Method for predicting wear resistance

Abstract

To provide a method for predicting the wear resistance performance of a polymer composite material.SOLUTION: A method for predicting wear resistance performance includes: irradiating a polymer composite material containing a sulfur compound with a high-intensity X-ray, and measuring the amount of X-ray absorption in a micro area while changing the energy of the X-ray, thereby investigating the dispersion state and the chemical state of the sulfur compound; and converting a nonuniform state of cross-link deterioration in the polymer composite material into a numerical form from the dispersion state and the chemical state.SELECTED DRAWING: None

Description

[Technical Field]

[0001] This disclosure relates to a method for predicting wear resistance. [Background technology]

[0002] Rubber materials exhibit unique physical properties such as strength, mechanical fatigue resistance, energy loss due to repeated deformation, and frequency response by forming a cross-linked structure using sulfur to bridge polymers. Therefore, they are applied to tires, vibration damping materials, and other applications, making them indispensable materials. One key to improving rubber's strength and mechanical fatigue properties is controlling the cross-linked structure. For example, when the cross-linked portion deteriorates due to heat, the sulfur cross-linking the polymers can break, leading to a decrease in physical properties, or conversely, re-cross-linking can cause the rubber to harden and further decrease its properties.

[0003] As various analytical methods, for example, Patent Documents 1 to 4 disclose methods for analyzing the degradation of crosslinks in polymer composite materials, methods for visualizing the crosslink structure in polymer composite materials, methods for visualizing the dispersion and chemical state of each vulcanization material, and methods for measuring the hardness of crosslink materials in polymer composite materials. However, there is a need for more precise degradation analysis methods. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2014-115102 [Patent Document 2] Japanese Patent Publication No. 2020-027084 [Patent Document 3] Japanese Patent Publication No. 2017-201252 [Patent Document 4] Japanese Patent Publication No. 2018-178016 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present disclosure aims to solve the above problems and provide a method for predicting the wear resistance performance of polymer composite materials.

Means for Solving the Problems

[0006] The present disclosure examines the dispersion state and chemical state of a sulfur compound by irradiating a polymer composite material containing the sulfur compound with high-intensity X-rays and measuring the X-ray absorption amount in a minute region while changing the energy of the X-rays, and relates to a method for predicting wear resistance performance by quantifying the non-uniform state of crosslinking degradation in the polymer composite material from the dispersion state and the chemical state.

Advantages of the Invention

[0007] According to the present disclosure, by irradiating a polymer composite material containing a sulfur compound with high-intensity X-rays and measuring the X-ray absorption amount in a minute region while changing the energy of the X-rays, the dispersion state and chemical state of the sulfur compound are examined, and the non-uniform state of crosslinking degradation in the polymer composite material is quantified from the dispersion state and the chemical state, so that the wear resistance performance of the polymer composite material can be precisely predicted. Therefore, by using this method, a polymer composite material excellent in wear resistance performance can be provided.

Brief Description of the Drawings

[0008] [Figure 1] An example of a mapping image near the sulfur L-shell absorption edge of a polymer composite material (post-degradation sample). [Figure 2] An example of an enlarged view of the broken line portion in FIG. 1. [Figure 3] An example of an X-ray absorption spectrum of each material near the sulfur L-shell absorption edge.

Embodiments for Carrying Out the Invention

[0009] This disclosure provides a method for predicting wear resistance by irradiating a polymer composite material containing a sulfur compound with high-intensity X-rays and measuring the amount of X-ray absorption in a minute region while changing the X-ray energy, thereby investigating the dispersion state and chemical state of the sulfur compound, and quantifying the non-uniform state of crosslinking degradation in the polymer composite material from the dispersion state and chemical state.

[0010] The method disclosed herein first measures the amount of X-ray absorption in a minute region of a polymer composite material containing sulfur compounds using a scanning transmission X-ray microscope (STXM) or the like to visualize the dispersion of sulfur compounds (such as sulfur aggregate structure) and analyze their chemical state, thereby calculating the amount of sulfur oxides (SOx) and other substances that serve as evidence of crosslinking degradation. The method then finds a relationship between the numerical value representing the non-uniformity state of evidence of crosslinking degradation (such as SOx) in the polymer composite material and the wear resistance performance, and based on this numerical value, the wear resistance performance can be predicted.

