Polyarylene sulfide as well as preparation method and application thereof

Abstract

The invention discloses polyarylene sulfide as well as a preparation method and application thereof, belongs to the technical field of polyarylene sulfide, and overcomes the defect of low particle strength caused by small microcrystal size of polyarylene sulfide in the prior art. The invention provides polyarylene sulfide. The grain size of the polyarylene sulfide is smaller than 75%, and the crystallinity of the polyarylene sulfide is smaller than 75%. The weight-average molecular weight of the polyarylene sulfide is 55000 or below, and the mass content of the chlorine element is 1200 ppm or below. The particle strength of oversize products of the polyarylene sulfide passing through a 100-mesh screen is 85% or above.

Description

Technical Field

[0001] The present invention belongs to the technical field of polyarylene sulfide, and in particular relates to polyarylene sulfide and a preparation method and application thereof. Background Art

[0002] As an emerging type of high-performance thermoplastic resin material, polyarylene sulfide is known as the world's sixth largest engineering plastic due to its extremely excellent high-temperature resistance, outstanding corrosion resistance, relatively balanced mechanical properties and outstanding dimensional stability. It is widely used in many fields such as the automotive industry, electronic appliances, and environmental protection industry.

[0003] At present, the preparation of polyarylene sulfide usually adopts the Phillips method. This method is to make sulfide and dihalogenated aromatic compound undergo condensation reaction under high temperature conditions in a polar solvent system to generate polyarylene sulfide. After the reaction is terminated, the polyarylene sulfide is precipitated in the form of particles through the cooling crystallization process. However, the polyarylene sulfide resin prepared by the Phillips method inevitably contains a large amount of chlorine end groups (1500-5000ppm). Due to the strong chemical inertness and low nucleation activity of the chlorine end groups, it is not conducive to the formation of larger crystallite size of polyarylene sulfide during the cooling crystallization process. Therefore, the crystallite size of the granular polyarylene sulfide resin prepared by conventional polymerization process is usually smaller than According to polymer crystallization theory, when the crystallite size is less than When the polyarylene sulfide is granulated, the intermolecular forces between the chains are weakened, resulting in the granule strength failing to meet the process requirements. Such granular polyarylene sulfide is very prone to fragmentation and breakage during post-processing, ultimately resulting in a decrease in polymerization yield. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that polyarylene sulfide has a small crystallite size due to its low nucleation activity and high end group, thereby providing a polyarylene sulfide and its preparation method and application.

[0005] To this end, the present invention provides the following technical solutions.

[0006] In the first aspect, the present application provides a polyarylene sulfide having a crystal size of The crystallinity of the polyarylene sulfide is less than 75%;

[0007] The weight average molecular weight of the polyarylene sulfide is less than 55,000, and the mass content of chlorine element is less than 1,200 ppm.

[0008] In one possible embodiment, the crystallinity of the polyarylene sulfide is 40%≤75%.

[0009] In one possible implementation, the weight average molecular weight of the polyarylene sulfide is 20,000 to 55,000.

[0010] In one possible implementation, the mass content of chlorine element is 500 to 1200 ppm.

[0011] In one possible embodiment, the polyarylene sulfide includes a first repeating unit represented by formula (1):

[0012]

[0013] In formula (1), R1 and R2 are each independently selected from a hydrogen atom, a C1-C4 alkyl group, a nitro group, an amino group, a phenyl group, a methoxy group, and an ethoxy group;

[0014] In one possible embodiment, the first repeating unit comprises and / or

[0015] Preferably, R1 and R2 are arranged in the para position or the meta position on the benzene ring;

[0016] In one possible embodiment, R1 and R2 are hydrogen atoms;

[0017] In one possible embodiment, the first repeating unit comprises and / or

[0018] In a possible embodiment, it further comprises one or more of a second repeating unit, a third repeating unit, a fourth repeating unit, a fifth repeating unit, and a sixth repeating unit;

[0019] The second repeating unit is shown in formula (4),

[0020] The third repeating unit is shown in formula (5),

[0021] The fourth repeating unit is shown in formula (6),

[0022] The fifth repeating unit is shown in formula (7),

[0023] The sixth repeating unit is shown in formula (8),

[0024] The second repeating unit, the third repeating unit, the fourth repeating unit, the fifth repeating unit, and the sixth repeating unit are all less than 10% of the total molar number of repeating units, preferably less than 3%;

[0025] In a possible embodiment, the particle strength of the oversize material obtained by passing through a 100-mesh sieve is above 85%.

