Method for characterizing molecular weight and molecular weight distribution of crystalline polyaryletherketone
The generation of soluble iminolated polyarylether ketones via Schiff base reaction solves the problem of the poor solubility of crystalline polyarylether ketones in common solvents, enabling accurate determination of their molecular weight and distribution at room temperature. This overcomes the shortcomings of existing technologies and is applicable to the entire family of crystalline polyarylether ketones.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- JILIN UNIVERSITY
- Filing Date
- 2025-12-29
- Publication Date
- 2026-05-19
AI Technical Summary
Crystalline polyaryletherketones are difficult to dissolve in common solvents, and existing molecular weight characterization methods lack accuracy and universality, are complex to operate, and cannot provide molecular weight distribution information.
The Schiff base reaction was used to reflux crystalline polyarylether ketones with arylalkylamine compounds under an inert atmosphere to generate soluble iminolated polyarylether ketones. The molecular weight and distribution of the iminolated polyarylether ketones were determined by gel permeation chromatography, and the molecular weight and distribution of the original polyarylether ketones were deduced by using quantitative conversion relationships.
It enables accurate determination of the molecular weight and distribution of crystalline polyaryletherketones at room temperature, avoiding the use of highly corrosive and toxic solvents, reducing operational risks and equipment requirements, and improving the accuracy and repeatability of the determination results. It is applicable to the entire family of crystalline polyaryletherketones.
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Abstract
Description
Technical Field
[0001] This invention belongs to the technical field of material characterization methods, specifically relating to a method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones, and more particularly to a method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones based on the Schiff base reaction. Background Technology
[0002] Crystalline polyaryletherketones (POPs) are a class of high-performance semi-crystalline thermoplastic polymers composed of alternating aromatic rings, ether bonds, and carbonyl groups. Their rigid molecular chain structure endows these materials with excellent high-temperature resistance, high chemical stability, and mechanical strength, making them widely used in aerospace structural components, orthopedic implants, automotive powertrain components, and electronic packaging materials.
[0003] The molecular weight and distribution of polymers are key parameters determining their processing rheological behavior and directly affect melt flowability. However, crystalline polyarylether ketones have extremely poor solubility, being difficult to dissolve in common organic solvents and usually requiring highly corrosive solvents such as concentrated sulfuric acid. This severely limits the accurate and convenient determination of their molecular weight and molecular weight distribution, thus hindering the precise evaluation of the material's processing performance.
[0004] In existing methods, the molecular weight characterization of crystalline polyaryletherketones typically employs intrinsic viscosity determination based on a concentrated sulfuric acid system. This involves measuring the intrinsic viscosity of a dilute solution and indirectly estimating the molecular weight using empirical formulas. This method has several drawbacks: first, the obtained molecular weight data heavily relies on the empirical relationship between intrinsic viscosity and molecular weight, making accuracy and universality difficult to guarantee; second, this method inherently fails to provide the crucial parameter of molecular weight distribution. Although studies have attempted to develop alternatives, the methods developed still exhibit significant shortcomings in terms of operability, universality, and practical feasibility.
[0005] Existing literature on the determination of molecular weight of polyether ether ketone (PEEK) (Polymer, 1985, 26(13): 1994-2000) reports a phenol / 1,2,4-trichlorobenzene (50 / 50, w / w) mixed solvent system that can dissolve PEEK at 115 °C, allowing for the determination of its molecular weight by gel permeation chromatography. However, the solvent used in this system is biotoxic, and the solution stability must be maintained at high temperatures, placing high demands on the high-temperature resistance and operational safety of the instrument system.
[0006] Existing literature on the chemical modification of polyether ether ketones for room temperature size exclusion chromatography includes: 1. Determination of the absolute molecular weight of sulfonated polyether ether ketones (Polymer, 1994, 35(25): 5491-7), which proposes sulfonating polyether ether ketones to make them soluble in N-methylpyrrolidone, thereby allowing for gel permeation chromatography analysis at room temperature to indirectly estimate the molecular weight. However, the applicability of this method is limited by the selectivity of the sulfonation reaction itself. The sulfonation process is affected by the carbonyl structure in the polymer chain, making this method difficult to apply to other crystalline polyarylether ketone homologues that are difficult to sulfonate, such as polyether ketones and polyether ketone ketones.
