CN117269365A - A method for comparing resin molecular weight and molecular weight distribution - Google Patents
A method for comparing resin molecular weight and molecular weight distribution Download PDFInfo
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- CN117269365A CN117269365A CN202311259732.8A CN202311259732A CN117269365A CN 117269365 A CN117269365 A CN 117269365A CN 202311259732 A CN202311259732 A CN 202311259732A CN 117269365 A CN117269365 A CN 117269365A
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- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N30/00—Investigating or analysing materials by separation into components using adsorption, absorption or similar phenomena or using ion-exchange, e.g. chromatography or field flow fractionation
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Abstract
The invention provides a method for comparing molecular weight and molecular weight distribution of resin, which relates to the technical field of relative molecular mass measurement and comprises the following steps: dissolving a resin sample to prepare a resin sample solution; checking whether leakage and residual samples exist in a pipeline and a sample injection system of the GPC device, and adjusting working parameters of the GPC device; starting a GPC device, injecting a resin sample solution after the image is stable, drawing a chromatographic image of the resin sample, and analyzing the accuracy of the chromatographic image of the resin sample; drawing a plurality of groups of chromatographic images of polystyrene with different known molecular weights according to the steps; drawing a correction curve and a working curve according to the chromatographic image of the polystyrene and the chromatographic image of the resin sample; the molecular weight and molecular weight distribution of the resin sample were calculated by data analysis. The method solves the technical problems that in the detection process of the existing gel permeation chromatography, the chromatographic image of the resin material is not checked, the chromatographic image used for drawing the working curve is inaccurate, and the accuracy of the detection result is affected.
Description
Technical Field
The invention relates to the technical field of relative molecular mass measurement, in particular to a method for comparing the molecular weight and molecular weight distribution of resin.
Background
The molecular weight distribution of the resin is an important index for characterizing the polymer, and has remarkable influence on the physical and mechanical properties and molding processability of the resin material. The usual measurement methods are: viscosity method, laser light scattering method, mass spectrometry and size exclusion chromatography (SEC method), wherein gel permeation chromatography (GPC method) is a type of size exclusion chromatography, which is convenient and quick, popular in equipment, and has wide applicability.
The detection of existing gel permeation chromatography has the following problems:
1. in the detection process, the chromatographic image of the resin material is not checked, which may cause inaccuracy of the chromatographic image used for drawing the working curve and influence the accuracy of the detection result;
2. the lack of a device for collecting and treating waste liquid is easy to cause environmental pollution.
Disclosure of Invention
The present invention provides a method for comparing the molecular weight and molecular weight distribution of a resin, which is used for solving at least one of the above-mentioned technical problems.
In order to solve the technical problems, the invention discloses a method for comparing the molecular weight and the molecular weight distribution of resin, which comprises the following steps:
step S1: dissolving a resin sample to prepare a resin sample solution;
step S2: checking whether leakage and residual samples exist in a pipeline and a sample injection system of the GPC device, and adjusting working parameters of the GPC device;
step S3: starting a GPC device, injecting a resin sample solution after the image is stable, drawing a chromatographic image of the resin sample, and analyzing the accuracy of the chromatographic image of the resin sample;
step S4: drawing a plurality of groups of chromatographic images of polystyrene with different known molecular weights according to the steps of the steps S1-S3;
step S5: drawing a correction curve and a working curve according to the chromatographic image of the polystyrene and the chromatographic image of the resin sample;
step S6: the molecular weight and molecular weight distribution of the resin sample were calculated by data analysis.
Preferably, step S1 includes:
step S11: weighing 40mg of resin sample, putting the sample into a wide-mouth bottle, and adding 10ml of tetrahydrofuran solution for dissolution;
step S12: after the resin sample was completely dissolved, the solution was filtered through a 2 μm filter membrane.
Preferably, step S3 includes:
step S31: dividing the resin sample solution into a plurality of groups of test samples uniformly;
step S32: sequentially testing by using a plurality of groups of test samples to obtain chromatographic images of a plurality of resin samples;
step S33: sequentially comparing the similarity of the chromatographic images of the plurality of resin samples, dividing all the chromatographic images into a first group and a second group, wherein the similarity of any two chromatographic images in the first group is larger than a preset first threshold value, and the rest chromatographic images are placed in the second group;
step S34: calculating a first ratio of the number of chromatographic images in the first group to the number of chromatographic images of all the resin samples, judging whether the first ratio is larger than a preset second threshold, if the first ratio is larger than the preset second threshold, drawing a working curve by using the chromatographic images in the first group, and if the first ratio is smaller than or equal to the preset second threshold, repeating the steps S31-S33 after preparing the resin sample solution again.
