Method and system for detecting antioxidant content in polyethylene materials

Abstract

The present invention relates to the technical field of material property detection, and specifically to a method and system for detecting the content of an antioxidant in a polyethylene material. The method sets a test group solution adjusted at different temperatures, and the test group solution includes a material solution and a food solution for soaking the material. The target antioxidant content and the target degradation product content in the test group solution are characterized by a difference index by comparing with the control group solution. Further, in a cycle, the content characteristics between the material solution and the food solution are compared, and the antioxidant failure index of each cycle is determined by the data changes between the cycles. The antioxidant failure index between different temperatures under the same cycle is compared to determine the probability of antioxidant failure under each temperature condition, and determine the antioxidant failure group. The present invention effectively evaluates and detects the antioxidant content and antioxidant status of the polyethylene material by comparing the content characteristics in the polyethylene material and the food solution.

Description

Technical Field

[0001] The present invention relates to the technical field of material property detection, and in particular to a method and system for detecting the content of an antioxidant in a polyethylene material. Background Art

[0002] Polyethylene is widely used as a food packaging material. Polyethylene materials need to effectively block environmental interference such as moisture, gas, and light to prevent the food in the package from being affected by the environment and deteriorating. In order to enable polyethylene materials to achieve the function of food packaging, antioxidants and other substances are added to the materials during the production process to improve the packaging performance of the materials. However, antioxidants will degrade and volatilize during use, which will gradually reduce the effect of antioxidants until they become ineffective. Therefore, during the production process of polyethylene materials, it is necessary to test the performance of antioxidants in the materials for evaluating the production process or further optimization.

[0003] In order to detect the antioxidant performance in the production process of polyethylene materials, the existing technology can use chromatographic detection methods to detect the target antioxidant content in polyethylene. However, in the actual application of polyethylene materials, in addition to the antioxidant degradation of the material itself, the packaged food may also react to reduce the antioxidant content. This process has an obvious temporal change trend, and the existing technology cannot accurately and effectively detect the antioxidants in polyethylene materials in combination with the impact caused by this process. Summary of the invention

[0004] In order to solve the technical problem that the prior art does not take into account the time-sequential degradation failure of polyethylene-packaged food, resulting in inaccurate material performance evaluation results, the purpose of the present invention is to provide a method and system for detecting the content of antioxidants in polyethylene materials. The technical solutions adopted are as follows:

[0005] The present invention provides a method for detecting the content of an antioxidant in a polyethylene material, the method comprising:

[0006] The target antioxidant and the target degradation product of the same specification are respectively used as control group solutions; multiple groups of test group solutions are set, and the temperatures in different groups of test group solutions are different, and each group of test group solutions contains a material solution and a food solution for soaking the material; multiple chromatographic tests are performed in a preset cycle to obtain chromatograms of the target antioxidant and the target degradation product of each solution;

[0007] The target antioxidant and the target degradation product are respectively used as dimensions to be analyzed. Under the dimensions to be analyzed, for each chromatographic test, according to the peak difference between the chromatograms of the control group solution and the test group solution, the difference index of each test group solution under the dimensions to be analyzed is obtained;

[0008] For each group of solutions to be tested, within one cycle, a two-dimensional sample space of each cycle is constructed according to the difference index of the two dimensions obtained during each chromatographic detection process, wherein the horizontal axis of the two-dimensional sample space represents the relative difference of the two difference indexes of the material solution, and the vertical axis represents the magnitude of the two difference indexes of the food solution; a sample point cluster in the two-dimensional sample space is obtained, and an antioxidant effectiveness index of the sample point cluster is obtained according to the data of the sample points in the sample point cluster; and a sample aggregation index within the cycle is obtained according to the data distribution between the sample point clusters;

[0009] For each group of solutions to be tested, the antioxidant failure index of each cycle is obtained according to the changes in the sample aggregation index and the difference in the antioxidant effectiveness index between cycles;

[0010] According to the difference in antioxidant failure index between the test group solutions at different temperatures under the same cycle, the antioxidant failure probability of the test group solutions at each temperature is obtained, and the antioxidant failure group is screened out according to the antioxidant failure probability.

[0011] Furthermore, for each chromatographic detection, multiple repeatability detections are performed, and an initial difference index of the target antioxidant and an initial difference index of the target degradation product are obtained in each repeatability detection; invalid detection data in the repeatability detection are screened out according to the initial difference index under the target antioxidant dimension, and the average value of the initial difference index of the target antioxidant under the remaining repeatability detections is used as the difference index of the chromatographic detection under the target antioxidant dimension, and the average value of the initial difference index of the target degradation product under the remaining repeatability detections is used as the difference index of the chromatographic detection under the target degradation product dimension.

