Method for analyzing and evaluating degradation resistance of plastic based on fitting derivation method of aerobic biological decomposition test result under controlled composting condition

Abstract

The invention relates to a method for analyzing and evaluating the degradation resistance of plastics based on a fitting derivation method of aerobic biological decomposition test results under a controlled composting condition. The method comprises the following steps: obtaining the aerobic biological decomposition test results of the plastics under the controlled composting condition; drawing a scatter diagram of the decomposition rate relative to time; a section is selected from the scatter diagram, a continuous derivable function is used for curve fitting of the section, and a curve fitting result with the best fitting degree is obtained and used for subsequent steps; and obtaining the corresponding time when the third-order derivative and / or the fourth-order derivative of the curve is zero and the fourth-order derivative and / or the fifth-order derivative of the curve is negative, and / or taking the numerical value of the second-order derivative of the curve at the time as the output result of the method. The method can be used for quantitatively describing a transformation critical point between non-microorganism-participated chemical degradation behaviors and microorganism-participated biological decomposition behaviors of plastics in the early and middle stages of an aerobic biological decomposition test under a controlled composting condition, and can be used for quantitatively evaluating the advantages and disadvantages of hydrolysis resistance or hydrolysis resistance of plastics of different types, processes, formulas and batches.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer material analysis, and in particular relates to a method for evaluating the anti-degradation performance of plastics, and also relates to a system, equipment and a medium thereof adopting the method. Background Art

[0002] The invention and use of plastics have greatly facilitated people's lives, but at the same time they have also caused serious environmental pollution. Biodegradable polymer materials represented by polylactic acid and polybutylene adipate terephthalate are committed to solving the problem of plastic / microplastic pollution. In addition, in the field of engineering, high-performance polymer materials represented by polyamide are also increasingly widely used. However, most of the above materials are hydrolyzable, that is, they have the necessary conditions for hydrolysis. For example, the ester bond (-COO-) in polyester materials and the amide bond (-CO-NH-) in polyamide materials can undergo hydrolysis in the presence of water and catalysts, resulting in a significant decrease in the molecular weight of the polymer and rapid deterioration of the material properties. Therefore, scientifically and reliably characterizing and evaluating the hydrolysis resistance or hydrolysis resistance of plastics is an important means to ensure the large-scale promotion and application of such plastics, and is of great significance.

[0003] At present, some characterization and analysis techniques have been developed to evaluate the properties related to plastic degradation. For example, visual observation, weight loss weighing, mechanical property evaluation, molecular weight evaluation, melt index evaluation, etc. can reflect the degree of degradation of the tested plastic at a certain moment to a certain extent, but each has its own defects. For example, the visual observation method requires a high time cost to make the sample achieve visible degradation, and the results are somewhat subjective; the weight loss weighing method cannot measure the degradation fluctuations in the short term, and cannot reflect the impact of rapid changes in process parameters on the degradation rate of plastics; the mechanical property evaluation method cannot be used to test broken plastics during the degradation process; the molecular weight evaluation method requires the use of advanced chromatographic instruments to separate and characterize the polymer chains of different molecular weights during the degradation process, and has high requirements for testing instruments and testers; the melt index evaluation method measures the comprehensive properties of degraded and undegraded polymer mixtures, especially in the early stage of degradation, the impact of a small amount of degraded polymers on the overall melt index may be lower than the accidental error of this method, and accurate results cannot be obtained. It is known in the art that the test and evaluation methods known in the prior art are usually extra destructive to the samples being tested, and therefore require a large number of parallel sample tests to obtain the trend of changes in relevant performance over time, and have relatively high requirements for the samples, personnel, equipment, environment, etc. tested, and the test repeatability is also poor. In addition, the above methods are usually insensitive to the small amount of degradation behavior of plastics in the early stage or on the surface of the material, and cannot sensitively and accurately reflect the anti-degradation performance (such as hydrolysis resistance or hydrolysis resistance) of the plastic test material.

[0004] Therefore, there is still a need to develop characterization analysis methods for evaluating the degradation performance of plastics to achieve a simple test analysis process without relying on a large number of parallel sample tests. More ideally, the method can sensitively and accurately reflect the hydrolysis resistance or hydrolysis resistance of plastics.

[0005] The inventors unexpectedly discovered that by analyzing and characterizing the results of aerobic biodegradation tests of plastics known in the art under controlled composting conditions, the critical transition time point (i.e., critical point) of the test in the early, middle or early stages of the transition from a chemical degradation process involving no microorganisms (i.e., the hysteresis stage) to a biochemical process involving microorganisms (i.e., the biodegradation stage) can be obtained. The numerical value of the critical point reflects the precise information on the length of time or speed required for the plastic to decompose to a molecular weight level that can be digested and absorbed by microorganisms under aerobic controlled composting conditions, thereby solving the above-mentioned deficiencies in the prior art and further serving as an indicator parameter for evaluating the hydrolysis resistance or hydrolysis resistance of plastics. Summary of the invention

[0006] An object of the present invention is to overcome at least one shortcoming of the prior art, and in particular to provide a method for evaluating the anti-degradation performance of plastics. The method analyzes the aerobic biodegradation test results of plastics under controlled composting conditions based on the curve fitting derivative method. The method can quantitatively describe the critical point of transition between chemical degradation (mainly hydrolysis reaction) involving non-microorganisms and biodegradation behavior involving microorganisms in the early, middle or early stages of the aerobic biodegradation test, thereby being used to evaluate the anti-hydrolysis or hydrolysis resistance of plastics (especially hydrolyzable plastics such as polyesters and polyamides) of different types, processes, formulas, and batches.

[0007] According to one aspect of the present invention, a method for analyzing and evaluating the anti-degradation performance of plastics based on the fitting derivative method of aerobic biodegradation test results under controlled composting conditions is provided, characterized in that it comprises the following steps:

[0008] (1) conducting aerobic biodegradation tests on plastics under controlled composting conditions and obtaining the results of said tests,

[0009] The biodegradation rate or relative biodegradation rate (%) of the plastic at each time point t is denoted as D t ;

[0010] (2) Draw a scatter plot selected from the following:

[0011] (a)D t a scatter plot against t, or

[0012] (b) D t Preprocessing Then draw the preprocessed Scatter plot relative to t;

[0013] (3) Perform curve fitting on the scatter plot in step (2),

[0014] Wherein, all possible segments containing at least 7 continuous data points are selected from the scatter plot, and a continuously differentiable function is used to perform curve fitting on the continuous data points of each segment to obtain each curve fitting function for each region,

[0015] The fitting function of the jth region is denoted as y j =f j (t)|t∈[t A,j ,t B,j ],

[0016] The size or number of continuous data points in the jth region is recorded as m. j , and m j ≥7, t A,j is the starting time point of the jth region, t B,j is the end time point of the j-th region, and wherein the continuously differentiable function is selected from at least fifth-order differentiable functions, particularly preferably from at least sixth-order differentiable functions, for example, seventh-order, eighth-order or ninth-order differentiable functions;

[0017] (4) Obtaining a curve fitting result with the best fitting degree from the curve fitting function of step (3),

[0018] Each y is expressed by the following equation 1 j Calculate the adjusted coefficient of determination separately, namely

[0019]

[0020] in, m is the coefficient of determination of the curve fitting function of each segment; j As defined in step (3); k is the number of free parameters in the fitting function; m j -k>0; the power exponent q is 2.0 to 7.0, and

[0021] From the various The maximum value is selected from the above, and the curve fitting function corresponding to the maximum value is limited to the curve fitting result with the best fitting degree, which is recorded as y opt =f opt (t)|t∈[t A,opt ,t B,opt ];

[0022] (5) Analyze the curve fitting result of the best fit in step (4),

[0023] Calculate y opt The fourth-order derivative y″″ and the fifth-order derivative y″″′ of , the time t corresponding to y″″=0 and y″″′<0 is obtained c , where t c is a real number solution and satisfies t A,opt ≤t c ≤t B,opt , optionally, when there are at least 2 t satisfying the above conditions c solution, then take the minimum solution,

[0024] Optionally, additionally calculate y opt The third-order derivative y″′ and the fourth-order derivative y″″ of , the time t corresponding to y″′=0 and y″″<0 is obtained m , where t m is a real number solution and satisfies t A,opt ≤t m ≤t B,opt , and t m ≥t c , optionally, when there are at least 2 t satisfying the above conditions m solution, then take the minimum solution,

[0025] And optionally, calculate y opt The second-order derivative y″ of y″ is obtained at t c The value of time y″ c , and / or get y″ at t m The value of time y″ m ;and

[0026] (6) Output the evaluation results,

[0027] The evaluation result includes the t obtained in step (5). c and preferably additionally comprises t m , optionally including y″ c and / or y″ m .

[0028] According to another aspect of the present invention, a system for evaluating the anti-degradation performance of plastics is provided, characterized in that the system adopts the method of the present invention.

[0029] According to yet another aspect of the present invention, there is provided a computer device, characterized in that it comprises:

[0030] Processor; and

[0031] A memory for storing executable instructions;

[0032] The processor is used to read and execute the executable instructions from the memory to implement the method described above.

[0033] According to yet another aspect of the present invention, a computer-readable storage medium is provided, characterized in that a computer program is stored therein, and when the computer program is executed by a processor, the method described above is implemented. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The figure is a scatter plot of the biodegradation rate of Example 1 versus time.

[0035] Figure 2 The scatter plot of the biodegradation rate of Example 2 versus time is shown in FIG.

