A kind of testing method of hydrogenation degree of hydrogenated styrene butadiene rubber

Abstract

The present invention provides a method for testing the hydrogenation degree of hydrogenated styrene butadiene rubber. The method first uses infrared spectroscopy to test the absorbance of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene in the hydrogenated styrene butadiene rubber sample, and then substitutes the absorbance of the above three structures into formula I to calculate the mass percentage of cis-1,4-butadiene in the hydrogenated styrene butadiene rubber sample, and finally uses the relationship between the mass percentage of cis-1,4-butadiene and the absorbance to directly calculate the hydrogenation degree of hydrogenated styrene butadiene rubber through formula II. The method is simple to operate, efficient and has accurate test results, and provides a new idea for the detection of the hydrogenation degree of hydrogenated styrene butadiene rubber.

Description

Technical Field

[0001] The invention belongs to the technical field of detection, and in particular relates to a method for testing the hydrogenation degree of hydrogenated styrene butadiene rubber. Background Art

[0002] Hydrogenated butadiene styrene rubber (SEBS) is a linear triblock copolymer with polystyrene as the terminal segment, ethylene-butene copolymer as the middle elastic block obtained by hydrogenating polybutadiene. It is prepared by selective hydrogenation of block copolymer (styrene-butadiene-styrene, SBS). The so-called selective hydrogenation means that the polybutadiene segment of SBS is mainly hydrogenated, while the benzene ring of the polystyrene segment is basically not hydrogenated. Since only the double bonds of the polybutadiene segment in SEBS are hydrogenated, and only a small amount of unhydrogenated saturation, it not only has the elasticity, easy processing, and environmental protection properties unique to thermoplastic elastomers, but also has good temperature resistance, excellent electrical properties, good solubility, excellent weather resistance, and the ability to be blended with a variety of polymers. Specifically, the brittle temperature of SEBS is generally not higher than -60°C, but the maximum use temperature can reach 149°C. Its decomposition temperature is greater than 270°C in an oxygen atmosphere. At the same time, it has good tolerance to ozone, ultraviolet rays, and arcs. The volume resistance is about 10 to 100Ω·cm, and the electrical strength is as high as 39MV / m. It can be dissolved in many common solvents, and its solubility parameter is between 7.2 and 9.6. Due to the above excellent properties, SEBS is currently widely used in the production of high-end elastomers, adhesives, coatings, plastic modifiers, automotive parts, lubricant thickeners, wires and cables, food, medical and other fields.

[0003] Generally, in SEBS products, the number of unsaturated bonds has a very important influence on the properties of the products. Therefore, during the hydrogenation reaction, it is necessary to accurately monitor the degree of hydrogenation of the samples after the reaction. At present, in the industrial production process, the degree of hydrogenation of the products after the reaction is mostly measured by the halogenation method. The halogenation method mainly uses reagents such as iodine, iodine bromide, and iodine chloride to add to the double bonds in the sample, and calculates the total number of residual unsaturated double bonds in the sample and the degree of hydrogenation of the sample through the amount of reagents consumed. However, the halogenation method can only be manually sampled for offline analysis, and the analysis cycle is slightly long. In many cases, it is difficult to provide sample property data for production in a timely manner, and there is a certain lag.

[0004] With the continuous maturity of nuclear magnetic technology, there are also reports on the use of nuclear magnetic analyzers to detect the degree of hydrogenation of hydrogenated styrene butadiene rubber. CN111157565A discloses a method for analyzing the degree of hydrogenation of styrene butadiene rubber SEBS using nuclear magnetic resonance technology, comprising the following steps: (1) adding the analysis sample to a nuclear magnetic tube; (2) placing the nuclear magnetic tube in a nuclear magnetic resonance analyzer, and selecting a corresponding analysis scheme, scanning the sample, and obtaining a sample nuclear magnetic resonance hydrogen spectrum; (3) integrating the area of ​​each structural characteristic peak in the sample nuclear magnetic resonance hydrogen spectrum, and calculating the relative content of double bonds before and after the reaction of the styrene butadiene rubber sample according to the area of ​​the corresponding structural characteristic peak, thereby further calculating the degree of hydrogenation of the sample, and the above method can be used for rapid analysis, and the analysis result is highly accurate, and the analysis equipment runs stably. However, in nuclear magnetic resonance detection, it is necessary to use an expensive deuterated reagent as a solvent for detection, so that the cost of detection is high, which is not conducive to large-scale sample detection and analysis.