[0012] Furthermore, the method for obtaining the difference index under the dimension to be analyzed includes:

[0013] Under the dimension to be analyzed, the peak point in the chromatogram of the control group is used as a reference point, and the matching index of each peak in the chromatogram of the test group solution is obtained according to the difference between the peak point of each peak in the chromatogram of the test group solution and the reference point; the target dimension peak is screened out in the chromatogram of the test group solution according to the matching index;

[0014] In the dimension to be analyzed, the difference index is obtained according to the matching index of the target dimension peak and the area difference between the target dimension peak and the peak corresponding to the reference point.

[0015] Furthermore, the method for obtaining the matching index includes:

[0016] Under the dimension to be analyzed, for each peak in the chromatogram of the test group solution, the signal value difference and time interval between the peak point and the reference point are obtained, the point with the first tangent slope of 0 on the right side of the peak point is taken as the tailing point to be tested, the point with the first tangent slope of 0 on the right side of the reference point is taken as the reference tailing point, and the time interval between the tailing point to be tested and the reference tailing point is taken as the tailing difference; the signal value difference, the time interval and the tailing difference are multiplied, negative correlation mapping is performed and normalized to obtain the matching index.

[0017] Furthermore, the horizontal axis of the two-dimensional sample space is the ratio of the difference index of the target antioxidant of the material solution to the difference index of the target degradation product; and the vertical axis is the product of the two difference indexes of the food solution.

[0018] Furthermore, the method for obtaining the antioxidant effectiveness index includes:

[0019] For each sample point cluster, the ratio of the average ordinate to the average abscissa of the sample points in the sample point cluster is used as the initial antioxidant effectiveness index; the maximum distance between the sample points in the sample point cluster is negatively correlated to obtain a distance weight, and the distance weight is multiplied by the initial antioxidant effectiveness index to obtain the antioxidant effectiveness index.

[0020] Furthermore, the method for obtaining the sample aggregation index includes:

[0021] In the two-dimensional sample space, the centroid of all sample points is obtained, and the average value of the distance between the cluster center point of the sample point cluster and the centroid is negatively correlated to obtain an initial sample aggregation index; the difference between the average antioxidant effectiveness index of all sample point clusters and the maximum antioxidant effectiveness index is negatively correlated to obtain an antioxidant effectiveness index weight; the antioxidant effectiveness index weight is multiplied by the initial sample aggregation index to obtain the sample aggregation index.

[0022] Furthermore, the method for obtaining the antioxidant failure index includes:

[0023] Obtain the average antioxidant effectiveness index under each cycle;

[0024] For a cycle, the difference between the average antioxidant effective index of the previous cycle and the cycle is obtained as the first antioxidant attenuation degree; the ratio of the sample aggregation index between the previous cycle and the cycle is obtained as the second antioxidant attenuation degree; the product of the first antioxidant attenuation degree and the second antioxidant attenuation degree is used as the third antioxidant attenuation degree; the cycle before the current cycle is taken as the historical cycle, and the ratio of the average antioxidant effective index between the first cycle in the historical cycle and the current cycle is taken as the fourth antioxidant attenuation degree; the third antioxidant attenuation degree in the historical cycle is accumulated and multiplied by the fourth antioxidant attenuation degree to obtain the antioxidant failure index of the current cycle.

[0025] Furthermore, the method for obtaining the antioxidant failure probability includes:

[0026] For a test group solution within a cycle, the index difference between the average value of the antioxidant failure index of all the test group solutions and the antioxidant failure index of the test group solution is obtained, and the index difference is multiplied by the antioxidant failure index of the test group solution and then normalized to obtain the antioxidant failure probability of the test group solution.

[0027] The present invention also proposes a system for detecting the content of antioxidants in polyethylene materials, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements any one of the steps of the method for detecting the content of antioxidants in polyethylene materials when executing the computer program.

[0028] The present invention has the following beneficial effects:

[0029] In order to accurately evaluate the antioxidant components in polyethylene materials, the present invention sets a control group solution and sets a test group solution at different temperatures, wherein the test group solution includes a material solution and a food solution. Finally, the possibility of antioxidant failure in each period at each temperature can be obtained. In the analysis process, based on the chromatographic detection technology, it is easy to compare with the control group to analyze the difference index of the target antioxidant and its target degradation product in the test group solution. The content characteristics of the antioxidant in the test solution can be characterized by the size of the difference index. Further construct a two-dimensional sample space for each cycle, and compare the substance content between the material solution and the food solution in the two-dimensional sample space. Based on the change of the difference index under different detection processes in one cycle, the sample aggregation index is determined, and the sample aggregation index characterizes the degree of data change in the current cycle, that is, the more aggregated, the smaller the change in the time series in the cycle. By comparing the changes in the sample aggregation index between the cycles and the difference in the antioxidant effective index, the content changes of the antioxidant in the test group solution can be further analyzed in time series, and then the antioxidant failure index of each cycle is determined. By further comparing the differences in antioxidant failure indicators between different temperatures in the same cycle, the probability of antioxidant failure at each temperature in each cycle can be obtained, thereby determining the antioxidant failure group and accurately detecting and evaluating the content and status of antioxidants in polyethylene materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 A flow chart of a method for detecting the content of antioxidant in a polyethylene material provided by one embodiment of the present invention;