[0036] Figure 3 The scatter plot of the biodegradation rate of Example 3 versus time is shown in FIG.

[0037] Figure 4 The scatter plot of the biodegradation rate of Example 4 versus time is shown in FIG.

[0038] Figure 5 : is a scatter plot of the relative biodegradation rate of Example 10 versus time. DETAILED DESCRIPTION

[0039] The present invention is described in more detail in the following paragraphs. Unless explicitly stated otherwise, each aspect described can be combined with any other one or more aspects. In particular, any feature indicated as being preferred can be combined with any other one or more features indicated as being preferred.

[0040] The recitation of numerical endpoints includes all numbers and fractions within the corresponding range, as well as the recited endpoints. It should be noted that when specifying any range of numerical values, any particular upper value can be associated with any particular lower value.

[0041] All references cited in this specification are incorporated herein by reference in their entirety.

[0042] In the context of the present invention, unless otherwise defined, all terms used in the present invention, including technical and scientific terms, have the meanings commonly understood by one of ordinary skill in the art to which the present invention belongs.

[0043] As used herein, the terms "comprising" and "consisting of" are synonymous with "including" or "containing" and are inclusive or open-ended and do not exclude additional, unrecited ingredients, components or process steps.

[0044] The term "degradation" or "decomposition" as used in this article refers to the significant change in the chemical structure of plastics under specific environmental conditions, resulting in the loss of certain properties. It can be any process that can lead to a decrease in the molecular weight of polymers or the conversion of long-chain structures into shorter-chain low-molecular substances.

[0045] There are three main possible ways of degradation of plastics, depending on the process that occurs, namely biological degradation, chemical degradation and physicochemical degradation.

[0046] The term "biodegradation" as used herein refers to the process by which plastics, as a source of nutrition for microbial life activities, are digested and absorbed by organisms such as bacteria, fungi and certain algae, transformed into simpler compounds, and ultimately into small molecules such as methane, carbon dioxide, and water. For example, the degradation of biodegradable plastics relies on biological processes that use the carbon-containing substances present in the plastics as a source of nutrition for microorganisms.

[0047] The term "chemical degradation" as used herein refers to the process in which plastics are degraded by oxidative degradation, photodegradation or hydrolysis, including oxidative degradation of plastics, photodegradable plastics, hydrolytic degradation of plastics, etc. In particular, the chemical degradation of the present invention refers to the degradation process before plastics can be digested and absorbed by organisms. As known to those skilled in the art, the aerobic biodegradation test under controlled composting conditions of the present invention is carried out under specified temperature, oxygen concentration, humidity and dark or weak light conditions, so the chemical degradation involved is mainly hydrolytic degradation.

[0048] The term "physical and chemical degradation" as used herein refers to the process in which plastics are degraded under the action of physical fields such as thermal fields, electric fields, and stress fields. In particular, the physicochemical degradation of the present invention refers to the degradation process before plastics can be digested and absorbed by organisms. As known to those skilled in the art, the aerobic biodegradation test under controlled composting conditions of the present invention is carried out under dark or weak light conditions, so the physicochemical degradation effect involved therein is relatively weak.

[0049] It is known in the art that the degradation rate of plastics is affected by many factors, including environmental factors such as temperature, humidity, pH, chemical media, light irradiation, etc., and factors of the plastic itself such as the primary structure, secondary structure, tertiary structure, molecular weight and its distribution, as well as composition, interface structure, physical form, porosity, impurities, etc. of the polymer. One object of the present invention is to reflect the comprehensive anti-degradation performance of plastics through the method of the present invention.

[0050] The term "aerobic biodegradation test under controlled composting conditions" as used herein refers to the determination of the final aerobic biodegradability and disintegration degree of plastic materials by measuring the amount of carbon dioxide emitted by plastic materials as organic compounds under controlled composting conditions according to methods known in the art. By observing the trend of its biodegradability or relative biodegradability over time, it can be found that there is a zero decomposition rate or even a negative decomposition rate in the initial stage of degradation, which is called the "hysteresis stage". Related studies have found (Handbook of Biodegradable Polymer, Edited by Abraham J.Domb, Joseph Kost and David M.Wiseman, published in 1997 by CRC Press, pages 451-453) that in the hysteresis stage, plastics can produce chemical structural changes before biodegradation through chemical degradation (such as hydrolysis, oxidative degradation, photodegradation, etc.) involving non-microorganisms under the action of factors such as water, temperature, pH, and chemical substances. For example, before aerobic biodegradation begins, polylactic acid first needs to break ester bonds and reduce molecular weight through hydrolysis (Hamad, Kotiba, et al. Properties and medical applications of polylactic acid: A review. Express polymer letters, 2015, 9 (5): 435-455). When the molecular weight is as low as a certain threshold, such as less than 10 kDa, its oligomers or monomers are water-soluble and can be digested and absorbed by microorganisms or cells (Lunt, J. Large-scale production, properties and commercial applications of polylactic acid polymers. Polymer Degradation and Stability, 1998, 59: 145-152). In the biochemical process involving aerobic microorganisms, its oligomers or monomers can be further decomposed into small molecules until they are finally decomposed into carbon dioxide and water.

[0051] As is known in the art, in an aerobic biodegradation test under controlled composting conditions, the cumulative production of carbon dioxide gas released is calculated by continuously monitoring and periodically measuring the production of carbon dioxide in the test container and the blank container. The ratio of the actual amount of carbon dioxide gas released by the plastic test material in the test to the theoretical amount of carbon dioxide that the material can produce is the biodegradation rate. It is known to those skilled in the art that the aerobic biodegradability test of plastic test materials under controlled composting conditions can be carried out according to the test procedures in the following standards: GB / T 19277.1 "Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions—Method by analysis of evolved carbon dioxide—Part 1: General method", or GB / T 19277.2 "Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions—Method by analysis of evolved carbon dioxide—Part 2: Gravimetric measurement of carbon dioxide evolved in a laboratory-scale test", or ISO 14855-1, or ISO 14855-2, or ASTM D5929 "Standard Test Method for Determining Biodegradability of Materials Exposed to Source-Separated Organic Municipal Solid Waste Mesophilic Composting Conditions by Respirometryor ASTM D5338 “Standard Test Method for Determining Aerobic Biodegradation of Plastic Materials Under Controlled Composting Conditions, Incorporating Thermophilic Temperatures”, or EN ISO 14855-1, or EN ISO 14855-2, or BS EN ISO 14855-1, or BS EN ISO 14855-2, or DIN EN ISO 14855-1, or DIN EN ISO 14855-2, or KS T ISO 20200 “Plastics-Determination of the degree of disintegration of plastic materials under simulated composting conditions in a laboratory-scale test”, or UNE-EN 14995 “Plastics-Evaluation of compostability-Test scheme andspecifications” (Test plans and specifications for the assessment of the compostability of plastics), or AS5810 “Biodegradable plastics—Biodegradable plastics suitable for home composting” (Biodegradable plastics—Biodegradable plastics suitable for home composting).

[0052] The "biodegradation rate" used in the present invention can be determined according to methods known in the art. For example, the biodegradation rate of the plastic test material can be calculated according to the following equation in GB / T19277.1:

[0053]

[0054] Among them (CO2) T The cumulative amount of carbon dioxide released from the compost container containing the test material, (CO2) B is the average amount of carbon dioxide released from the blank container, and ThCO2 is the theoretical amount of carbon dioxide released by the test material. The same equation applies to the biodegradation rate of the reference material.

[0055] The aerobic biodegradation test under controlled composting conditions of the present invention can be carried out in a container or room, in darkness or weak light, without any steam that may affect the growth of microorganisms.

[0056] The "relative biodegradability" used in the present invention can be determined according to methods known in the art. For example, the relative biodegradability of the plastic test material can be further obtained according to the following equation:

[0057]

[0058] in, and are the plastic and the reference material at each time point {t i |i=1,2,3,...,p} biodegradation rate (%).

[0059] The term "digestion container / compost container" used herein refers to a container known in the art for aerobic biodegradation tests under controlled composting conditions. The digestion container can usually have a tightly connected glass container or a vessel made of other materials that does not affect the composting effect to avoid gas loss. The container may include a container with test materials, a container with reference materials or a blank container. The container can be connected to an air system and a carbon dioxide measurement system.

[0060] The term "plastic" as used herein refers to all types of plastics generally known in the art, in particular plastics that can be used for aerobic biodegradation tests under controlled composting conditions, such as plastics that can be subjected to aerobic biodegradation tests under controlled composting conditions according to the above 15 standards. The plastics may include, but are not limited to, all polymer compounds containing chemical bonds such as ester bonds, anhydride bonds (-RCOOOC-), orthoester bonds (-OCOR'R"OR-, ortho ester bonds), carbonate bonds (-ROCOO-), phosphate bonds (-OPOR'OOR-), ketal bonds (-OCR'R"OR-), acetal bonds (-OCHR'OR-), imino-carbonate bonds (-ROCNHO-), peptide bonds / amide bonds (-CONH-), and / or phosphazene bonds (-RR'P=N-), etc. on the main chain or branched chain skeleton structure.

[0061] The term "critical point" or "critical transition time point" as used herein refers to the critical state of transition from a chemical degradation process (such as hydrolytic degradation, oxidative degradation, etc.) involving no microorganisms to a biochemical process (biodegradation stage) involving microorganisms. The critical point is defined in the present invention as the t c orm .