[0005] Therefore, developing a method for testing the hydrogenation degree of hydrogenated styrene-butadiene rubber with low cost, simple and fast operation and accurate test results is a technical problem that urgently needs to be solved in the field. Summary of the invention

[0006] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for testing the hydrogenation degree of hydrogenated styrene butadiene rubber. The testing method first uses infrared spectroscopy to test the absorbance of three types of butadiene structures in the hydrogenated styrene butadiene rubber sample, then substitutes the obtained absorbance into formula I to calculate the mass percentage of cis-1,4-butadiene in the hydrogenated styrene butadiene rubber sample, and finally uses the mass percentage of cis-1,4-butadiene to directly calculate the hydrogenation degree of the hydrogenated styrene butadiene rubber. The testing method is low in cost, simple and efficient, and the detection structure is accurate.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for testing the hydrogenation degree of hydrogenated styrene-butadiene rubber, the testing method comprising the following steps:

[0009] (1) Performing infrared spectroscopy test on a hydrogenated styrene butadiene rubber sample to obtain the absorbance of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene in the hydrogenated styrene butadiene rubber sample;

[0010] (2) Substituting the absorbances of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene obtained in step (1) into formula I for calculation, the mass percentage of cis-1,4-butadiene in the hydrogenated styrene-butadiene rubber sample is obtained;

[0011] (3) Substituting the mass percentage of cis-1,4-butadiene obtained in step (2) into formula II for calculation to obtain the detection result of the hydrogenation degree of the hydrogenated styrene-butadiene rubber;

[0012]

[0013] X=(Wt 顺1,4 +28.056) / 1.2407 Formula II;

[0014] In Formula I and Formula II, Wt 顺1,4 Represents the mass percentage of cis-1,4-butadiene, A 1,2 represents the absorbance of 1,2-butadiene, A 顺1,4 represents the absorbance of cis-1,4-butadiene, A 反1,4 represents the absorbance of trans-1,4-butadiene, and X represents the degree of hydrogenation.

[0015] The test method provided by the present invention firstly uses infrared spectroscopy to test the hydrogenated styrene butadiene rubber sample to obtain the infrared spectrum of the hydrogenated styrene butadiene rubber sample. From the infrared spectrum, the absorbance of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene in the hydrogenated styrene butadiene rubber sample can be directly obtained (in the infrared spectrum, at the wave number of 756cm -1 The corrected peak height corresponding to cis-1,4-butadiene is read at the position of 909 cm -1 The corrected peak height corresponding to 1,2-butadiene was read at the position of 966 cm -1 The corrected peak height corresponding to the position is read as the absorbance of trans-1,4-butadiene); then the absorbance of the three types of butadiene structures obtained is substituted into Ⅰ to calculate the mass percentage of cis-1,4-butadiene in the hydrogenated styrene butadiene rubber sample. After analysis, it is found that the degree of hydrogenation of hydrogenated styrene butadiene rubber is directly connected to the cis-1,4-butadiene structure therein. After establishing a standard curve, a linear equation of the cis-1,4-butadiene content and the degree of hydrogenation in hydrogenated styrene butadiene rubber is obtained as shown in Formula Ⅱ. Then, the degree of hydrogenation of hydrogenated styrene butadiene rubber can be directly calculated by Formula Ⅱ through the cis-1,4-butadiene content. The instrument used in the test method provided by the present invention is only an infrared spectrometer, which has the advantages of simple and fast operation and low cost. At the same time, the test results obtained by the test method provided by the present invention are also very accurate.

[0016] It should be noted that in the test method provided by the present invention, when reading the absorbance of a certain wave number in the infrared spectrum, what is read is the corrected peak height after instrument correction at the corresponding wave number.

[0017] In the present invention, the method for verifying the accuracy of the test method provided by the present invention is to compare and analyze the test results provided by the present invention with the results obtained by the nuclear iodine value method. If the error between the two test results is within 3%, the test is determined to be accurate.