Preferably, step S5 includes:
step S51: measuring the retention volume corresponding to the sample peak in the chromatographic image of each polystyrene of different molecular weight;
step S52: drawing a correction curve on a semi-logarithmic coordinate system by taking the reserved volume of polystyrene as an abscissa and the molecular weight of polystyrene as an ordinate;
step S53: taking the molecular weights of a plurality of polystyrene on the correction curve, and calculating the molecular weight of a resin sample through a formula I;
step S54: drawing a working curve on a semi-logarithmic coordinate system by taking the reserved volume of the resin sample as an abscissa and the molecular weight of the resin sample calculated in the step S53 as an ordinate;
step S55: and obtaining a working curve equation according to the working curve.
Preferably, step S6 includes:
step S61, labeling V on the chromatographic image A Point and V B Point, V A The point is the point just lifted by the sample peak, V B The point is the point at which the sample peak reverts back to baseline;
step S62, dividing a chromatographic image of a resin sample into a plurality of equal fragments through a straight line perpendicular to a base line, recording the reserved volume, peak height, area and molecular weight of each equal fragment, and leading the molecular weight into a working curve equation by the reserved volume of each point;
step S63: and calculating the distribution width index of the molecular weight through a formula II.
Preferably, formula one is:
wherein: k (K) 1 Is a constant related to temperature in the polystyrene viscosity coefficient; k (K) 2 A temperature dependent constant in the viscosity coefficient of the resin sample; alpha 1 Is a characteristic constant related to a high polymer system in a polystyrene viscosity coefficient; alpha 2 Characteristic constants related to a high polymer system in the viscosity coefficient of the resin sample; m is M 1 Is the molecular weight of polystyrene; m is M 2 Molecular weight of the resin sample; lg is a base 10 logarithmic function;
the formula II is:
wherein: d is a molecular weight distribution breadth index; a is that i Peak area for the ith slice; m is M i Molecular weight for the ith aliquot; t is the total number of equal slices.
Preferably, the GPC device comprises a solvent tank, the solvent tank is used for storing filtered tetrahydrofuran, the solvent tank is communicated with a liquid inlet of a high-pressure flow pump, a liquid outlet of the high-pressure flow pump is connected with a sample injector, a liquid outlet of the sample injector is communicated with a liquid inlet of a chromatographic column, a liquid outlet of the chromatographic column is connected with a differential detector, a liquid outlet of the differential detector is connected with a waste liquid treatment tank, and a liquid outlet of the waste liquid treatment tank is connected with a waste liquid collecting tank.
Preferably, the waste liquid treatment box comprises a box body, the upper end of the left side wall of the box body is provided with a liquid inlet, the lower end of the right side wall of the box body is provided with a liquid outlet, the liquid outlet is provided with an electric valve, the upper surface of the box body is connected with an oxide storage box and a gas purifying box, an oxidant is stored in the oxide storage box, the inner wall of the oxide storage box is fixedly connected with a transverse plate, an electric control gate is arranged on the transverse plate, the left side wall of the box body is fixedly connected with a waste tank, the outer wall of the waste tank is provided with a detection window, the inner wall of the waste tank is fixedly connected with a filter plate, the waste tank is communicated with the inside of the box body through a waste port and a backflow port, the backflow port is arranged on the lower side of the filter plate, the waste port of the inner wall of the box body is fixedly connected with a collecting tank, a central rod is fixedly connected with the inner wall of the front side and the box body, a bearing groove is sleeved on the central rod in a rotating way, the inner wall of the right side of the box is fixedly connected with a limiting plate, and the upper surface of the limiting plate is contacted with the right side of the bottom surface of the bearing groove.
Preferably, the top surface fixedly connected with T shape seat in the box, the cover is equipped with the floating plate on the T shape seat, the right side lower surface of floating plate passes through connecting rope one with the loading tank right part and is connected, the vertical portion left and right sides wall symmetry sliding connection of T shape seat has two stoppers, be provided with the conical surface on the stopper, fixedly connected with spring one between two stoppers, the one end hinge that two stoppers are close to each other has the connecting rod, the other end and the center plate hinge of connecting rod, the center plate upper surface is connected with control assembly, the top surface fixedly connected with connecting plate in the box, the top surface is provided with the flitch along left and right sides direction sliding connection in the box, be provided with the unloading hole on the flitch, fixedly connected with spring two between flitch left end and the connecting plate right side wall, flitch right-hand member fixedly connected with connecting rope three, the other end of connecting rope three is walked around the steering wheel back fixed connection at center plate upper surface.