[0062] The term “coefficient of determination” or “R 2 " is a statistical indicator known to those skilled in the art for determining the correlation between the fitted curve and the selected data points. 2 is defined as follows:

[0063]

[0064] In this paper, TSS is the total sum of squares, SSE is the sum of squared errors, and y i is the measured value or smoothed value of the biodegradation test data point set in the selected fitting area, for y i The arithmetic mean of The regression value is obtained by calculating the biodegradation test data point set in the selected fitting area after curve fitting.

[0065] The term "adjusted coefficient of determination" or "Adj.R" is used in this article. 2 ” refers to the “coefficient of determination” or “R 2 "Introducing adjustment coefficients based on This can penalize the error level of the object fitted with a too small set of data points. For example, Adj.R 2 It can be defined as follows:

[0066]

[0067] Among them, R 2 is the coefficient of determination of the curve fitting function of the selected data point set; m is the size of the data point set; k is the number of free parameters in the fitting function; mk>0; and the power exponent q is 2.0 to 7.0.

[0068] The term "free parameter" as used herein refers to the number of parameters in a fitting function that can vary independently without affecting the basic structure or constraints of the function. For example, when the fitting function is a polynomial function, the number of free parameters of the function is equal to the polynomial order + 1. Taking a seventh-order polynomial as an example, its order is 7, and the number of its free parameters is 8.

[0069] The term "best fit" as used herein refers to the highest correlation between the fitting curve function or result and the data points as the fitting object. In particular, in the present invention, when the "adjusted coefficient of determination" is the largest, the corresponding curve fitting function can be the curve fitting result with the best fit.

[0070] The plastic test material used in the present invention may have a form known in the art for aerobic biodegradation tests under controlled composting conditions, and may be added in a solid form, generally including a film, granules, powder, or a simple shape (e.g., dumbbell shape), etc., preferably in the form of granules or powder, more preferably in the form of granules, such as plastic masterbatch. Generally, the maximum surface area of ​​each piece of the plastic test material should not exceed 4 cm 2 , wherein if the size of the test material original exceeds the above maximum surface area, its size can be reduced to meet the requirements. For example, the test material can be in the form of particles with a diameter of about 1 cm or less, such as particles with a diameter of less than about 9 mm, less than about 8 mm, less than about 7 mm, less than about 6 mm, less than about 5 mm, less than about 4 mm, less than about 3 mm, less than about 2 mm or less.

[0071] The term "preprocessing" used in the present invention refers to the data preprocessing methods generally known in the art for data reprocessing, and its main tasks are generally including data cleaning, data integration, data conversion, data reduction, etc. Commonly used data preprocessing methods include denoising, missing value processing, outlier processing, and baseline correction processing. The term "smoothing" used in the present invention refers to the preprocessing methods of data known in the art to eliminate the noise in the data so as to highlight the trend in the data. Those skilled in the art can perform smoothing by methods known in the art, such as moving average smoothing (MA), Savitzky-Golay smoothing (also known as convolution smoothing), Whittaker smoothing, etc. In addition to the method based on smoothing denoising, those skilled in the art can also perform data preprocessing by methods known in the art such as modeling denoising (such as Wiener Filtering, deep learning, etc.) or decomposition denoising (such as Fourier Transform, Wavelet Transform, Variational Mode Decomposition, etc.) to eliminate the noise in the data so as to highlight the trend in the data.

[0072] According to one aspect of the present invention, a method for analyzing and evaluating the anti-degradation performance of plastics based on the fitting derivative method of aerobic biodegradation test results under controlled composting conditions is provided, characterized in that it comprises the following steps:

[0073] (1) conducting an aerobic biodegradation test of plastics under controlled composting conditions and obtaining the results of the test, which include the biodegradation rate or relative biodegradation rate at each time point;

[0074] (2) draw a scatter plot of the decomposition rate of step (1) versus time;

[0075] (3) selecting a plurality of segments containing at least 7 continuous data points from the scatter plot of step (2), performing curve fitting on each of the segments using a function that is at least fifth-order continuously differentiable, and obtaining respective curve fitting functions;

[0076] (4) selecting a function with the best fit from the curve fitting functions of step (3) as the curve fitting result; and

[0077] (5) Obtain the time corresponding to when the third-order derivative of the curve fitting result of step (4) is zero and the fourth-order derivative is negative, and / or the time corresponding to when the fourth-order derivative of the curve fitting result is zero and the fifth-order derivative is negative, and / or the second-order derivative value of the curve corresponding to the time, as the output evaluation result.

[0078] According to another aspect of the present invention, a method for analyzing and evaluating the anti-degradation performance of plastics based on the fitting derivative method of aerobic biodegradation test results under controlled composting conditions is provided, characterized in that it comprises the following steps:

[0079] (1) conducting aerobic biodegradation tests on plastics under controlled composting conditions and obtaining the results of said tests,

[0080] The biodegradation rate or relative biodegradation rate (%) of the plastic at each time point t is denoted as D t ;

[0081] (2) Draw a scatter plot selected from the following:

[0082] (a)D t a scatter plot against t, or

[0083] (b) D t Preprocessing Then draw the preprocessed Scatter plot relative to t;

[0084] (3) Perform curve fitting on the scatter plot in step (2),

[0085] Wherein, all possible segments containing at least 7 continuous data points are selected from the scatter plot, and a continuously differentiable function is used to perform curve fitting on the continuous data points of each segment to obtain each curve fitting function for each region,

[0086] The fitting function of the jth region is denoted as y j =f j (t)|t∈[t A,j ,tB,j ],

[0087] The size or number of continuous data points in the jth region is recorded as m. j , and m j ≥7, t A,j is the starting time point of the jth region, t B,j is the end time point of the j-th region, and wherein the continuously differentiable function is selected from at least fifth-order differentiable functions, particularly preferably from at least sixth-order differentiable functions, for example, seventh-order, eighth-order or ninth-order differentiable functions;

[0088] (4) Obtaining a curve fitting result with the best fitting degree from the curve fitting function of step (3),

[0089] Each y is expressed by the following equation 1 j Calculate the adjusted coefficient of determination separately, namely

[0090]

[0091] in, m is the coefficient of determination of the curve fitting function of each segment; j As defined in step (3); k is the number of free parameters in the fitting function; m j -k>0; the power exponent q is 2.0 to 7.0, and

[0092] From the various The maximum value is selected from the above, and the curve fitting function corresponding to the maximum value is limited to the curve fitting result with the best fitting degree, which is recorded as y opt =f opt (t)|t∈[t A,opt ,t B,opt ];

[0093] (5) Analyze the curve fitting result of the best fit in step (4),

[0094] Calculate y opt The fourth-order derivative y″″ and the fifth-order derivative y″″′ of , the time t corresponding to y″″=0 and y″″′<0 is obtained c , where t c is a real number solution and satisfies t A,opt ≤t c ≤t B,opt , optionally, when there are at least 2 t satisfying the above conditions c solution, then take the minimum solution,

[0095] Optionally, additionally calculate y optThe third-order derivative y″′ and the fourth-order derivative y″″ of , the time t corresponding to y″′=0 and y″″<0 is obtained m , where t m is a real number solution and satisfies t A,opt ≤t m ≤t B,opt , and t m ≥t c , optionally, when there are at least 2 t satisfying the above conditions m solution, then take the minimum solution,

[0096] And optionally, calculate y opt The second-order derivative y″ of y″ is obtained at t c The value of time y″ c , and / or get y″ at t m The value of time y″ m ;and

[0097] (6) Output the evaluation results,

[0098] The evaluation result includes the t obtained in step (5). c and preferably additionally comprises t m , optionally including y″ c and / or y″ m .

[0099] In step (1) of the method of the present invention, the aerobic biodegradation test of the plastic under controlled composting conditions can be carried out according to any method known in the prior art, and the results of the test can be obtained, including the biodegradation rate or relative biodegradation rate of the plastic at each time point t. In step (1) of the method of the present invention, the validity of the results of the aerobic biodegradation test under controlled composting conditions can be evaluated according to methods known in the art, for example, according to the methods required in standards GB / T 19277.1 or GB / T 19277.2.

[0100] According to the method of the present invention, the aerobic biodegradation test in step (1) can be carried out under the conditions of constant temperature and darkness or weak light, and the constant temperature can be at least 45°C, at least 46°C, at least 47°C, at least 48°C, at least 49°C, at least 50°C, at least 51°C, at least 52°C, at least 53°C, at least 54°C, at least 55°C, at least 56°C, at least 57°C, at least 58°C, at least 59°C, at least 60°C or higher. Preferably, the aerobic biodegradation test can be carried out under the conditions of constant temperature of 58°C±2°C and darkness or weak light.

[0101] According to the method of the present invention, the time described in step (1) can be in minutes (m), hours (h), or days (d). In some preferred embodiments, the time is in days (d).

[0102] According to the method of the present invention, the pre-processing in step (2) can be any data pre-processing method known in the art, such as smoothing. In one embodiment of the present invention, the smoothing can be moving average smoothing known in the art. Typically, the moving average smoothing method can be a symmetric window moving average smoothing method or an asymmetric window moving average smoothing method.