[0011] Therefore, by subjecting a polymer composite material (test specimen) containing a sulfur compound to the method of this disclosure, the wear resistance performance of a product such as a tire can be predicted without actually manufacturing the product and subjecting it to durability testing.

[0012] The polymer composite material containing a sulfur compound used in the method of this disclosure is a material containing a "sulfur compound" (a compound containing sulfur), and this disclosure is a method for investigating the dispersion state and chemical state of the "sulfur compound" contained in the polymer composite material. In this disclosure, the polymer composite material used is typically a polymer composite material that has undergone crosslinking degradation (after the crosslinked portion has deteriorated).

[0013] Examples of the aforementioned sulfur compounds (compounds containing sulfur) include sulfur-containing compounds produced by crosslinking degradation, vulcanizing agents, and sulfur-containing compounds related to vulcanization. Among these, sulfur-containing compounds produced by crosslinking degradation are preferable from the viewpoint of being able to suitably investigate the state of crosslinking degradation.

[0014] The sulfur-containing compounds produced by the aforementioned crosslinking degradation include (1) compounds produced when SS bonds are cleaved due to crosslinking degradation and bond with oxygen (such as sulfur oxides (SOx)), and (2) various compounds produced when SS bonds are cleaved due to crosslinking degradation and recombine with the polymer. In the case of (1), as described later, analysis can be performed using, for example, X-ray absorption spectra (XAFS) of the sulfur L-shell absorption edge and sulfur K-shell absorption edge. In the case of (2), for example, the X-ray absorption spectrum (XAFS) of the sulfur K-shell absorption edge can be used and analyzed by assigning the peak to SC, the peak height, or the area.

[0015] Examples of the aforementioned vulcanizing agents include those commonly used in the tire industry, such as sulfur vulcanizing agents (vulcanizing agents consisting of sulfur, such as powdered sulfur); and sulfur-containing vulcanizing agents such as 1,6-hexamethylene-dithiosulfate sodium dihydrate and 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane.

[0016] Examples of sulfur-containing compounds related to vulcanization include vulcanization accelerators and additives similar to vulcanization accelerators. Here, a vulcanization accelerator is a compound that has a vulcanization-promoting effect and is generally added (blended) and mixed during the kneading process of a rubber composition.

[0017] Examples of vulcanization accelerators include guanidines, sulfenamides, thiazoles, thirams, dithiocarbamates, thioureas, xanthogenic salts, and various other vulcanization accelerators known in the tire industry.

[0018] Examples of additives similar to vulcanization accelerators include 4,4'-dithiodimorpholine, 2-(4'-morpholinodithio)benzothiazole, and tetramethylthiuram disulfide.

[0019] Examples of polymer composite materials include materials containing one or more diene polymers, and composite materials formed by combining one or more rubber materials with one or more resins.

[0020] Examples of the above-mentioned diene polymers include polymers having double bonds, such as natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), acrylonitrile-butadiene rubber (NBR), chloroprene rubber (CR), butyl rubber (IIR), halogenated butyl rubber (X-IIR), and styrene-isoprene-butadiene rubber (SIBR).

[0021] The above resins are not particularly limited and include, for example, those commonly used in the rubber industry, such as petroleum resins like C5 aliphatic petroleum resins and cyclopentadiene petroleum resins.

[0022] In this disclosure, methods for measuring X-ray absorption can include micro-XAFS (X-ray Absorption Fine Structure), a technique that uses high-brightness X-rays to measure the X-ray absorption spectrum in a minute region of a sample. While conventional XAFS does not have spatial resolution and therefore detects the absorption amount of the entire sample, micro-XAFS is a measurement method that measures the X-ray absorption spectrum in a minute region of a sample and typically has a spatial resolution of about 100 nm or less. Therefore, by employing micro-XAFS, it is possible to detect differences in absorption amounts for various components contained in the sample, such as sulfur-containing compounds generated by crosslinking degradation, vulcanizing agents, and sulfur-containing compounds related to vulcanization.

[0023] Due to its superior spatial resolution, micro-XAFS is preferably measured in the soft X-ray region (micro-NEXAFS), and examples include scanning transmission X-ray microscopy (STXM) and X-ray photoemission electron microscopy (XPEEM).

[0024] In the present disclosure, since sulfur, vulcanization accelerators, etc. in the polymer are easily damaged by X-rays, it is desirable to measure by a method in which X-ray damage is unlikely to occur. From this point of view, the STXM method in which X-ray damage is unlikely to occur is more suitable. Further, it is more preferable to prevent X-ray damage by cooling the sample during measurement.

