A modified polyphenylene sulfide and its synthesis method

Abstract

The invention relates to the technical field of polymer materials, and discloses a modified polyphenylene sulfide and a synthesis method thereof. By adding 0.5-2% of a potassium end group-containing polyaryletherketone (such as PEEK or PEEKK) during the synthesis of the polyphenylene sulfide, the potassium end group of the polyaryletherketone reacts with the chlorine end group of the polyphenylene sulfide during a heating and heat preservation treatment process, more chain extensions can be formed in a polycondensation reaction, and the directional growth of the chain can be ensured, thereby improving the orderly arrangement of polymer molecules and increasing the crystallinity of the polymer; the need to introduce oxygen into the polyphenylene sulfide to generate thermal oxidation crosslinking in the prior art can be avoided, so that the polyphenylene sulfide resin is modified and the polyphenylene sulfide resin has a linear structure, which is beneficial to the modification processing of the polyphenylene sulfide resin and the application of the polyphenylene sulfide resin, and at the same time, the electrical insulation of the polyphenylene sulfide resin in a humid environment is maintained.

Description

Technical Field

[0001] The invention relates to the technical field of polymer materials and discloses modified polyphenylene sulfide and a synthesis method thereof. Background Art

[0002] The crystallinity of polyphenylene sulfide refers to the degree of order in which its molecular chains are arranged in the solid state, that is, the integrity of the crystal structure. This is because the interactions and arrangements between polyphenylene sulfide molecular chains are different, resulting in different degrees of crystal structure formation and different crystallinity. The degree of crystallinity directly affects the thermal stability, mechanical properties, physical properties and chemical stability of polyphenylene sulfide, so it is one of the important physical properties of polyphenylene sulfide materials.

[0003] The crystallinity of polyphenylene sulfide prepared by the sodium sulfide method is relatively low, which makes the molecules of the polyphenylene sulfide material not arranged tightly, resulting in poor thermal stability of the material, and a decrease in strength, hardness and rigidity.

[0004] In the prior art, heat treatment is often used to improve the crystallinity of polyphenylene sulfide. However, the improvement of the crystallinity of polyphenylene sulfide obtained by this treatment method is limited and the energy consumption is relatively high. Summary of the invention

[0005] The object of the present invention is to provide a modified polyphenylene sulfide and a synthesis method thereof, which can ensure the directional growth of the chain, thereby improving the orderly arrangement of the polymer molecules and increasing the crystallinity of the polymer; it is beneficial to the modification processing of the polyphenylene sulfide resin and also to the application of the polyphenylene sulfide resin; at the same time, it also maintains the electrical insulation of the polyphenylene sulfide resin in a humid environment.

[0006] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0007] A modified polyphenylene sulfide is obtained by mixing a sodium sulfide solution, a polyaryletherketone containing a potassium end group and an N-methyl-2-pyrrolidone solution containing p-dichlorobenzene, heating and heat-insulating the mixture, and then sequentially flashing, acid washing, water washing, filtering and drying.

[0008] Furthermore, the molar concentration of the sodium sulfide solution in the raw material is between 0.5 and 0.6 mol / L, the molar ratio of p-dichlorobenzene to sodium sulfide is (1.05-1.15):1, the amount of the polyaryletherketone containing potassium end groups is 0.5-2.0% of the amount of p-dichlorobenzene, and the molar ratio of N-methyl-2-pyrrolidone to sodium sulfide is (3.0-3.8):1.

[0009] Furthermore, the polyaryletherketone containing potassium end groups is PEEK or PEEKK, or a mixture of the two.

[0010] In order to achieve the above technical effects, the present invention provides a method for synthesizing modified polyphenylene sulfide, which is used to prepare the modified polyphenylene sulfide, comprising:

[0011] Adding sodium hydroxide to a liquid sodium hydrosulfide aqueous solution and performing a dehydration treatment to obtain a sodium sulfide solution;

[0012] Mixing a liquid sodium sulfide solution with an N-methyl-2-pyrrolidone solution containing p-dichlorobenzene under protective gas conditions, and heating and heat-insulating the mixed solution to obtain a mixed solution containing polyphenylene sulfide resin;

[0013] The mixed solution containing the polyphenylene sulfide resin is flash-evaporated, acid-washed, and water-washed in sequence to obtain a suspension containing the polyphenylene sulfide resin mixture;

[0014] The suspension containing the polyphenylene sulfide resin mixture is filtered and dried to obtain a phenylene sulfide resin product.