[0032] Figure 2 A chromatogram of a target antioxidant in a control solution provided by one embodiment of the present invention;

[0033] Figure 3 A schematic diagram of a two-dimensional sample space provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0034] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the following is a detailed description of the antioxidant content detection method and system in polyethylene material according to the present invention, its specific implementation, structure, characteristics and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0035] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0036] The embodiment of the present invention is aimed at detecting the antioxidant content of polyethylene materials. The detection technology used is based on chromatographic detection technology. The substance is chromatographically detected by gas chromatography-mass spectrometry to obtain a chromatogram of the substance to be detected, and further analysis is performed based on the data in the chromatogram. The target antioxidant type targeted by the embodiment of the present invention is antioxidant 168, and its main degradation product is 2,4-di-tert-butylphenol (DBP). In other embodiments of the present invention, the type of antioxidant to be detected can also be changed, and adjustments can be made according to specific detection requirements. In the subsequent descriptions in the specification, the target antioxidant and the target degradation product are described.

[0037] The specific scheme of the method and system for detecting the content of antioxidant in polyethylene material provided by the present invention is described in detail below in conjunction with the accompanying drawings.

[0038] See also Figure 1 , which shows a flow chart of a method for detecting the content of an antioxidant in a polyethylene material provided by an embodiment of the present invention, the method comprising:

[0039] Step S1: The target antioxidant and the target degradation product of the same specification are respectively used as control group solutions; multiple groups of test group solutions are set, and the temperatures in different groups of test group solutions are different, and each group of test group solutions contains a material solution and a food solution for soaking the material; in a preset cycle, multiple chromatographic tests are performed to obtain chromatograms of the target antioxidant and the target degradation product of each solution.

[0040] In an embodiment of the present invention, the control group solution is 100 milliliters of antioxidant 168 and DBP of the same concentration, and n-hexane is selected to make up the volume. The preparation method of the test group solution is: first prepare a material solution of the material to be tested, then cut the material to be tested into pieces and soak it in liquid food to obtain a food solution. A food solution and a material solution are used as a group of test groups, which are further divided into multiple temperature groups. The embodiment of the present invention selects five temperature groups of 20 degrees, 40 degrees, 60 degrees, 80 degrees and 100 degrees, and uses a water bath method to maintain the temperature of the solution. So far, a control group solution containing only the target antioxidant, a control group solution containing only the target degradation product, and five test group solutions of different temperatures are obtained, and each group of test group solutions contains a food solution and a material solution.

[0041] The embodiment of the present invention aims to analyze the degradation changes of antioxidants in the test group solution in time series. Therefore, the embodiment of the present invention presets the detection cycle, performs multiple chromatographic detections within the preset cycle, and performs time series analysis by comparing the multiple detection results within the cycle and the detection results between different cycles. The embodiment of the present invention sets the cycle to 24 hours, sets the gas chromatograph-mass spectrometer to perform chromatographic detection once every hour, and outputs the chromatograms of the target antioxidant and target degradation products of each solution. Please refer to Figure 2 , which shows a chromatogram of a target antioxidant in a control solution provided by an embodiment of the present invention. Since the control solution contains only one substance, Figure 2 As shown, there is only one obvious peak, and the information corresponding to the peak is the information of the target antioxidant. Similarly, the chromatogram of the target degradation product of the control group solution also contains only one obvious peak.

[0042] Step S2: The target antioxidant and the target degradation product are respectively used as dimensions to be analyzed. Under the dimensions to be analyzed, for each chromatographic detection, the difference index of each solution to be tested under the dimensions to be analyzed is obtained according to the peak difference between the chromatograms of the control group solution and the solution to be tested.

[0043] Because the chromatogram of the control group solution only contains information about one substance, the chromatogram of the control group solution can be used as a reference for comparative analysis with the chromatogram of the test group solution to determine the substance content during each chromatographic detection process.

[0044] It should be noted that, because the analysis methods of the target antioxidant and the target degradation product are the same, both are based on the comparison of chromatograms to determine the substance content, so the embodiment of the present invention takes the target antioxidant and the target degradation product as the dimensions to be analyzed respectively, and analyzes the two dimensions to be analyzed in turn. Under the dimension to be analyzed, by comparing the peak difference between the chromatograms of each control group solution and the test group solution in each chromatographic detection, the difference index of each test group solution under the dimension to be analyzed can be obtained. That is, there will be four difference indices for each group of test group solutions under each chromatographic detection, namely, the difference index of the target antioxidant of the material solution and the difference index of the target degradation product, the difference index of the target antioxidant of the food solution and the difference index of the target degradation product.

