Method for determining real molecular weight of PPS resin by using gel chromatograph

Abstract

The invention discloses a method for determining the real molecular weight of PPS (polyphenylene sulfide) by using a gel chromatograph, which comprises the following steps: 1) mixing PPS resin, an oxidant A, an auxiliary agent and 1-chloronaphthalene, and carrying out reflux reaction at the temperature not lower than 190 DEG C; 2) standing the reaction liquid after the reaction in the step 1) to room temperature, and adding an organic solvent and an oxidizing agent B for reflux reaction; the reflux reaction temperature is lower than the boiling point of the organic solvent; (3) adding water into the reaction liquid after the reaction in the step (2), standing, separating the liquid, and taking an organic phase layer, so as to obtain a PPS derivative solution; (4) testing the PPS derivative solution prepared in the step (3) by adopting a triple detector GPC and taking the organic solvent in the step (2) as a mobile phase to obtain the molecular weight of the derivatized PPS, and then calculating to obtain the real molecular weight of the PPS resin.According to the method, the real molecular weight of the PPS is tested through the normal-temperature GPC, and the PPS is detected and analyzed through the GPC for the first time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of material analysis and detection, and particularly relates to a method for measuring real molecular weight of PPS resin by using a gel chromatograph. BACKGROUND

[0002] The triple detector gel chromatograph (GPC) refers to a GPC device equipped with differential refractometer (RI), light scattering (LS) and viscosity (VS) three detectors. It can not only measure and calculate the real molecular weight of polymers at normal temperature, but also measure the size and branching degree of polymers, which has important significance for in-depth understanding of the molecular behavior of polymers in solution.

[0003] Polyphenylene sulfide (PPS) is a new type of high-performance thermoplastic resin, which has high thermal stability, good chemical corrosion resistance, excellent electrical properties and other characteristics, and is widely used in electronic, automobile, mechanical and chemical fields. PPS has excellent resistance to most acids (such as hydrochloric acid and phosphoric acid), bases, esters, alcohols, aliphatic hydrocarbons and aromatic hydrocarbons, and shows good resistance to organic solvents. PPS is insoluble in any organic reagent at room temperature and can be dissolved in 1-chloronaphthalene at 200℃ or above. The molecular weight of PPS cannot be analyzed and detected by normal temperature GPC, which greatly limits the detection method of PPS molecular weight.

[0004] At present, high-temperature GPC can test the molecular weight of PPS, but this test has great defects. On the one hand, the high-temperature GPC runs at 200℃ or above from the sample injection system to the detection system. Under this condition, the current detection system can only be equipped with a single concentration detector, the differential (RI) detector. The PPS molecular weight obtained by the single RI detector is actually a conversion based on the comparison technique, which is not the real molecular weight of PPS. It is impossible to understand the structural characteristics of PPS, such as PPS molecular solution behavior and branching degree, by using a single differential detector. This requires the use of multiple detectors (such as viscosity detector and light scattering detector) together. On the other hand, the mobile phase 1-chloronaphthalene used for detection has high toxicity and high price. This not only requires a high level laboratory, but also inevitably causes potential harm to the operator. Moreover, the modules of GPC need to run at 200℃ or above, which will reduce the service life of the instrument, increase the use frequency of consumables, and especially shorten the service time of the chromatographic column. SUMMARY

[0005] In view of the defects of the prior art, the present application discloses a method for measuring the real molecular weight of PPS resin by using a gel chromatograph. By converting the polyphenylene sulfide insoluble in chemical reagents into soluble polyphenyl sulfone, the real molecular weight of PPS resin is tested by using normal temperature GPC for the first time, and the method for GPC multiple detection analysis of PPS is realized.

[0006] The specific technical solution is as follows:

[0007] A method for determining the real molecular weight of PPS resin by using a gel chromatograph, comprising the following steps:

[0008] 1) mixing PPS resin, oxidant A, auxiliary agent and 1-chloronaphthalene, and performing reflux reaction at not less than 190 DEG C;

[0009] 2) placing the reaction liquid after the reaction in step 1) to room temperature, adding organic solvent and oxidant B to perform reflux reaction;

[0010] The temperature of the reflux reaction is lower than the boiling point of the organic solvent;

[0011] 3) adding water to the reaction liquid after the reaction in step 2), and after standing and separating, taking the organic phase layer in the liquid to obtain PPS derivative solution;

[0012] 4) using a triple detector GPC, taking the organic solvent in step 2) as the mobile phase, testing the PPS derivative solution prepared in step 3), obtaining the molecular weight of the derivatized PPS, and then calculating the real molecular weight of the PPS resin.