Preferably, the control assembly comprises a limiting box, the limiting box is fixedly connected to the right side wall of the box body, a communication hole is formed in the bottom surface of the limiting box, a floating block is placed in the limiting box, the upper surface of the floating block is fixedly connected with a supporting rod, the supporting rod penetrates through the upper wall of the limiting box in a sliding mode along the up-down direction, the upper end of the supporting rod is fixedly connected with a balancing weight, the upper surface of the balancing weight is fixedly connected with a connecting rope II, and the other end of the connecting rope II bypasses a steering wheel and is fixedly connected to the upper surface of the center plate.
The technical scheme of the invention is further described in detail through the drawings and the embodiments.
Compared with the prior art, the invention has the following beneficial effects:
the prepared resin sample solution is evenly divided into a plurality of groups of test samples, the chromatographic images of a plurality of resin samples are obtained, the similarity between the chromatographic images of the resin samples exceeding the second threshold ratio is ensured to be larger than the first threshold value by comparing the chromatographic images of the plurality of resin samples, the accuracy of the chromatographic images is ensured, and the accuracy of the molecular weight of the resin and the molecular weight distribution result is effectively improved.
Drawings
The accompanying drawings are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate the invention and together with the embodiments of the invention, serve to explain the invention. In the drawings:
FIG. 1 is a flow chart of the method of the present invention;
FIG. 2 is a schematic view of the GPC apparatus of the present invention;
FIG. 3 is a schematic view of a waste liquid treatment tank according to the present invention;
fig. 4 is an enlarged schematic view of the area a in fig. 3.
In the figure: 1. a solvent tank; 2. a high pressure flow pump; 3. a sample injector; 4. a chromatographic column; 5. a differential detector; 6. a waste liquid treatment tank; 7. a waste liquid collection box; 8. a case; 9. an electric valve; 10. an oxide storage tank; 11. a gas purifying tank; 12. a cross plate; 13. an electric control gate; 14. a waste tank; 15. a detection window; 16. a filter plate; 17. a waste port; 18. a return port; 19. a collection tank; 20. a central rod; 21. a carrying groove; 22. a limiting plate; 23. a T-shaped seat; 24. a floating plate; 25. a first connecting rope; 26. a limiting block; 27. a conical surface; 28. a first spring; 29. a connecting rod; 30. a center plate; 31. a connecting plate; 32. a discharge plate; 33. a second spring; 34. a third connecting rope; 35. a steering wheel; 36. a limit box; 37. a communication hole; 38. a floating block; 39. a support rod; 40. balancing weight; 41. and a second connecting rope.
Detailed Description
The preferred embodiments of the present invention will be described below with reference to the accompanying drawings, it being understood that the preferred embodiments described herein are for illustration and explanation of the present invention only, and are not intended to limit the present invention.
In addition, the descriptions of the "first," "second," and the like, herein are for descriptive purposes only and are not intended to be specifically construed as order or sequence, nor are they intended to limit the invention solely for distinguishing between components or operations described in the same technical term, but are not to be construed as indicating or implying any relative importance or order of such features. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, technical solutions and technical features between the embodiments may be combined with each other, but it is necessary to base that a person skilled in the art can implement the combination of technical solutions, when the combination of technical solutions contradicts or cannot be implemented, should be considered that the combination of technical solutions does not exist, and is not within the scope of protection claimed by the present invention.
The invention provides the following examples
Example 1
The embodiment of the invention provides a method for comparing the molecular weight and molecular weight distribution of resin, which comprises the following steps:
step S1: dissolving a resin sample to prepare a resin sample solution;
step S2: checking whether leakage and residual samples exist in a pipeline and a sample injection system of the GPC device, and adjusting working parameters of the GPC device;
step S3: starting a GPC device, injecting a resin sample solution after the image is stable, drawing a chromatographic image of the resin sample, and analyzing the accuracy of the chromatographic image of the resin sample;
step S4: drawing a plurality of groups of chromatographic images of polystyrene with different known molecular weights according to the steps of the steps S1-S3;
step S5: drawing a correction curve and a working curve according to the chromatographic image of the polystyrene and the chromatographic image of the resin sample;
step S6: the molecular weight and molecular weight distribution of the resin sample were calculated by data analysis.