[0018] For example, the test process of the iodine value method can be tested with reference to the test method provided by the enterprise standard "Q / ZZL YF001-2019" of Zhejiang Zhonghecheng Materials Technology Co., Ltd. The steps of the test method are as follows:

[0019] (1) Specific operation: Weigh 0.0600g of dry hydrogenated styrene butadiene rubber sample into a 250mL iodine volumetric flask, add 25mL of chloroform, shake until it is completely dissolved, then add 10mL of 0.1mol / L IBr solution, seal with a small amount of water, store in a dark place for 30min, add 80mL of distilled water to rinse the bottle cap, shake 15mL of 20% KI solution, and titrate with 0.1mol / L Na2S2O3 standard solution until the solution turns light yellow, then add 2mL of 1% starch indicator. The solution turns blue, and continue to titrate until the blue disappears as the end point, record the volume of Na2S2O3 standard solution consumed, and do a blank experiment at the same time, record the volume of Na2S2O3 standard solution consumed;

[0020] (2) Calculation of results: Calculate according to, where V0 represents the volume of Na2S2O3 standard solution consumed in titrating the blank solution (mL), V represents the volume of Na2S2O3 standard solution consumed in titrating the sample (mL), c represents the concentration of Na2S2O3 standard solution (mol / L), and m represents the mass of the sample (g).

[0021] Preferably, the hydrogenated styrene butadiene rubber sample in step (1) is prepared by the following method, which comprises: spreading the hydrogenated styrene butadiene rubber solution on a base film, and drying to obtain the hydrogenated styrene butadiene rubber sample.

[0022] Preferably, the solid content of the hydrogenated styrene butadiene rubber solution is 10-20%, for example 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18% or 19%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0023] As a preferred technical solution of the present invention, the hydrogenated styrene butadiene rubber sample prepared from hydrogenated styrene butadiene rubber solution with a solid content of 10-20% is selected for testing, which will further improve the accuracy of the test results.

[0024] Preferably, the base film comprises a polytetrafluoroethylene film.

[0025] Preferably, the drying time is 10 to 20 minutes, for example, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes or 19 minutes, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0026] Preferably, the drying temperature is 100-110°C, for example, 101°C, 102°C, 103°C, 104°C, 105°C, 106°C, 107°C, 108°C or 109°C, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0027] Preferably, the thickness of the hydrogenated styrene butadiene rubber sample in step (1) is 0.01 to 0.05 mm, for example, 0.015 mm, 0.02 mm, 0.025 mm, 0.03 mm, 0.035 mm, 0.04 mm or 0.045 mm, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0028] As a preferred technical solution of the present invention, a hydrogenated styrene butadiene rubber sample with a thickness of 0.01 to 0.05 mm is selected for testing, which can make the test result most accurate. On the one hand, if the thickness of the hydrogenated styrene butadiene rubber sample is too thin, the infrared absorption peak in the infrared spectrum obtained by the test will have a higher peak with a wave number of 756 cm -1 The peak at the position is wide and not on the same baseline, resulting in a large error; on the other hand, if the thickness of the hydrogenated styrene butadiene rubber sample is too thick, the infrared spectrum obtained in the test will be 756cm -1 There is a flat peak at the position and the error is also large.

[0029] Preferably, the infrared spectroscopy test in step (1) is an attenuated total reflection infrared spectroscopy test.

[0030] Preferably, the infrared spectrum test in step (1) is performed using a Fourier transform infrared spectrometer.

[0031] Preferably, the scanning wavelength of the infrared spectrum test in step (1) is 1100-600 cm -1 , for example 1000cm -1 、950cm -1 、900cm -1 、850cm -1 、800cm -1 、750cm -1 、700cm -1 or 650cm-1 , as well as specific point values ​​between the above point values, due to space limitations and for the sake of brevity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0032] As a preferred technical solution, the testing method comprises the following steps:

[0033] (1) Spreading a hydrogenated styrene butadiene rubber solution having a solid content of 10 to 20% on a polytetrafluoroethylene film, and drying at 100 to 110° C. for 10 to 20 minutes to obtain a hydrogenated styrene butadiene rubber sample having a thickness of 0.01 to 0.05 mm;

[0034] (2) Using a Fourier transform infrared spectrometer to perform an attenuated total reflection infrared spectrum scanning test on the hydrogenated styrene butadiene rubber sample obtained in step (1), the scanning wavelength is 1100-600 cm -1 , obtain the absorbance of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene in the hydrogenated styrene-butadiene rubber sample;

[0035] (3) Substituting the absorbances of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene obtained in step (2) into formula I for calculation, the mass percentage of cis-1,4-butadiene in the hydrogenated styrene butadiene rubber sample is obtained;