[0045] Preferably, in one embodiment of the present invention, in order to avoid experimental errors caused by a single chromatographic detection, multiple repetitive detections are performed for each chromatographic detection process, and each repetitive detection obtains an initial difference index of the target antioxidant and an initial difference index of the target degradation product.

[0046] Invalid test data in repeatability testing were screened out based on the initial difference index under the target antioxidant dimension, and the average value of the initial difference index of the target antioxidant under the remaining repeatability testing was used as the difference index of the chromatographic testing under the target antioxidant dimension, and the average value of the initial difference index of the target degradation product under the remaining repeatability testing was used as the difference index of the chromatographic testing under the target degradation product dimension.

[0047] In the embodiment of the present invention, the repetitive detection data whose initial difference index is greater than the preset difference index threshold is regarded as invalid detection data, that is, if the difference index is greater than the difference index threshold, it is considered that the current solution of the group to be detected does not contain the target antioxidant. This situation is considered to be a calculation error, and such error data needs to be eliminated. After normalizing the initial difference index, the difference index threshold can be set to 0.7.

[0048] Preferably, in one embodiment of the present invention, the method for obtaining the difference index under the dimension to be analyzed includes:

[0049] In the dimension to be analyzed, because the chromatogram of the control group contains only one obvious peak, which is the target peak in the dimension to be analyzed, the peak point in the chromatogram of the control group is used as the reference point. The chromatogram of the solution in the test group contains multiple peaks, only one of which is the target dimension peak representing the dimension to be analyzed. Therefore, in order to evaluate the substance content in the solution in the test group, the target dimension peak needs to be screened out first.

[0050] According to the difference between the peak point of each peak in the chromatogram of the test group solution and the reference point, the matching index of each peak in the chromatogram of the test group solution is obtained. That is, the difference between the peak point and the reference point is used to evaluate the similarity between the corresponding peaks. If they all represent the same substance, they will have similar chromatographic signal values ​​and peak shapes. Therefore, the target dimension peak can be screened out in the chromatogram of the test group solution according to the matching index.

[0051] Under the dimension to be analyzed, the difference index is obtained according to the matching index of the target dimension peak and the area difference between the target dimension peak and the peak corresponding to the reference point. That is, the smaller the matching index of the target dimension peak, the greater the area difference between the target dimension peak and the peak corresponding to the reference point, indicating that the difference index is greater. In one embodiment of the present invention, after the matching index is negatively correlated and mapped, the product of the area difference is used as the difference index.

[0052] As an example, the difference index is formulated as:

[0053] ;in It indicates the difference index of the solution of the test group under the dimension to be analyzed in a certain chromatographic detection process. is the matching index of the target dimension peak of the test group solution, Indicates the area of ​​the target dimension peak of the test group solution, It represents the peak area corresponding to the reference point, and norm represents the normalization function.

[0054] In the difference index formula, the matching index is negatively correlated using the inverse form. In order to avoid the denominator being 0, a positive integer 1 is added to the denominator. Indicates the area difference, that is, the closer the area ratio of the two peaks is to 1, the smaller the area difference is, and the greater the difference from 1, the greater the area difference between the two peaks is. In the embodiment of the present invention, the norm function can be normalized using a sigmoid function or a hyperbolic tangent function, which will not be described in detail here.

[0055] It should be noted that in some embodiments of the present invention, there may be multiple repetitive detections in a chromatographic detection process, and each repetitive detection can use the above-mentioned difference index acquisition method to obtain its initial difference index, and then obtain the difference index by screening data and averaging.

[0056] Preferably, in one embodiment of the present invention, the method for obtaining the matching index includes:

[0057] Under the dimension to be analyzed, for each peak in the chromatogram of the test group solution, the signal value difference and time interval between the peak point and the reference point are obtained. The greater the signal value difference of a peak in the chromatogram of the test group solution and the longer the time interval, the greater the difference between the peak and the reference point, and the less likely it is to be the chromatographic peak corresponding to the substance under the dimension to be analyzed, and the smaller the corresponding matching index should be.

[0058] The first point on the right side of the peak point with a tangent slope of 0 is taken as the tailing point to be measured, the first point on the right side of the reference point with a tangent slope of 0 is taken as the reference tailing point, and the time interval between the tailing point to be measured and the reference tailing point is taken as the tailing difference. The larger the tailing difference, the less similar the tailing conditions between the two peaks are, and the lower the matching index should be.

[0059] After multiplying the signal value difference, time interval and tail difference, negative correlation mapping is performed and normalized to obtain the matching index. After obtaining the matching index, the peak with the largest matching index is selected as the target dimension peak.