[0007] US Patent Application US 2011 / 0040045 A1 discloses a method for the reversible derivatization of polyaryletherketones (PAEs). This method is based on the modification of PAEs using a thioketal reaction, facilitating molecular weight characterization by gel permeation chromatography at room temperature. However, the modification reaction conditions are complex, requiring a reaction time of up to 24 hours to achieve a high conversion rate. Therefore, consistent control of the conversion rate is difficult, affecting the solubility of the modified polymer and impacting the accuracy and repeatability of the final molecular weight determination results. Summary of the Invention
[0008] This invention addresses the challenges of molecular weight characterization caused by the poor solubility of crystalline polyaryletherketones in common solvents, the difficulty in ensuring the accuracy, repeatability, and universality of existing molecular weight characterization methods, the high requirements for instruments, the complexity of operation, and the inability to provide complete molecular weight and molecular weight distribution information. It provides a method for characterizing the molecular weight and molecular weight distribution of crystalline polyaryletherketones, particularly a method based on the Schiff base reaction.
[0009] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows.
[0010] The method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones of the present invention comprises the following steps:
[0011] (1) Mix crystalline polyarylether ketone with arylalkylamine compound in solvent and reflux for 1-3 hours under inert atmosphere. After the reaction is completed, pour the resulting mixture into water to precipitate the product. After filtration, the crude product (containing soluble iminolated polyarylether ketone and unreacted arylalkylamine compound) is obtained.
[0012] (2) The crude product obtained in step (1) is thoroughly washed with detergent, then dissolved in a good solvent, and then precipitated in a poor solvent (to remove unreacted aryl amine compounds and other impurities), filtered and dried to obtain purified imine polyaryl ether ketone.
[0013] (3) Dissolve the purified imino-polyarylether ketone obtained in step (2) in a solvent to prepare a solution with a concentration of 1 mg / mL to 5 mg / mL, filter, and obtain the test solution;
[0014] (4) The molecular weight and molecular weight distribution of iminopolyaryletherketone were determined by gel permeation chromatography. Based on the quantitative conversion relationship between the molecular weight of crystalline polyaryletherketone and iminopolyaryletherketone, the molecular weight and molecular weight distribution of crystalline polyaryletherketone were deduced.
[0015] The quantitative conversion relationship between the molecular weights of the crystalline polyarylether ketone and the iminoized polyarylether ketone is as follows:
[0016] ;
[0017] In the formula, M x M is the molecular weight of crystalline polyaryletherketone. y M represents the molecular weight of iminolated polyaryletherketone. O-x M is the molar mass of a repeating structural unit of a crystalline polyaryletherketone. O-y is the molar mass of a repeating structural unit of iminolated polyaryletherketone.
[0018] Furthermore, in step (1), the crystalline polyaryletherketone includes one or more of polyetheretherketone, polyetherketoneketone, polyetherketone, polyetheretherketoneketone, polyetherketoneketone, biphenyl-type polyetheretherketone, and biphenyl-type polyetheretherketoneketone, with the following structural formulas:
[0019] ;
[0020] In the formula, n are independent integers greater than or equal to 10 and less than or equal to 300.
[0021] Furthermore, in step (1), the arylalkylamine compound includes one or more of phenethylamine, 2,2-diphenylethylamine, p-methylphenethylamine, p-nitrophenethylamine, p-carboxyphenethylamine, p-sulfonylphenethylamine, amphetamine, 3,3-diphenylpropylamine, p-methylphenethylamine, p-nitrophenethylamine, p-carboxyphenethylamine, and p-sulfonylphenethylamine.
[0022] Furthermore, in step (1), the inert atmosphere is one or more of nitrogen, argon, and helium.
[0023] Furthermore, in step (1), the solvent includes one or more of sulfolane, diphenyl sulfone, N-methylpyrrolidone, and dimethyl sulfoxide.
[0024] Furthermore, in step (1), the temperature of the reflux reaction is 140-280℃.
[0025] Furthermore, in step (1), the molar ratio of the crystalline polyarylether ketone to the arylalkylamine compound is 1:2 to 1:10.
[0026] Furthermore, in step (1), the mass ratio of the crystalline polyarylether ketone to the solvent is 1:5-1:20.
[0027] Furthermore, in step (2), the detergent includes one or more of ethanol and methanol.