[0015] Further, the step of adding sodium hydroxide to the liquid sodium hydrosulfide aqueous solution and performing a dehydration treatment to obtain a sodium sulfide solution comprises:

[0016] A 30-40%wt sodium hydrosulfide aqueous solution is added to a reaction kettle and heated to 80-90°C, and solid sodium hydroxide is added at a molar ratio of sodium hydrosulfide to sodium hydroxide of 1:(1.0-1.3), and the mixture is stirred and heated to raise the material temperature in the reaction kettle to 130-180°C. After the excess water is removed by heat preservation, the molar concentration of sodium sulfide is controlled between 0.5 and 0.6 mol / L.

[0017] Further, the steps of mixing the liquid sodium sulfide solution with the N-methyl-2-pyrrolidone solution containing p-dichlorobenzene under protective gas conditions and heating and heat-insulating the mixed solution include:

[0018] The air in the reaction kettle is replaced with nitrogen, and then an N-methyl-2-pyrrolidone solution containing p-dichlorobenzene and a dehydrated sodium sulfide solution are added to the reaction kettle; wherein the molar ratio of p-dichlorobenzene to sodium sulfide is (1.05-1.15):1, the amount of the polyaryletherketone containing potassium end groups is 0.5-2.0% of the amount of p-dichlorobenzene, and the molar ratio of N-methyl-2-pyrrolidone to sodium sulfide is (3.0-3.8):1;

[0019] After the reactor is sealed, the temperature of the mixed solution in the reactor is controlled to be 220-260°C, and nitrogen is continuously charged to make the pressure in the reactor range 8-20kg / cm 2 , keeping warm for 2 to 5 hours, then controlling the temperature in the reactor to 260-280°C and keeping warm for 3 to 4 hours to obtain a mixed solution containing polyphenylene sulfide resin.

[0020] Further, the mixed solution containing polyphenylene sulfide resin is flashed, acid-washed, and water-washed in sequence to obtain a suspension containing the polyphenylene sulfide resin mixture, comprising:

[0021] The mixed solution containing polyphenylene sulfide resin in the reactor is flashed out from the reactor over a period of 2 to 4 hours, and the evaporated material is condensed and transferred to the solvent;

[0022] Add hydrochloric acid solution to the solvent adsorbing the evaporated material, control the solution temperature range to 30-40°C, and stir and add a low-boiling point organic solvent to extract organic impurities;

[0023] Deionized water is added to the solution from which organic impurities have been removed for washing to obtain a suspension containing a polyphenylene sulfide resin mixture.

[0024] Furthermore, the steps of filtering and drying the suspension containing the polyphenylene sulfide resin mixture to obtain a polyphenylene sulfide resin product include:

[0025] The suspension containing the polyphenylene sulfide resin mixture is input into the fluidized bed for filtration and drying. The drying process is that the hot air temperature of the fluidized bed is 120-140°C, and the filtered material stays in the fluidized bed for 30-480 minutes, so that the fluidized bed dries the polyphenylene sulfide resin with a water content of less than 0.5%wt.

[0026] Compared with the prior art, the present invention has the following beneficial effects: by adding 0.5-2% of polyaryletherketone (such as PEEK or PEEKK) containing potassium end groups during the synthesis of polyphenylene sulfide, the potassium end groups of the polyaryletherketone react with the chlorine end groups of the polyphenylene sulfide during the heating and heat preservation treatment, more chain extensions can be formed in the polycondensation reaction, and the directional growth of the chain can be ensured, thereby improving the orderly arrangement of the polymer molecules and increasing the crystallinity of the polymer; the need to introduce oxygen into the polyphenylene sulfide to cause thermal oxidation crosslinking in the prior art can be avoided, so that the polyphenylene sulfide resin is modified and the polyphenylene sulfide resin has a linear structure, which is beneficial to the modification processing of the polyphenylene sulfide resin and the application of the polyphenylene sulfide resin, and at the same time, the electrical insulation of the polyphenylene sulfide resin in a humid environment is maintained. DETAILED DESCRIPTION

[0027] The present invention is further described in detail below in conjunction with the embodiments. However, it should not be understood that the scope of the above subject matter of the present invention is limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.