[0103] In one embodiment of the present invention, in step (2) of the method of the present invention, D can be converted into t Smoothing is the preprocessed decomposition rate

[0104]

[0105] Where i is the position of the smoothed data point; p is the total number of time points of the decomposition rate before preprocessing; for The i-th preprocessed decomposition rate in ; g is the size of the left smoothing window and does not include data point i; h is the size of the right smoothing window and does not include data point i; g or h are independently 0, 1, 2, 3 or a larger integer, where g and h are not 0 at the same time; u is the number of D t Position; D u is D at position u in the smoothing window t In a preferred embodiment of the present invention, in equation 2, g=h=1. In a preferred embodiment of the present invention, in equation 2, g≠0 and h=0, preferably, g=5 and h=0.

[0106] According to the method of the present invention, the scale of the continuous data points in step (3) is the number m j It may be at least 8, at least 9 or at least 10, preferably at least 15, particularly preferably at least 20, still more preferably at least 30 or at least 60.

[0107] According to the method of the present invention, in step (3) A,j It can be at least the 6th, 12th, 18th, 24th, 30th, 36th, 42nd or 48th hour, or at least the 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th, 15th or 20th day, or at least the 30th, 40th, 50th, 60th, 70th or 80th day.

[0108] According to the method of the present invention, in step (3) A,jIt may be up to the 12th or 24th hour, or up to the 3rd, 6th, 10th, 15th, 30th, 60th or 90th day.

[0109] According to the method of the present invention, in step (3) B,j It may be at least 24, at least 36 or at least 48 hours, or at least 3, at least 6 or at least 10 days, preferably at least 15 days, more preferably at least 30 days, particularly preferably at least 60 days, still more preferably at least 90 days, even at least 120 days.

[0110] According to the method of the present invention, in step (3), the above range of t can be selected according to actual needs such as degradation conditions, material type and / or shape size. A,j and t B,j To avoid or reduce t c and / or m Not in A,j to B,j The occurrence of incomprehensible situations within the section.

[0111] According to the method of the present invention, the continuously differentiable function in step (3) can be selected from the continuously differentiable function selected from at least fifth-order differentiable functions, preferably selected from at least sixth-order differentiable functions, more preferably selected from at least seventh-order differentiable functions, for example, seventh-order, eighth-order or ninth-order differentiable functions. In one embodiment of the present invention, the continuously differentiable function in step (3) can be selected from polynomial functions, Boltzmann functions or Bezier curves, preferably polynomial functions. In some embodiments, the continuously differentiable function can be a polynomial function or a Boltzmann function. In a preferred embodiment, the continuously differentiable function can be a polynomial function.

[0112] In some preferred embodiments of the present invention, the continuously differentiable function in step (3) of the method may be a polynomial function, such as a quintic polynomial function or a higher polynomial function, more preferably a 6th, 7th, 8th or 9th degree polynomial. Particularly preferably, the continuously differentiable function in step (3) may be a 7th degree polynomial function.

[0113] In the method of the present invention, "a" related to a continuously differentiable function refers to the same type of differentiable functions of the same order, wherein the coefficients, i.e., free parameters, may be different. For example, a continuously differentiable function may be a seventh-order polynomial function with different coefficients.

[0114] In one embodiment, in step (4), is the coefficient of determination of the curve fitting function of each of the segments, specifically, m j -k>0;D tjis the biodegradation rate of the jth segment (i.e. D t ); is the D of the jth segment t The arithmetic mean of tj The arithmetic mean of is the D of the jth segment t The regression value calculated after curve fitting in step (3).

[0115] In a preferred embodiment of the present invention, a scatter plot of the biodegradation rate of the plastic relative to t is drawn in step (2), wherein the biodegradation rate of the plastic is a smoothed biodegradation rate And in step (4) is based on The coefficient of determination of the curve fitting function obtained with respect to the scatter plot of t, specifically, m j -k>0; is the smoothed biodegradation rate of the jth segment (i.e. ); For the jth segment The arithmetic mean of The arithmetic mean of For the jth segment The regression value calculated after curve fitting in step (3).

[0116] According to the method of the present invention, in step (4), the coefficient of determination can be adjusted by To analyze the goodness of fit of the curve obtained in step (3), the coefficient of determination R 2 The adjustment factor can be introduced based on The error level of the fitting solution for a data set that is too small is penalized and amplified, where m j -k>0;m j is the size or number of continuous data points contained in the jth segment, and m j ≥7; k is the number of free parameters in the fitting function; q is the power index in the adjustment coefficient. The maximum error analysis optimization method can obtain a continuous differentiable function with a moderate data point set size and can describe the biodegradation test data related to the biodegradation critical point region as completely and accurately as possible, such as a polynomial fitting function. The maximization principle can avoid the problem of selecting a fitting solution with too small a data set for curve fitting analysis.

[0117] In some preferred embodiments of the present invention, when the continuously differentiable function in step (3) of the method is a polynomial function, for example, the form of the polynomial function can be as shown in the following equation 3:

[0118] y=a n ×t n +a n-1 ×t n-1 +...+a2×t 2 +a1×t+a0 Equation 3

[0119] Where n is the order of the polynomial function, a0 to a n are the coefficients of the terms of the polynomial function. Then, in the adjusted coefficient of determination in step (4), the number k of free parameters in the fitting function is equal to the number of parameters, i.e., coefficients, of the polynomial function. That is to say, when the continuously differentiable function in step (3) of the method is a polynomial function, k is equal to the order of the polynomial function + 1, i.e., k = n + 1.

[0120] In some embodiments of the present invention, when the continuously differentiable function in step (3) of the method is a polynomial function, the scale of the continuous data points in step (3), i.e., the number m j It may be at least the order of the polynomial function +2, preferably at least the order of the polynomial function +3, more preferably at least the order of the polynomial function +4, even more preferably at least the order of the polynomial function +5, further more preferably at least the order of the polynomial function +10, still more preferably at least the order of the polynomial function +15, most preferably at least the order of the polynomial function +20, or more.

[0121] In some embodiments of the present invention, the power exponent q in the adjustment coefficient may be 2.0 to 7.0.

[0122] In one embodiment of the present invention, the continuously differentiable function in step (3) of the method may be a fifth-order polynomial function. Preferably, the adjusted coefficient of determination of the fifth-order polynomial function in step (4) is The power index q in step (3) is 4.0 to 7.0, preferably 5.0 to 7.0, for example 4.0, 4.5, 5.0, 5.5, 6.0, 6.5 or 7.0. In a preferred embodiment, the continuously differentiable function in step (3) may be a quintic polynomial function, and the adjustment coefficient of determination in step (4) may be The power exponent q in may be between 5.0 and 7.0, typically 5.0.

[0123] In a preferred embodiment of the present invention, the continuously differentiable function in step (3) of the method may be a sixth-order polynomial function. Preferably, the adjusted coefficient of determination of the sixth-order polynomial function in step (4) is The power index q in step (3) is 3.0 to 6.5, preferably 3.6 to 5.6, for example 4.0, 4.2, 4.4, 4.6, 4.8, 5.0 or 5.2. In a particularly preferred embodiment, the continuously differentiable function in step (3) may be a sixth-order polynomial function, and the adjustment coefficient of determination in step (4) may be The power exponent q in can be between 3.0 and 6.5, typically 4.6.

[0124] In a preferred embodiment of the present invention, the continuously differentiable function in step (3) of the method may be a seventh-order polynomial function. Preferably, the adjusted coefficient of determination of the seventh-order polynomial function in step (4) is The power exponent q in step (3) is 2.5 to 6.0, preferably 3.3 to 5.3, for example 3.7, 3.9, 4.1, 4.3, 4.5, 4.7 or 4.9. In a particularly preferred embodiment, the continuously differentiable function in step (3) may be a seventh-order polynomial function, and the adjustment coefficient of determination in step (4) may be The power exponent q in may be between 2.5 and 6.0, typically 4.3.

[0125] In a preferred embodiment of the present invention, the continuously differentiable function in step (3) of the method may be an octave polynomial function, and preferably, the adjusted coefficient of determination of the octave polynomial function in step (4) is The power index q in step (3) is 2.0 to 5.5, preferably 3.1 to 5.1, for example 3.5, 3.7, 3.9, 4.1, 4.3, 4.5 or 4.7. In a particularly preferred embodiment, the continuously differentiable function in step (3) may be an octave polynomial function, and the adjustment coefficient of determination in step (4) may be The power exponent q in may be between 2.0 and 5.5, typically 4.1.

[0126] In a preferred embodiment of the present invention, the continuously differentiable function in step (3) of the method may be a ninth-order polynomial function. Preferably, the adjusted coefficient of determination of the ninth-order polynomial function in step (4) is The power index q in step (3) is 2.0 to 5.5, preferably 2.9 to 5.9, for example 3.3, 3.5, 3.7, 3.9, 4.1, 4.3 or 4.5. In a particularly preferred embodiment, the continuously differentiable function in step (3) may be a ninth-order polynomial function, and the adjustment coefficient of determination in step (4) may be The power exponent q in may be between 2.0 and 5.5, typically 3.9.

[0127] According to the method of the present invention, the y calculated in step (5) opt The third-order derivatives y″′, y opt The fourth-order derivatives y″″ and y opt The second-order derivative y″ can be independently solved numerically or analytically.

[0128] In some embodiments of the present invention, in step (5), t is calculated c and / or m If there is no real number solution or an unreasonable solution in the process, we can return to step (4) and select Select the next largest value from the above, use the curve fitting function corresponding to this value as the new curve fitting result, and obtain its corresponding t according to step (5). c and / or m And so on, until we get a t that satisfies the conditions. c and / or m The evaluation results are given as output.