[0060] As an example, the matching index in the embodiment of the present invention is expressed by the formula:

[0061] ;in It represents the matching index of the i-th peak in the chromatogram of the solution of the test group under the dimension to be analyzed during a certain chromatographic detection process. is the chromatographic signal value of the peak point of the i-th peak, is the chromatographic signal value of the reference point, is the time interval between the peak point of the i-th peak and the reference point, is the tailing difference between the ith peak and the peak corresponding to the reference point, Function used for normalization.

[0062] In the matching index formula, the inverse form is also used for negative correlation mapping, and the sigmoid function is used for normalization.

[0063] Step S3: For each group of solutions to be tested, within one cycle, a two-dimensional sample space of each cycle is constructed according to the difference index of the two dimensions obtained during each chromatographic detection process, wherein the horizontal axis of the two-dimensional sample space represents the relative difference of the two difference indexes of the material solution, and the vertical axis represents the magnitude of the two difference indexes of the food solution; a sample point cluster in the two-dimensional sample space is obtained, and an antioxidant effectiveness index of the sample point cluster is obtained according to the data of the sample points in the sample point cluster; and a sample aggregation index within the cycle is obtained according to the data distribution between the sample point clusters.

[0064] For each group of solutions to be tested, there are multiple chromatographic tests in each cycle. For example, in one embodiment of the present invention, there are 24 chromatographic tests in one cycle. Therefore, in order to facilitate the analysis of the temporal changes of antioxidants in polyethylene materials, the embodiment of the present invention first performs statistical analysis on the test results in each cycle. In one cycle, a two-dimensional sample space for each cycle is constructed according to the difference index of the two dimensions obtained during each chromatographic test, wherein the data generated by each chromatographic test can correspond to a sample point in the two-dimensional sample space. If the content of the target antioxidant in the polyethylene material is greater, the difference index corresponding to the material solution is smaller, the degree of degradation and migration of the substance in the current food solution is smaller, and the corresponding difference index is smaller; if the target degradation product in the material is less, the corresponding difference index is larger, and the degree of degradation and migration of the substance in the current solution to be tested is also smaller, then the corresponding difference index is smaller. For the material solution, the greater the target antioxidant content and the less the target degradation product content, the better the performance of the material, that is, the smaller the difference index of the target antioxidant in the material solution and the greater the difference index of the target degradation product, the better the material performance; for the food solution, it is mainly necessary to detect whether the food solution will be affected by the polyethylene material, resulting in the inclusion of antioxidants and degradation products in the solution, that is, the target antioxidant content and the target degradation product content in the food solution are both as small as possible, and the corresponding two difference indexes are as large as possible. Therefore, the horizontal axis of the two-dimensional sample space set in the embodiment of the present invention represents the relative difference between the two difference indexes of the material solution, and the vertical axis represents the size of the two difference indexes of the food solution. Subsequent analysis and processing are carried out by constructing a two-dimensional sample space.

[0065] In one embodiment of the present invention, the ISODATA algorithm is used to cluster sample points in a two-dimensional sample space, the initial number of categories is set to 4, the maximum number of iterations is set to 5, the number of initial samples in each category is the result of rounding down the total number of sample points divided by 6, and the final clustering result is obtained through iteration. Figure 3 As shown, it shows a schematic diagram of a two-dimensional sample space provided by an embodiment of the present invention. The specific clustering algorithm is a technical means well known to those skilled in the art, and will not be described in detail here.

[0066] In the two-dimensional sample space of a cycle, if the substance content in the test group solution is relatively stable, and the antioxidant has not undergone obvious degradation and precipitation in the food solution, the sample points in the two-dimensional sample space should be in a clustered state, and no obvious discreteness will occur. Therefore, the embodiment of the present invention further obtains sample point clusters in the two-dimensional sample space for analysis. For each sample point cluster, the more concentrated its sample point distribution is, and the numerical characteristics it exhibits can reflect that the material solution has a rich antioxidant content and a low content of degradation products; if both substances are less in the food solution, it means that the sample point cluster presents a relatively obvious antioxidant effectiveness index, that is, the larger the antioxidant effectiveness index, the better the antioxidant content detection state of the test group solution in the corresponding chromatographic detection process.

[0067] The sample aggregation index within the cycle is further obtained based on the data distribution between the sample point clusters. The larger the sample aggregation index, the more concentrated the sample points are in the two-dimensional sample space of the current cycle, and the antioxidant in the test group solution has not changed significantly. The more stable the antioxidant is, the stronger its performance on the material performance is.

