Method for detecting residual solvent content in polyetherketoneketone by headspace-gas chromatography

Abstract

The invention discloses a method for detecting residual solvent content in polyetherketoneketone through headspace-gas chromatography, and belongs to the technical field of analysis and detection methods.A headspace sampling mode is adopted, PEKK does not need to be dissolved through a solvent, volatile components are volatilized from a solid sample matrix through heating, balance is achieved in a gas phase and a solid phase, and the residual solvent content in the PEKK is detected. Top gas is directly extracted for chromatographic analysis, so that components and contents of volatile components in a sample are detected, a tedious sample pretreatment process can be omitted, interference of a solvent on analysis is avoided, pollution to a chromatographic column and a sample inlet is reduced, sample introduction is convenient and accurate, test precision is improved, and the method is high in accuracy of a determination result and high in repeatability. The recovery rate of each solvent is in a range of 95-110%; the result repeatability RSD of the method is less than 2%, and the repeatability is good.

Description

Technical Field

[0001] The invention belongs to the technical field of analysis and detection methods, and specifically is a method for detecting the residual solvent content in polyetherketoneketone by headspace-gas chromatography. Background Art

[0002] Polyetherketoneketone (PEKK) resin is a special engineering plastic with excellent properties. It is a type of polyaryletherketone. The chemical structure of the benzene ring, ether bond and ketone group in its molecular structure is neatly arranged, which gives the molecule highly stable chemical bond characteristics, making it have excellent mechanical properties, radiation resistance, high temperature resistance, chemical corrosion resistance, good electrical insulation and flame retardant properties. It can be processed and formed by extrusion, injection molding, molding and other processing methods. It has extremely high application demand in aerospace, electronics and electrical, automobile and petroleum.

[0003] PEKK is an organic substance obtained through chemical synthesis. Various organic solvents must be used in the synthesis and purification process. If these solvents remain in the material, it will cause melt instability of PEKK during high-temperature processing. Due to its instability, it causes performance changes such as the formation of voids and discoloration during the manufacturing process, leading to serious problems in molding, extrusion, and the preparation of composite materials, thus affecting its performance. Therefore, in the quality standard of PEKK materials, solvent residue is an important control indicator. Usually, solvent residue needs to be determined by gas chromatography, and PEKK has a high polarity and can only be dissolved in strong polar solvents such as sulfuric acid and trifluoroacetic acid. However, these solvents are highly corrosive and cannot be used as gas chromatography detection solvents. There are currently no reports on solvent residues in PEKK. Therefore, in view of the special properties of PEKK, it is necessary to develop a detection method suitable for PEKK solvent residues. Summary of the invention

[0004] To solve the above problems, the object of the present invention is to provide a method for detecting the residual solvent content in polyetherketoneketone by headspace-gas chromatography.

[0005] To achieve the above object, the present invention is implemented in the following manner:

[0006] A method for detecting the residual solvent content in polyetherketoneketone by headspace-gas chromatography, the process is as follows: in a headspace bottle, using purified water to prepare a sample solution, using a headspace automatic sampler for injection, using an SE-30 capillary chromatographic column as a column, using a programmed temperature increase mode, using a hydrogen flame detector to detect the gas to be tested, using the same method to measure a mixed standard solution with a known gradient content and establish a standard curve, and obtaining a linear equation; according to the response value of the sample solution and the linear equation, calculating the residual solvent content in the polyetherketoneketone.

[0007] The method for detecting the residual solvent content in polyetherketoneketone by headspace-gas chromatography comprises the following steps:

[0008] (1) Preparation of sample solution: Weigh 0.1-0.3 g of sample powder and place it in a headspace bottle, then add 1-3 mL of purified water, seal with a cap, and shake well to obtain a sample solution;

[0009] (2) Preparation of mixed standard solutions with gradient contents: Weigh 25 mg of solvent into a 250 mL volumetric flask, add methanol to the mark, shake well, and obtain a mother solution A with a solvent mass concentration of 100 μg / mL; pipette 0.1 mL, 0.2 mL, 0.4 mL, 0.6 mL, 0.8 mL, 1.0 mL, 2.0 mL, 5.0 mL and 8.0 mL of mother solution A into a 10 mL volumetric flask, add purified water to the mark, shake well, and prepare mixed standard solutions with gradient contents with mass concentrations of 1 μg / mL, 2 μg / mL, 4 μg / mL, 6 μg / mL, 8 μg / mL, 10 μg / mL, 20 μg / mL, 50 μg / mL, 80 μg / mL and 100 μg / mL, respectively;