[0026] In a second aspect, the present application provides a method for preparing polyarylene sulfide, comprising the following steps:

[0027] S1, dehydration stage: heating a mixture of N-methylpyrrolidone, sulfur source, water and alkali metal hydroxide to remove part of the water in the system;

[0028] S2, one-stage polymerization: after dehydration is completed, a mixture of dihalogen aromatic compound and N-methylpyrrolidone is added, and the temperature is raised to T1 to react to form a prepolymer;

[0029] S3, second stage polymerization: After the first stage polymerization is completed, the temperature is continued to rise to T2, a phase separation agent is added, and the prepolymer is reacted under a certain pressure;

[0030] S4, end-capping stage: after the second stage polymerization is completed, an alkali metal hydroxide aqueous solution is added, and then the reaction is carried out at an end-capping temperature of 150-240°C for 10-180 minutes;

[0031] S5, post-processing stage: centrifuging the reaction slurry obtained in S4, washing the solids, and drying them.

[0032] In S1, the dehydration stage is completed when the temperature is raised to the end temperature.

[0033] In a possible implementation manner, S4 satisfies at least one of the following conditions:

[0034] (1) The alkali metal hydroxide includes one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, and francium hydroxide, preferably sodium hydroxide;

[0035] (2) the molar ratio of the added alkali metal hydroxide to the sulfur source is 0.01-0.2, preferably 0.02-0.07;

[0036] When the ratio of the amount of alkali metal hydroxide to the sulfur source is within the above range, the amount of SMAB produced can be guaranteed, the chlorine content of the polyarylene sulfide can be significantly reduced, the carboxyl end group content can be higher, the crystal size of the polyarylene sulfide resin can be larger, and the particle strength can be significantly improved. At the same time, problems such as poor fluidity and decreased whiteness of the polyarylene sulfide caused by NMP deterioration can be avoided.

[0037] (3) The end-capping temperature is 200-220°C;

[0038] (4) The reaction time is 30 to 90 minutes.

[0039] In a possible implementation manner, S1 satisfies at least one of the following conditions:

[0040] (1) the rate of the temperature increase is 0.1-3.5°C / min, preferably 0.5-2.0°C / min;

[0041] (2) the terminal temperature of the temperature increase is 120-260°C, preferably 180-220°C;

[0042] (3) the molar ratio of the residual water amount in the dehydration stage to the sulfur source is 0.5-3.0, preferably 0.8-1.8;

[0043] the residual water amount in the dehydration stage = total water amount at the time of feeding - removed water amount.

[0044] (4) the molar ratio of the amount of the alkali metal hydroxide to the sulfur source is 0.8-2, preferably 0.9-1.5;

[0045] (5) the molar ratio of the amount of N-methylpyrrolidone to the sulfur source is 0.2-4.0, preferably 0.5-3;

[0046] (6) the sulfur source is selected from lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, preferably sodium sulfide or sodium hydrosulfide;

[0047] (7) the alkali metal hydroxide is selected from sodium hydroxide, calcium hydroxide, lithium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide;

[0048] (8) the molar ratio of water to the sulfur source is 1-20, preferably 4-10.

[0049] In a possible implementation manner, the S2 satisfies at least one of the following conditions:

[0050] (1) the molar ratio of the dihalogen aromatic compound to the sulfur source is 0.5-2.0, preferably 0.9-1.1;

[0051] (2) T1 is 180-260°C, preferably 200-240°C;

[0052] (3) after the temperature is increased to T1, the reaction is performed for 30-240 min, preferably 60-180 min;

[0053] (4) in the S2, the dihalogen aromatic compound includes one or more of o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, dichlorotoluene, dichlorobiphenyl, dichlorobenzoic acid, dichlorodiphenyl ether, dichlorodiphenyl sulfoxide, and dichlorodiphenyl ketone, preferably p-dichlorobenzene;

[0054] (5) in the S2, the molar ratio of the total amount of N-methylpyrrolidone to the sulfur source is 1-6, preferably 2-5.