[0028] Furthermore, in step (2), the good solvent includes one or more of N,N-dimethylformamide, tetrahydrofuran, N-methylpyrrolidone, chloroform, and dichloromethane.
[0029] Furthermore, in step (2), the undesirable solvent includes one or more of ethanol, methanol, and petroleum ether.
[0030] Furthermore, in step (2), the iminolated polyaryletherketone includes one or more of the following: iminolated polyetheretherketone, iminolated polyetherketoneketone, iminolated polyetheretherketone, iminolated polyetheretherketoneketone, iminolated polyetherketone etherketone, iminolated biphenyl-type polyetheretherketone, and iminolated biphenyl-type polyetheretherketoneketone, with the following structural formulas respectively:
[0031] ;
[0032] In the formula, n is an independent integer greater than or equal to 10 and less than or equal to 300, and X is an aralkyl group (specifically corresponding to the aralkyl group in aralkylamine compounds).
[0033] Furthermore, in step (3), the solvent includes one or more of N,N-dimethylformamide, tetrahydrofuran, N-methylpyrrolidone, and chloroform.
[0034] Furthermore, in step (3), the filtration is performed using a filter head with a pore size of 0.22-0.45 μm.
[0035] Furthermore, in step (4), the constant temperature is 30-80℃.
[0036] Furthermore, in step (4), the mobile phase used in the gel permeation chromatography is the same as the solvent of the test solution.
[0037] Furthermore, in step (4), the standard used in the gel permeation chromatography is a narrow distribution polymer standard;
[0038] Furthermore, the narrow distribution polymer standard includes one or more of polystyrene standards and polymethyl methacrylate standards.
[0039] It should be noted that there are no special limitations on the molecular weight in this invention; it can be the peak molecular weight, the number-average molecular weight, or the weight-average molecular weight, etc.
[0040] The principle of this invention is as follows: Utilizing the high reactivity of the carbonyl groups in the main chain of a crystalline polyarylether ketone polymer, it undergoes a highly efficient Schiff base reaction with a nucleophilic arylalkylamine compound, disrupting the crystalline structure and transforming the originally insoluble crystalline polymer into a soluble, amorphous iminolated polyarylether ketone. Subsequently, this amorphous iminolated polyarylether ketone can be dissolved in common organic solvents such as N,N-dimethylformamide, tetrahydrofuran, N-methylpyrrolidone, and chloroform at room temperature. Its molecular weight and molecular weight distribution can then be directly determined using gel permeation chromatography under mild conditions. By establishing a quantitative conversion relationship between the polymer molecular weights before and after iminolation, the molecular weight and molecular weight distribution of the original crystalline polyarylether ketone can be accurately deduced. Since the derivatization reaction is a quantitative reaction and does not destroy the polymer main chain, the shape of the molecular weight distribution curve of the crystalline polyarylether ketone is essentially the same as that of the iminolated polyarylether ketone, with only a shift along the molecular weight axis.
[0041] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0042] This invention utilizes iminolated polyarylether ketones obtained through Schiff base reaction, which avoids polymer chain degradation or cross-linking. The number-average molecular weight (Mn) of soluble polyarylether ketone derivatives can be accurately determined using gel permeation chromatography. n ), weight-average molecular weight (M w By obtaining the complete molecular weight distribution (MWD) and the quantitative conversion relationship between the molecular weights of polymers before and after derivatization, the molecular weight and molecular weight distribution of the original crystalline polyaryletherketone can be accurately deduced, thus obtaining complete molecular weight information.
[0043] This invention successfully avoids the use of highly corrosive solvents such as concentrated sulfuric acid, or toxic high-temperature solvent systems such as phenol / trichlorobenzene. The iminolated polyarylether ketone is soluble in common organic solvents such as N,N-dimethylformamide, tetrahydrofuran, and N-methylpyrrolidone at room temperature, significantly reducing operational risks and reliance on special corrosion-resistant high-temperature chromatographic equipment, exhibiting excellent operational safety and convenience.
[0044] This invention utilizes the carbonyl group inherent in the chain of crystalline polyaryletherketones as the reaction site. This functional group is ubiquitous in all its homologues (such as polyetheretherketone, polyetherketoneketone, polyetherketone, polyetheretherketoneketone, polyetherketoneetherketone, biphenyl-type polyetheretherketone, biphenyl-type polyetheretherketoneketone, etc.). Therefore, this method overcomes the dependence of existing sulfonation methods on specific structural units of polymers and provides a universal molecular weight characterization method applicable to the entire family of crystalline polyaryletherketones.