[0010] The solvent is one or more of dichloromethane, 1,2-dichloroethane, chlorobenzene, o-dichlorobenzene, N,N-dimethylformamide and N-methylpyrrolidone;

[0011] (3) Setting analysis conditions;

[0012] (4) Establishment of standard curve: 1-3 ml of the mixed standard solution with gradient content prepared in step (2) was respectively transferred into a headspace bottle, which was sealed with a cover, and measured by headspace-gas chromatography. A standard curve was established based on the corresponding relationship between the chromatographic peak area and the mass concentration of the solvent in the mixed standard solution with gradient content;

[0013] (5) Determination of sample solution: The sample solution prepared in step (1) is measured by headspace-gas chromatography, and the residual solvent content in the polyetherketoneketone is calculated using a standard curve.

[0014] The analysis conditions in step (3) are:

[0015] Instrument: Gas chromatograph equipped with headspace sampler;

[0016] Chromatographic column: SE-30 capillary column, specification: 30m×0.32mm×0.5um;

[0017] Injection bottle: 20mL headspace injection bottle;

[0018] Headspace autosampler conditions: headspace equilibrium temperature: 80-100°C; injection loop temperature: 100-120°C; transfer line temperature: 110-130°C; headspace equilibrium time: 30-50 min; pressurization time: 1 min; introduction time: 0.5 min; injection time: 1 min;

[0019] Inlet temperature: 230~250℃;

[0020] Column temperature: maintain at 40-60℃ for 4-6 minutes, increase to 220-240℃ at 10-20℃ / min, maintain for 2-4 minutes;

[0021] Detector temperature: 250°C;

[0022] Carrier gas: high-purity nitrogen, flow rate 1 mL / min;

[0023] Injection mode: split injection, split ratio is 20:1;

[0024] Hydrogen flow rate: 40mL / min;

[0025] Air flow rate: 400mL / min;

[0026] Tail blowing flow rate: 30mL / min.

[0027] Preferably, the analysis conditions in step (3) are: headspace equilibrium temperature: 90°C; headspace equilibrium time: 30 min; injection port temperature: 230°C; column temperature: 60°C for 4 min, increased to 240°C at 10°C / min, and maintained for 4 min.

[0028] The amount of purified water added in the preparation of the sample solution in step (1) and the volume of the mixed standard solution removed in the establishment of the standard curve in step (4) must be consistent.

[0029] Compared with the prior art, the present invention has the following advantages:

[0030] The headspace-gas chromatography method for detecting the residual solvent content in polyetherketoneketone adopts a headspace injection mode, does not need a solvent to dissolve PEKK, evaporates volatile components from a solid sample matrix by heating, reaches equilibrium in the gas-solid two-phase, directly extracts the top gas for chromatographic analysis, and thus verifies the composition and content of the volatile components in the sample. The lengthy and cumbersome sample pretreatment process can be avoided, the interference of the solvent on the analysis can be avoided, the contamination of the chromatographic column and the injection port can be reduced, the injection is convenient and accurate, and the test accuracy is improved.

[0031] The headspace-gas chromatography method for detecting the residual solvent content in polyetherketoneketone has high accuracy, low detection limit, and each solvent recovery rate is within the range of 95-110%. The method has good precision, and the result repeatability RSD of the method is less than 2%, and the repeatability is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The gas chromatogram of the mixed standard solution with a gradient content of 50 μg / mL in Example 1 of the present invention;

[0033] In the figure, 1 is methanol; 2 is dichloromethane; 3 is 1,2-dichloroethane; 4 is N,N-dimethylformamide; 5 is chlorobenzene; 6 is N-methylpyrrolidone; 7 is o-dichlorobenzene. DETAILED DESCRIPTION

[0034] In order to better understand the technical solution of the present invention, the above content of the present invention is further described in detail below through specific implementation methods in the form of embodiments, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above content of the present invention belong to the scope of the present invention.