[0129] Specifically, in step (5), t is calculated c and / or m If there is no real number solution or an unreasonable solution in the process, we can return to step (4) and select The second largest value is selected, and the curve fitting function corresponding to the second largest value is used as the new curve fitting result, and the corresponding t is obtained according to step (5). c and / or m . It is still impossible to calculate t from the curve fitting function corresponding to the second largest value c and / or m In the case of The third largest value is selected, and the curve fitting function corresponding to the third largest value is used as the new curve fitting result, and the corresponding t is obtained according to step (5). c and / or m And so on, until we get a t that satisfies the conditions. c and / or m It should be noted that when calculating t according to the method of the present invention, c and t m When both are used as evaluation results, the same curve fitting result should be used to calculate t in any case. c and t m both.

[0130] In some embodiments of the present invention, the biodegradation rate or relative biodegradation rate D is obtained in step (1) of the method. t The maximum value may be less than 10%, less than 9%, less than 8%, less than 7%, less than 10%, less than 9%, less than 8%, less than 7%, less than 6%, less than 5%, less than 4.5%, less than 4%, less than 3.5%, less than 3%, less than 2.5%, less than 2%, or less than 1.5%.

[0131] In some embodiments of the present invention, the biodegradation rate or relative biodegradation rate D is obtained in step (1) of the method. t The maximum value may be at least 1%, at least 1.5%, at least 2%, at least 2.5%, at least 3%, at least 3.5%, at least 4%, at least 4.5%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, or at least 10%.

[0132] In some embodiments of the present invention, the minimum value of each time point t in step (1) of the method may be the 0th hour or the 0th day, and the maximum value of each time point t may be at least the 48th hour, the 3rd, 4th, 5th, 10th, 15th, 20th, 25th, 30th, 35th, 45th, 60th or 90th day, as long as the scatter plot in the corresponding step (2) of the method can reflect the trend of the biodegradation rate or relative biodegradation rate in the hysteresis stage over time (that is, it can be found that there is a zero decomposition rate or even a negative decomposition rate in the initial stage of degradation) and the trend of the biodegradation rate or relative biodegradation rate in the biodegradation stage increasing over time.

[0133] According to another aspect of the present invention, a system for evaluating the anti-degradation performance of plastics is provided, characterized in that the system adopts the method of the present invention.

[0134] According to yet another aspect of the present invention, there is provided a computer device, characterized in that it comprises:

[0135] Processor; and

[0136] A memory for storing executable instructions;

[0137] The processor is used to read and execute the executable instructions from the memory to implement the method described above.

[0138] According to yet another aspect of the present invention, a computer-readable storage medium is provided, characterized in that a computer program is stored therein, and when the computer program is executed by a processor, the method described above is implemented.

[0139] Example

[0140] In order to further understand the present invention, the preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

[0141] The materials and test equipment used in the aerobic biodegradation tests under controlled composting conditions in Examples 1 to 11 are shown below:

[0142] -Testing instrument: Bioprocess Control Gas Endeavour biodegradation test system produced by Bioprocess Control Sweden AB;

[0143] -Plastic: All are polyester plastics, specifically poly (L-lactic acid) resin (PLA, CAS: 26100-51-6, molecular formula (C3H4O2) n The dosage is 7.5 g, in the form of particles with a diameter of about 3 mm, wherein the melting point of poly (L-lactic acid) resin 1# is 174.6°C, the melt index is 4.9 g / 10 min (190°C, 2.16 kg), the molecular weight distribution index is 1.65, and the glass transition temperature (T g ) is 58.7°C and the density is 1.25g / cm 3 , lactide content is 0.33%, the melting point of poly (L-lactic acid) resin 2# is 177.3℃, the melt index is 4.6g / 10min (190℃, 2.16kg), the molecular weight distribution index is 1.62, and the glass transition temperature (T g ) is 60.8℃ and the density is 1.25g / cm 3 , lactide content is 0.20%, the melting point of poly (L-lactic acid) resin 3# is 160.0℃, the melt index is 17.1g / 10min (190℃, 2.16kg), the molecular weight distribution index is 1.58, and the glass transition temperature (T g ) is 59.9°C and the density is 1.25g / cm 3 , lactide content is 0.11%, the performance index test method of the above poly (L-lactic acid) resin is carried out in accordance with the national standard GB / T 29284-2024 "Polylactic Acid"; the modified polylactic acid resin, the amount is 7.5g, in the form of particles with a diameter of about 3mm, including 181 type modified polylactic acid resin.

[0144] -Inoculum: All were aerobic compost from Bipu Instrument (Zhejiang) Co., Ltd., and the dosage was 500g;

[0145] - Reference material: cellulose powder from Shanghai Aladdin Biochemical Technology Co., Ltd. (α-cellulose powder, CAS: 9004-34-6, particle size ≤ 25 μm);

[0146] -Digestion vessel: 1L Schott blue cap glass reagent bottle.

[0147] Example 1

[0148] According to GB / T 19277.1 "Determination of the ultimate aerobic biodegradability of materials under controlled composting conditions - Method for determination of released carbon dioxide - Part 1: General method", poly (L-lactic acid) resin 1# was tested for aerobic biodegradability under controlled composting conditions, with α-cellulose powder as the reference material, and the test was conducted under weak light conditions at a temperature of 58℃±2℃. The cumulative carbon dioxide gas release in each digestion container was counted and recorded in units of days (d), and the biodegradation rate of the test material was calculated.

[0149] Plot a scatter plot of the biodegradation rate versus time, see Figure 1 We exhaustively enumerate all regions in the scatter plot that contain at least 9 consecutive data points, and use a seventh-order polynomial to fit curves for each region, and calculate the corresponding adjusted coefficient of determination. The power exponent q is 4.3. After calculation, we find that The largest area corresponds to the data point set from the 2nd to the 42nd day, and the corresponding curve fitting function is:

[0150] y opt =–2.22483321746615×10 -11 ×t 7 +3.49921656327096×10 -9 ×t 6 –2.03282902465231×10 -7 ×t 5 +5.17125289554367×10 -6 ×t 4 –4.78818761596649×10 -5 ×t 3 +8.29194633109149×10 -5 ×t 2 –5.05774357023876×10 -3 ×t+2.4372002915553×10 -2

[0151] Calculate the numerical solution of the fourth-order derivative of the above function y″″=0, and get t c =8.00, and its fifth-order derivative y″″′=–7.824×10 -6 <0|t=t c , and 2≤t c ≤42, get the evaluation result t c =8.00d.

[0152] In addition, the numerical solution of the third-order derivative y″′=0 of the above function is calculated, and the solution is t m =15.50, and its fourth-order derivative y″″=–2.094×10 -5 <0|t=t m , and 2≤t m ≤42 and t m ≥t c , and get the evaluation result t m =15.50d.

[0153] Example 2

[0154] According to ISO 14855-1 “Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions-Method by analysis of evolved carbon dioxide-Part 1: General method”, poly (L-lactic acid) resin 2# was subjected to aerobic biodegradation test, with α-cellulose powder as reference material, and the test was carried out under weak light conditions at a temperature of 58℃±2℃. The cumulative carbon dioxide gas release in each digestion container was counted and recorded in units of days (d), and the biodegradation rate of the test material was calculated.

[0155] Plot a scatter plot of the biodegradation rate versus time, see Figure 2 We exhaustively enumerate all regions in the scatter plot that contain at least 9 consecutive data points, and use a seventh-order polynomial to fit curves for each region, and calculate the corresponding adjusted coefficient of determination. The power exponent q is 4.3. After calculation, we find that The largest area corresponds to the data point set from day 2 to day 43, and the corresponding curve fitting function is:

[0156] y opt =–1.31414836271717×10 -10×t 7 +1.9883622665005×10 -8 ×t 6 –1.19097923793376×10 -6 ×t 5 +3.57824185692077×10 -5 ×t 4 –5.61979273799354×10 -4 ×t 3 +4.43019536100526×10 -3 ×t 2 –1.72691823101215×10 -2 ×t+1.59750691563909×10 -2

[0157] Calculate the numerical solution of the fourth-order derivative of the above function y″″=0, and get t c =11.24, and its fifth-order derivative y″″′=–2.385×10 -5 <0|t=t c , and 2≤t c ≤43, get the evaluation result t c =11.24d.

[0158] In addition, the numerical solution of the third-order derivative y″′=0 of the above function is calculated, and the solution is t m =16.85, and its fourth-order derivative y″″=–4.513×10 -5 <0|t=t m , and 2≤t m ≤43 and t m ≥t c , and get the evaluation result t m =16.85d.

[0159] Example 3

[0160] According to ISO 14855-1 “Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions-Method by analysis of evolved carbon dioxide-Part 1: General method”, poly (L-lactic acid) resin 3# was tested for aerobic biodegradability. α-cellulose powder was used as the reference material. The test was carried out under weak light conditions at a temperature of 58℃±2℃. The cumulative carbon dioxide gas release in each digestion container was counted and recorded in units of days (d), and the biodegradation rate of the test material was calculated.