[0013] The preparation method disclosed in the application converts the Ph-S-Ph chemical bond in PPS into Ph-SO2-Ph through two-step oxidation reaction by adding different oxidants step by step, so that the polyphenylene sulfide which is insoluble in chemical reagents at room temperature is converted into soluble polyphenylene sulfone, and the reaction equation is as follows:

[0014] .

[0015] The real molecular weight of PPS is obtained by GPC analysis and testing of the derivatized PPS. The testing method is simple, efficient and low in testing cost, and has important guiding significance for studying the reaction mechanism and modified application of PPS.

[0016] In the method, the first-step oxidation reaction uses inorganic strong oxidant, and the second-step oxidation reaction uses organic strong oxidant, and the two-step oxidation can ensure that the Ph-S-Ph chemical bond in PPS is completely converted into Ph-SO2-Ph. It is found through experiments that if only the first-step oxidation reaction is used, the molecular weight of the obtained PPS resin is quite different from the real molecular weight; even if the time of the first-step oxidation reaction is prolonged or the temperature of the first-step oxidation reaction is increased, the above result cannot be changed.

[0017] It is also found through experiments that the temperature of the first-step oxidation reaction should be not less than 190 DEG C, and the reaction time should be not less than 2h, and if the temperature is too low or the time is too short, the molecular weight of the obtained PPS resin will be quite different from the real molecular weight.

[0018] In step 1) :

[0019] Preferably, the oxidant A is selected from one or more of sodium bismuthate, potassium dichromate, potassium permanganate;

[0020] The auxiliary agent is selected from one or more of 4-chlorobenzenesulfonic acid, oxalic acid, methanesulfonic acid;

[0021] The auxiliary agent is selected from one or more of 4-chlorobenzenesulfonic acid, oxalic acid, methanesulfonic acid;

[0022] In the present application, the oxidant A and the auxiliary agent have certain matching properties. When the oxidant A is selected from sodium bismuthate, the optimal auxiliary agent is selected from 4-chlorobenzenesulfonic acid; when the oxidant A is selected from potassium dichromate, the optimal auxiliary agent is oxalic acid; when the oxidant A is selected from potassium permanganate, the optimal auxiliary agent is selected from methanesulfonic acid.

[0023] Preferably, the oxidant A is selected from one or more of sodium bismuthate, potassium dichromate, potassium permanganate;

[0024] The mass ratio of PPS resin to oxidant A is 1: (1.5-2.5);

[0025] The mass ratio of oxidant A to auxiliary agent is 1: (0.8-1.2);

[0026] The mass-volume ratio of PPS resin to 1-chloronaphthalene is 1: (180-220) g / mL.

[0027] Further preferably, the oxidant A is selected from one or more of sodium bismuthate, potassium dichromate, potassium permanganate;

[0028] The mass ratio of PPS resin to oxidant A is 1:2;

[0029] The mass ratio of oxidant A to auxiliary agent is 1:1;

[0030] The mass-volume ratio of PPS resin to 1-chloronaphthalene is 1: (190-200) g / mL.

[0031] Preferably, the reaction temperature is 190-250℃, and the reaction time is not less than 2h.

[0032] Further preferably, the reaction temperature is 200-220℃.

[0033] In step 2) :

[0034] Preferably, the oxidant B is selected from one or more of magnesium monoperoxysuccinate hexahydrate, peroxydodecanoic acid, and peroxybenzoic acid;

[0035] It has been found through experiments that the organic oxidant used in the second step of oxidation has special properties. If dimethyl dioxolane or N-methyl morpholine oxide is used instead, the molecular weight of the obtained PPS resin will be significantly different from the true molecular weight.

[0036] Preferably, the organic solvent is selected from polyphenylsulfone, a nonpolar good solvent, specifically one or more of chloroform, toluene, and cyclohexane.

[0037] Preferably, the temperature difference between the reflux reaction temperature in step 2) and the boiling point of the organic solvent is approximately 10°C.

[0038] Preferred:

[0039] In step 1), the mass ratio of PPS resin to oxidant B is 1:(1.8~2.2); more preferably 1:2.