[0055] In a possible implementation manner, S3 satisfies at least one of the following conditions:

[0056] (1) T2 is 240-290°C, preferably 250-270°C;

[0057] (2) The phase separation agent is selected from one or more of water, organic carboxylic acid metal salts, organic sulfonic acid metal salts, metal halides, alcohols and paraffinic hydrocarbons;

[0058] Optionally, the organic carboxylic acid metal salt includes one or more of lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, lithium benzoate, sodium benzoate, sodium phenylacetate, and potassium p-methylbenzoate;

[0059] Optionally, the organic sulfonic acid metal salt includes one or more of sodium p-toluenesulfonate, sodium dodecylbenzenesulfonate, calcium ligninsulfonate, and barium petroleum sulfonate;

[0060] Optionally, the metal halide includes one or more of lithium chloride, potassium chloride, and sodium chloride;

[0061] Optionally, the alcohols include one or more of ethylene glycol and xylitol;

[0062] Optionally, the paraffinic hydrocarbons include one or more of n-octadecane, n-octacosane, and n-dotriacontane;

[0063] (3) The reaction pressure is 0.2 to 3 MPa, preferably 0.5 to 2.5 MPa;

[0064] (4) The reaction time after adding the phase separation agent is 0 to 300 min, preferably 30 to 240 min;

[0065] (5) The molar ratio of the phase separation agent to the sulfur source is 0.1 to 5, preferably 0.2 to 3.

[0066] In one possible embodiment, in S2, the reaction pressure is 0 to 2 MPa, preferably 0.2 to 0.8 MPa;

[0067] In one possible embodiment, in S2, the conversion rate of the dihalogen aromatic compound is 50% to 98%, preferably 60 to 95%;

[0068] In one possible embodiment, in S3, the conversion rate of the dihalogen aromatic compound is 60% to 100%, preferably 80 to 99.5%.

[0069] In the S3 two-stage polymerization, the polymerization system enters a phase-separated state in the presence of a phase separation agent. Phase separation polymerization is the process of continuing the polymerization reaction while the reaction system is phase-separated into a polymer-rich phase and a polymer-lean phase. The addition of a phase separation agent causes the polymerization reaction system (polymerization reaction mixture) to phase-separate into a polymer-rich phase (primarily composed of molten polyarylene sulfide) and a polymer-lean phase (primarily composed of N-methylpyrrolidone).

[0070] In the S4 end-capping stage, after the second-stage polymerization is completed, an alkali metal hydroxide aqueous solution is added to cool the polymerization system. Then, at a certain temperature (150-240°C), the polymer is simultaneously in the stage of crystallization and end-capping reaction.

[0071] In the post-treatment stage S5, the reaction slurry obtained in S4 is cooled, centrifuged, washed, and dried, preferably washed and filtered with acetone, then washed and filtered with an acid solution, and finally washed multiple times with hot water.

[0072] In one possible embodiment, the reaction slurry is cooled to 20-120°C.

[0073] As a preferred embodiment, the acid solution is preferably hydrochloric acid, sulfuric acid, nitric acid, carbonic acid, acetic acid, oxalic acid, malic acid, or citric acid, more preferably hydrochloric acid or acetic acid.

[0074] In a third aspect, the present application provides applications of the polyarylene sulfide or the polyarylene sulfide prepared according to the preparation method in the automotive industry, electronic appliances, or environmental protection industry.

[0075] The technical solution of the present invention has the following advantages:

[0076] 1. The weight average molecular weight of the polyarylene sulfide of the present application is less than 55,000, the mass content of chlorine in the polyarylene sulfide is less than 1200 ppm; the crystallinity of the polyarylene sulfide is less than 75%, and the grain size is less than 100%.

[0077] The present application provides a polyarylene sulfide having a low chlorine content and a large grain size. The polyarylene sulfide having a grain size within this range has a strong particle strength, which can reduce the product particle breakage rate during post-processing and improve the product yield. The particle strength of the polyarylene sulfide of the present application passing through a 100-mesh sieve is greater than 85%.