[0035] The instrument used in the following examples is a GC-2010Pro gas chromatograph (Shimadzu), equipped with a hydrogen flame ionization detector and a HS-10 headspace sampler (Shimadzu).

[0036] Example 1 (1) Preparation of sample solution: Weigh 0.2 g of sample powder 1#, 2# and 3# respectively and place them in 20 mL headspace bottles, then add 2 mL of purified water, cover and seal, shake well to obtain 3 sample solutions;

[0037] (2) Preparation of mixed standard solutions with gradient contents: Weigh 25 mg each of dichloromethane, 1,2-dichloroethane, chlorobenzene, o-dichlorobenzene, N,N-dimethylformamide and N-methylpyrrolidone in a 250 ml volumetric flask, add methanol to the mark, shake well, and obtain a mother solution A with a solvent mass concentration of 100 μg / mL; pipette 0.1 mL, 0.2 mL, 0.4 mL, 0.6 mL, 0.8 mL, 1.0 mL, 2.0 mL, 5.0 mL and 8.0 mL of mother solution A in a 10 mL volumetric flask, dilute to the mark with purified water, shake well, and prepare mixed standard solutions with gradient contents with mass concentrations of 1 μg / mL, 2 μg / mL, 4 μg / mL, 6 μg / mL, 8 μg / mL, 10 μg / mL, 20 μg / mL, 50 μg / mL, 80 μg / mL and 100 μg / mL, respectively;

[0038] (3) Setting analysis conditions;

[0039] Chromatographic column: SE-30 capillary column, specification: 30m×0.32mm×0.5um;

[0040] Injection bottle: 20mL headspace injection bottle;

[0041] Headspace autosampler conditions: headspace equilibrium temperature: 90°C; injection loop temperature: 100°C; transfer line temperature: 110°C; headspace equilibrium time: 30 min; pressurization time: 1 min; introduction time: 0.5 min; injection time: 1 min;

[0042] Inlet temperature: 230°C;

[0043] Column temperature: 60°C for 4 min, increase to 240°C at 10°C / min, and maintain for 4 min;

[0044] Detector temperature: 250°C;

[0045] Carrier gas: high-purity nitrogen, flow rate 1 mL / min;

[0046] Injection mode: split injection, split ratio is 20:1;

[0047] Hydrogen flow rate: 40mL / min;

[0048] Air flow rate: 400mL / min;

[0049] Tail blowing flow rate: 30mL / min.

[0050] (4) Establishment of standard curve: 2 ml of the mixed standard solution with gradient content prepared in step (2) was respectively transferred into a 20 mL headspace bottle, which was sealed with a cover and measured by headspace-gas chromatography. The detection spectrum of the mixed standard solution with gradient content of 50 μg / mL was as follows: Figure 1 As shown; a standard curve is established based on the corresponding relationship between the chromatographic peak area and the mass concentration of the solvent in the mixed standard solution of the gradient content; the standard curve results are shown in Table 1;

[0051] (5) Determination of sample solution: The three sample solutions prepared in step (1) were determined by headspace-gas chromatography, and the residual solvent content in polyetherketoneketone was calculated using the standard curve. The test results are shown in Table 2.

[0052] Table 1 Standard curve determination results

[0053] Component name Concentration linear range (μg / mL) Linear equations Correlation coefficient Detection limit (μg / mL) Dichloromethane 0.942-94.2 y=69526x+22186 0.9987 0.03 1,2-Dichloroethane 0.976～97.6 y=41099x-2099.2 0.9986 0.02 N,N-Dimethylformamide 1.092～109.2 y=43243x-3972.2 0.9997 0.06 chlorobenzene 0.912～91.2 y=19421x+111.9 0.9949 0.05 N-Methylpyrrolidone 1.032-103.2 y=36133x+8395.1 0.9973 0.07 o-Dichlorobenzene 1.056-105.6 y=16065x+3224.9 0.9982 0.05

[0054] It can be seen from the results in Table 1 that the solvent components show a good linear correlation within the corresponding concentration range and the method has a high sensitivity.