[0036] (4) Substituting the mass percentage of cis-1,4-butadiene obtained in step (3) into formula II for calculation to obtain the detection result of the hydrogenation degree of the hydrogenated styrene-butadiene rubber;

[0037]

[0038] X=(Wt 顺1,4 +28.056) / 1.2407 Formula II;

[0039] In Formula I and Formula II, Wt 顺1,4 Represents the mass percentage of cis-1,4-butadiene, A 1,2 represents the absorbance of 1,2-butadiene, A 顺1,4 represents the absorbance of cis-1,4-butadiene, A 反1,4 represents the absorbance of trans-1,4-butadiene, and X represents the degree of hydrogenation.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The method for testing the hydrogenation degree of hydrogenated styrene butadiene rubber provided by the present invention first uses infrared spectroscopy to test the absorbance of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene in the hydrogenated styrene butadiene rubber sample, and then substitutes the absorbance of the above three structures into formula I to calculate the mass percentage of cis-1,4-butadiene in the hydrogenated styrene butadiene rubber sample, and finally uses the relationship between the mass percentage of cis-1,4-butadiene and the absorbance to directly calculate the hydrogenation degree of hydrogenated styrene butadiene rubber according to formula II. The test method is simple and efficient to operate, low in cost, and has a smaller error than the conventional iodine value method, indicating that the test result is accurate, and provides a new idea for the detection of the hydrogenation degree of hydrogenated styrene butadiene rubber. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The infrared spectrum of the hydrogenated styrene-butadiene rubber obtained by the test in Example 1;

[0043] Figure 2 The infrared spectrogram of the hydrogenated styrene-butadiene rubber obtained by the test of Example 2;

[0044] Figure 3 The infrared spectrum of the hydrogenated styrene-butadiene rubber obtained by the test in Example 3;

[0045] Figure 4 The infrared spectrogram of the hydrogenated styrene-butadiene rubber obtained by the test of Example 4;

[0046] Figure 5 This is the infrared spectrum of the hydrogenated styrene-butadiene rubber obtained by testing in Example 5. DETAILED DESCRIPTION

[0047] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0048] Example 1

[0049] A method for testing the hydrogenation degree of hydrogenated styrene-butadiene rubber, the method comprising the following steps:

[0050] (1) Spreading a hydrogenated styrene butadiene rubber solution with a solid content of 15% (the mass percentage of styrene is 30%) on a polytetrafluoroethylene film and drying it at 105° C. for 15 min to obtain a hydrogenated styrene butadiene rubber sample with a thickness of 0.03 mm;

[0051] (2) A Fourier transform infrared spectrometer (NICOLET, USA, model NEXUS, OMNI sampler, measurement type T%) was used in the scanning range of 1100-600 cm -1 , scanning speed is 2.8mm / sec, resolution is 4.0cm-1 , under the setting parameters of automatic gain and accumulation times of 40 times, the ATR accessory is placed in the optical path of the infrared spectrometer, the air background is scanned, the hydrogenated styrene butadiene rubber sample obtained in step (1) is placed closely on the infrared transparent crystal surface of the ATR accessory, and then under the same conditions, an attenuated total reflection infrared spectrum scanning test is performed on it to obtain the absorbance of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene in the hydrogenated styrene butadiene rubber sample;

[0052] (3) Substituting the absorbances of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene obtained in step (2) into formula I for calculation, the mass percentage of cis-1,4-butadiene in the hydrogenated styrene butadiene rubber sample is obtained;

[0053] (4) Substituting the mass percentage of cis-1,4-butadiene obtained in step (3) into formula II for calculation to obtain the detection result of the hydrogenation degree of the hydrogenated styrene-butadiene rubber;

[0054]

[0055] X=(Wt 顺1,4 +28.056) / 1.2407 Formula II;

[0056] In Formula I and Formula II, Wt 顺1,4 Represents the mass percentage of cis-1,4-butadiene, A 1,2 represents the absorbance of 1,2-butadiene, A 顺1,4 represents the absorbance of cis-1,4-butadiene, A 反1,4 represents the absorbance of trans-1,4-butadiene, and X represents the degree of hydrogenation.