[0078] 2. The preparation method of the polyarylene sulfide of the present application comprises the following steps: S1, a dehydration stage: a mixture of N-methylpyrrolidone, a sulfur source, water and an alkali hydroxide is heated to remove part of the water in the system; S2, a one-stage polymerization: after the dehydration is completed, a mixed solution of a dihalogen aromatic compound and N-methylpyrrolidone is added, and the temperature is raised to T1, and a prepolymer is generated by reaction; S3, a two-stage polymerization: after the one-stage polymerization is completed, the temperature is continuously raised to T2, a phase separation agent is added, and the prepolymer is reacted under a certain pressure; S4, an end-capping stage: after the two-stage polymerization is completed, an aqueous alkali hydroxide solution is added, and then the reaction is carried out at 150-240℃ for 10-180min; S5, a post-treatment stage: the reaction slurry obtained in S4 is centrifuged, the solid is washed and dried.

[0079] The preparation method provided by the present application promotes the ring opening of N-methylpyrrolidone to generate sodium N-methyl-4-aminobutanoate (SMAB) by adding an aqueous alkali hydroxide solution in the end-capping stage, and SMAB reacts with the chloro end group of the polyarylene sulfide to generate the polyarylene sulfide with a sodium carboxyl end group, which significantly reduces the chlorine content of the polyarylene sulfide resin. At the same time, the sodium carboxyl end group has higher nucleation activity than the chloro end group, so that the polyarylene sulfide resin has larger crystal grain size. Since the end-capping reaction and the crystallization process occur at the same time, the entanglement of the polyarylene sulfide molecular chain is disturbed, the migration of the grain boundary is inhibited, and the crystallinity is reduced.

[0080] The end-capping stage of the present application is carried out at 150-240℃ for 10-180min. If the end-capping temperature is too high, the activity of the chain extension reaction in the end-capping stage is greater than the activity of the end-capping reaction, which will cause the molecular weight of the polyarylene sulfide to increase and the fluidity to become poor. When the end-capping temperature is too low, the end-capping reaction occurs with low activity, and it is difficult to obtain the target product.

[0081] The polyarylene sulfide of the present application has a chlorine content of <1200ppm, reduced crystallinity and increased crystal grain size, which ultimately exhibits enhanced particle strength, reduces the product particle breakage rate during post-treatment, and improves the product yield. DETAILED DESCRIPTION

[0082] The following examples are provided to better further understand the present application and are not limited to the best mode, and do not constitute a limitation on the content and scope of protection of the present application. Any person under the inspiration of the present application or the combination of the present application with other prior art features will fall within the scope of protection of the present application.

[0083] The specific experimental steps or conditions are not specified in the examples, and can be carried out according to the conventional experimental steps described in the literature in the art. The reagents or instruments used are not specified by the manufacturer, and are conventional reagent products that can be obtained by purchase.

[0084] The analysis and evaluation methods involved in the examples or comparative examples are as follows:

[0085] (1) Weight average molecular weight

[0086] The weight average molecular weight (Mw) of the polymer was measured using a high-temperature gel permeation chromatograph (GPC) SSC-7000 under the following conditions. The weight average molecular weight was calculated as a polystyrene-equivalent value.

[0087] Solvent: 1-chloronaphthalene;

[0088] Temperature: 210℃;

[0089] Detector: UV detector (360 nm);

[0090] Sample injection volume: 200 μl (concentration: 0.05 mass %);

[0091] Flow rate: 0.7 ml / min;

[0092] Standard polystyrene: 5 kinds of standard polystyrene: 616000, 113000, 26000, 8200 and 600.

[0093] (2) Chlorine content

[0094] The chlorine content was determined by oxygen bomb combustion-ion chromatography. The test conditions were as follows:

[0095] Ion chromatograph: DX320 manufactured by DIONEX;

[0096] Combustion pretreatment equipment: AQF-100, ABC, WS-100, GA-100 manufactured by Mitsubishi Chemical;

[0097] Sample: 10mg.

[0098] Heater: Inlet Temp / 900°C, Outlet Temp / 1000°C Absorbent: H2O2 900ppm, internal standard PO4 3- 25ppm.

