under a nitrogen atmosphere, 1,4-dibromobenzene, potassium thioacetate, and CuI are added to dry DMF. SJ3, heat to 100-12℃, stir and react for 12 hours; SJ4. Cool to room temperature, pour the reaction solution into ice water, extract with ethyl acetate, wash with saturated brine, dry with anhydrous sodium sulfate, remove the solvent by rotary evaporation under reduced pressure, and purify to obtain 1-bromo-4-(thioacetoxy)benzene. SJ5. Under a N2 atmosphere, 1-bromo-4-(thioacetoxy)benzene, 2,5-dimethyl-1H-pyrrole, K2CO3, CuI and Phen are added to dry toluene. SJ6, heat to 110℃ and stir for 24 hours; SJ7, cooled to room temperature, quenched the reaction with saturated ammonium chloride solution, extracted with ethyl acetate, washed with saturated brine, dried over anhydrous sodium sulfate, removed the solvent by rotary evaporation under reduced pressure, and purified to obtain 4-(2,5-dimethyl-1H-pyrrolo-1-yl)phenylthioacetic acid ester; SJ8. Dissolve [4-(thioacetoxy)phenyl]-2,5-dimethyl-1H-pyrrole in a methanol / water mixed solvent; SJ9, add KOH, heat to 40℃, and stir to react for 1 hour; SJ0, after the reaction is complete, acidify the reaction solution with dilute hydrochloric acid to pH≈5-6; SJ11 was extracted with dichloromethane, washed with saturated brine, dried over anhydrous sodium sulfate, and the solvent was removed by rotary evaporation under reduced pressure to obtain 4-(2,5-dimethyl-1H-pyrrole)benzylthiol.

10. A low dielectric constant polyphenylene sulfide composite material, characterized in that, It was prepared according to any of the low dielectric constant polyphenylene sulfide composite material preparation methods in claims 1-11.

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