[0161] Plot a scatter plot of the biodegradation rate versus time, see Figure 3 We exhaustively enumerate all regions in the scatter plot that contain at least 9 consecutive data points, and use a seventh-order polynomial to fit curves for each region, and calculate the corresponding adjusted coefficient of determination. The power exponent q is 4.3. After calculation, we find that The largest area corresponds to the data point set from day 0 to day 42, and the corresponding curve fitting function is:

[0162] y opt =–3.5959282934999×10 -11 ×t 7 +2.9984520756262×10 -9 ×t 6 +1.64139843166322×10 -8 ×t 5 –8.22860759207612×10 -6 ×t 4 +2.83611124872035×10 -4 ×t 3 –3.32507447042611×10 -3 ×t 2 +1.61898207300958×10 -2 ×t–4.18749380483645×10 -3

[0163] Calculate the real number solution of the fourth-order derivative of the above function y″″=0, and get t c =-10.34, however, the t c<0, that is, it is not within the range of the 0th to 42nd day of the data point set, that is, in Calculate t when the maximum value is taken c In the process, unreasonable solutions appeared.

[0164] Therefore, from various The second largest value is selected, and its corresponding data point set is from day 0 to day 43, and the corresponding curve fitting function is:

[0165] y opt =–7.18008925086128×10 -11 ×t 7 +7.95459645858276×10 -9 ×t 6 –2.5235783572402×10 -7 ×t 5 –1.00410326543275×10 -6 ×t 4 +1.83692370488336×10 -4 ×t 3 –2.71993765571635×10 -3 ×t 2 +1.46448947806362×10 -2 ×t+2.64176580789852×10 -4

[0166] Calculate the real number solution of the fourth-order derivative of the above function y″″=0, and get t c =-0.74, however, the t c <0, that is, it is not within the range of the 0th to 43rd day of the data point set, that is, in Calculate t when taking the second largest value c In the process, unreasonable solutions appeared.

[0167] Therefore, from various The third largest value is selected, and its corresponding data point set is from day 1 to day 42, and the corresponding curve fitting function is:

[0168] y opt =–3.49506937392479×10 -11 ×t 7 +2.75626102692637×10 -9 ×t 6 +3.69752844248873×10 -8 ×t 5–9.06507989006697×10 -6 ×t 4 +3.0129555216914×10 -4 ×t 3 –3.57410792686069×10 -3 ×t 2 +1.72615307029147×10 -2 ×t–1.90474672447274×10 -3

[0169] Calculate the real number solution of the fourth-order derivative of the above function y″″=0, and get t c =-14.11, however, the t c <1, that is, not within the range of day 1 to day 42 of the data point set, that is, Calculate t when taking the third largest value c In the process, unreasonable solutions appeared.

[0170] Therefore, from various The fourth largest value is selected, and its corresponding data point set is from the 1st day to the 43rd day. The corresponding curve fitting function is:

[0171] y opt =–7.4126940976463×10 -11 ×t 7 +8.33234678340413×10 -9 ×t 6 –2.77022327655295×10 -7 ×t 5 –1.77411171833121×10 -7 ×t 4 +1.68658915087824×10 -4 ×t 3 –2.57637032006149×10 -3 ×t 2 +1.40128728940951×10 -2 ×t+1.16005524278218×10 -3

[0172] Calculate the real number solution of the fourth-order derivative of the above function y″″=0, and get t c =-0.13, however, the t c <1, that is, not within the range of the 1st to 43rd day of the data point set, that is, Take the fourth time to calculate t cIn the process, unreasonable solutions appeared.

[0173] Therefore, from various The fifth largest value is selected, and its corresponding data point set is from the 2nd day to the 42nd day. The corresponding curve fitting function is:

[0174] y opt =–4.90476620209193×10 -11 ×t 7 +5.03902984840981×10 -9 ×t 6 –1.12483568245987×10 -7 ×t 5 –4.00015471712182×10 -6 ×t 4 +2.06968740032992×10 -4 ×t 3 –2.63162431021857×10 -3 ×t 2 +1.27453367584566×10 -2 ×t+5.68266612575028×10 -3

[0175] Calculate the real number solution of the fourth-order derivative of the above function y″″=0, and get t c =-4.34, however, the t c <2, that is, not within the range of the 2nd to 42nd day of the data point set, that is, Take the fifth time to calculate t c In the process, unreasonable solutions appeared.

[0176] Therefore, from various The sixth largest value is selected, and its corresponding data point set is from the 2nd day to the 43rd day. The corresponding curve fitting function is:

[0177] y opt =–9.30009110505888×10 -11 ×t 7 +1.14591343651394×10 -8 ×t 6 –4.86429015996485×10 -7 ×t 5 +7.07993736973606×10 -6 ×t 4 +3.04838731246372×10-5 ×t 3 –1.16571339459982×10 -3 ×t 2 +7.11267255276953×10 -3 ×t+1.29723122871096×10 -2

[0178] Calculate the numerical solution of the fourth-order derivative of the above function y″″=0, and get t c =3.91, and its fifth-order derivative y″″′=–2.968×10 -5 <0|t=t c , and 2≤t c ≤43, get the evaluation result t c =3.91d.

[0179] In addition, the numerical solution of the third-order derivative y″′=0 of the above function is calculated, and the solution is t m =11.87, and its fourth-order derivative y″″=–7.239×10 -5 <0|t=t m , and 2≤t m ≤43 and t m ≥t c , and get the evaluation result t m =11.87d.

[0180] Example 4

[0181] According to ISO 14855-1 “Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions-Method by analysis of evolved carbon dioxide-Part 1: General method”, the samples from Zhejiang Hisun Biomaterials Co., Ltd. were analyzed. The 181 type modified polylactic acid resin was subjected to an aerobic biodegradation test, with α-cellulose powder as the reference material, and the test was conducted under weak light conditions at a temperature of 58°C±2°C. The cumulative carbon dioxide gas release in each digestion container was counted and recorded in units of days (d), and the biodegradation rate of the test material was calculated.

[0182] Plot a scatter plot of the biodegradation rate versus time, see Figure 4We exhaustively enumerate all regions in the scatter plot that contain at least 9 consecutive data points, and use a seventh-order polynomial to fit curves for each region, and calculate the corresponding adjusted coefficient of determination. The power exponent q is 4.3. After calculation, we find that The largest area corresponds to the data point set from day 3 to day 41, and the corresponding curve fitting function is:

[0183] y opt =–2.53972582084636×10 -10 ×t 7 +3.76231120340404×10 -8 ×t 6 –2.21582739640101×10 -6 ×t 5 +6.57825442591369×10 -5 ×t 4 –1.03466020869181×10 -3 ×t 3 +8.62538068756277×10 -3 ×t 2 –4.00425470608963×10 -2 ×t+6.93840584917279×10 -2

[0184] Calculate the numerical solution of the fourth-order derivative of the above function y″″=0, and get t c =11.20, and its fifth-order derivative y″″′=–4.279×10 -5 <0|t=t c , and 3≤t c ≤41, get the evaluation result t c =11.20d.

[0185] In addition, the numerical solution of the third-order derivative y″′=0 of the above function is calculated, and the solution is t m =16.18, and its fourth-order derivative y″″=–8.133×10 -5 <0|t=t m , and 3≤t m ≤41 and t m ≥t c , and get the evaluation result t m =16.18d.

[0186] Example 5

[0187] The scatter plot of Example 1 is subjected to curve fitting. All regions in the scatter plot containing at least 11 consecutive data points are exhaustively enumerated, and a ninth-order polynomial is used to perform curve fitting on each region, and the corresponding adjusted coefficient of determination is calculated respectively. The power exponent q is 3.9. After calculation, we found that The largest area corresponds to the data point set from day 2 to day 42, and the corresponding curve fitting function is:

[0188] y opt =–1.31902670959225×10 -13 ×t 9 +3.15657922619443×10 -11 ×t 8 –3.16386857859078×10 -9 ×t 7 +1.73280816436763×10 -7 ×t 6 –5.64556611756845×10 -6 ×t 5 +1.11077917362539×10 -4 ×t 4 –1.27590129894226×10 -3 ×t 3 +8.05220061984835×10 -3 ×t 2 –3.0382839784887×10 -2 ×t+5.30204443633206×10 -2

[0189] Calculate the numerical solution of the fourth-order derivative of the above function y″″=0, and get t c =9.15, and its fifth-order derivative y″″′=–5.491×10 -5 <0|t=t c , and 2≤t c ≤42, get the evaluation result t c =9.15d.

[0190] In addition, the numerical solution of the third-order derivative y″′=0 of the above function is calculated, and the solution is t m =14.20, and its fourth-order derivative y″″=–5.934×10 -5 <0|t=t m , and 2≤t m ≤42 and t m ≥t c , and get the evaluation result tm =14.20d.

[0191] Example 6

[0192] The scatter plot of Example 2 is subjected to curve fitting. All regions in the scatter plot containing at least 11 consecutive data points are exhaustively enumerated, and a ninth-order polynomial is used to perform curve fitting on each region, and the corresponding adjusted coefficient of determination is calculated respectively. The power exponent q is 3.9. After calculation, we found that The largest area corresponds to the data point set from day 1 to day 45, and the corresponding curve fitting function is:

[0193] y opt =5.73162454592436×10 -13 ×t 9 –1.17472461668288×10 -10 ×t 8 +1.00673682953582×10 -8 ×t 7 –4.68373606265947×10 -7 ×t 6 +1.28651664715183×10 -5 ×t 5 –2.13124401414326×10 -4 ×t 4 +2.10029946087793×10 -3 ×t 3 –1.17541456475382×10 -2 ×t 2 +3.18361112167389×10 -2 ×t–3.83800520889604×10 -2

[0194] Calculate the numerical solution of the fourth-order derivative of the above function y″″=0, and get t c =14.15, and its fifth-order derivative y″″′=–3.749×10 -5 <0|t=t c , and 1≤t c ≤45, get the evaluation result t c =14.15d.