Preferably, step S1 includes:
step S11: weighing 40mg of resin sample, putting the sample into a wide-mouth bottle, and adding 10ml of tetrahydrofuran solution for dissolution;
step S12: after the resin sample was completely dissolved, the solution was filtered through a 2 μm filter membrane.
Preferably, step S3 includes:
step S31: dividing the resin sample solution into a plurality of groups of test samples uniformly;
step S32: sequentially testing by using a plurality of groups of test samples to obtain chromatographic images of a plurality of resin samples;
step S33: sequentially comparing the similarity of the chromatographic images of the plurality of resin samples, dividing all the chromatographic images into a first group and a second group, wherein the similarity of any two chromatographic images in the first group is larger than a preset first threshold value, and the rest chromatographic images are placed in the second group;
step S34: calculating a first ratio of the number of chromatographic images in the first group to the number of chromatographic images of all the resin samples, judging whether the first ratio is larger than a preset second threshold, if the first ratio is larger than the preset second threshold, drawing a working curve by using the chromatographic images in the first group, and if the first ratio is smaller than or equal to the preset second threshold, repeating the steps S31-S33 after preparing the resin sample solution again.
Preferably, step S5 includes:
step S51: measuring the retention volume corresponding to the sample peak in the chromatographic image of each polystyrene of different molecular weight;
step S52: drawing a correction curve on a semi-logarithmic coordinate system by taking the reserved volume of polystyrene as an abscissa and the molecular weight of polystyrene as an ordinate;
step S53: taking the molecular weights of a plurality of polystyrene on the correction curve, and calculating the molecular weight of a resin sample through a formula I;
step S54: drawing a working curve on a semi-logarithmic coordinate system by taking the reserved volume of the resin sample as an abscissa and the molecular weight of the resin sample calculated in the step S53 as an ordinate;
step S55: and obtaining a working curve equation according to the working curve.
Preferably, step S6 includes:
step S61, labeling V on the chromatographic image A Point and V B Point, V A The point is the point just lifted by the sample peak, V B The point is the point at which the sample peak reverts back to baseline;
step S62, dividing a chromatographic image of a resin sample into a plurality of equal fragments through a straight line perpendicular to a base line, recording the reserved volume, peak height, area and molecular weight of each equal fragment, and leading the molecular weight into a working curve equation by the reserved volume of each point;
step S63: and calculating the distribution width index of the molecular weight through a formula II.
Preferably, formula one is:
wherein: k (K) 1 Is a constant related to temperature in the polystyrene viscosity coefficient; k (K) 2 A temperature dependent constant in the viscosity coefficient of the resin sample; alpha 1 Is a characteristic constant related to a high polymer system in a polystyrene viscosity coefficient; alpha 2 Characteristic constants related to a high polymer system in the viscosity coefficient of the resin sample; m is M 1 Is the molecular weight of polystyrene; m is M 2 Molecular weight of the resin sample; lg is a base 10 logarithmic function;
the formula II is:
wherein: d is a molecular weight distribution breadth index; a is that i Peak area for the ith slice; m is M i Molecular weight for the ith aliquot; t is the total number of equal slices.
Wherein, optionally, the reliability P of the molecular weight calculation is calculated based on the formula III, and when the reliability is smaller than the corresponding preset value, early warning is carried out;
B 1 at a first ratio, B 2 Is the ratio of the number of chromatographic patterns in the second group to the number of chromatographic images of all resin samples;an average value of the similarity of any two chromatographic images in the first group; w (w) 1 Maximum value of similarity of any two chromatographic images in the first group; w (w) 2 For the minimum similarity of any two chromatographic images in the first groupA value; w (w) 3k Is the average of the similarity of the kth Zhang Sepu image in the second group to all of the chromatographic images in the first group; f is the total number of chromatogram images in the second group; min () is a minimum function.
Preferably, the GPC device comprises a solvent tank 1, wherein the solvent tank 1 is used for storing filtered tetrahydrofuran, the solvent tank 1 is communicated with a liquid inlet of a high-pressure flow pump 2, a liquid outlet of the high-pressure flow pump 2 is connected with a sample injector 3, a liquid outlet of the sample injector 3 is communicated with a liquid inlet of a chromatographic column 4, a liquid outlet of the chromatographic column 4 is connected with a differential detector 5, a liquid outlet of the differential detector 5 is connected with a waste liquid treatment tank 6, and a liquid outlet of the waste liquid treatment tank 6 is connected with a waste liquid collecting tank 7.
In this example, each set of test samples was tested individually, and the next set of test samples was injected after the recorder had completely drawn the chromatographic image of the previous set of test samples.