[0025] In the STXM method, high-intensity X-rays condensed by a Fresnel zone plate are irradiated onto a minute region of a sample, and the X-ray absorption amount of the minute region can be measured by measuring the light (transmitted light) that has passed through the sample and the incident light. Note that, instead of the Fresnel zone plate, high-intensity X-rays may be condensed by a Kirkpatrick-Baez (K-B) condenser system using X-ray reflection mirrors.

[0026] Since a continuous X-ray generator is required as the light source for scanning with X-ray energy, it is necessary to measure X-ray absorption spectra with high S / N and S / B ratios in order to analyze detailed chemical states. Therefore, the X-rays emitted from a synchrotron have a luminance of at least 10 10 (photons / s / mrad 2 / mm 2 / 0.1%bw) or more, and since it is a continuous X-ray source, it is optimal for measurement. Note that bw indicates the band width of the X-rays emitted from the synchrotron.

[0027] The luminance of the high-intensity X-rays (photons / s / mrad 2 / mm 2 / 0.1%bw) is preferably 10 10 or more, more preferably 10 11 [[ID=2 six]]or more, and still more preferably 10 12 or more. The upper limit is not particularly limited, but it is preferable to use an X-ray intensity below the level where there is no radiation damage.

[0028] Further, the number of photons of the high-intensity X-rays (photons / s) is preferably 10 7 or more, more preferably 10 9 or more. The upper limit is not particularly limited, but it is preferable to use an X-ray intensity below the level where there is no radiation damage.

[0029] The energy range for scanning using high-brightness X-rays is preferably 4000 eV or less, more preferably 1500 eV or less, and even more preferably 1000 eV or less. Above 4000 eV, it may not be possible to analyze the target polymer composite material. The lower limit is not particularly limited.

[0030] In particular, it is preferable to use high-brightness X-rays to scan the energy range of 130 to 280 eV to measure the amount of X-ray absorption of sulfur at the sulfur L-shell absorption edge, and to scan the energy range of 2300 to 3200 eV to measure the amount of X-ray absorption of sulfur at the sulfur K-shell absorption edge.

[0031] Furthermore, the energy range of the sulfur L-shell absorption edge is more preferably 140 to 200 eV, and even more preferably 150 to 180 eV. The energy range of the sulfur K-shell absorption edge is more preferably 2300 to 3000 eV, and even more preferably 2400 to 2600 eV.

[0032] Furthermore, in this disclosure, the dispersion state and chemical state of the "sulfur compound" (preferably a sulfur-containing compound generated by crosslinking degradation) contained in a polymer composite material containing a sulfur compound (sample after crosslinking degradation) are investigated, and the heterogeneity of the crosslinking degradation in the material is quantified from the results.

[0033] For example, by examining the dispersion and chemical state of sulfur compounds using the following methods, the heterogeneity of crosslink degradation can be quantified. First, for a polymer composite material (a sample after crosslinking degradation) containing a sulfur aggregate structure portion (a portion where components such as sulfur oxides, which are thought to be generated by degradation, are aggregated) and a matrix portion (a portion where the sulfur aggregate structure is not formed), the X-ray absorption amount of the same minute region including both portions is measured while changing the energy, and an X-ray absorption spectrum (a spectrum containing spectral information of both the sulfur aggregate structure portion and the matrix portion) is obtained. Regarding peak assignment, in the case of sulfur oxides, the spectra of individual reagents such as ZnSO4 and dimethyl sulfone are measured and used as standard spectra. Additionally, if information on the dispersion state of ZnO in sulfur crosslinking and vulcanization accelerators is also required, the spectra of sulfur, vulcanization accelerators, and ZnO are measured beforehand as standard samples. By using the spectrum of a standard sample and employing analysis methods such as singular value decomposition, the location of the compound can be identified from the measured image. Then, by comparing the peak intensity and peak area of ​​the peaks attributed to components such as sulfur oxides, the degree of heterogeneity of the cross-linked state after cross-linking degradation can be investigated. For example, if the peak intensity and peak area are larger in the sulfur aggregate structure portion compared to the matrix portion, it means that a large amount of components such as sulfur oxides are present, and therefore, the cross-linking degradation has progressed more, and the degree of heterogeneity of the cross-linked state can be evaluated as high.