[0055] Table 2 Sample test results

[0056] Sample No. Dichloromethane 1,2-Dichloroethane N,N-Dimethylformamide chlorobenzene N-Methylpyrrolidone o-Dichlorobenzene 1# Not detected Not detected Not detected Not detected Not detected 0.0033％ 2# Not detected Not detected Not detected Not detected Not detected 0.0024％ 3# Not detected Not detected Not detected Not detected Not detected 0.0027％

[0057] Example 2 The method and steps in Example 1 were used to repeat the measurement of sample powder 2# three times. The test results are shown in Table 3.

[0058] Table 3 Repeatability test results of sample powder 2#

[0059] Repetitions Dichloromethane 1,2-Dichloroethane N,N-Dimethylformamide chlorobenzene N-Methylpyrrolidone o-Dichlorobenzene 1 Not detected Not detected Not detected Not detected Not detected 0.0023％ 2 Not detected Not detected Not detected Not detected Not detected 0.0024％ 3 Not detected Not detected Not detected Not detected Not detected 0.0024％ average value - - - - - 0.0024％ RSD(%) - - - - - 1.88

[0060] It can be seen from the results in Table 3 that, using the test method of the present invention, the repeatability RSD of the determination results of the content of each component is less than 2%, and the repeatability is good.

[0061] Example 3 Weigh 9 portions of sample powder 2#0.2g, place in 20mL headspace bottles, add 2mL of the mixed standard solution of 1μg / mL, 2μg / mL and 4μg / mL of three concentrations of gradient content in Example 1, seal with a cover, as the spiked test solution, prepare 3 portions of each concentration in parallel. Detect according to the method and steps in Example 1, calculate the recovery rate, and the results are shown in Table 4. It can be seen from the results in Table 4 that the recovery rates of each solvent are in the range of 95% to 110%, indicating that the method has good accuracy.

[0062] Table 4 Test results of recovery rate of each component

[0063]

[0064] Example 4 (1) Preparation of sample solutions: Weigh 0.1 g of sample powders 1#, 2# and 3# respectively and place them in 20 mL headspace bottles, then add 1 mL of purified water, cover and seal, and shake to obtain 3 sample solutions;

[0065] (2) Preparation of mixed standard solutions with gradient contents: Weigh 25 mg each of dichloromethane, 1,2-dichloroethane, chlorobenzene, o-dichlorobenzene, N,N-dimethylformamide and N-methylpyrrolidone in a 250 ml volumetric flask, add methanol to the mark, shake well, and obtain a mother solution A with a solvent mass concentration of 100 μg / mL; pipette 0.1 mL, 0.2 mL, 0.4 mL, 0.6 mL, 0.8 mL, 1.0 mL, 2.0 mL, 5.0 mL and 8.0 mL of mother solution A in a 10 mL volumetric flask, dilute to the mark with purified water, shake well, and prepare mixed standard solutions with gradient contents with mass concentrations of 1 μg / mL, 2 μg / mL, 4 μg / mL, 6 μg / mL, 8 μg / mL, 10 μg / mL, 20 μg / mL, 50 μg / mL, 80 μg / mL and 100 μg / mL, respectively;

[0066] (3) Setting analysis conditions;

[0067] Chromatographic column: SE-30 capillary column, specification: 30m×0.32mm×0.5um;

[0068] Injection bottle: 20mL headspace injection bottle;

[0069] Headspace autosampler conditions: headspace equilibrium temperature: 80°C; injection loop temperature: 110°C; transfer line temperature: 120°C; headspace equilibrium time: 40 min; pressurization time: 1 min; introduction time: 0.5 min; injection time: 1 min;

[0070] Inlet temperature: 240°C;

[0071] Column temperature: 40°C for 6 min, then increase to 230°C at 15°C / min, and hold for 2 min;

[0072] Detector temperature: 250°C;

[0073] Carrier gas: high-purity nitrogen, flow rate 1 mL / min;

[0074] Injection mode: split injection, split ratio is 20:1;

[0075] Hydrogen flow rate: 40mL / min;

[0076] Air flow rate: 400mL / min;

[0077] Tail blowing flow rate: 30mL / min.