[0195] In addition, the numerical solution of the third-order derivative y″′=0 of the above function is calculated, and the solution is t m =18.27, and its fourth-order derivative y″″=–8.060×10 -5<0|t=t m , and 1≤t m ≤45 and t m ≥t c , and get the evaluation result t m =18.27d.

[0196] Example 7

[0197] The scatter plot of Example 3 was subjected to curve fitting. All regions in the scatter plot that contained at least 11 consecutive data points were exhaustively enumerated, and a ninth-order polynomial was used to perform curve fitting on each region, and the corresponding adjusted coefficient of determination was calculated. The power exponent q is 3.9. After calculation, we found that The largest area corresponds to the data point set from day 0 to day 43, and the corresponding curve fitting function is:

[0198] y opt =–2.03253141701116×10 -13 ×t 9 +3.63639364249766×10 -11 ×t 8 –2.73836057508396×10 -9 ×t 7 +1.10946800405038×10 -7 ×t 6 –2.48827177964377×10 -6 ×t 5 +2.57935305595126×10 -5 ×t 4 +2.49144464576113×10 -5 ×t 3 –2.4027009676927×10 -3 ×t 2 +1.49270472208×10 -2 ×t–2.275619827647×10 -4

[0199] Calculate the numerical solution of the fourth-order derivative of the above function y″″=0, and get t c =3.23, and its fifth-order derivative y″″′=–1.046×10 -4 <0|t=t c , and 0≤t c ≤43, get the evaluation result t c =3.23d.

[0200] In addition, the numerical solution of the third-order derivative y″′=0 of the above function is calculated, and the solution is t m =10.82, and its fourth-order derivative y″″=–1.034×10 -4 <0|t=t m , and 0≤t m ≤43 and t m ≥t c , and get the evaluation result t m =10.82d.

[0201] Example 8

[0202] The scatter plot of Example 4 was curve fitted. The biodegradability was smoothed by an asymmetric window moving average with a window size of 5 on the left and 0 on the right. All regions in the scatter plot containing at least 9 consecutive data points were exhaustively enumerated, and curve fitting was performed on each region using a seventh-order polynomial, and the corresponding adjusted coefficient of determination was calculated. The power exponent q is 4.3. After calculation, we find that The largest area corresponds to the data point set from day 8 to day 41, and the corresponding curve fitting function is:

[0203] y opt =–2.5769287835971×10 -10 ×t 7 +4.25488871943111×10 -8 ×t 6 –2.85184431054741×10 -6 ×t 5 +9.94195953264661×10 -5 ×t 4 –1.92563121420163×10 -3 ×t 3 +2.08317308296463×10 -2 ×t 2 –0.122261153002679×t+0.295607262189315

[0204] Calculate the numerical solution of the fourth-order derivative of the above function y″″=0, and get t c =14.08, and its fifth-order derivative y″″′=–3.960×10 -5 <0|t=t c , and 8≤t c ≤41, get the evaluation result t c =14.08d.

[0205] In addition, the numerical solution of the third-order derivative y″′=0 of the above function is calculated, and the solution is t m =18.71, and its fourth-order derivative y″″=–7.250×10 -5 <0|t=t m , and 8≤t m ≤41 and t m ≥t c , and get the evaluation result t m =18.71d.

[0206] Example 9

[0207] The scatter plot of Example 2 was curve fitted. The biodegradability was smoothed by an asymmetric window moving average with a window size of 5 on the left and 0 on the right. All regions in the scatter plot containing at least 9 consecutive data points were exhaustively enumerated, and curve fitting was performed on each region using a seventh-order polynomial, and the corresponding adjusted coefficient of determination was calculated. The power exponent q is 4.3. After calculation, we find that The largest area corresponds to the data point set from day 7 to day 43, and the corresponding curve fitting function is:

[0208] y opt =–1.54973697579025×10 -10 ×t 7 +2.65288276838355×10 -8 ×t 6 –1.84389912310913×10 -6 ×t 5 +6.67838031167046×10 -5 ×t 4 –1.3447863653956×10 -3 ×t 3 +1.4938963890991×10 -2 ×t 2 –8.64165479378314×10 -2 ×t+0.192275886400494

[0209] Calculate the numerical solution of the fourth-order derivative of the above function y″″=0, and get t c =14.72, and its fifth-order derivative y″″′=–2.475×10 -5 <0|t=t c , and 7≤t c ≤43, get the evaluation result t c =14.72d.

[0210] In addition, the numerical solution of the third-order derivative y″′=0 of the above function is calculated, and the solution is t m =19.87, and its fourth-order derivative y″″=–4.436×10 -5 <0|t=t m , and 7≤t m ≤43 and t m ≥t c , and get the evaluation result t m =19.87d.

[0211] Example 10

[0212] According to ISO 14855-1 “Determination of the ultimate aerobic biodegradability of plastic materials under controlled composting conditions-Method by analysis of evolved carbon dioxide-Part 1: General method”, poly (L-lactic acid) resin 2# was subjected to aerobic biodegradation test, with α-cellulose powder as the reference material, and the test was carried out under weak light conditions at a temperature of 58℃±2℃. The cumulative carbon dioxide gas release in each digestion container was counted and recorded in units of days (d), and the relative biodegradability of the test material was calculated.

[0213] Plot a scatter plot of the relative biodegradation rate versus time, see Figure 5 After the biodegradation rate was smoothed by a symmetrical window moving average with a window size of 3, all regions in the scatter plot containing at least 9 consecutive data points were exhaustively enumerated, and curve fitting was performed on each region using an eighth-order polynomial, and the corresponding adjusted coefficient of determination was calculated respectively. The power exponent q is 4.1. After calculation, we find that The largest area corresponds to the data point set from day 5 to day 44, and the corresponding curve fitting function is:

[0214] y opt =1.08744054080412×10 -11 ×t 8 –2.23313309027131×10 -9 ×t 7 +1.89409483694555×10 -7 ×t 6 –8.57698250746627×10 -6 ×t 5+2.23642446024907×10 -4 ×t 4 –3.37294974365525×10 -3 ×t 3 +2.80980694262728×10 -2 ×t 2 –0.117256233421027×t+0.155604023098694

[0215] Calculate the numerical solution of the fourth-order derivative of the above function y″″=0, and get t c =11.67, and its fifth-order derivative y″″′=–8.796×10 -5 <0|t=t c , and 5≤t c ≤44, get the evaluation result t c =11.67d.

[0216] In addition, the numerical solution of the third-order derivative y″′=0 of the above function is calculated, and the solution is t m =16.76, and its fourth-order derivative y″″=–1.186×10 -4 <0|t=t m , and 5≤t m ≤44 and t m ≥t c , and get the evaluation result t m =16.96d.

[0217] Embodiment 11

[0218] The scatter plot of Example 4 was subjected to curve fitting. All regions in the scatter plot that contained at least 11 consecutive data points were exhaustively enumerated, and a ninth-order polynomial was used to perform curve fitting on each region, and the corresponding adjusted coefficient of determination was calculated. The power exponent q is 3.9. After calculation, we found that The largest area corresponds to the data point set from day 7 to day 45, and the corresponding curve fitting function is:

[0219] y opt =7.93333220564456×10 -13 ×t 9 –1.69813332245602×10 -10 ×t 8 +1.54177228820223×10 -8 ×t 7 –7.7606617848566×10 -7 ×t 6+2.38084116990179×10 -5 ×t 5 –4.62533941987951×10 -4 ×t 4 +5.74258346258761×10 -3 ×t 3 –4.43585148321059×10 -2 ×t 2 +0.189852894002362×t–0.347515045877234

[0220] Calculate the numerical solution of the fourth-order derivative of the above function y″″=0, and get t c =14.27, and its fifth-order derivative y″″′=–2.351×10 -5 <0|t=t c , and 7≤t c ≤45, get the evaluation result t c =14.27d.

[0221] In addition, the numerical solution of the third-order derivative y″′=0 of the above function is calculated, and the solution is t m =18.28, and its fourth-order derivative y″″=–8.249×10 -5 <0|t=t m , and 7≤t m ≤45 and t m ≥t c , and get the evaluation result t m =18.28d.

[0222] As can be seen from Examples 1 to 11, the method of the present invention can transform the "rough" raw data reflecting the initial aerobic degradation characteristics of the degradable plastic into an accurate mathematical function by fitting the biodegradation rate or relative biodegradation rate curve into a function that is at least 5th order differentiable and calculating and analyzing the adjusted coefficient of determination, and the output result that can reflect the corresponding degradation characteristics of the degradable plastic is clearly defined and calculated through the mathematical function. At the same time, it is believed that when the same continuously differentiable function is used to fit the biodegradation rate collected under the same test conditions and the optional additional same data preprocessing process according to the method of the present invention, and the adjusted coefficient of determination with the same power exponent is used, i.e. When , according to the output evaluation result, for example, t c or m It can be used to compare the comprehensive anti-degradation performance of different plastics. cIt can be understood as the critical moment when the outermost layer of the test material directly contacts the biodegradation test environment and the part of the plastic begins to biodegrade (the plastic molecular weight is reduced to a level that can be digested and decomposed by microorganisms through chemical degradation). m It can be understood as the critical moment when the surface plastic of the test material begins to biodegrade. c and / or m The larger the value, the better the plastic's resistance to chemical degradation.