[0068] Preferably, in one embodiment of the present invention, the horizontal axis of the two-dimensional sample space is the ratio of the difference index of the target antioxidant of the material solution to the difference index of the target degradation product; the vertical axis is the product of the two difference indexes of the food solution. That is, the smaller the horizontal axis, the more antioxidant content and the less degradation product content in the material solution; the larger the vertical axis, the less antioxidant content and the less degradation product content in the food solution. Further, based on the above two-dimensional sample space, the method for obtaining the antioxidant effectiveness index includes:

[0069] For each sample point cluster, the ratio of the average ordinate to the average abscissa of the sample points in the sample point cluster is used as the initial antioxidant effectiveness index. The smaller the average abscissa, the more antioxidant content of the material solution and the less degradation product content in the sample point cluster; the smaller the average ordinate, the less antioxidant content and degradation product content of the food solution in the sample point cluster. This means that the solution of the group to be tested in the sample point cluster has the characteristics of stable material performance and low degree of degradation, and the larger the initial antioxidant effectiveness index.

[0070] The maximum distance between sample points in the sample point cluster is negatively correlated and mapped to obtain a distance weight. That is, the degree of aggregation in the sample point cluster is further analyzed by example weights. The larger the distance weight, the more aggregated the sample point distribution is. The distance weight is multiplied by the initial antioxidant effectiveness index to obtain the antioxidant effectiveness index. In the embodiment of the present invention, the method of negative correlation mapping also adopts the inverse form, which has been explained in the above description and will not be repeated here.

[0071] Preferably, in one embodiment of the present invention, the method for obtaining the sample aggregation index includes:

[0072] In the two-dimensional sample space, the centroids of all sample points are obtained, and the average value of the distance between the cluster center and the centroid of the sample point cluster is negatively correlated to obtain the initial sample aggregation index. That is, the smaller the distance between the cluster center and the centroid, the more aggregated the sample points in the current two-dimensional sample space are.

[0073] The difference between the average antioxidant effective index of all sample point clusters and the maximum antioxidant effective index is negatively correlated to obtain the antioxidant effective index weight. The difference in the embodiment of the present invention is the absolute value of the difference. The smaller the difference, the more concentrated the distribution of the effective index between different sample point clusters, and the greater the antioxidant effective index weight.

[0074] The antioxidant effective index weight is multiplied by the initial sample aggregation index to obtain the sample aggregation index. That is, the larger the sample aggregation index, the more uniform the distribution of antioxidant effective index in the current cycle, and the more uniform the test results, and the more stable the test group solution in the current cycle.

[0075] It should be noted that the negative correlation mapping method in the embodiments of the present invention adopts the inverse form, and those skilled in the art may select other basic mathematical means, which will not be described in detail.

[0076] Step S4: For each group of solutions to be tested, the antioxidant failure index of each cycle is obtained according to the changes in the sample aggregation index and the difference in the antioxidant effectiveness index between cycles.

[0077] The present invention aims to analyze the substance change state of the solution of the test group under different temperature conditions as time changes, and then accurately detect the antioxidant content and antioxidant state of the polyethylene material. Therefore, after the embodiment of the present invention obtains the aggregation index of each cycle and the antioxidant effectiveness index therein, it is necessary to compare with the data of other cycles to determine the antioxidant failure index of each cycle. The larger the antioxidant failure index, the greater the change in the sample aggregation index between cycles, the more unstable the antioxidant state of the material, the greater the change in the antioxidant effectiveness index, and the more the antioxidant is ineffective.

[0078] Preferably, in one embodiment of the present invention, the method for obtaining the antioxidant failure index includes:

[0079] Because there is an antioxidant effectiveness index for each sample point cluster in a cycle, firstly, all antioxidant effectiveness indexes in a cycle are quantified and unified to obtain the average antioxidant effectiveness index in each cycle;

[0080] For a cycle, the difference between the average antioxidant effective index of the previous cycle and the current cycle is obtained as the first antioxidant attenuation degree. The ratio of the sample aggregation index between the previous cycle and the cycle is obtained as the second antioxidant attenuation degree; the product of the first antioxidant attenuation degree and the second antioxidant attenuation degree is taken as the third antioxidant attenuation degree. The difference between the average antioxidant effective index of the previous cycle and the current cycle is a positive number and the larger it is, it means that after a cycle, the content of antioxidants in this cycle is no longer ideal, and the first antioxidant attenuation degree is greater. Similarly, the larger the ratio of the sample aggregation index between the previous cycle and the current cycle is and is greater than 1, it means that after a cycle, the antioxidant state becomes unstable and produces obvious attenuation, then the second antioxidant attenuation degree is greater. The third antioxidant attenuation degree can be obtained by combining the two antioxidant attenuation degrees. The third antioxidant attenuation degree is expressed by the formula: ;in is the attenuation degree of the third antioxidant in the Tth cycle, is the average antioxidant effectiveness index under T-1 cycles, is the average antioxidant effectiveness index under T cycles, is the sample aggregation index in the T-1th period, Sample aggregation index in the Tth period.