[0078] (4) Establishment of standard curve: 1 ml of the mixed standard solution with gradient content prepared in step (2) was respectively transferred into a 20-mL headspace bottle, which was sealed with a cover, and measured by headspace-gas chromatography. A standard curve was established based on the correspondence between the chromatographic peak area and the mass concentration of the solvent in the mixed standard solution with gradient content;

[0079] (5) Determination of sample solution: The three sample solutions prepared in step (1) were measured by headspace-gas chromatography, and the residual solvent content in polyetherketoneketone was calculated using the standard curve. The test results are shown in Table 5.

[0080] Table 5 Sample test results

[0081] Sample No. Dichloromethane 1,2-Dichloroethane N,N-Dimethylformamide chlorobenzene N-Methylpyrrolidone o-Dichlorobenzene 1# Not detected Not detected Not detected Not detected Not detected 0.0032％ 2# Not detected Not detected Not detected Not detected Not detected 0.0024％ 3# Not detected Not detected Not detected Not detected Not detected 0.0026％

[0082] Example 5 (1) Preparation of sample solutions: Weigh 0.3 g of sample powders 1#, 2# and 3# respectively and place them in 20 mL headspace bottles, then add 3 mL of purified water, cover and seal, and shake to obtain three sample solutions;

[0083] (2) Preparation of mixed standard solutions with gradient contents: Weigh 25 mg each of dichloromethane, 1,2-dichloroethane, chlorobenzene, o-dichlorobenzene, N,N-dimethylformamide and N-methylpyrrolidone in a 250 ml volumetric flask, add methanol to the mark, shake well, and obtain a mother solution A with a solvent mass concentration of 100 μg / mL; pipette 0.1 mL, 0.2 mL, 0.4 mL, 0.6 mL, 0.8 mL, 1.0 mL, 2.0 mL, 5.0 mL and 8.0 mL of mother solution A in a 10 mL volumetric flask, dilute to the mark with purified water, shake well, and prepare mixed standard solutions with gradient contents with mass concentrations of 1 μg / mL, 2 μg / mL, 4 μg / mL, 6 μg / mL, 8 μg / mL, 10 μg / mL, 20 μg / mL, 50 μg / mL, 80 μg / mL and 100 μg / mL, respectively;

[0084] (3) Setting analysis conditions;

[0085] Chromatographic column: SE-30 capillary column, specification: 30m×0.32mm×0.5um;

[0086] Injection bottle: 20mL headspace injection bottle;

[0087] Headspace autosampler conditions: headspace equilibrium temperature: 100°C; injection loop temperature: 120°C; transfer line temperature: 130°C; headspace equilibrium time: 50 min; pressurization time: 1 min; introduction time: 0.5 min; injection time: 1 min;

[0088] Inlet temperature: 250°C;

[0089] Column temperature: 50°C for 5 min, increase to 220°C at 20°C / min, and maintain for 3 min;

[0090] Detector temperature: 250°C;

[0091] Carrier gas: high-purity nitrogen, flow rate 1 mL / min;

[0092] Injection mode: split injection, split ratio is 20:1;

[0093] Hydrogen flow rate: 40mL / min;

[0094] Air flow rate: 400mL / min;

[0095] Tail blowing flow rate: 30mL / min.

[0096] (4) Establishment of standard curve: 3 ml of the mixed standard solution with gradient content prepared in step (2) was respectively transferred into a 20-mL headspace bottle, which was sealed with a cover, and measured by headspace-gas chromatography. A standard curve was established based on the correspondence between the chromatographic peak area and the mass concentration of the solvent in the mixed standard solution with gradient content;

[0097] (5) Determination of sample solution: The three sample solutions prepared in step (1) were determined by headspace-gas chromatography, and the residual solvent content in polyetherketoneketone was calculated using the standard curve. The test results are shown in Table 6.