[0040] The volume ratio of the organic solvent to 1-chloronaphthalene in step 1) is (4~8):1; more preferably 5:1.

[0041] In step 4):

[0042] Preferably, the test:

[0043] The chromatographic column was selected from Plgel MIXED-B column;

[0044] The flow rate was selected from 0.8 to 1.5 mL / min;

[0045] The column temperature is selected from 25~35℃.

[0046] The specific formula for the calculation is as follows:

[0047] .

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] This invention discloses a method for determining the true molecular weight of PPS using gel permeation chromatography (GPC). The method involves a two-step oxidation process to convert chemically insoluble polyphenylene sulfide (PPS) into soluble polyphenylene sulfone (PPS). This is the first time that the true molecular weight of PPS resin can be obtained at room temperature using a triple detector (GPC). This testing method is simple, efficient, uses a small amount of 1-chloronaphthalene without harming the test personnel, and has low testing costs. It provides important guidance for studying the reaction mechanism and modified applications of PPS. Attached Figure Description

[0050] Figure 1 The Fourier transform infrared (FT-IR) spectrum of the PPS resin raw material used in Example 1 is shown below.

[0051] Figure 2 The Fourier transform infrared (FT-IR) spectrum of the derivatized PPS resin prepared in step 1.4 of Example 1 is shown below.

[0052] Figure 3The total ion current (PY-GCMS-TIC) spectrum of the PPS resin raw material used in Example 1 is obtained from the thermal decomposition gas chromatography-mass spectrometry.

[0053] Figure 4 The image shows the total ion current (PY-GCMS-TIC) spectrum of the derivatized PPS resin prepared in step 1.4 of Example 1.

[0054] Figure 5 The images show the chromatogram (top) and a magnified view (bottom) of the PPS derivatized solution obtained by GPC testing with a triple detector in step 1.5 of Example 1. In the images, line 1 represents the LS detector, line 2 represents the VS detector, and line 3 represents the RI detector; the first chromatographic peak (RT=12~16min) represents the sample peak, and the second chromatographic peak (RT=20~22min) represents the solvent peak.

[0055] Figure 6 This is a molecular weight distribution diagram of the PPS-derived solution obtained by GPC testing with a triple detector in step 1.5 of Example 1, where 1 represents the differential distribution curve of molecular weight, with the vertical axis on the left, and 2 represents the integral distribution curve of molecular weight, with the vertical axis on the right.

[0056] Figure 7 The image shows the Mark-Houwink spectrum of the derivatized PPS resin obtained in step 1.4 of Example 1.

[0057] Figure 8 This is a molecular conformation diagram of the derivatized PPS resin obtained in step 1.4 of Example 1. Detailed Implementation

[0058] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0059] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0060] The PPS resin raw material used was the 3450 specification produced by Zhejiang Xinhecheng Special Materials Co., Ltd., and the PPS raw materials used in the examples were all of the same specification.

[0061] Example 1

[0062] 1.1 Accurately measure 0.0525 g of PPS resin, add 10 mL of 1-chloronaphthalene, 0.1002 g of 4-chlorobenzenesulfonic acid, and 0.1005 g of sodium bismuthate to a 100 mL flask, and reflux at 200 °C for 2 h.

[0063] 1.2 After the reaction is complete, let the reaction solution from 1.1 stand at room temperature, then add 50 mL of chloroform and 0.1002 g of magnesium monoperoxyphthalate hexahydrate (MMPP), and reflux at 50 °C for 1 h.

[0064] 1.3 Add 50 mL of aqueous solution to the reaction solution in 1.2, let it stand and separate the layers, and take the lower organic phase from the liquid.

[0065] 1.4 The organic phase was divided into two portions. 5 mL of one portion was filtered through a 0.45 μm filter membrane to obtain a PPS derivatization solution, which was then loaded onto a GPC sample for later use. The remaining organic phase was vacuum dried at 150 °C to constant weight to obtain the derivatized PPS resin.

[0066] 1.5 The PPS derivatized solution obtained in 1.4 was subjected to GPC (RI+LS+VS) triple detector testing, with polystyrene (PS) used as the calibration curve; the test conditions are as follows:

[0067] Mobile phase: chloroform;

[0068] Column: PL 10μm MIXED-B300×7.5mm;

[0069] Flow rate: 1 mL / min;

[0070] Column temperature: 30℃;

[0071] Detectors: RI+LS+VS;

[0072] Injection volume: 100 μL.