[0045] The Schiff base reaction used in this invention has high efficiency, requiring only 1-3 hours to achieve a fairly high conversion rate, which is beneficial for controlling the conversion efficiency and thus helps to improve the accuracy and repeatability of the final molecular weight determination results. Attached Figure Description
[0046] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0047] Figure 1 This is the chemical reaction formula for the derivatization reaction in Example 1 of the present invention; in the figure, DPS represents diphenyl sulfone.
[0048] Figure 2 The ¹H NMR spectrum of the purified phenethylamine imined polyether ether ketone in Example 1 of this invention.
[0049] Figure 3 This is a gel permeation chromatography elution time diagram of the purified phenylethylamine iminoized polyether ether ketone in Example 1 of the present invention. In the diagram, n is an integer greater than or equal to 10 and less than or equal to 300.
[0050] Figure 4 This is a gel permeation chromatography molecular weight distribution diagram of the purified phenethylamine imined polyether ether ketone in Example 1 of the present invention. Detailed Implementation
[0051] The method of the present invention will be described below through embodiments. The embodiments are merely specific descriptions of the claims of the present invention, and the claims include, but are not limited to, the contents of the embodiments.
[0052] Unless otherwise specified, the reagents and materials described in the following examples are commercially available; and the test methods described are conventional methods unless otherwise specified.
[0053] Example 1
[0054] Polyetheretherketone (3.47 mmol) and phenylethylamine (6.94 mmol) were added to diphenyl sulfone (10 g) and mixed. Under a nitrogen atmosphere, the mixture was heated to 240 °C and maintained at that temperature, and refluxed for 2 h. The chemical reaction formula is as follows. Figure 1 As shown. After the reaction was complete, the resulting mixture was poured into water to precipitate the product. After filtration, a crude product containing phenylethylamine iminolated polyether ether ketone and unreacted phenylethylamine was obtained.
[0055] The crude product was washed three times by heating and reflux with ethanol, then dissolved in tetrahydrofuran, and precipitated again by pouring into ethanol. After drying, purified phenylethylamine imined polyether ether ketone was obtained. Analysis by ¹H NMR showed the following results: Figure 2 As shown, the target structure product was successfully synthesized, and the carbonyl conversion rate was calculated to be greater than 98%.
[0056] The purified phenylethylamine imine-modified polyether ether ketone was dissolved in N,N-dimethylformamide to prepare a solution with a concentration of 4 mg / mL. The solution was then filtered using a filter with a pore size of 0.22 μm to obtain the test solution.
[0057] Subsequently, using N,N-dimethylformamide as the mobile phase and narrow-distribution polystyrene standard as the standard, gel permeation chromatography was performed at 80°C to obtain the elution time and molecular weight distribution maps of phenylethylamine iminolated polyetheretherketone, as shown in the figures below. Figure 3 and Figure 4 As shown in the effluent time graph, it can be demonstrated that there is no polymer degradation or crosslinking. This is based on the quantitative conversion relationship between the molecular weights of polyetheretherketone (PEEK) and phenylethylamine iminolated PEEK. (M) x-PEEK M represents the molecular weight of polyetheretherketone. y-PEEK (where is the molecular weight of phenylethylamine iminolated polyether ether ketone). Based on the molecular weight and molecular weight distribution of phenylethylamine iminolated polyether ether ketone, the molecular weight and molecular weight distribution of polyether ether ketone are deduced, and the data are shown in Table 1.
[0058] Table 1. Molecular weight information of phenylethylamine iminoized polyether ether ketone and the calculated molecular weight information of polyether ether ketone.
[0059]
[0060] Among them, M p M represents the peak molecular weight. n M is the number average molecular weight. w denoted as weight-average molecular weight, and PD as the polydispersity coefficient of the molecular weight distribution.
[0061] Example 2
[0062] Polyether ketone ketone (3.33 mmol) and phenylethylamine (6.66 mmol) were added to diphenyl sulfone (10 g) and mixed. The mixture was heated to 240 °C and maintained at this temperature under a nitrogen atmosphere, and the reaction was carried out under reflux for 2 h. After the reaction was completed, the resulting mixture was poured into water to precipitate the product. After filtration, a crude product containing phenylethylamine imidized polyether ketone ketone and unreacted phenylethylamine was obtained.