In this embodiment, the operating parameters of the GPC device include the sensitivity of the instrument, the type of detector, the polarity, the pump flow rate, and the sample injection volume.
In this example, the correction curve is a curve drawn using a chromatographic image of polystyrene of known molecular weight.
In this embodiment, the working curve is a curve for calculating the molecular weight of the resin drawn based on the correction curve and the chromatographic image of the resin sample.
In this example, the reason why the dissolved resin sample solution is filtered is that the solution detected by gel permeation chromatography cannot contain solid components, so that the detection result is not affected and the instrument is prevented from being destroyed.
In this embodiment, when analyzing the similarity of the chromatographic images, the sample peaks in the chromatographic images are cut out, the points where the sample peaks are lifted are overlapped, and then the similarity of the sample peaks in the two chromatographic images is analyzed, wherein the similarity of the sample peaks is the similarity of the chromatographic images, except for the similarity analysis of the first group of chromatographic images, one of the two chromatographic images used in the similarity analysis of all subsequent chromatographic images is derived from the first group, and the other chromatographic image is derived from the non-analyzed group, which is the group where the chromatographic images are not subjected to the similarity analysis of the chromatographic images.
In this example, the retention volume refers to the volume of mobile phase consumed from the beginning of sample injection to the time when the concentration of the measured component after the column is maximized.
In this embodiment, the baseline is a horizontal straight line, which is a measurement reference and one of indexes for checking whether the instrument works normally.
In this example, the vertical distance from the highest point of the sample peak to the base line is referred to as the peak height.
In this example, the area of the sample peak is the area of the image of the sample peak and the baseline composition.
In this example, the distribution width index is an index indicating the degree of dispersion of the molecular weight distribution.
The beneficial effects of the technical scheme are as follows:
the prepared resin sample solution is evenly divided into a plurality of groups of test samples, chromatographic images of a plurality of resin samples are obtained, and by comparing the chromatographic images of the plurality of resin samples, the first ratio of a first group with similarity larger than a first threshold value is ensured to be larger than a preset second threshold value, the accuracy of the chromatographic images is ensured, and the accuracy of the molecular weight of the resin and the molecular weight distribution result is effectively improved.
Example 2
On the basis of embodiment 1, waste liquid treatment box 6 includes box 8, box 8 left side wall upper end is provided with the inlet, box 8 right side wall lower extreme is provided with the liquid outlet, the liquid outlet is provided with motorised valve 9, box 8 upper surface is connected with oxide storage box 10 and gas purification case 11, it has the oxidant to deposit in the oxide storage box 10, oxide storage box 10 inner wall fixedly connected with diaphragm 12, be provided with automatically controlled gate 13 on the diaphragm 12, box 8 left side wall fixedly connected with waste tank 14, waste tank 14 outer wall is provided with the sight glass 15, waste tank 14 inner wall fixedly connected with filter 16, waste tank 14 communicates with box 8 inside through waste port 17 and return port 18, return port 18 sets up in filter 16 downside, box 8 inner wall waste port 17 department fixedly connected with collecting vat 19, fixedly connected with center rod 20 on the inner wall of box 8 front and back side, the cover is equipped with loading groove 21 on the center rod 20, box 8 right side inner wall fixedly connected with limiting plate 22, limiting plate 22 upper surface contacts with loading groove 21 bottom right side.
Preferably, the top surface fixedly connected with T shape seat 23 in box 8, the cover is equipped with the floating plate 24 on the T shape seat 23, the right side lower surface of floating plate 24 is connected through connecting rope one 25 with the right part of loading tank 21, the vertical portion left and right sides wall symmetry sliding connection of T shape seat 23 has two stopper 26, be provided with conical surface 27 on the stopper 26, fixedly connected with spring one 28 between two stopper 26, the one end that two stopper 26 are close to each other articulates there is connecting rod 29, the other end of connecting rod 29 articulates with center plate 30, center plate 30 upper surface is connected with control assembly, the top surface fixedly connected with connecting plate 31 in the box 8, the top surface is provided with discharge plate 32 along left and right directions sliding connection in box 8, be provided with the unloading hole on the discharge plate 32, fixedly connected with spring two 33 between the left end of discharge plate 32 and the right side wall of connecting plate 31, discharge plate 32 right end fixedly connected with connecting rope three 34, the other end of connecting rope three 34 walks around steering wheel 35 after fixedly connected with the upper surface of center plate 30.