[0099] (3) Crystallinity

[0100] The Kα radiation (40 kV, 50 mA, wavelength) was used with a nickel-filtered copper target. ) was used to obtain the X-ray diffraction pattern of polyarylene sulfide using a Rigaku D / max-rA diffractometer. The measurement was performed by symmetric reflection in the range of 2θ values ​​of 15° to 30°. Based on the reasonable assumption that there is no diffraction contribution from crystalline polyarylene sulfide at 2θ values ​​of 17° and 24°, and that the measured values ​​at these two angles are all from the contribution of amorphous polyarylene sulfide, the boundary between the crystalline and amorphous patterns was determined based on Brady's amorphous pattern. The area under the diffraction curve attributed to crystalline diffraction was divided by the total area to obtain the area ratio, i.e., the crystallinity index (C i ):

[0101] C i =A cryst / (A cryst +A amorp )×100%

[0102] (4) Grain size

[0103] After measuring the FWHM of the strongest diffraction peak, we calculated the normalized crystallite size D hkl , and consider it as the crystallite size:

[0104] D hkl =κλ / βcosθ hkl

[0105] Where κ is 0.89; β is the half-height width; θ hkl It is the Prague corner.

[0106] (5) Particle strength

[0107] In a 1 L polyethylene bottle, 500 g of glass beads and 30 g of a 100-mesh screen portion of granular polyarylene sulfide were placed and shaken for 30 minutes. After shaking, the granular polyarylene sulfide in the polyethylene bottle was sieved using a 100-mesh screen, and the mass ratio of the 100-mesh screen portion to the total of the 100-mesh screen portion and the 100-mesh screen portion was calculated as the granular strength.

[0108] (6) Conversion rate of dihalogen aromatic compounds

[0109] The amount of dihalogen aromatic compound remaining in the slurry after the polymerization was determined by gas chromatography (Agilent 7890B), and the conversion rate of the dihalogen aromatic compound was calculated based on the residual amount and the feed amount of the dihalogen aromatic compound.

[0110] Example 1

[0111] This embodiment provides a method for preparing polyarylene sulfide, comprising the following steps:

[0112] 1. Dehydration stage:

[0113] In a 50L titanium reactor, 6855.16g of NaSH aqueous solution (wherein the mass fraction of NaSH is 46%, 56.25mol NaSH), 4275g of NaOH aqueous solution (the mass fraction of NaOH is 50%, 53.44mol NaOH), and NMP9466g (N-methylpyrrolidone, 95.63mol) were added. The molar ratio of NaOH / NaSH was 0.95, and the temperature was raised to 180°C at a heating rate of 1.2°C / min. 5248.9g of liquid (water content 88.1wt%) was removed. At this time, the molar ratio of the remaining water content in the system to the sulfur source NaSH was 1.2. After dehydration, the material temperature was reduced to 150°C.

[0114] 2. One-stage aggregation:

[0115] p-Dichlorobenzene (8434.86 g, 57.38 mol) and NMP (9466 g, 95.63 mol) were pumped into the reactor at a p-dichlorobenzene / NaSH molar ratio of 1.02. While stirring at a Reynolds number of 100, the temperature was raised to 230°C over 90 minutes. The first stage polymerization was completed at 230°C for 3 hours. At the end of the first stage polymerization, the p-dichlorobenzene conversion was 88%.

[0116] 3. Two-stage polymerization

[0117] After the completion of the first-stage polymerization, the temperature was raised to 260°C at a heating rate of 2.0°C / min. Pure water (1518.75 g, 84.38 mol) was added to the reactor via a high-pressure pump. The total water content in the system had a molar ratio of H2O / NaSH of 2.7. The second-stage polymerization was completed at 1.8 MPa and 260°C for 3 hours. After the completion of the second-stage polymerization, the conversion of p-dichlorobenzene was 99.3%.

[0118] 4. Capping stage

[0119] After the second stage polymerization, an alkali metal hydroxide aqueous solution (67.5 g, 1.6875 mol of sodium hydroxide and 1518.75 g, 84.38 mol of water) was immediately pumped into the reactor through a high-pressure pump, and the temperature was lowered to 200°C (i.e., the end-capping temperature) at a cooling rate of 2.0°C / min, and the reaction was carried out at a constant temperature for 60 minutes, and then the temperature was quickly lowered to 120°C.