[0063] The crude product was washed three times by heating and reflux with ethanol, then dissolved in tetrahydrofuran, and precipitated again by pouring into ethanol. After drying, purified phenylethylamine imined polyether ketone was obtained. Analysis by ¹H NMR confirmed the synthesis of the target structure product, and the carbonyl conversion was calculated to be greater than 98%.
[0064] The purified phenylethylamine imine polyether ketone was dissolved in N,N-dimethylformamide to prepare a solution with a concentration of 4 mg / mL. The solution was then filtered using a filter with a pore size of 0.22 μm to obtain the test solution.
[0065] Subsequently, gel permeation chromatography was performed in a system using N,N-dimethylformamide as the mobile phase and narrow-distribution polystyrene standard as the standard, at 80°C. Elution time and molecular weight distribution maps of phenylethylamine iminolated polyether ketone ketone were obtained. The elution time maps confirmed the absence of polymer degradation or cross-linking. The quantitative conversion relationship between the molecular weights of polyether ketone ketone and phenylethylamine iminolated polyether ketone ketone was then established. (M) x-PEKK M represents the molecular weight of polyetherketoneketone. y-PEKK (where is the molecular weight of phenylethylamine iminolated polyether ketone ketone). Based on the molecular weight and molecular weight distribution of phenylethylamine iminolated polyether ketone ketone, the molecular weight and molecular weight distribution of polyether ketone ketone are deduced, and the data are shown in Table 2.
[0066] Table 2. Molecular weight information of phenylethylamine imide polyether ketone ketone and the calculated molecular weight information of polyether ketone ketone.
[0067]
[0068] Among them, M p M represents the peak molecular weight. n M is the number average molecular weight. w denoted as weight-average molecular weight, and PD as the polydispersity coefficient of the molecular weight distribution.
[0069] Example 3
[0070] Polyether ketone (5.10 mmol) and phenethylamine (10.20 mmol) were added to diphenyl sulfone (10 g) and mixed. The mixture was heated to 240 °C and maintained at this temperature under a nitrogen atmosphere, and the reaction was carried out under reflux for 2 h. After the reaction was completed, the resulting mixture was poured into water to precipitate the product. After filtration, a crude product containing phenethylamine-iminolated polyether ketone and unreacted phenethylamine was obtained.
[0071] The crude product was washed three times by heating and reflux with ethanol, then dissolved in tetrahydrofuran, and precipitated again by pouring into ethanol. After drying, purified phenylethylamine imine-modified polyether ketone was obtained. Analysis by ¹H NMR confirmed the synthesis of the target structure product, and the carbonyl conversion was calculated to be greater than 98%.
[0072] The purified phenylethylamine imine polyether ketone was dissolved in N,N-dimethylformamide to prepare a solution with a concentration of 4 mg / mL. The solution was then filtered using a filter with a pore size of 0.22 μm to obtain the test solution.
[0073] Subsequently, gel permeation chromatography was performed in a system using N,N-dimethylformamide as the mobile phase and narrow-distribution polystyrene standard as the standard, at 80°C. Elution time and molecular weight distribution maps of phenylethylamine iminolated polyetherketone were obtained. The elution time maps confirmed the absence of polymer degradation or cross-linking. The quantitative conversion relationship between the molecular weights of polyetherketone and phenylethylamine iminolated polyetherketone was then established. (M) x-PEK M represents the molecular weight of polyetherketone. y-PEK (where is the molecular weight of phenylethylamine imide polyetherketone). Based on the molecular weight and molecular weight distribution of phenylethylamine imide polyetherketone, the molecular weight and molecular weight distribution of polyetherketone are deduced, and the data are shown in Table 3.
[0074] Table 3. Molecular weight information of phenylethylamine iminolated polyetherketone and the calculated molecular weight information of polyetherketone.
[0075]
[0076] Among them, M p M represents the peak molecular weight. n M is the number average molecular weight. w denoted as weight-average molecular weight, and PD as the polydispersity coefficient of the molecular weight distribution.
[0077] Example 4
[0078] Polyether ether ketone ketone (2.55 mmol) and phenylethylamine (5.10 mmol) were added to diphenyl sulfone (10 g) and mixed. The mixture was heated to 240 °C and maintained at this temperature under a nitrogen atmosphere, and the reaction was carried out under reflux for 2 h. After the reaction was completed, the resulting mixture was poured into water to precipitate the product. After filtration, a crude product containing phenylethylamine imidized polyether ether ketone ketone and unreacted phenylethylamine was obtained.