[0073] The PPS resin raw material and the derivatized PPS obtained in section 1.4 were characterized by FT-IR, and the infrared spectra were obtained as follows: Figure 1 (PPS resin) and Figure 2 (Derivatized PPS resin) is shown.

[0074] Depend on Figure 1 The FT-IR spectrum of PPS resin shows that at 3050 cm⁻¹... -1 The absorption peak is the CH stretching vibration of the benzene ring, at 1469 cm⁻¹. -1 and 1571cm -1 The absorption peak is the stretching vibration of the benzene ring, at 1090 cm⁻¹. -1 1072cm -1 1007cm -1The absorption peak is due to the deformation vibration of the benzene ring, at 804 cm⁻¹. -1 This is a characteristic peak of para-substitution of the benzene ring.

[0075] Depend on Figure 2 The FT-IR spectrum of the derivatized PPS resin shows that at 3056 cm⁻¹ -1 The absorption peak is the CH stretching vibration of the benzene ring, at 1485 cm⁻¹. -1 1502cm -1 and 1582cm -1 The absorption peak is the stretching vibration of the benzene ring, at 1101 cm⁻¹. -1 1078cm -1 1012cm -1 The absorption peak is due to the deformation vibration of the benzene ring, at 872 cm⁻¹. -1 852cm -1 830cm -1 This is a characteristic peak for para-substitution of the benzene ring. 1146 cm⁻¹ -1 1167cm -1 and 1293cm -1 1321cm -1 The absorption peaks of the two w groups are characteristic infrared peaks of the symmetric and asymmetric stretching vibrations of the sulfone group. Due to the influence of the sulfone group, the stretching vibration peak of the benzene ring and the characteristic peak of para-substitution show a bifurcation of absorption peaks.

[0076] FT-IR results showed that obvious sulfone functional groups appeared in the derivatized PPS resin, and no infrared characteristic absorption peak of CO functional groups was detected, indicating that the derivatization effect of PPS was good. The derivatization reaction not only oxidized Ph-S-Ph in PPS to Ph-SO2-Ph, but also accurately targeted the derivatization without oxidation reactions occurring at other positions of the benzene ring.

[0077] The PPS resin raw material and the derivatized PPS resin obtained in section 1.4 were characterized by PY-GCMS under the following test conditions:

[0078] Thermolytic temperature: 600℃;

[0079] Thermolysis time: 5 min;

[0080] Column: DB-5 (60*0.25mm, 0.25μm);

[0081] Flow rate: 1.0 mL / min;

[0082] Inlet temperature: 340℃;

[0083] Column temperature: 40℃ for 5 min, then increase to 300℃ at a rate of 10℃ / min and hold for 14 min;

[0084] Ion source temperature: 320℃;

[0085] Transmission line temperature: 320℃;

[0086] Scan range: 15~550;

[0087] Sample size: 0.4 mg;

[0088] Split ratio: 200:1.

[0089] The PY-GCMS-TIC spectra of PPS resin and derivatized PPS resin obtained under the above conditions are shown below. Figure 3 and Figure 4 As shown in Tables 1 and 2, the thermal decomposition components of PPS resin and derivatized PPS resin were obtained by analyzing the test spectra of PY-GCMS.

[0090] Table 1. Overview of PPS Resin's Pyrolytic Components

[0091]

[0092] Table 2. Summary of the thermal decomposition components of derivatized PPS resin

[0093]

[0094]

[0095] As shown in Table 1, after high-temperature pyrolysis, the main pyrolysis components of PPS are thiophenol, phenyl sulfide, and polyphenyl sulfide, which are monomers and polymers of PPS polymers.

[0096] As shown in Table 2, after high-temperature pyrolysis, the derivatized PPS mainly consists of sulfur dioxide, benzene, diphenyl sulfone, and polyphenyl sulfone, etc. There are no PPS monomers such as thiophenol and phenyl sulfide, nor are there any components containing sulfoxide groups.

[0097] As can be seen from the results in Tables 1 and 2, after the derivatization reactions in Examples 1.1 and 1.2, the repeating unit of PPS resin has been changed from phenyl sulfide to phenyl sulfone, and PPS resin has been oxidized into polyphenyl sulfone that is easily soluble in chloroform.