[0028] Example 1

[0029] A modified polyphenylene sulfide is obtained by mixing a sodium sulfide solution, a polyaryletherketone containing a potassium end group and an N-methyl-2-pyrrolidone solution containing p-dichlorobenzene, heating and heat-insulating the mixture, and then sequentially flashing, acid washing, water washing, filtering and drying.

[0030] In this embodiment, polyphenylene sulfide is obtained by a polycondensation reaction after sodium sulfide and p-dichlorobenzene undergo a substitution reaction in a polar solvent. By adding 0.5-2% p-dichlorobenzene to a potassium-terminated polyaryletherketone (such as PEEK or PEEKK) during the synthesis of polyphenylene sulfide, the potassium end group of the polyaryletherketone reacts with the chlorine end group of the polyphenylene sulfide during the heating and heat preservation treatment, more chain extensions can be formed in the polycondensation reaction, and the directional growth of the chain can be ensured, thereby improving the orderly arrangement of the polymer molecules and increasing the crystallinity of the polymer; the need to introduce oxygen into the polyphenylene sulfide in the prior art to cause thermal oxidation crosslinking can be avoided, so that the polyphenylene sulfide resin is modified and the polyphenylene sulfide resin is linearly structured, which is beneficial to the modification and processing of the polyphenylene sulfide resin and the application of the polyphenylene sulfide resin. At the same time, the electrical insulation of the polyphenylene sulfide resin in a humid environment is maintained, which is beneficial to the modification and processing and application of the polyphenylene sulfide resin.

[0031] Example 2

[0032] A method for synthesizing modified polyphenylene sulfide comprises the following process steps:

[0033] Step 1, adding sodium hydroxide to a liquid sodium hydrosulfide aqueous solution, and performing a dehydration treatment to obtain a sodium sulfide solution;

[0034] In this embodiment, a 30%wt sodium hydrosulfide aqueous solution is added to a reactor and heated to 85±2°C, solid sodium hydroxide is added at a molar ratio of sodium hydrosulfide to sodium hydroxide of 1:1.0, and the mixture is stirred and heated to raise the material temperature in the reactor to 160°C. After the excess water is removed by heat preservation, the molar concentration of sodium sulfide is controlled to be between 0.6 mol / L to obtain a sodium sulfide solution.

[0035] Step 2: Mixing a liquid sodium sulfide solution, a polyaryletherketone containing a potassium end group, and an N-methyl-2-pyrrolidone solution containing p-dichlorobenzene under protective gas conditions, and heating and heat-insulating the mixed solution to obtain a mixed solution containing a polyphenylene sulfide resin;

[0036] In this embodiment, the air in the reactor is replaced with nitrogen, and then PEEK containing potassium end groups, N-methyl-2-pyrrolidone solution containing p-dichlorobenzene, and sodium sulfide solution after dehydration are added to the reactor; wherein the molar ratio of p-dichlorobenzene to sodium sulfide is 1.1:1, the amount of PEEK is 1.0% of the amount of p-dichlorobenzene, and the molar ratio of N-methyl-2-pyrrolidone to sodium sulfide is 3.0:1;

[0037] After sealing the reactor, control the temperature of the mixed solution in the reactor to 240±5℃, and continuously fill it with nitrogen to make the pressure in the reactor range 15kg / cm 2 , keeping warm for 5 hours, then controlling the temperature in the reactor to 270±5°C and keeping warm for 4 hours to obtain a mixed solution containing polyphenylene sulfide resin.