[0079] The crude product was washed three times by heating and reflux with ethanol, then dissolved in tetrahydrofuran, and precipitated again by pouring into ethanol. After drying, purified phenylethylamine imined polyether ether ketone ketone was obtained. Analysis by ¹H NMR confirmed the synthesis of the target structure product, and the carbonyl conversion was calculated to be greater than 98%.
[0080] The purified phenylethylamine imide polyether ether ketone was dissolved in N,N-dimethylformamide to prepare a solution with a concentration of 4 mg / mL. The solution was then filtered using a filter with a pore size of 0.22 μm to obtain the test solution.
[0081] Subsequently, using N,N-dimethylformamide as the mobile phase and narrow-distribution polystyrene standard as the standard, gel permeation chromatography was performed at 80°C to obtain the elution time and molecular weight distribution maps of phenylethylamine imidized polyether ether ketone ketone. The elution time maps confirmed the absence of polymer degradation or cross-linking. Based on the quantitative conversion relationship between the molecular weights of polyether ether ketone ketone and phenylethylamine imidized polyether ether ketone ketone, further analysis was conducted. (M) x-PEEKK M represents the molecular weight of polyetheretherketoneketone. y-PEEKK (where is the molecular weight of phenylethylamine iminolated polyether ether ketone ketone). Based on the molecular weight and molecular weight distribution of phenylethylamine iminolated polyether ether ketone ketone, the molecular weight and molecular weight distribution of polyether ether ketone ketone are deduced, and the data are shown in Table 4.
[0082] Table 4. Molecular weight information of phenylethylamine imide polyether ether ketone ketone and the calculated molecular weight information of polyether ether ketone ketone.
[0083]
[0084] Among them, M p M represents the peak molecular weight. n M is the number average molecular weight. w denoted as weight-average molecular weight, and PD as the polydispersity coefficient of the molecular weight distribution.
[0085] Example 5
[0086] Polyetherketone (2.02 mmol) and phenethylamine (4.04 mmol) were added to diphenyl sulfone (10 g) and mixed. The mixture was heated to 240 °C and maintained at this temperature under a nitrogen atmosphere, and the reaction was carried out under reflux for 2 h. After the reaction was completed, the resulting mixture was poured into water to precipitate the product. After filtration, a crude product containing phenethylamine-iminolated polyetherketone and unreacted phenethylamine was obtained.
[0087] The crude product was washed three times by heating and reflux with ethanol, then dissolved in tetrahydrofuran, and precipitated again by pouring into ethanol. After drying, purified phenethylamine imined polyetherketone etherketone ketone was obtained. Analysis by ¹H NMR confirmed the synthesis of the target structure product, and the carbonyl conversion was calculated to be greater than 98%.
[0088] The purified phenylethylamine imine-modified polyether ketone was dissolved in N,N-dimethylformamide to prepare a solution with a concentration of 4 mg / mL. The solution was then filtered using a filter with a pore size of 0.22 μm to obtain the test solution.
[0089] Subsequently, using N,N-dimethylformamide as the mobile phase and narrow-distribution polystyrene standard as the standard, gel permeation chromatography was performed at 80°C to obtain the elution time and molecular weight distribution maps of phenethylamine-iminolated polyetherketone etherketone ketone. The elution time maps confirmed the absence of polymer degradation or cross-linking. Based on the quantitative conversion relationship between the molecular weights of polyetherketone etherketone ketone and phenethylamine-iminolated polyetherketone etherketone ketone, further analysis was conducted. (M) x-PEKEKK M represents the molecular weight of polyetherketone (PEK). y-PEKEKK (where is the molecular weight of phenylethylamine iminolated polyetherketone etherketone). Based on the molecular weight and molecular weight distribution of phenylethylamine iminolated polyetherketone etherketone, the molecular weight and molecular weight distribution of polyetherketone etherketone are deduced, and the data are shown in Table 5.
[0090] Table 5. Molecular weight information of phenylethylamine imide polyetherketone and etherketone ketone and the calculated molecular weight information of polyetherketone.