[0081] Further, by comparing multiple cycles, the change trend in the current cycle is analyzed, and the cycle before the current cycle is taken as the historical cycle. In the historical cycle, the first cycle is the initial detection process in the detection process of the embodiment of the present invention, so the ratio of the average antioxidant effective index between the first cycle in the historical cycle and the current cycle is taken as the fourth antioxidant attenuation degree. That is, the fourth antioxidant attenuation degree represents the change range between the initial state and the current cycle state. The greater the fourth antioxidant attenuation degree, it means that after multiple historical cycles, the state of the antioxidant has obviously decayed and changed in the current cycle.

[0082] After further accumulating the attenuation degree of the third antioxidant in the historical cycle, multiply it by the attenuation degree of the fourth antioxidant to obtain the antioxidant failure index of this cycle. That is, the larger the antioxidant failure index of this cycle, the worse the antioxidant in this cycle is compared with the initial state, the more serious the attenuation, and the more obvious the change trend is after multiple historical cycles.

[0083] Step S5: according to the difference of antioxidant failure index between the tested group solutions at different temperatures under the same cycle, the antioxidant failure probability of the tested group solutions at each temperature is obtained, and the antioxidant failure group is screened out according to the antioxidant failure probability.

[0084] In the above steps, the antioxidant failure index of the solution to be tested in each cycle is analyzed. The temperature conditions of different groups of solutions to be tested are different, and the migration and degradation of antioxidants are also greatly affected by temperature. The higher the temperature, the more unstable the antioxidant is. Therefore, the difference in antioxidant failure index between the solutions to be tested at different temperatures in the same cycle can be further compared to determine the probability of antioxidant failure under each temperature condition. That is, the greater the difference, the less conditions are available to ensure the performance of the antioxidant at the corresponding temperature, and the greater the probability of antioxidant failure. The antioxidant failure group can be screened out according to the antioxidant failure probability.

[0085] Preferably, in one embodiment of the present invention, the method for obtaining the failure probability of the antioxidant includes:

[0086] For a group of solutions to be tested within a cycle, the average value of the antioxidant failure index of all the groups of solutions to be tested and the index difference of the antioxidant failure index of the group of solutions to be tested are obtained, and the index difference is multiplied by the antioxidant failure index of the group of solutions to be tested and normalized to obtain the antioxidant failure probability of the group of solutions to be tested. The index difference is the absolute value of the difference between the two data. The smaller the index difference, the smaller the antioxidant failure index of the group of solutions to be tested, which means that the group of solutions to be tested under the current temperature conditions in the current cycle is more stable, the possibility of failure is smaller, and the probability of antioxidant failure is smaller.

[0087] In one embodiment of the present invention, because the antioxidant failure probability is a normalized result, the probability threshold is set to 0.7, and the test group solutions with a probability greater than the probability threshold are taken as the antioxidant failure group.

[0088] In summary, through the processing and testing of the above steps, and the results of each test and analysis can be stored in the system, the staff can determine the content of polyethylene antioxidant and the conditions for the failure of the antioxidant based on the data generated during the test and the final results, making the final test results more accurate and more meaningful for reference.

[0089] Based on the same inventive concept, the present invention also proposes a system for detecting the content of antioxidants in polyethylene materials, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the system implements any one of the steps of a method for detecting the content of antioxidants in polyethylene materials.

[0090] It should be noted that the sequence of the above embodiments of the present invention is only for description and does not represent the advantages and disadvantages of the embodiments. The processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0091] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

Claims

1. A method for detecting the content of antioxidant in polyethylene material, characterized in that: The method comprises: The target antioxidant and the target degradation product of the same specification are respectively used as control group solutions; multiple groups of test group solutions are set, and the temperatures in different groups of test group solutions are different, and each group of test group solutions contains a material solution and a food solution for soaking the material; multiple chromatographic tests are performed in a preset cycle to obtain chromatograms of the target antioxidant and the target degradation product of each solution; The target antioxidant and the target degradation product are respectively used as dimensions to be analyzed. Under the dimensions to be analyzed, for each chromatographic test, according to the peak difference between the chromatograms of the control group solution and the test group solution, the difference index of each test group solution under the dimensions to be analyzed is obtained; For each group of solutions to be tested, within one cycle, a two-dimensional sample space of each cycle is constructed according to the difference index of the two dimensions obtained during each chromatographic detection process, wherein the horizontal axis of the two-dimensional sample space represents the relative difference of the two difference indexes of the material solution, and the vertical axis represents the magnitude of the two difference indexes of the food solution; a sample point cluster in the two-dimensional sample space is obtained, and an antioxidant effectiveness index of the sample point cluster is obtained according to the data of the sample points in the sample point cluster; and a sample aggregation index within the cycle is obtained according to the data distribution between the sample point clusters; For each group of solutions to be tested, the antioxidant failure index of each cycle is obtained according to the changes in the sample aggregation index and the difference in the antioxidant effectiveness index between cycles; According to the difference in antioxidant failure index between the test group solutions at different temperatures under the same cycle, the antioxidant failure probability of the test group solutions at each temperature is obtained, and the antioxidant failure group is screened out according to the antioxidant failure probability.