Claims

1. A method for analyzing and evaluating the anti-degradation performance of plastics based on the fitting derivative method of aerobic biodegradation test results under controlled composting conditions, characterized in that: It includes the following steps: (1) conducting an aerobic biodegradation test of plastics under controlled composting conditions and obtaining the results of the test, which include the biodegradation rate or relative biodegradation rate at each time point; (2) draw a scatter plot of the decomposition rate of step (1) versus time; (3) selecting a plurality of segments containing at least 7 continuous data points from the scatter plot of step (2), performing curve fitting on each of the segments using a function that is at least fifth-order continuously differentiable, and obtaining respective curve fitting functions; (4) selecting a function with the best fit from the curve fitting functions of step (3) as the curve fitting result; and (5) Obtain the time corresponding to when the third-order derivative of the curve fitting result of step (4) is zero and the fourth-order derivative is negative, and / or the time corresponding to when the fourth-order derivative of the curve fitting result is zero and the fifth-order derivative is negative, and / or the second-order derivative value of the curve corresponding to the time, as the output evaluation result.

2. A method for analyzing and evaluating the anti-degradation performance of plastics based on the fitting derivative method of aerobic biodegradation test results under controlled composting conditions, characterized in that: It includes the following steps: (1) conducting aerobic biodegradation tests on plastics under controlled composting conditions and obtaining the results of said tests, The biodegradation rate or relative biodegradation rate (%) of the plastic at each time point t is denoted as D t ; (2) Draw a scatter plot selected from the following: (a)D t a scatter plot against t, or (b) D t Preprocessing Then draw the preprocessed Scatter plot relative to t; (3) Perform curve fitting on the scatter plot in step (2), Wherein, all possible segments containing at least 7 continuous data points are selected from the scatter plot, and a continuously differentiable function is used to perform curve fitting on the continuous data points of each segment to obtain each curve fitting function for each region, and the fitting function of the jth region is recorded as y j =f j (t)|t∈[t A,j ,t B,j ]; The size or number of continuous data points in the jth region is recorded as m. j , and m j ≥7, t A,j is the starting time point of the jth region, t B,j is the end time point of the j-th region, and wherein the continuously differentiable function is selected from at least fifth-order differentiable functions, particularly preferably from at least sixth-order differentiable functions, for example, seventh-order, eighth-order or ninth-order differentiable functions; (4) Obtaining a curve fitting result with the best fitting degree from the curve fitting function of step (3), Each y is expressed by the following equation 1 j Calculate the adjusted coefficient of determination separately, namely in, m is the coefficient of determination of the curve fitting function of each segment; j As defined in step (3); k is the number of free parameters in the fitting function; m j -k>0; the power exponent q is 2.0 to 7.0, and From the various The maximum value is selected from the above, and the curve fitting function corresponding to the maximum value is limited to the curve fitting result with the best fitting degree, which is recorded as y opt =f opt (t)|t∈[t A,opt ,t B,opt ]; (5) Analyze the curve fitting result of the best fit in step (4), Calculate y opt The fourth-order derivative y″″ and the fifth-order derivative y″″′ of , the time t corresponding to y″″=0 and y″″′<0 is obtained c , where t c is a real number solution and satisfies t A,opt ≤t c ≤t B,opt , optionally, when there are at least 2 t satisfying the above conditions c solution, then take the minimum solution, Optionally, additionally calculate y opt The third-order derivative y″′ and the fourth-order derivative y″″ of , the time t corresponding to y″′=0 and y″″<0 is obtained m , where t m is a real number solution and satisfies t A,opt ≤t m ≤t B,opt , and t m ≥t c , optionally, when there are at least 2 t satisfying the above conditions m solution, then take the minimum solution, And optionally, calculate y opt The second-order derivative y″ of y″ is obtained at t c The value of time y″ c , and / or get y″ at t m The value of time y″ m ;and (6) Output the evaluation results, The evaluation result includes the parameter t obtained in step (5) c and preferably additionally comprises t m , optionally including y″ c and / or y″ m .

3. The method according to claim 1 or 2, characterized in that: The aerobic biodegradation test in step (1) is carried out at a constant temperature of 58°C ± 2°C and in darkness or weak light.

4. The method according to any one of the preceding claims, characterized in that The time described in step (1) is in units of minutes (m), hours (h) or days (d).

5. The method according to any one of claims 2 to 4, characterized in that: The preprocessing in step (2) is smoothing.

6. The method according to claim 5, characterized in that The smoothing process is moving average smoothing. For example, D in step (2) is converted into t Moving smoothing is the preprocessed decomposition rate Where i is the position of the smoothed data point; p is the total number of time points of the decomposition rate before preprocessing; for The i-th preprocessed decomposition rate in ; g is the size of the left smoothing window and does not include the data point i; h is the size of the right smoothing window and does not include the data point i; g or h is independently 0, 1, 2, 3 or a larger integer, wherein g and h are not 0 at the same time, preferably wherein g = h = 1 or wherein g ≠ 0 and h = 0, more preferably wherein g = 5 and h = 0; u is each D in the smoothing window t Position; D u is D at position u in the smoothing window t .

7. The method according to any one of claims 2 to 6, characterized in that: In step (3), m j It is at least 8, at least 9 or at least 10, preferably at least 15, particularly preferably at least 20.

8. The method according to any one of claims 2 to 7, characterized in that In step (3), t A,j It can be at least the 6th, 12th, 18th, 24th, 30th, 36th, 42nd or 48th hour, or at least the 3rd, 4th, 5th, 6th, 7th, 8th, 9th, 10th, 15th or 20th day, or at least the 30th, 40th, 50th, 60th, 70th or 80th day.

9. The method according to any one of claims 2 to 8, characterized in that: In step (3), t A,j It may be up to the 12th or 24th hour, or up to the 3rd, 6th, 10th, 15th, 30th, 60th or 90th day.

10. The method according to any one of claims 2 to 9, characterized in that: In step (3), t B,j It may be at least 48 hours, or at least 6, at least 10 or at least 15 days, preferably at least 30 days, more preferably at least 60 days, particularly preferably at least 120 days.

11. The method according to any one of the preceding claims, characterized in that The continuously differentiable function in step (3) is selected from a polynomial function, a Boltzmann function or a Bezier curve, and is preferably a polynomial function.

12. The method according to any one of claims 2 to 10, characterized in that: The continuously differentiable function in step (3) is a polynomial function, such as the polynomial function represented by the following equation 3, y=a n ×t n +a n-1 ×t n-1 +...+a2×t 2 +a1×t+a0 Equation 3 Where n is the order of the polynomial function, a0 to a n are the coefficients of the polynomial functions, Preferably, the polynomial is a fifth-order polynomial function or a higher-order polynomial function, more preferably a sixth-order, seventh-order, eighth-order or ninth-order polynomial function, particularly preferably a seventh-order polynomial function.

13. The method according to claim 12, characterized in that The scale of continuous data points in step (3) is the number m j It may be at least the order of the polynomial function +2, preferably at least the order of the polynomial function +3, more preferably at least the order of the polynomial function +4, even more preferably at least the order of the polynomial function +5, further more preferably at least the order of the polynomial function +10, still more preferably at least the order of the polynomial function +15, most preferably at least the order of the polynomial function +20, or more.

14. The method according to claim 12, characterized in that In the adjusted coefficient of determination in step (4), the number of free parameters in the fitting function is equal to the order of the curve fitting function defined in step (3) + 1.

15. The method according to claim 12, characterized in that The continuously differentiable function in step (3) is: 1) A fifth-order polynomial function, preferably, the adjusted coefficient of determination of the fifth-order polynomial function in step (4) is The power index q in is 4.0 to 7.0, preferably 5.0 to 7.0, for example 4.0, 4.5, 5.0, 5.5, 6.0, 6.5 or 7.0; or 2) A sixth-order polynomial function, preferably, the adjusted coefficient of determination of the sixth-order polynomial function in step (4) is The power index q in is 3.0 to 6.5, preferably 3.6 to 5.6, for example 4.0, 4.2, 4.4, 4.6, 4.8, 5.0 or 5.2; or 3) A seventh-order polynomial function, preferably, the seventh-order polynomial function has an adjusted coefficient of determination in step (4) The power index q in is from 2.5 to 6, preferably from 3.3 to 5.3, for example 3.7, 3.9, 4.1, 4.3, 4.5, 4.7 or 4.9; or 4) an octave polynomial function, preferably, the adjusted coefficient of determination of the octave polynomial function in step (4) is The power index q in is from 2.0 to 5.5, preferably from 3.1 to 5.1, for example 3.5, 3.7, 3.9, 4.1, 4.3, 4.5 or 4.7; or 5) A ninth-order polynomial function, preferably, the adjusted coefficient of determination of the ninth-order polynomial function in step (4) is The power index q in is from 2.0 to 5.5, preferably from 2.9 to 5.9, for example 3.3, 3.5, 3.7, 3.9, 4.1, 4.3 or 4.

5.

16. A system for evaluating the anti-degradation performance of plastics, characterized in that: The system employs a method according to any one of the preceding claims.

17. A computer device, characterized in that: It includes: processor; and A memory for storing executable instructions; The processor is used to read and execute the executable instructions from the memory to implement the method according to any one of claims 1 to 15.

18. A computer-readable storage medium, characterized in that: The device stores a computer program, which, when executed by a processor, enables the method according to any one of claims 1 to 15 to be implemented.

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