Preferably, the control assembly comprises a limiting box 36, the limiting box 36 is fixedly connected to the right side wall of the box body 8, a communication hole 37 is formed in the bottom surface of the limiting box 36, a floating block 38 is placed in the limiting box 36, the upper surface of the floating block 38 is fixedly connected with a supporting rod 39, the supporting rod 39 penetrates through the upper wall of the limiting box 36 in a sliding mode along the up-down direction, the upper end of the supporting rod 39 is fixedly connected with a balancing weight 40, the upper surface of the balancing weight 40 is fixedly connected with a second connecting rope 41, and the other end of the second connecting rope 41 bypasses the steering wheel 35 and is fixedly connected to the upper surface of the central plate 30.
The beneficial effects of the technical scheme are as follows:
after the tetrahydrofuran is inspected and flows into the box body 8 through the liquid inlet, when the tetrahydrofuran is accumulated to a certain liquid level, the tetrahydrofuran reacts with oxides carried on the carrying groove 21 to enable the tetrahydrofuran to react with the oxides, so that the concentration of the tetrahydrofuran in the waste liquid is reduced, the volatilization of the tetrahydrofuran into the air is avoided to influence the physical health of an experimenter, meanwhile, the volatilized tetrahydrofuran gas is absorbed through the gas purifying box 11, the influence of the tetrahydrofuran gas on the physical health of the experimenter is further prevented by entering the experiment space, along with the continuous rising of the liquid level of the waste liquid, the floating plate 24 is lifted under the action of the buoyancy until the floating plate 24 moves to the upper side of the limiting block 26, the right part of the carrying groove 21 is lifted through the first connecting rope 25, the oxides on the carrying groove 21 fall into the collecting groove 19 along the carrying groove 21, finally fall into the waste groove 14, and meanwhile, the electric valve 9 is opened, and the treated waste liquid in the waste liquid treating box 6 flows into the waste liquid collecting box 7 for storage. As the waste liquid flows out, the liquid level of the waste liquid drops, the floating block 38 drops along with the waste liquid, the connecting rope II 41 is pulled under the action of the balancing weight 40, the central plate 30 moves upwards, the two limiting blocks 26 are mutually close, the floating plate 24 drops below the limiting blocks 26 after losing the limiting, meanwhile, the connecting rope III 34 does not exert pulling force on the discharging plate 32 any more, the discharging plate 32 moves leftwards under the action of the spring II 33, the discharging hole on the discharging plate 32 is communicated with the discharging hole of the oxide storage box 10, the oxide below the partition plate falls onto the bearing groove 21 from the discharging hole, the replacement of the oxide is completed, after the waste liquid flows out, the electric valve 9 is closed, as the liquid level of the waste liquid rises again, the floating block 38 is lifted under the action of the floating force, the central plate 30 losing the pulling force of the connecting rope II 41 moves downwards under the action of the spring I, the electric control 13 is started, the oxide above the partition plate quantitatively drops below the partition plate, and the oxide is replaced.
Through the periodic replacement oxide, guaranteed the purifying effect to the waste liquid, can be convenient through the observation window 15 high of waste material in the waste tank 14, be convenient for the experimenter in time clear up the waste oxide, the reflow mouth 18 that the waste tank 14 lower part set up simultaneously communicates with box 8 is inside, make the oxide in the waste tank 14 still can participate in the reaction, the utilization ratio of oxide has been improved, separate the oxide bin 10 into upper and lower two parts through the baffle, the tetrahydrofuran gas that has avoided volatilizing reacts with all oxides, influence the quality of all oxides, accomplish the ration of oxide through automatically controlled gate 13 and put in, the quantity accuracy of oxide has been ensured, the whereabouts of floating plate 24 before guaranteeing the purifying effect is restricted through stopper 26, ensure that the change of oxide is more thorough, it is stifled to prevent to accumulate too much oxide on the loading tank 21, ensure the fluxion of loading tank 21, accomplish the automatic reset of device after the waste liquid stream, the operation of experimenter's processing box 6 has been reduced, the volume of volatilizing of tetrahydrofuran entering environment has been reduced, the healthy experiment personnel's life-span of life has been guaranteed, the health of the experiment box 6 has been guaranteed.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (10)
1. A method for comparing molecular weight and molecular weight distribution of a resin, characterized by: comprising the following steps:
step S1: dissolving a resin sample to prepare a resin sample solution;
step S2: checking whether leakage and residual samples exist in a pipeline and a sample injection system of the GPC device, and adjusting working parameters of the GPC device;
step S3: starting a GPC device, injecting a resin sample solution after the image is stable, drawing a chromatographic image of the resin sample, and analyzing the accuracy of the chromatographic image of the resin sample;
step S4: drawing a plurality of groups of chromatographic images of polystyrene with different known molecular weights according to the steps of the steps S1-S3;
step S5: drawing a correction curve and a working curve according to the chromatographic image of the polystyrene and the chromatographic image of the resin sample;
step S6: the molecular weight and molecular weight distribution of the resin sample were calculated by data analysis.