[0091]
[0092] Among them, M p M represents the peak molecular weight. n M is the number average molecular weight. w denoted as weight-average molecular weight, and PD as the polydispersity coefficient of the molecular weight distribution.
[0093] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the embodiments. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all embodiments here. However, obvious variations or modifications derived therefrom are still within the protection of this invention.
Claims
1. A method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones, characterized in that, The steps are as follows: (1) Mix crystalline polyarylether ketone with arylalkylamine compound in the first solvent and reflux for 1-3 hours under an inert atmosphere. After the reaction is complete, pour the resulting mixture into water to precipitate the product. After filtration, the crude product is obtained. The first solvent includes one or more of sulfolane, diphenyl sulfone, N-methylpyrrolidone, and dimethyl sulfoxide; (2) The crude product obtained in step (1) is thoroughly washed with detergent, then dissolved in a good solvent, precipitated in a poor solvent, filtered and dried to obtain purified imino-polyarylether ketone. (3) Dissolve the purified imino-polyarylether ketone obtained in step (2) in a second solvent to prepare a solution with a concentration of 1 mg / mL to 5 mg / mL, filter, and obtain the test solution; The second solvent includes one or more of N,N-dimethylformamide, tetrahydrofuran, N-methylpyrrolidone, and chloroform; (4) The molecular weight and molecular weight distribution of iminopolyaryletherketone were determined by gel permeation chromatography. Based on the quantitative conversion relationship between the molecular weight of crystalline polyaryletherketone and iminopolyaryletherketone, the molecular weight and molecular weight distribution of crystalline polyaryletherketone were deduced. The quantitative conversion relationship between the molecular weights of the crystalline polyarylether ketone and the iminoized polyarylether ketone is as follows: ； In the formula, M x M is the molecular weight of crystalline polyaryletherketone. y M represents the molecular weight of iminolated polyaryletherketone. O-x M is the molar mass of a repeating structural unit of a crystalline polyaryletherketone. O-y The molar mass of a repeating structural unit of iminolated polyaryletherketone.
2. The method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones according to claim 1, characterized in that, In step (1), the crystalline polyaryletherketone comprises one or more of the following structural formulas: ； In the formula, n are independent integers greater than or equal to 10 and less than or equal to 300.
3. The method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones according to claim 1, characterized in that, In step (1), the arylalkylamine compound includes one or more of phenethylamine, 2,2-diphenylethylamine, p-methylphenethylamine, p-nitrophenylethylamine, p-carboxyphenylethylamine, p-sulfonylphenylethylamine, amphetamine, 3,3-diphenylpropylamine, p-methylphenoxyamine, p-nitrophenylethylamine, p-carboxyphenylethylamine, and p-sulfonylphenylethylamine.
4. The method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones according to claim 1, characterized in that, In step (1), the inert atmosphere includes one or more of nitrogen, argon, and helium.
5. The method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones according to claim 1, characterized in that, In step (1), the temperature of the reflux reaction is 140-280℃.
6. The method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones according to claim 1, characterized in that, In step (1), one or more of the following characteristics are present: The molar ratio of the crystalline polyarylether ketone to the arylalkylamine compound is 1:2 to 1:10; The mass ratio of the crystalline polyaryletherketone to the first solvent is 1:5 to 1:
20.
7. The method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones according to claim 1, characterized in that, In step (2), one or more of the following characteristics are present: The detergent includes one or more of ethanol and methanol; The good solvent includes one or more of N,N-dimethylformamide, tetrahydrofuran, N-methylpyrrolidone, chloroform, and dichloromethane; The unsuitable solvents include one or more of ethanol, methanol, and petroleum ether.
8. The method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones according to claim 1, characterized in that, In step (3), the filtration is performed using a filter head with a pore size of 0.22-0.45 μm.
9. The method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones according to claim 1, characterized in that, In step (4), one or more of the following characteristics are present: The test solution obtained in step (3) was determined by gel permeation chromatography at a constant temperature of 30-80℃; The mobile phase used in the gel permeation chromatography is the same as the second solvent used in the test solution; The standard used in the gel permeation chromatography is a narrow distribution polymer standard.
10. The method for characterizing the molecular weight and molecular weight distribution of crystalline polyarylether ketones according to claim 9, characterized in that, In step (4), the narrow distribution polymer standard includes one or more of polystyrene standard and polymethyl methacrylate standard.