[0034] The following provides a more detailed explanation of the method of this disclosure. Figure 1 is a mapping image of the area near the sulfur L-shell absorption edge of the sample (a polymer composite material containing a sulfur compound), and Figure 2 is a magnified view of the dashed line area in Figure 1. The black areas represent sulfur aggregated regions (areas where sulfur is aggregated), and the gray areas represent matrix regions (areas where sulfur is not aggregated). In the mapping image, the black areas have a higher X-ray absorption rate, which indicates the presence of sulfur in the black areas. Therefore, there is a larger amount of sulfur in the black areas compared to the gray areas.

[0035] STXM measurements were performed on the field of view shown in Figure 2 in the energy range of 162-174 eV, and the resulting X-ray absorption spectra of the sulfur aggregation region and the matrix region are shown in Figure 3. Figure 3 also shows the X-ray absorption spectrum (standard spectrum) of dimethyl sulfone ((CH3)2SO2). Sulfur oxides (SOx) generated by crosslinking degradation have a peak around 173 eV, similar to dimethyl sulfone. The peak intensity or peak area around 173 eV in the sulfur aggregation region and the peak intensity or peak area around 173 eV in the matrix region are calculated and quantified. When comparing the two calculated values, the larger the peak intensity or peak area in the sulfur aggregation region compared to the matrix region, the more advanced the crosslinking degradation is in the sulfur aggregation region, and the more heterogeneous the crosslinking state after the degradation is.

[0036] The heterogeneity of crosslinking in polymer composite materials (samples after crosslinking degradation) can be suitably evaluated by the degree of heterogeneity calculated by the following formula (Equation 1). (Formula 1) [Degree of heterogeneity in crosslinking degradation] = SO A / SO M (In the formula, SO A SO represents the amount of sulfur oxides in the sulfur aggregate structure portion of the polymer composite material. M This represents the amount of sulfur oxides in the matrix portion of the polymer composite material. Here, SO A , SO M The values ​​obtained by any method that allows for the measurement of sulfur oxide content in the sulfur aggregate structure and the matrix can be adopted. In particular, the peak intensity or peak area of ​​the sulfur aggregate portion calculated from the X-ray absorption spectra of the sulfur aggregate portion and the matrix portion, as shown in Figure 3, can be used as SO A , the peak intensity or peak area of ​​the matrix portion is SO M It is preferable to use it as such. In this case, SO A / SO MThis means the peak intensity or peak area attributable to sulfur oxides, etc., in the X-ray absorption spectrum of the sulfur aggregate portion / the peak intensity or peak area attributable to sulfur oxides, etc., in the X-ray absorption spectrum of the matrix portion.

[0037] SO A / SO M A value closer to 1.0 indicates that there is little difference between the cross-linking state of the sulfur aggregate portion and the cross-linking state of the matrix portion, resulting in a uniform cross-linking state even after degradation. Therefore, in this case, it can be predicted that the wear resistance of the polymer composite material is excellent.

[0038] SO A / SO M From the viewpoint of minimizing the non-uniformity of crosslinking degradation, it is desirable that the value be below a predetermined level, and for example, it is preferable that it satisfies the following equation. SO A / SO M ≤100.0 SO A / SO M The upper limit is preferably 50.0 or less, more preferably 10.0 or less, even more preferably 3.0, and particularly preferably 2.0 or less. The closer it is to 1.0, the more uniform the crosslinking state is considered to be even after degradation. SO A / SO M In principle, the lower limit is considered to be 1.0 or higher, but it can also be 0.1 or higher, 0.3 or higher, or 0.7 or higher.

[0039] SO A , SO M When calculating this, it is desirable to find the average value in a field of view of several micrometers in size of the mapping image. In this case, measuring multiple fields of view of this size and calculating based on the results will result in higher accuracy. Note, SO A , SO M The numerical value changes depending on the method of normalizing the spectrum, SO A / SO M It is considered desirable to evaluate using the following numerical values.

[0040] Figures 1-3 show examples of measurements at the sulfur L-shell absorption edge, but measurements at the sulfur K-shell absorption edge are also possible.

[0041] By the method described above, the dispersion state and chemical state of the sulfur compound contained in a polymer composite material (sample after crosslinking degradation) containing a sulfur compound can be investigated. Furthermore, the numerical value obtained from the obtained dispersion state and chemical state of the sulfur compound, which represents the heterogeneity of the crosslinking degradation, correlates with the wear resistance performance of products such as tires using the material, thereby allowing for the prediction of the wear resistance performance of the material. [Examples]

[0042] The present disclosure will be described in detail based on examples, but the present disclosure is not limited to these examples.