[0098] Table 6 Sample test results

[0099] Sample No. Dichloromethane 1,2-Dichloroethane N,N-Dimethylformamide chlorobenzene N-Methylpyrrolidone o-Dichlorobenzene 1# Not detected Not detected Not detected Not detected Not detected 0.0034％ 2# Not detected Not detected Not detected Not detected Not detected 0.0023％ 3# Not detected Not detected Not detected Not detected Not detected 0.0027％

[0100] Although the above describes the specific implementation methods of the present invention, it does not limit the scope of protection of the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. A method for detecting the residual solvent content in polyetherketoneketone by headspace-gas chromatography, characterized in that: The process is as follows: in a headspace bottle, purified water is used to prepare the sample solution, and the sample is injected using a headspace autosampler. The column uses a SE-30 capillary column, the heating mode is programmed heating, and a hydrogen flame detector is used to detect the gas to be tested. The mixed standard solution with known gradient content is measured using the same method and a standard curve is established to obtain a linear equation; based on the response value of the sample solution and the linear equation, the residual solvent content in the polyetherketoneketone is calculated.

2. The method for detecting the residual solvent content in polyetherketoneketone by headspace-gas chromatography according to claim 1, characterized in that: The following steps are involved: (1) Preparation of sample solution: Weigh 0.1-0.3 g of sample powder and place it in a headspace bottle, then add 1-3 mL of purified water, cover and seal, and shake to obtain a sample solution; (2) Preparation of mixed standard solutions with gradient contents: Weigh 25 mg of solvent into a 250 mL volumetric flask, add methanol to the mark, shake well, and obtain a mother solution A with a solvent mass concentration of 100 μg / mL; pipette 0.1 mL, 0.2 mL, 0.4 mL, 0.6 mL, 0.8 mL, 1.0 mL, 2.0 mL, 5.0 mL and 8.0 mL of mother solution A into a 10 mL volumetric flask, add purified water to the mark, shake well, and prepare mixed standard solutions with gradient contents with mass concentrations of 1 μg / mL, 2 μg / mL, 4 μg / mL, 6 μg / mL, 8 μg / mL, 10 μg / mL, 20 μg / mL, 50 μg / mL, 80 μg / mL and 100 μg / mL, respectively; The solvent is one or more of dichloromethane, 1,2-dichloroethane, chlorobenzene, o-dichlorobenzene, N,N-dimethylformamide and N-methylpyrrolidone; (3) Setting analysis conditions; (4) Establishment of standard curve: 1-3 ml of the mixed standard solution with gradient content prepared in step (2) was respectively transferred into a headspace bottle, which was sealed with a cover, and measured by headspace-gas chromatography. A standard curve was established based on the corresponding relationship between the chromatographic peak area and the mass concentration of the solvent in the mixed standard solution with gradient content; (5) Determination of sample solution: The sample solution prepared in step (1) is measured by headspace-gas chromatography, and the residual solvent content in the polyetherketoneketone is calculated using a standard curve.

3. The method for detecting the residual solvent content in polyetherketoneketone by headspace-gas chromatography as claimed in claim 2, characterized in that: The analysis conditions in step (3) are: Instrument: Gas chromatograph equipped with headspace sampler; Chromatographic column: SE-30 capillary column, specification: 30m×0.32mm×0.5um; Injection bottle: 20mL headspace injection bottle; Headspace autosampler conditions: headspace equilibrium temperature: 80-100°C; injection loop temperature: 100-120°C; transfer line temperature: 110-130°C; headspace equilibrium time: 30-50 min; pressurization time: 1 min; introduction time: 0.5 min; injection time: 1 min; Inlet temperature: 230~250℃; Column temperature: maintain at 40-60℃ for 4-6 minutes, increase to 220-240℃ at 10-20℃ / min, maintain for 2-4 minutes; Detector temperature: 250°C; Carrier gas: high-purity nitrogen, flow rate 1 mL / min; Injection mode: split injection, split ratio is 20:1; Hydrogen flow rate: 40mL / min; Air flow rate: 400mL / min; Tail blowing flow rate: 30mL / min.

4. The method for detecting the residual solvent content in polyetherketoneketone by headspace-gas chromatography as claimed in claim 2, characterized in that: The analysis conditions in step (3) are: headspace equilibrium temperature: 90°C; headspace equilibrium time: 30 min; injection port temperature: 230°C; Column temperature: 60°C for 4 min, increase to 240°C at 10°C / min, and maintain for 4 min.

Images