[0098] The test results of FT-IR and PY-GCMS show that the derivatization reaction in this embodiment is sufficient and complete, in which the main functional group Ph-S-Ph of PPS can be completely transformed into Ph-SO2-Ph.

[0099] Figure 5 The image shows the chromatogram of the PPS-derived solution obtained by GPC testing with a triple detector in section 1.5. Figure 6The molecular weight distribution of the PPS-derived solution obtained from the test is shown in Table 3. The true molecular weight of the PPS-derived solution obtained by the triple detector is shown in Table 3.

[0100] Table 3. Summary of the true molecular weight of PPS-derived solutions

[0101]

[0102] Where Mp is the peak molecular weight, Mn is the number-average molecular weight, Mw is the weight-average molecular weight, Mz is the Z-average molecular weight, Mv is the viscosity-average molecular weight, and PD is the polydispersity index.

[0103] During PPS derivatization, the monomer is transformed from phenyl sulfide to phenyl sulfone. Since the derivatization reaction introduces no other functional groups besides the sulfone group, and the derivatization reaction is thorough and complete, the reaction equation (I) is shown below based on the reaction relationship during PPS derivatization. Dividing the molecular weight of the derivatized PPS resin in Table 3 by 140 and then multiplying by 108 yields the true molecular weight of the PPS resin, as shown in Table 4.

[0104] (I)

[0105] in: (n=1, PPS resin monomer M) W =108, M of the derivatized PPS resin monomer W =140).

[0106] Table 4. Summary of the True Molecular Weight of PPS Resin

[0107]

[0108] The GPC (RI+LS+VS) test results can not only obtain the true molecular weight of PPS resin, but also analyze and characterize the conformation and structure of PPS resin molecules. Figure 7 and Figure 8 The images show the Mark-Houwink spectrum and molecular conformation diagram of the derivatized PPS resin, respectively. The Mark-Houwink spectrum reflects the relationship between intrinsic viscosity and molecular weight, while the molecular conformation diagram reflects the relationship between molecular size and molecular weight. Both provide information on polymer molecular dynamics in solution and are a good way to understand the solution behavior of polymer molecules.

[0109] Although the structures of derivatized PPS resin and PPS resin itself differ slightly, they still hold significant reference value for evaluating PPS models. Furthermore, the molecular models obtained from the characterization of derivatized PPS provide a valuable reference standard for cross-sectional comparisons of molecular models of different specifications and types of PPS resins.

[0110] Comparative Example 1

[0111] Accurately weigh 0.05g of PPS resin, use polystyrene (PS) as a calibration curve, and obtain its molecular weight using high-temperature GPC (RI), as shown in Table 5.

[0112] Table 5. Molecular Weight of PPS Resin (High Temperature GPC)

[0113]

[0114] Compared to the results in Example 1, the molecular weight obtained by the high-temperature GPC test is smaller than the actual molecular weight. This is because any sphere formed by the entanglement of PPS of a specific molecular weight in a 1-chloronaphthalene solution will be smaller than that of PS of the same molecular weight. Therefore, if the high-temperature GPC system is calibrated with PS standards to analyze PPS, the calculated results for all PPS samples will be lower because the molecules eluted on the column are treated as smaller PS molecules.

[0115] Comparative Example 2

[0116] 1.1 Accurately measure 0.0525 g of PPS resin, add 10 mL of 1-chloronaphthalene, 0.1002 g of 4-chlorobenzenesulfonic acid, and 0.1005 g of sodium bismuthate to a 100 mL flask, and reflux at 200 °C for 2 h.

[0117] 1.2 Add 50 mL of aqueous solution to the reaction solution in 1.1, let stand and separate the layers, and take the lower organic phase;

[0118] 1.3 The organic phase was filtered through a 0.45 μm filter membrane to obtain a PPS-derived solution;

[0119] 1.4 The PPS derivative solution obtained in 1.3 was subjected to GPC (RI+LS+VS) triple detector testing, with polystyrene (PS) as the calibration curve; the test conditions were the same as in Example 1, and the molecular weight of PPS resin was calculated, as shown in Table 6.