[0120] 5. Post-processing stage

[0121] The product was sieved using an 80-mesh sieve, and the material on the sieve was centrifugally filtered. The filter cake was washed with acetone and filtered, and then washed with a hydrochloric acid solution and filtered. It was washed with boiling water four times, and the obtained granular polyarylene sulfide was dried at 120° C. for 8 hours.

[0122] Example 2

[0123] This example is basically the same as Example 1, except that the end-capping temperature in the end-capping stage is 180℃.

[0124] Example 3

[0125] This example is basically the same as Example 1, except that the end-capping temperature in the end-capping stage is 220℃.

[0126] Example 4

[0127] This example is basically the same as Example 1, except that the end-capping stage is reacted for 30 min at the end-capping temperature.

[0128] Example 5

[0129] This example is basically the same as Example 1, except that the end-capping stage is reacted for 120 min at the end-capping temperature.

[0130] Example 6

[0131] This example is basically the same as Example 1, except that the molar ratio of sodium hydroxide to sulfur source added in the end-capping stage is 0.05.

[0132] Comparative Example 1

[0133] This comparative example provides a method for preparing a polyarylene sulfide, which is basically the same as Example 1, except that there is no end-capping stage, and after the two-stage polymerization is completed, pure water (water 1518.75 g, 84.38 mol) is pumped into the reaction kettle through a high-pressure pump, and the temperature is lowered to 120℃ at a cooling rate of 2.0℃ / min.

[0134] Comparative Example 2

[0135] This comparative example provides a method for preparing a polyarylene sulfide, which is basically the same as Example 1, except that the constant temperature time in the end-capping stage is changed to 0 min, and after the alkali water is added, the temperature is lowered to 120℃ at a cooling rate of 2.0℃ / min.

[0136] The test data of each example and comparative example is shown in Table 1.

[0137] Table 1 Test data of examples and comparative examples

[0138]

[0139] As can be seen from the comparison of the examples and comparative examples in Table 1, the polyarylene sulfide provided by the present application has significantly reduced chlorine content, increased grain size, and significantly improved particle strength.

[0140] As can be seen from the comparison of Example 1 and Example 2, the end-capping temperature in the range of 200-220℃ can improve the reactivity and further reduce the chlorine content.

[0141] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A polyarylene sulfide, characterized in that Grain size The crystallinity of the polyarylene sulfide is less than 75%; The weight average molecular weight of the polyarylene sulfide is less than 55,000, and the mass content of chlorine element is less than 1,200 ppm.

2. The polyarylene sulfide according to claim 1, characterized in that The first repeating unit comprises the following formula (1): In formula (1), R1 and R2 are each independently selected from a hydrogen atom, a C1-C4 alkyl group, a nitro group, an amino group, a phenyl group, a methoxy group, and an ethoxy group; Preferably, the first repeating unit comprises and / or Preferably, R1 and R2 are arranged in the para position or the meta position on the benzene ring; Preferably, R1 and R2 are hydrogen atoms; Preferably, the first repeating unit comprises and / or 3. The polyarylene sulfide according to claim 2, characterized in that further comprising one or more of a second repeating unit, a third repeating unit, a fourth repeating unit, a fifth repeating unit, and a sixth repeating unit; The second repeating unit is shown in formula (4), The third repeating unit is shown in formula (5), The fourth repeating unit is shown in formula (6), The fifth repeating unit is shown in formula (7), The sixth repeating unit is shown in formula (8), The second repeating unit, the third repeating unit, the fourth repeating unit, the fifth repeating unit and the sixth repeating unit are all less than 10% of the total molar number of repeating units, preferably less than 3%.

4. The polyarylene sulfide according to claim 1, characterized in that The particle strength of the oversize obtained by passing through a 100-mesh sieve is above 85%.

5. A method for preparing polyarylene sulfide, characterized in that: The following steps are involved: S1, dehydration stage: heating a mixture of N-methylpyrrolidone, sulfur source, water and alkali metal hydroxide to remove part of the water in the system; S2, one-stage polymerization: after dehydration is completed, a mixture of dihalogen aromatic compound and N-methylpyrrolidone is added, and the temperature is raised to T1 to react to form a prepolymer; S3, second stage polymerization: After the first stage polymerization is completed, the temperature is continued to rise to T2, a phase separation agent is added, and the prepolymer is reacted under a certain pressure; S4, end-capping stage: after the second stage polymerization is completed, an alkali metal hydroxide aqueous solution is added, and then the reaction is carried out at an end-capping temperature of 150-240°C for 10-180 minutes; S5, post-processing stage: centrifuging the reaction slurry obtained in S4, washing the solids, and drying them.