2. The method for detecting the content of antioxidant in polyethylene material according to claim 1, characterized in that: For each chromatographic detection, multiple repeatability detections are performed, and an initial difference index of the target antioxidant and an initial difference index of the target degradation product are obtained in each repeatability detection; invalid detection data in the repeatability detection are screened out according to the initial difference index under the target antioxidant dimension, and the average value of the initial difference index of the target antioxidant under the remaining repeatability detections is used as the difference index of the chromatographic detection under the target antioxidant dimension, and the average value of the initial difference index of the target degradation product under the remaining repeatability detections is used as the difference index of the chromatographic detection under the target degradation product dimension.

3. The method for detecting the content of antioxidant in polyethylene material according to claim 1, characterized in that: The method for obtaining the difference index under the dimension to be analyzed includes: Under the dimension to be analyzed, the peak point in the chromatogram of the control group is used as a reference point, and the matching index of each peak in the chromatogram of the test group solution is obtained according to the difference between the peak point of each peak in the chromatogram of the test group solution and the reference point; the target dimension peak is screened out in the chromatogram of the test group solution according to the matching index; In the dimension to be analyzed, the difference index is obtained according to the matching index of the target dimension peak and the area difference between the target dimension peak and the peak corresponding to the reference point.

4. The method for detecting the content of antioxidant in polyethylene material according to claim 3, characterized in that: The method for obtaining the matching index includes: Under the dimension to be analyzed, for each peak in the chromatogram of the test group solution, the signal value difference and time interval between the peak point and the reference point are obtained, the point with the first tangent slope of 0 on the right side of the peak point is taken as the tailing point to be tested, the point with the first tangent slope of 0 on the right side of the reference point is taken as the reference tailing point, and the time interval between the tailing point to be tested and the reference tailing point is taken as the tailing difference; the signal value difference, the time interval and the tailing difference are multiplied, negative correlation mapping is performed and normalized to obtain the matching index.

5. The method for detecting the content of antioxidant in polyethylene material according to claim 1, characterized in that: The horizontal axis of the two-dimensional sample space is the ratio of the difference index of the target antioxidant of the material solution to the difference index of the target degradation product; the vertical axis is the product of the two difference indexes of the food solution.

6. The method for detecting the content of antioxidant in polyethylene material according to claim 5, characterized in that: The method for obtaining the antioxidant effectiveness index comprises: For each sample point cluster, the ratio of the average ordinate to the average abscissa of the sample points in the sample point cluster is used as the initial antioxidant effectiveness index; the maximum distance between the sample points in the sample point cluster is negatively correlated to obtain a distance weight, and the distance weight is multiplied by the initial antioxidant effectiveness index to obtain the antioxidant effectiveness index.

7. The method for detecting the content of antioxidant in polyethylene material according to claim 1, characterized in that: The method for obtaining the sample aggregation index includes: In the two-dimensional sample space, the centroid of all sample points is obtained, and the average value of the distance between the cluster center point of the sample point cluster and the centroid is negatively correlated to obtain an initial sample aggregation index; the difference between the average antioxidant effectiveness index of all sample point clusters and the maximum antioxidant effectiveness index is negatively correlated to obtain an antioxidant effectiveness index weight; the antioxidant effectiveness index weight is multiplied by the initial sample aggregation index to obtain the sample aggregation index.

8. The method for detecting the content of antioxidant in polyethylene material according to claim 1, characterized in that: The method for obtaining the antioxidant failure index comprises: Obtain the average antioxidant effectiveness index under each cycle; For a cycle, the difference between the average antioxidant effective index of the previous cycle and the current cycle is obtained as the first antioxidant attenuation degree; the ratio of the sample aggregation index between the previous cycle and the current cycle is obtained as the second antioxidant attenuation degree; the product of the first antioxidant attenuation degree and the second antioxidant attenuation degree is used as the third antioxidant attenuation degree; the cycle before the current cycle is taken as the historical cycle, and the ratio of the average antioxidant effective index between the first cycle in the historical cycle and the current cycle is taken as the fourth antioxidant attenuation degree; the third antioxidant attenuation degree in the historical cycle is accumulated and multiplied by the fourth antioxidant attenuation degree to obtain the antioxidant failure index of the current cycle.

9. The method for detecting the content of antioxidant in polyethylene material according to claim 1, characterized in that: The method for obtaining the antioxidant failure probability includes: For a test group solution within a cycle, the index difference between the average value of the antioxidant failure index of all the test group solutions and the antioxidant failure index of the test group solution is obtained, and the index difference is multiplied by the antioxidant failure index of the test group solution and then normalized to obtain the antioxidant failure probability of the test group solution.

10. A system for detecting antioxidant content in polyethylene material, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps of the method for detecting the content of antioxidant in a polyethylene material as described in any one of claims 1 to 9 are implemented.

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