[0120] Table 6. A summary of the molecular weight of PPS resins (Comparative Example 2)

[0121]

[0122] As shown in Table 6, compared to the results of Example 1, the molecular weight of the PPS resin obtained by performing only step 1) oxidation without step 2) oxidation is lower. Under the condition that other factors remain unchanged, performing only one oxidation step in step 1) is insufficient to completely derivatize PPS, and therefore the true molecular weight of PPS cannot be obtained.

[0123] Comparative Example 3

[0124] The preparation process is basically the same as that in Comparative Example 2, except that the reaction temperature in step 1.1 is replaced with 260℃.

[0125] The molecular weights of the PPS resins obtained in this comparative example are shown in Table 7.

[0126] Table 7. A summary of the molecular weights of PPS resins (Comparative Example 3)

[0127]

[0128] As shown in Table 7, although the reaction temperature was increased, the molecular weight of the obtained PPS resin still differed significantly from the true molecular weight. If the reaction temperature is further increased, the solvent 1-chloronaphthalene will be lost during the reaction, and the solvent may even evaporate completely. Therefore, simply increasing the reaction temperature in step 1) without secondary oxidation cannot completely derivatize PPS, and thus the true molecular weight of PPS cannot be obtained.

[0129] Comparative Example 4

[0130] The preparation process is basically the same as that in Comparative Example 2, except that the reaction time in step 1.1 is replaced with 4 hours.

[0131] The molecular weights of the PPS resins obtained in this comparative example are shown in Table 8.

[0132] Table 8. A summary of the molecular weight of PPS resins (Comparative Example 4)

[0133]

[0134] As shown in Table 8, although the reaction time was increased, the molecular weight of the obtained PPS resin was not significantly different from that in Comparative Example 2. This indicates that simply increasing the reaction time in step 1) without performing a secondary oxidation reaction is insufficient to fully derivatize PPS, thus failing to obtain the true molecular weight of PPS.

[0135] Example 2

[0136] The preparation process is basically the same as in Example 1, except that the reaction temperature in step 1.1 is replaced with 190°C.

[0137] The molecular weight of the PPS resin obtained in this embodiment is shown in Table 9.

[0138] Table 9. A summary of the molecular weight of PPS resins (Example 2)

[0139]

[0140] 94. If the temperature is too high and the viscosity is too low, the lower layer is separated after standing. As shown in Table 9, after lowering the reaction temperature in step 1.1 to 190℃, the molecular weight of PPS obtained is almost the same as that of PPS in Example 1. In the GPC test, the relative error of the measured value is less than 10%, and the test results can be considered reliable. This shows that lowering the reaction temperature in step 1) to 190℃ can still meet the test requirements.

[0141] Example 3

[0142] The preparation process is basically the same as in Example 1, except that the reaction temperature in step 1.1 is replaced with 220°C.

[0143] The molecular weight of the PPS resin obtained in this embodiment is shown in Table 10.

[0144] Table 10. List of molecular weights of PPS resins (Example 3)

[0145]

[0146] 94. If the temperature is too high and the viscosity is too low, the lower layer is separated after standing. As shown in Table 10, after raising the reaction temperature in step 1.1 to 220°C, the molecular weight of PPS obtained is almost the same as that of PPS in Example 1. This shows that raising the reaction temperature in step 1) to 220°C can still meet the testing requirements.

[0147] Comparative Example 5

[0148] The preparation process is basically the same as in Example 1, except that the reaction temperature in step 1.1 is replaced with 150°C.

[0149] The molecular weights of the PPS resins obtained in this comparative example are shown in Table 11.

[0150] Table 11. A summary of the molecular weight of PPS resins (Comparative Example 5)

[0151]

[0152] As shown in Table 11, lowering the reaction temperature in step 1.1 to 150℃ resulted in a significantly different molecular weight of the obtained PPS resin compared to its true molecular weight. After derivatization, a distinct white insoluble substance, PPS, was observed in the chloroform solution. This indicates that at this temperature, PPS cannot be completely derivatized and oxidized to polyphenylsulfone, and this temperature does not meet the testing requirements.

[0153] Comparative Example 6

[0154] The preparation process is basically the same as in Example 1, except that the reaction temperature in step 1.1 is replaced with 180℃. The molecular weight of the PPS resin obtained in this comparative example is shown in Table 12.