[0038] Step 3, flash evaporating, acid washing, and water washing the mixed solution containing the polyphenylene sulfide resin in sequence to obtain a suspension containing the polyphenylene sulfide resin mixture;

[0039] In this embodiment, the mixed solution containing polyphenylene sulfide resin in the reactor is flashed out from the reactor over a period of 4 hours, and the evaporated material is condensed and transferred to the solvent;

[0040] Add hydrochloric acid solution to the solvent adsorbing the evaporated material, control the solution temperature range to 35±2°C, and add low-boiling point organic solvent to extract organic impurities while stirring;

[0041] Deionized water is added to the solution from which organic impurities have been removed for washing to obtain a suspension containing a polyphenylene sulfide resin mixture.

[0042] Step 4: Filter and dry the suspension containing the polyphenylene sulfide resin mixture to obtain a polyphenylene sulfide resin product.

[0043] In this embodiment, a suspension containing a polyphenylene sulfide resin mixture is input into a fluidized bed for filtration and drying. The drying process is that the hot air temperature of the fluidized bed is 130±5°C, and the filtered material stays in the fluidized bed for 120 minutes, so that the fluidized bed is dried into a polyphenylene sulfide resin with a water content of less than 0.5%wt.

[0044] The modified polyphenylene sulfide prepared in this embodiment and the polyphenylene sulfide synthesized by the conventional method were subjected to differential scanning calorimetry (DSC) analysis, and the crystallinity of the two polyphenylene sulfides was analyzed. The conventional method in this embodiment synthesized polyphenylene sulfide by mixing a sodium sulfide solution with an N-methyl-2-pyrrolidone solution containing p-dichlorobenzene, heating and heat preservation, and then flashing, acid washing, water washing, filtering, and drying in sequence.

[0045] The DSC analysis process is as follows: take 5-10 mg of two PPS material samples respectively, place each PPS sample in an aluminum crucible, and then place the aluminum crucible and the reference crucible together in a differential scanning calorimeter, and test and characterize the crystallinity of the PPS samples prepared by the two methods in a nitrogen atmosphere, with a nitrogen flow rate of 10 mL / min. The temperature control program is: first increase from room temperature (20°C) to 340°C, with a heating rate of 10°C / min, and keep the temperature constant for 10 minutes; then reduce to room temperature (20°C) at a rate of 10°C / min, record the sample DSC heating curve, and calculate the melting heat ΔH of the corresponding PPS sample according to the melting peak area of ​​the DSC heating curve of the corresponding PPS sample m , from which the PPS crystallinity can be calculated The calculated crystallinity data results are shown in Table 1; wherein ΔH0 is the melting enthalpy of PPS under the condition of 100% crystallization, and in this embodiment, ΔH0=80 J / g.

[0046] Example 3

[0047] A method for synthesizing modified polyphenylene sulfide comprises the following process steps:

[0048] Step 1: add 30%wt sodium hydrosulfide aqueous solution to a reactor and heat to 85±2°C, add sodium hydroxide solid at a molar ratio of sodium hydrosulfide: sodium hydroxide of 1:1.0, stir and heat until the material temperature in the reactor rises to 160°C, keep warm to remove excess water, and control the molar concentration of sodium sulfide between 0.6 mol / L to obtain a sodium sulfide solution.

[0049] Step 2, replacing the air in the reactor with nitrogen, and then adding PEEKK containing potassium end groups, N-methyl-2-pyrrolidone solution containing p-dichlorobenzene, and dehydrated sodium sulfide solution into the reactor; wherein the molar ratio of p-dichlorobenzene to sodium sulfide is 1.1:1, the amount of PEEKK is 1.0% of the amount of p-dichlorobenzene, and the molar ratio of N-methyl-2-pyrrolidone to sodium sulfide is 3.0:1;

[0050] After sealing the reactor, control the temperature of the mixed solution in the reactor to 240±5℃, and continuously fill it with nitrogen to make the pressure in the reactor range 15kg / cm 2 , keeping warm for 5 hours, then controlling the temperature in the reactor to 270±5°C and keeping warm for 4 hours to obtain a mixed solution containing polyphenylene sulfide resin.