[0043] <Sample preparation method> According to the following formulation, all materials except sulfur and vulcanization accelerator were filled into a 1.7L Banbury mixer manufactured by Kobe Steel, Ltd. to a filling rate of 58%, and kneaded at 80 rpm until the temperature reached 140°C (Step 1). Sulfur and a vulcanization accelerator were added to the mixture obtained in step 1 in the following proportions, and the mixture was vulcanized at 160°C for 20 minutes to obtain a rubber sample (new sample) (step 2). Furthermore, the rubber sample (new sample) was degraded in an oven at 80°C for one week to obtain the degraded rubber material (degraded sample) (step 3).

[0044] (Composition) 50 parts by mass of natural rubber, 50 parts by mass of butadiene rubber, 60 parts by mass of carbon black, 5 parts by mass of oil, 2 parts by mass of antioxidant, 2.5 parts by mass of wax, 3 parts by mass of zinc oxide, 2 parts by mass of stearic acid, 1.2 parts by mass of powdered sulfur, and 1 part by mass of vulcanization accelerator.

[0045] The materials used are as follows: Natural rubber: TSR20 Butadiene rubber: BR150B manufactured by Ube Industries, Ltd. Carbon Black: Show Black N351 manufactured by Cabot Japan Co., Ltd. Oil: Process X-140 manufactured by Japan Energy Co., Ltd. Anti-aging agent: Nocrack 6C (N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine) manufactured by Ouchi Shinko Chemical Industry Co., Ltd. Wax: Ozoace 0355 manufactured by Nippon Seiro Co., Ltd. Zinc oxide: Ginrei R manufactured by Toho Zinc Co., Ltd. Stearic acid: Manufactured by Nippon Oil & Fats Co., Ltd. Powdered sulfur (5% oil content): 5% oil-treated powdered sulfur manufactured by Tsurumi Chemical Industries Co., Ltd. (soluble sulfur containing 5% oil by mass) Vulcanization accelerator: Noxellar CZ (N-cyclohexyl-2-benzothiadylsulfenamide) manufactured by Ouchi Shinko Chemical Industry Co., Ltd.

[0046] <Tire performance test> Wear resistance: Test tires were driven on actual vehicles, and the change in pattern groove depth before and after 30,000 km of driving was measured. The change for each new sample was set to 100, and the change for each deteriorated sample was expressed as an index. A smaller number compared to 100 indicates worse wear resistance.

[0047] <Calculation of the degree of non-uniformity in crosslinking degradation> (Sampling method) After removing free sulfur from the sample using the method described in Japanese Patent Publication No. 2014-238287, the samples were prepared as follows. • Comparative Example 1: The NEXAFS method involves mounting thinly sliced ​​pieces of material (cut with a knife) onto a holder for measurement. • Comparative Example 2: The TEM-EDX sample was cut with a microtome to a thickness of 100 nm and mounted on a Cu grid for TEM. • Example: The STXM sample was cut with a microtome to a thickness of 250 nm and mounted on a Cu grid for TEM.

[0048] [Comparative Example 1] The prepared samples were subjected to NEXAFS measurement under the following conditions. (Measurement location) Kyushu Synchrotron Radiation Research Center BL12 (Measured energy) S L-edge: 162~174eV

[0049] [Comparative Example 2] The prepared samples were subjected to TEM-EDX measurement (using a commercially available instrument).

[0050] [Examples] The prepared samples were subjected to STXM measurement under the following conditions. (Measurement location) Institute for Molecular Science, National Institutes of Natural Sciences, Extreme Ultraviolet Light Research Facility BL4U (Measurement conditions) Brightness: 1x10 16 (photons / s / mrad 2 / mm 2 (0.1% bw) Spectrometer: Grating (Measured energy) S L-edge: 162~174eV

[0051] 〔evaluation〕 For each of the three comparative examples (STXM, NEXAFS, and TEM-EDX), the feasibility of calculating the average sulfur oxide content in the sulfur aggregate portion and the average sulfur oxide content in the matrix portion of the sample was evaluated. For the example, analysis was performed using aXis2000 (free software) according to the methods shown in Figures 1-3, and the feasibility of the calculation was measured. The results are shown in Table 1.