[0057] The infrared spectrum of hydrogenated styrene-butadiene rubber obtained by testing in this embodiment is as follows: Figure 1 As shown, from Figure 1 It can be seen that the wave number is 756cm -1 Corrected peak heights for left and right controls read A 顺1,4 is 0.05246, and the wave number is 909 cm -1 Corrected peak heights for left and right controls read A 1,2 is 0.00713, and the wave number is 966 cm -1 Corrected peak heights for left and right controls read A 反1,4 is 0.01261. Substituting the above absorbance into formula I, we can calculate Wt 顺1,4 is 92.5, Wt 顺1,4 Substituting into formula II, the calculated value of X is 97.2%.

[0058] To verify the accuracy of the test results of this embodiment, the hydrogenated styrene butadiene rubber sample measured in this embodiment was tested by the iodine value method, and the test results are as follows: the volume V0 of the Na2S2O3 standard solution consumed by the titration blank solution is 9.51 mL, the volume V0 of the Na2S2O3 standard solution consumed by the titration sample is 9.10 mL, the concentration c of the Na2S2O3 standard solution is 0.1005 mol / L, the mass m of the sample is 0.0600 g, and the above parameters are substituted into y=(mass percentage of 1-styrene) / 54.0916 and y'=((V0-V)×c) / 1000(2×m), X 验证 = (y-y') / y calculated to obtain X obtained by iodine value test 验证 =97.3%; by comparison, it can be seen that the error is very small, only 0.1%, indicating that the detection method provided by the present invention is very accurate.

[0059] Example 2

[0060] A method for testing the hydrogenation degree of hydrogenated styrene-butadiene rubber, the method comprising the following steps:

[0061] (1) Spreading a hydrogenated styrene-butadiene rubber solution with a solid content of 10% (the mass percentage of styrene is 30%) on a polytetrafluoroethylene film and drying it at 110° C. for 10 min to obtain a hydrogenated styrene-butadiene rubber sample with a thickness of 0.01 mm;

[0062] (2) A Fourier transform infrared spectrometer (NICOLET, USA, model NEXUS, OMNI sampler) was used, with the measurement type being T% and the scanning range being 1100-600 cm -1 , scanning speed is 2.8mm / sec, resolution is 4.0cm -1 , automatic gain, cumulative times of 40 times, under the above-set parameter conditions, the ATR accessory is placed in the light path of the infrared spectrometer to scan the air background; the hydrogenated styrene butadiene rubber sample obtained in step (1) is placed closely on the infrared transparent crystal surface of the ATR accessory, and then under the same conditions, an attenuated total reflection infrared spectrum scanning test is performed on it to obtain the absorbance of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene in the hydrogenated styrene butadiene rubber sample;

[0063] (3) Substituting the absorbances of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene obtained in step (2) into formula I for calculation, the mass percentage of cis-1,4-butadiene in the hydrogenated styrene butadiene rubber sample is obtained;

[0064] (4) Substituting the mass percentage of cis-1,4-butadiene obtained in step (3) into formula II for calculation to obtain the detection result of the hydrogenation degree of the hydrogenated styrene-butadiene rubber;

[0065]

[0066] X=(Wt 顺1,4 +28.056) / 1.2407 Formula II;

[0067] In Formula I and Formula II, Wt 顺1,4 Represents the mass percentage of cis-1,4-butadiene, A 1,2 represents the absorbance of 1,2-butadiene, A 顺1,4 represents the absorbance of cis-1,4-butadiene, A 反1,4 represents the absorbance of trans-1,4-butadiene, and X represents the degree of hydrogenation.

[0068] The infrared spectrum of hydrogenated styrene-butadiene rubber obtained by testing in this embodiment is as follows: Figure 3 As shown, from Figure 3 The wave number is 756cm -1 Corrected peak heights for left and right controls read A 顺1,4 is 0.06118, and the wave number is 909cm -1 Corrected peak heights for left and right controls read A 1,2 is 0.00815, and the wave number is 966cm -1 Corrected peak heights for left and right controls read A 反1,4 is 0.09981. Substituting the above absorbance into formula I, we can calculate Wt 顺1,4 is 70.9, Wt 顺1,4 Substituting into formula II, we get X as 79.8%.

[0069] Similarly, the hydrogenated styrene-butadiene rubber sample measured in this embodiment was tested using the iodine value method. The test results are as follows: V0=9.51mL, V=6.36mL, c=0.1005mol / L, m=0.0600g, y=(mass percentage of 1-styrene) / 54.0916 and y'=((V0-V)×c) / 1000(2×m), substitute X 验证 = (y-y') / y calculated to obtain X obtained by iodine value test 验证 =79.6%, it can be seen that the error is very small, indicating that the detection result provided by this embodiment is very accurate.