[0051] Step 3: flash the mixed solution containing polyphenylene sulfide resin in the reactor from the reactor for 4 hours, and condense the evaporated material and transfer it to the solvent;

[0052] Add hydrochloric acid solution to the solvent adsorbing the evaporated material, control the solution temperature range to 35±2°C, and add low-boiling point organic solvent to extract organic impurities while stirring;

[0053] Deionized water is added to the solution from which organic impurities have been removed for washing to obtain a suspension containing a polyphenylene sulfide resin mixture.

[0054] Step 4: Input the suspension containing the polyphenylene sulfide resin mixture into a fluidized bed for filtration and drying. The drying process is that the hot air temperature of the fluidized bed is 130±5°C, and the filtered material stays in the fluidized bed for 120 minutes, so that the fluidized bed dries the polyphenylene sulfide resin with a water content of less than 0.5%wt.

[0055] Comparative Example

[0056] The modified polyphenylene sulfide prepared in Example 2 and Example 3 and the polyphenylene sulfide control sample synthesized by the conventional method were subjected to differential scanning calorimetry (DSC) analysis, and the crystallinity of the two polyphenylene sulfides was analyzed. The conventional method in this embodiment synthesized polyphenylene sulfide by mixing a sodium sulfide solution with an N-methyl-2-pyrrolidone solution containing p-dichlorobenzene, heating and heat preservation treatment, and then flashing, acid washing, water washing, filtering, and drying in sequence.

[0057] The DSC analysis process is as follows: take 5-10 mg of two PPS material samples respectively, place each PPS sample in an aluminum crucible, and then place the aluminum crucible and the reference crucible together in a differential scanning calorimeter, and test and characterize the crystallinity of the PPS samples prepared by the two methods in a nitrogen atmosphere, with a nitrogen flow rate of 10 mL / min. The temperature control program is: first increase from room temperature (20°C) to 340°C, with a heating rate of 10°C / min, and keep the temperature constant for 10 minutes; then reduce to room temperature (20°C) at a rate of 10°C / min, record the sample DSC heating curve, and calculate the melting heat ΔH of the corresponding PPS sample according to the melting peak area of ​​the DSC heating curve of the corresponding PPS sample m , from which the PPS crystallinity can be calculated The calculated crystallinity data results are shown in Table 1; wherein ΔH0 is the melting enthalpy of PPS under the condition of 100% crystallization, and in this embodiment, ΔH0=80 J / g.

[0058] sample <![CDATA[ΔH m (J / g)]]> Crystallinity(%) Example 2 61.8 77.2 Example 3 59.4 74.2 Control 43.3 54.1

[0059] From the above data, it can be seen that the crystallinity of the modified polyphenylene sulfide is above 74.2%. The reason is that after depolymerization, the polyaryletherketone containing potassium end groups produces thermal oxidation crosslinking with the polyphenylene sulfide, thereby improving the orderliness of the arrangement of the polymer molecules and increasing the crystallinity of the polymer.

[0060] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A modified polyphenylene sulfide, characterized in that: The modified polyphenylene sulfide is obtained by mixing a sodium sulfide solution, a polyaryletherketone containing a potassium end group and an N-methyl-2-pyrrolidone solution containing p-dichlorobenzene, heating and heat preservation treatment, and then sequentially flashing, acid washing, water washing, filtering and drying; wherein the molar concentration of the sodium sulfide solution in the raw material is between 0.5 and 0.6 mol / L, the molar ratio of the amount of p-dichlorobenzene to the amount of sodium sulfide is (1.05 to 1.15):1, the amount of the polyaryletherketone containing a potassium end group is 0.5 to 2.0% of the amount of p-dichlorobenzene, and the molar ratio of N-methyl-2-pyrrolidone to the amount of sodium sulfide is (3.0 to 3.8):

1.

2. The modified polyphenylene sulfide according to claim 1, characterized in that The polyaryletherketone containing potassium end groups is PEEK or PEEKK or a mixture of the two.