[0052] [Table 1]

[0053] The NEXAFS method in Comparative Example 1 was a bulk measurement, and therefore could not separate the measurement of the matrix portion and the sulfur aggregate portion, making analysis impossible. The TEM-EDX method in Comparative Example 2 could separate the sulfur aggregate portion and the matrix portion, but it was impossible to analyze the chemical state, and therefore analysis was impossible. On the other hand, the STXM method in the example made it possible to visualize the sulfur aggregation and matrix regions by measuring the X-ray absorption amount in a minute area, and further calculate the degree of non-uniformity of crosslinking degradation by calculating the average amount of sulfur oxides in those regions. It was found that new samples with good wear resistance had a value of crosslinking degradation non-uniformity closer to 1.0 compared to deteriorated samples, predicting good wear resistance, and that this correlated with the wear resistance performance in actual vehicles.

[0054] This disclosure (1) is a method for predicting wear resistance by irradiating a polymer composite material containing a sulfur compound with high-intensity X-rays and measuring the amount of X-ray absorption in a minute region while changing the energy of the X-rays to investigate the dispersion state and chemical state of the sulfur compound, and quantifying the non-uniform state of crosslinking degradation in the polymer composite material from the dispersion state and the chemical state.

[0055] Disclosure (2) is a method for predicting the wear resistance performance described in Disclosure (1), in which the non-uniform state of crosslinking degradation is quantified by the degree of non-uniformity calculated by the following formula (Equation 1). (Formula 1) [Degree of heterogeneity in crosslinking degradation] = SO A / SO M (In the formula, SO A SO represents the amount of sulfur oxides in the sulfur aggregate structure portion of the polymer composite material. M This represents the amount of sulfur oxides in the matrix portion of the polymer composite material.

[0056] This disclosure (3) is SO A / SO M The method for predicting wear resistance described in disclosure (2) is such that the closer the value is to 1.0, the better the wear resistance of the polymer composite material is predicted to be.

[0057] This disclosure (4) is SO A / SO M This is a method for predicting the wear resistance performance described in (2) or (3) of this disclosure, which is ≤ 100.0.

[0058] (5) of this disclosure is a method for predicting wear resistance according to any of (1) to (4) of this disclosure, which involves measuring at least one of the X-ray absorption of sulfur at the sulfur L-shell absorption edge in the energy range of 130 to 280 eV and the X-ray absorption of sulfur at the sulfur K-shell absorption edge in the energy range of 2300 to 3200 eV.

[0059] This disclosure (6) describes a high-intensity X-ray with an intensity of 10 10 (photons / s / mrad 2 / mm 2 This is a method for predicting the wear resistance performance described in any of (1) to (5) of this disclosure, which is 0.1% bw or more.

Claims

1. By irradiating a polymer composite material containing a sulfur compound with high-intensity X-rays and measuring the amount of X-ray absorption in a minute region while changing the X-ray energy, the dispersion state and chemical state of the sulfur compound are investigated. By quantifying the non-uniform state of crosslinking degradation in the polymer composite material from the aforementioned dispersion state and chemical state, wear resistance performance can be predicted. A method for predicting wear resistance, wherein the non-uniform state of the aforementioned crosslinking deterioration is quantified by the degree of non-uniformity calculated by the following (Equation 1). (Formula 1) [Degree of heterogeneity in crosslinking degradation] = SO₂A / SO₂M (In the formula, SO A represents the amount of sulfur oxides in the sulfur aggregate structure portion of the polymer composite material. SO M represents the amount of sulfur oxides in the matrix portion of the polymer composite material.)

2. SO Ａ / SO Ｍ A method for predicting wear resistance according to claim 1, wherein the closer the value is to 1.0, the better the wear resistance performance of the polymer composite material is predicted to be.

3. SO Ａ / SO Ｍ A method for predicting wear resistance performance according to claim 1 or 2, wherein the value is ≤ 100.

0.

4. A method for predicting wear resistance according to any one of claims 1 to 3, which involves measuring at least one of the amount of X-ray absorption of sulfur at the sulfur L-shell absorption edge in the energy range of 130 to 280 eV and the amount of X-ray absorption of sulfur at the sulfur K-shell absorption edge in the energy range of 2300 to 3200 eV.

5. High-intensity X-rays have an intensity of 10 １０ (photons / s / mrad ２ / mm ２ A method for predicting wear resistance according to any one of claims 1 to 4, wherein the wear resistance is 0.1% bw or more.

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