[0070] Example 3

[0071] A method for testing the hydrogenation degree of hydrogenated styrene-butadiene rubber, the method comprising the following steps:

[0072] (1) Spreading a hydrogenated styrene-butadiene rubber solution with a solid content of 20% (the mass percentage of styrene is 30%) on a polytetrafluoroethylene film and drying it at 100° C. for 20 min to obtain a hydrogenated styrene-butadiene rubber sample with a thickness of 0.05 mm;

[0073] (2) A Fourier transform infrared spectrometer (NICOLET, USA, model NEXUS, OMNI sampler) was used, with the measurement type being T% and the scanning range being 1100-600 cm -1 , scanning speed is 2.8mm / sec, resolution is 4.0cm -1 , automatic gain, cumulative times of 40 times, under the above-set parameter conditions, the ATR accessory is placed in the light path of the infrared spectrometer to scan the air background; the hydrogenated styrene butadiene rubber sample obtained in step (1) is placed closely on the infrared transparent crystal surface of the ATR accessory, and then under the same conditions, an attenuated total reflection infrared spectrum scanning test is performed on it to obtain the absorbance of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene in the hydrogenated styrene butadiene rubber sample;

[0074] (3) Substituting the absorbances of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene obtained in step (2) into formula I for calculation, the mass percentage of cis-1,4-butadiene in the hydrogenated styrene butadiene rubber sample is obtained;

[0075] (4) Substituting the mass percentage of cis-1,4-butadiene obtained in step (3) into formula II for calculation to obtain the detection result of the hydrogenation degree of the hydrogenated styrene-butadiene rubber;

[0076]

[0077] X=(Wt 顺1,4 +28.056) / 1.2407 Formula II;

[0078] In Formula I and Formula II, Wt 顺1,4 Represents the mass percentage of cis-1,4-butadiene, A 1,2 represents the absorbance of 1,2-butadiene, A 顺1,4 represents the absorbance of cis-1,4-butadiene, A 反1,4 represents the absorbance of trans-1,4-butadiene, and X represents the degree of hydrogenation.

[0079] The infrared spectrum of hydrogenated styrene-butadiene rubber obtained by testing in this embodiment is as follows: Figure 4 As shown, from Figure 4 The wave number is 756cm -1 Corrected peak heights for left and right controls read A 顺1,4 is 0.06125, and the wave number is 909cm -1 Corrected peak heights for left and right controls read A 1,2 is 0.00759, and the wave number is 966 cm -1 Corrected peak reading for left and right controls A 反1,4 is 0.05786. Substituting the above absorbance into formula I, we can calculate Wt顺1,4 is 80.3, Wt 顺1,4 Substituting into formula II, the calculated value of X is 87.3%.

[0080] Similarly, the hydrogenated styrene-butadiene rubber sample measured in this embodiment was tested using the iodine value method. The test results are as follows: V0=9.51mL, V=7.53mL, c=0.1005mol / L, m=0.0600g, y=(mass percentage of 1-styrene) / 54.0916 and y'=((V0-V)×c) / 1000(2×m). Substituting X 验证 = (y-y') / y calculated to obtain X obtained by iodine value test 验证 =87.2%, it can be seen that the error is very small, indicating that the detection result provided by the present invention is very accurate.

[0081] Example 4

[0082] A method for testing the hydrogenation degree of hydrogenated styrene butadiene rubber, which differs from Example 1 only in that the thickness of the hydrogenated styrene butadiene rubber sample is 0.1 mm, and other conditions and steps are the same as those of Example 1.

[0083] The thickness of the hydrogenated styrene butadiene rubber sample prepared in this embodiment is too thick, which results in the infrared absorption peak in the infrared spectrum being a flat peak. The infrared spectrum of the hydrogenated styrene butadiene rubber obtained by the test in this embodiment is as follows: Figure 4 As shown, from Figure 4 The wave number is 756cm -1 Corrected peak heights for left and right controls read A 顺1,4 is 0.06294, and the wave number is 909 cm -1 Corrected peak heights for left and right controls read A 1,2 is 0.25723, and the wave number is 966cm -1 Corrected peak heights for left and right controls read A 反1,4 is 0.16591. Substituting the above absorbance into formula I, we can calculate Wt 顺1,4 is 42.5, Wt 顺1,4 Substituting into formula II, we get X as 56.8%.