2. The method for comparing molecular weight and molecular weight distribution of resin according to claim 1, wherein: the step S1 comprises the following steps:
step S11: weighing 40mg of resin sample, putting the sample into a wide-mouth bottle, and adding 10ml of tetrahydrofuran solution for dissolution;
step S12: after the resin sample was completely dissolved, the solution was filtered through a 2 μm filter membrane.
3. The method for comparing molecular weight and molecular weight distribution of resin according to claim 1, wherein: the step S3 comprises the following steps:
step S31: dividing the resin sample solution into a plurality of groups of test samples uniformly;
step S32: sequentially testing by using a plurality of groups of test samples to obtain chromatographic images of a plurality of resin samples;
step S33: sequentially comparing the similarity of the chromatographic images of the plurality of resin samples, dividing all the chromatographic images into a first group and a second group, wherein the similarity of any two chromatographic images in the first group is larger than a preset first threshold value, and the rest chromatographic images are placed in the second group;
step S34: calculating a first ratio of the number of chromatographic images in the first group to the number of chromatographic images of all the resin samples, judging whether the first ratio is larger than a preset second threshold, if the first ratio is larger than the preset second threshold, drawing a working curve by using the chromatographic images in the first group, and if the first ratio is smaller than or equal to the preset second threshold, repeating the steps S31-S33 after preparing the resin sample solution again.
4. The method for comparing molecular weight and molecular weight distribution of resin according to claim 1, wherein: the step S5 comprises the following steps:
step S51: measuring the retention volume corresponding to the sample peak in the chromatographic image of each polystyrene of different molecular weight;
step S52: drawing a correction curve on a semi-logarithmic coordinate system by taking the reserved volume of polystyrene as an abscissa and the molecular weight of polystyrene as an ordinate;
step S53: taking the molecular weights of a plurality of polystyrene on the correction curve, and calculating the molecular weight of a resin sample through a formula I;
step S54: drawing a working curve on a semi-logarithmic coordinate system by taking the reserved volume of the resin sample as an abscissa and the molecular weight of the resin sample calculated in the step S53 as an ordinate;
step S55: and obtaining a working curve equation according to the working curve.
5. The method for comparing molecular weight and molecular weight distribution of resin according to claim 4, wherein: the step S6 comprises the following steps:
step S61, labeling V on the chromatographic image A Point and V B Point, V A The point is the point just lifted by the sample peak, V B The point is the point at which the sample peak reverts back to baseline;
step S62, dividing a chromatographic image of a resin sample into a plurality of equal fragments through a straight line perpendicular to a base line, recording the reserved volume, peak height, area and molecular weight of each equal fragment, and leading the molecular weight into a working curve equation by the reserved volume of each point;
step S63: and calculating the distribution width index of the molecular weight through a formula II.
6. The method for comparing molecular weight and molecular weight distribution of resin according to claim 5, wherein:
the first formula is:
wherein: k (K) 1 Is a constant related to temperature in the polystyrene viscosity coefficient; k (K) 2 A temperature dependent constant in the viscosity coefficient of the resin sample; alpha 1 Is a characteristic constant related to a high polymer system in a polystyrene viscosity coefficient; alpha 2 Characteristic constants related to a high polymer system in the viscosity coefficient of the resin sample; m is M 1 Is the molecular weight of polystyrene; m is M 2 Molecular weight of the resin sample; lg is a base 10 logarithmic function;
the formula II is:
wherein: d is a molecular weight distribution breadth index; a is that i Peak area for the ith slice; m is M i Molecular weight for the ith aliquot; t is the total number of equal slices.
7. The method for comparing molecular weight and molecular weight distribution of resin according to claim 1, wherein: the GPC device includes solvent tank (1), solvent tank (1) is used for storing through filterable tetrahydrofuran, the inlet intercommunication with high-pressure flow pump (2) on solvent tank (1), the liquid outlet of high-pressure flow pump (2) is connected with sample injector (3), the liquid outlet of sample injector (3) communicates with the inlet of chromatographic column (4), the liquid outlet of chromatographic column (4) is connected with differential detector (5), the liquid outlet of differential detector (5) is connected with waste liquid treatment case (6), the liquid outlet of waste liquid treatment case (6) is connected with waste liquid collecting box (7).