[0155] Table 12. A summary of the molecular weight of PPS resins (Comparative Example 6)

[0156]

[0157] As shown in Table 12, lowering the reaction temperature in step 1.1 to 180℃ resulted in a significant difference between the molecular weight of the obtained PPS resin and the actual molecular weight. This indicates that at this temperature, PPS cannot be completely derivatized and oxidized to polyphenylsulfone, and this temperature does not meet the testing requirements.

[0158] Comparing the results of Examples 1-3 and Comparative Examples 5-6, it can be seen that the molecular weight of PPS gradually increases with increasing derivatization temperature. When the temperature in step 1.1 reaches above 190°C, the molecular weight of the obtained PPS is consistent with the true molecular weight of PPS, indicating that PPS can be completely derivatized at temperatures above 190°C. To improve the reaction rate, ensure complete derivatization, and minimize instrument wear, a derivatization temperature of 200-220°C is most suitable.

[0159] Example 4

[0160] The preparation process is basically the same as in Example 1, except that the reaction time in step 1.1 is replaced with 2.5 h.

[0161] The molecular weight of the PPS resin obtained in this embodiment is shown in Table 13.

[0162] Table 13. List of molecular weights of PPS resins (Example 4)

[0163]

[0164] As shown in Table 13, increasing the reaction time in step 1.1 to 2.5 h resulted in a PPS resin with a molecular weight consistent with the actual molecular weight. This indicates that under these reaction time conditions, PPS can be completely derivatized and oxidized to polyphenylsulfone, meeting the testing requirements.

[0165] Comparative Example 7

[0166] The preparation process is basically the same as in Example 1, except that the reaction time in step 1.1 is replaced with 1 hour.

[0167] The molecular weights of the PPS resins obtained in this comparative example are shown in Table 14.

[0168] Table 14. A summary of the molecular weight of PPS resins (Comparative Example 7)

[0169]

[0170] As shown in Table 14, reducing the reaction time in step 1.1 to 1 hour resulted in a significant difference between the molecular weight of the obtained PPS resin and the true molecular weight. After derivatization, granular white insoluble matter was found in the chloroform solution, indicating that at this reaction time, PPS could not be completely derivatized and oxidized to polyphenylsulfone, and this reaction time did not meet the testing requirements.

[0171] Comparative Example 8

[0172] The preparation process is basically the same as in Example 1, except that the reaction time in step 1.1 is replaced with 1.5h.

[0173] The molecular weights of the PPS resins obtained in this comparative example are shown in Table 15.

[0174] Table 15. A summary of the molecular weights of PPS resins (Comparative Example 8)

[0175]

[0176] As shown in Table 15, reducing the reaction time in step 1.1 to 1.5 h resulted in a significant difference between the molecular weight of the obtained PPS resin and the true molecular weight. This indicates that at this reaction time, PPS cannot be completely derivatized and oxidized to polyphenylsulfone, and this reaction time does not meet the testing requirements.

[0177] Example 5

[0178] The preparation process is basically the same as in Example 1, except that:

[0179] Replace the oxidant A in step 1.1 with an equal mass of potassium dichromate, and replace the auxiliary agent with an equal mass of oxalic acid.

[0180] The molecular weight of the PPS resin obtained in this embodiment is shown in Table 16.

[0181] Table 16. A summary of the molecular weight of PPS resins (Example 5)

[0182]

[0183] As can be seen from the test results in Table 16, the molecular weight of the PPS resin obtained in this embodiment is consistent with the true molecular weight of PPS.

[0184] Example 6

[0185] The preparation process is basically the same as in Example 1, except that the oxidant B in step 1.2 is replaced with an equal mass of peroxydodecanoic acid.

[0186] The molecular weight of the PPS resin obtained in this embodiment is shown in Table 17.

[0187] Table 17. Molecular weight summary of PPS resin (Example 6)

[0188]

[0189] As can be seen from the test results in Table 17, the molecular weight of the PPS resin obtained in this embodiment is consistent with the true molecular weight of PPS.

[0190] Comparative Example 9

[0191] The preparation process is basically the same as in Example 1, except that the oxidant B in step 1.2 is replaced with an equal mass of N-methylmorpholine oxide.

[0192] The molecular weights of the PPS resins obtained in this comparative example are shown in Table 18.

[0193] Table 18. A summary of the molecular weight of PPS resins (Comparative Example 9)

[0194]

[0195] Comparing the data in Tables 4 and 18, the molecular weight obtained using N-methylmorpholine oxide as the oxidant differs significantly from the true molecular weight of PPS. This indicates that N-methylmorpholine oxide cannot sufficiently oxidize PPS into polyphenylsulfone.