6. The method for preparing polyarylene sulfide according to claim 5, characterized in that: The S4 satisfies at least one of the following conditions: (1) The alkali metal hydroxide includes one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, and francium hydroxide, preferably sodium hydroxide; (2) the molar ratio of the added alkali metal hydroxide to the sulfur source is 0.01-0.2, preferably 0.02-0.07; (3) The end-capping temperature is 200-220°C; (4) The reaction time is 30 to 90 minutes.

7. The method for preparing polyarylene sulfide according to claim 5 or 6, characterized in that: The S1 satisfies at least one of the following conditions: (1) The heating rate is 0.1 to 3.5°C / min, preferably 0.5 to 2.0°C / min; (2) The terminal temperature of the heating is 120 to 260°C, preferably 180 to 220°C; (3) The molar ratio of the residual water to the sulfur source in the dehydration stage is 0.5 to 3.0, preferably 0.8 to 1.8; (4) the molar ratio of the alkali metal hydroxide to the sulfur source is 0.8 to 2, preferably 0.9 to 1.5; (5) The molar ratio of N-methylpyrrolidone to sulfur source is 0.2 to 4.0, preferably 0.5 to 3; (6) The sulfur source is selected from lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide, lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, preferably sodium sulfide or sodium hydrosulfide; (7) The alkali metal hydroxide is selected from sodium hydroxide, calcium hydroxide, lithium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide; (8) The molar ratio of water to sulfur source is 1 to 20, preferably 4 to 10.

8. The method for preparing polyarylene sulfide according to claim 5 or 6, characterized in that: S2 satisfies at least one of the following conditions: (1) The molar ratio of the dihalogen aromatic compound to the sulfur source is 0.5 to 2.0, preferably 0.9 to 1.1; (2) T1 is 180-260°C, preferably 200-240°C; (3) After heating to temperature T1, react for 30 to 240 minutes, preferably 60 to 180 minutes; (4) The dihalogen aromatic compound includes one or more of o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, dichlorotoluene, dichlorobiphenyl, dichlorobenzoic acid, dichlorodiphenyl ether, dichlorodiphenyl sulfoxide, and dichlorobenzophenone.

9. The method for preparing polyarylene sulfide according to claim 5 or 6, characterized in that: S3 satisfies at least one of the following conditions: (1) T2 is 240-290°C, preferably 250-270°C; (2) The phase separation agent is selected from one or more of water, organic carboxylic acid metal salts, organic sulfonic acid metal salts, metal halides, alcohols and paraffinic hydrocarbons; Optionally, the organic carboxylic acid metal salt includes one or more of lithium acetate, sodium acetate, potassium acetate, sodium propionate, lithium valerate, lithium benzoate, sodium benzoate, sodium phenylacetate, and potassium p-methylbenzoate; Optionally, the organic sulfonic acid metal salt includes one or more of sodium p-toluenesulfonate, sodium dodecylbenzenesulfonate, calcium ligninsulfonate, and barium petroleum sulfonate; Optionally, the metal halide includes one or more of lithium chloride, potassium chloride, and sodium chloride; Optionally, the alcohols include one or more of ethylene glycol and xylitol; Optionally, the paraffinic hydrocarbons include one or more of n-octadecane, n-octacosane, and n-dotriacontane; (3) The reaction pressure is 0.2 to 3 MPa, preferably 0.5 to 2.5 MPa; (4) The reaction time after adding the phase separation agent is 0 to 300 min, preferably 30 to 240 min; (5) The molar ratio of the phase separation agent to the sulfur source is 0.1 to 5, preferably 0.2 to 3.

10. Use of the polyarylene sulfide according to any one of claims 1 to 4 or the polyarylene sulfide prepared according to the preparation method according to any one of claims 5 to 9 in the automotive industry, electronic appliances or environmental protection industry.

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