8. The method for comparing molecular weight and molecular weight distribution of resin according to claim 7, wherein: the waste liquid treatment box (6) comprises a box body (8), the upper end of the left side wall of the box body (8) is provided with a liquid inlet, the lower end of the right side wall of the box body (8) is provided with a liquid outlet, the liquid outlet is provided with an electric valve (9), the upper surface of the box body (8) is connected with an oxide storage box (10) and a gas purifying box (11), an oxidant is stored in the oxide storage box (10), the inner wall of the oxide storage box (10) is fixedly connected with a transverse plate (12), an electric control gate (13) is arranged on the transverse plate (12), the left side wall of the box body (8) is fixedly connected with a waste groove (14), the outer wall of the waste groove (14) is provided with a detection window (15), the inner wall of the waste groove (14) is fixedly connected with a filter plate (16), the waste groove (14) is communicated with the interior of the box body (8) through a waste hole (17) and a backflow hole (18), the backflow hole (18) is arranged on the lower side of the filter plate (16), the waste hole (17) is fixedly connected with a collecting groove (19), the inner wall of the box body (8) is fixedly connected with a front side and rear side inner wall of the box (8), the inner wall is fixedly connected with a central rod (20) and is provided with a central limiting sleeve (22), the upper surface of the limiting plate (22) is contacted with the right side of the lower bottom surface of the bearing groove (21).
9. The method for comparing molecular weight and molecular weight distribution of resin according to claim 8, wherein: top surface fixedly connected with T shape seat (23) in box (8), the cover is equipped with floating plate (24) on T shape seat (23), floating plate (24) right side lower surface is connected through connecting rope one (25) with carrier groove (21) right part, the vertical portion left and right sides wall symmetry sliding connection of T shape seat (23) has two stopper (26), be provided with conical surface (27) on stopper (26), fixedly connected with spring one (28) between two stopper (26), the one end hinge that two stopper (26) are close to each other has connecting rod (29), the other end and the center plate (30) hinge of connecting rod (29), center plate (30) upper surface is connected with control assembly, top surface fixedly connected with connecting plate (31) in box (8), top surface is provided with flitch (32) along left and right sides direction sliding connection in box (8), fixedly connected with unloading hole on flitch (32) left end and connecting plate (31) right side wall between fixedly connected with spring two (33), flitch (32) right end fixedly connected with connecting rope three (34), the other end of connecting rope three (34) are walked around on center plate (35) fixedly connected with the back surface of center plate (30).
10. A method of comparing molecular weight and molecular weight distribution of resins according to claim 9, wherein: the control assembly comprises a limiting box (36), the limiting box (36) is fixedly connected to the right side wall of the box body (8), a communication hole (37) is formed in the bottom surface of the limiting box (36), a floating block (38) is placed in the limiting box (36), a supporting rod (39) is fixedly connected to the upper surface of the floating block (38), the supporting rod (39) penetrates through the upper wall of the limiting box (36) in a sliding mode along the up-down direction, a balancing weight (40) is fixedly connected to the upper end of the supporting rod (39), a connecting rope II (41) is fixedly connected to the upper surface of the balancing weight (40), and the other end of the connecting rope II (41) bypasses a steering wheel (35) and is fixedly connected to the upper surface of the center plate (30).
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1316290A (en) * | 1999-11-30 | 2001-10-10 | 日本派欧尼股份株式会社 | Purifying method and device for harmful gas |
| CN113521749A (en) * | 2021-07-15 | 2021-10-22 | 珠海金山网络游戏科技有限公司 | Abnormal account detection model training method and abnormal account detection method |
| CN215005157U (en) * | 2021-07-22 | 2021-12-03 | 江苏泰华检验股份有限公司 | Ion chromatograph with waste overflow alarm function |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1316290A (en) * | 1999-11-30 | 2001-10-10 | 日本派欧尼股份株式会社 | Purifying method and device for harmful gas |
| CN113521749A (en) * | 2021-07-15 | 2021-10-22 | 珠海金山网络游戏科技有限公司 | Abnormal account detection model training method and abnormal account detection method |
| CN215005157U (en) * | 2021-07-22 | 2021-12-03 | 江苏泰华检验股份有限公司 | Ion chromatograph with waste overflow alarm function |
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