[0196] Comparative Example 10

[0197] The preparation process is basically the same as in Example 1, except that the oxidant B in step 1.2 is replaced with an equal mass of dimethyldioxyethylene.

[0198] The molecular weights of the PPS resins obtained in this comparative example are shown in Table 19.

[0199] Table 19. A summary of the molecular weight of PPS resins (Comparative Example 10)

[0200]

[0201] Comparing the data in Tables 4 and 19, the molecular weight obtained using dimethyl diethylene oxide as the oxidant differs significantly from the true molecular weight of PPS. This indicates that dimethyl diethylene oxide cannot sufficiently oxidize PPS into polyphenylene sulfone.

[0202] The above-described embodiments are preferred embodiments, but the scope of protection of the present invention is not limited thereto. Those skilled in the art can easily understand the spirit of the present invention based on the above embodiments and make different extensions and variations, but as long as they do not depart from the spirit of the present invention, they are all within the scope of protection of the present invention.

Claims

1. A method for determining the true molecular weight of PPS resin using gel permeation chromatography, characterized in that, Includes the following steps: 1) Mix PPS resin, oxidant A, additives and 1-chloronaphthalene, and reflux at a temperature not lower than 190°C; 2) Let the reaction solution after step 1) stand at room temperature, add organic solvent and oxidant B and reflux reaction; The reflux reaction temperature is below the boiling point of the organic solvent; 3) Add water to the reaction solution after step 2), let it stand and separate the liquid, take the organic phase layer in the liquid to obtain the PPS derivatized solution; 4) Using a triple detector (GPC), with the organic solvent from step 2) as the mobile phase, the PPS derivatized solution prepared in step 3) was tested to obtain the molecular weight of the derivatized PPS, and then the true molecular weight of the PPS resin was calculated.

2. The method for determining the true molecular weight of PPS resin using gel permeation chromatography according to claim 1, characterized in that, In step 1): The oxidant A is selected from one or more of sodium bismuthate, potassium dichromate, and potassium permanganate. The additive is selected from one or more of 4-chlorobenzenesulfonic acid, oxalic acid, and methanesulfonic acid.

3. The method for determining the true molecular weight of PPS resin using gel permeation chromatography according to claim 1, characterized in that, In step 1): The mass ratio of PPS resin to oxidant A is 1:(1.5~2.5). The mass ratio of oxidant A to auxiliary agent is 1:(0.8~1.2). The mass-to-volume ratio of PPS resin to 1-chloronaphthalene is 1:(180~220)g / mL.

4. The method for determining the true molecular weight of PPS resin using gel permeation chromatography according to claim 1, characterized in that, In step 1), the reaction temperature is 190~250℃ and the reaction time is not less than 2h.

5. The method for determining the true molecular weight of PPS resin using gel permeation chromatography according to claim 4, characterized in that, The reaction temperature is 200~220℃.

6. The method for determining the true molecular weight of PPS resin using gel permeation chromatography according to claim 1, characterized in that, In step 2): The oxidant B is selected from one or more of magnesium monoperoxyphthalate hexahydrate, peroxydodecanoic acid, and peroxybenzoic acid. The organic solvent is selected from polyphenylene sulfone, a nonpolar good solvent; The reaction time should be no less than 1 hour.

7. The method for determining the true molecular weight of PPS resin using gel permeation chromatography according to claim 6, characterized in that, The organic solvent is selected from one or more of chloroform, toluene, and cyclohexane.

8. The method for determining the true molecular weight of PPS resin using gel permeation chromatography according to claim 1, characterized in that, In step 2): In step 1), the mass ratio of PPS resin to oxidant B is 1:(1.8~2.2). The volume ratio of the organic solvent to 1-chloronaphthalene in step 1) is (4~8):

1.

9. The method for determining the true molecular weight of PPS resin using gel permeation chromatography according to claim 1, characterized in that, In step 4), the test is: The chromatographic column was selected from Plgel MIXED-B column; The flow rate was selected from 0.8 to 1.5 mL / min; The column temperature is selected from 25~35℃.

10. The method for determining the true molecular weight of PPS resin using gel permeation chromatography according to claim 1, characterized in that, In step 4), the calculation is specifically calculated using the following formula: 。

Images