3. A method for synthesizing modified polyphenylene sulfide, the method being used to prepare the modified polyphenylene sulfide according to any one of claims 1 or 2, characterized in that: include: Adding sodium hydroxide to a liquid sodium hydrosulfide aqueous solution and performing a dehydration treatment to obtain a sodium sulfide solution; A liquid sodium sulfide solution, a polyaryletherketone containing a potassium end group and an N-methyl-2-pyrrolidone solution containing p-dichlorobenzene are mixed under protective gas conditions, and the mixed solution is heated and heat-insulated to obtain a mixed solution containing polyphenylene sulfide resin; wherein the molar concentration of the sodium sulfide solution is between 0.5 and 0.6 mol / L, the molar ratio of the amount of p-dichlorobenzene to the amount of sodium sulfide is (1.05 to 1.15):1, the amount of the polyaryletherketone containing a potassium end group is 0.5 to 2.0% of the amount of p-dichlorobenzene, and the molar ratio of N-methyl-2-pyrrolidone to the amount of sodium sulfide is (3.0 to 3.8):1; The mixed solution containing the polyphenylene sulfide resin is flash-evaporated, acid-washed, and water-washed in sequence to obtain a suspension containing the polyphenylene sulfide resin mixture; The suspension containing the polyphenylene sulfide resin mixture is filtered and dried to obtain a phenylene sulfide resin product.

4. The method for synthesizing modified polyphenylene sulfide according to claim 3, characterized in that: The step of adding sodium hydroxide to a liquid sodium hydrosulfide aqueous solution and performing a dehydration treatment to obtain a sodium sulfide solution comprises: A 30-40%wt sodium hydrosulfide aqueous solution is added to a reaction kettle and heated to 80-90°C, and solid sodium hydroxide is added at a molar ratio of sodium hydrosulfide to sodium hydroxide of 1:(1.0-1.3), and the mixture is stirred and heated to raise the material temperature in the reaction kettle to 130-180°C. After the excess water is removed by heat preservation, the molar concentration of sodium sulfide is controlled between 0.5 and 0.6 mol / L.

5. The method for synthesizing modified polyphenylene sulfide according to claim 3, characterized in that: The steps of mixing a liquid sodium sulfide solution, a polyaryletherketone containing a potassium end group, and an N-methyl-2-pyrrolidone solution containing p-dichlorobenzene under a protective gas condition, and heating and heat-insulating the mixed solution include: The air in the reaction kettle is replaced with nitrogen, and then polyaryletherketone containing potassium end groups, N-methyl-2-pyrrolidone solution containing p-dichlorobenzene, and dehydrated sodium sulfide solution are added into the reaction kettle; After the reactor is sealed, the temperature of the mixed solution in the reactor is controlled to be 220-260°C, and nitrogen is continuously charged to make the pressure in the reactor range 8-20kg / cm 2 , keeping warm for 2 to 5 hours, then controlling the temperature in the reactor to 260-280°C and keeping warm for 3 to 4 hours to obtain a mixed solution containing polyphenylene sulfide resin.

6. The method for synthesizing modified polyphenylene sulfide according to claim 3, characterized in that: The steps of flash evaporating, acid washing and water washing the mixed solution containing polyphenylene sulfide resin in sequence to obtain a suspension containing the polyphenylene sulfide resin mixture include: The mixed solution containing polyphenylene sulfide resin in the reactor is flashed out from the reactor over a period of 2 to 4 hours, and the evaporated material is condensed and transferred to the solvent; Add hydrochloric acid solution to the solvent adsorbing the evaporated material, control the solution temperature range to 30-40°C, and stir and add a low-boiling point organic solvent to extract organic impurities; Deionized water is added to the solution from which organic impurities have been removed for washing to obtain a suspension containing a polyphenylene sulfide resin mixture.

7. The method for synthesizing modified polyphenylene sulfide according to claim 3, characterized in that: The steps of filtering and drying the suspension containing the polyphenylene sulfide resin mixture to obtain a polyphenylene sulfide resin product include: The suspension containing the polyphenylene sulfide resin mixture is input into the fluidized bed for filtration and drying. The drying process is that the hot air temperature of the fluidized bed is 120-140°C, and the filtered material stays in the fluidized bed for 30-480 minutes, so that the fluidized bed dries the polyphenylene sulfide resin with a water content of less than 0.5%wt.