[0084] Similarly, the hydrogenated styrene-butadiene rubber sample measured in this embodiment was tested using the iodine value method. The test results are as follows: V0=9.51mL, V=6.38mL, c=0.1005mol / L, m=0.0600g, y=(mass percentage of 1-styrene) / 54.0916 and y'=((V0-V)×c) / 1000(2×m). Substituting X 验证 = (y-y') / y calculated to obtain X obtained by iodine value test 验证=79.7%, it can be seen that the error is large, indicating that the sample thickness is too thick, which will lead to inaccurate test results.

[0085] Example 5

[0086] A method for testing the hydrogenation degree of hydrogenated styrene butadiene rubber, which differs from Example 1 only in that the thickness of the hydrogenated styrene butadiene rubber sample is 0.005 mm, and other conditions and steps are the same as those of Example 1.

[0087] The thickness of the hydrogenated styrene butadiene rubber sample prepared in this embodiment is too thin, which results in the presence of mixed peaks in the infrared absorption peaks in the infrared spectrum obtained by the test, with wide peaks and not on the same baseline, resulting in large errors. The infrared spectrum of the hydrogenated styrene butadiene rubber obtained by the test in this embodiment is shown in FIG. Figure 5 As shown, from Figure 5 The wave number is 756cm -1 Corrected peak heights for left and right controls read A 顺1,4 is 0.06199, and the wave number is 909cm -1 Corrected peak heights for left and right controls read A 1,2 is 0.00770, and the wave number is 966cm -1 Corrected peak heights for left and right controls read A 反1,4 is 0.08157. Substituting the above absorbance into formula I, we can calculate Wt 顺1,4 is 75.0, Wt 顺1,4 Substituting into formula II, the calculated value of X is 83.0%.

[0088] Similarly, the hydrogenated styrene-butadiene rubber sample measured in this embodiment was tested using the iodine value method. The test results are as follows: V0=9.51mL, V=7.25mL, c=0.1005mol / L, m=0.0600g, y=(mass percentage of 1-styrene) / 54.0916 and y'=((V0-V)×c) / 1000(2×m). Substituting X 验证 = (y-y') / y calculated to obtain X obtained by iodine value test 验证 =85.3%, it can be seen that the error is large, indicating that the sample thickness is too thick, which will lead to inaccurate test results.

[0089] In summary, it can be seen that the test method provided by the present invention is simple, efficient and accurate, and further helps to further improve the accuracy of the test results by limiting the solid content and thickness of the test sample.

[0090] The applicant declares that the present invention illustrates the process method of the present invention through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for testing the degree of hydrogenation of hydrogenated styrene-butadiene rubber, characterized in that: The test method comprises the following steps: (1) Performing infrared spectroscopy test on a hydrogenated styrene butadiene rubber sample to obtain the absorbance of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene in the hydrogenated styrene butadiene rubber sample; (2) Substituting the absorbances of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene obtained in step (1) into formula I for calculation, the mass percentage of cis-1,4-butadiene in the hydrogenated styrene-butadiene rubber sample is obtained; (3) Substituting the mass percentage of cis-1,4-butadiene obtained in step (2) into formula II for calculation to obtain the detection result of the hydrogenation degree of the hydrogenated styrene-butadiene rubber; X=(Wt 顺1,4 +28.056) / 1.2407 Formula II; In Formula I and Formula II, Wt 顺1,4 Represents the mass percentage of cis-1,4-butadiene, A 1,2 represents the absorbance of 1,2-butadiene, A 顺1,4 represents the absorbance of cis-1,4-butadiene, A 反1,4 represents the absorbance of trans-1,4-butadiene, and X represents the degree of hydrogenation; The thickness of the hydrogenated styrene-butadiene rubber sample in step (1) is 0.01 to 0.05 mm; In the infrared spectrum test, at a wave number of 756 cm -1 The corrected peak height corresponding to cis-1,4-butadiene is read at the position of 909 cm -1 The corrected peak height corresponding to 1,2-butadiene was read at the position of 966 cm -1 The corrected peak height corresponding to the corrected value is read at the position of trans-1,4-butadiene.

2. The testing method according to claim 1, characterized in that: The hydrogenated styrene butadiene rubber sample in step (1) is prepared by the following method, which comprises: spreading the hydrogenated styrene butadiene rubber solution on a base film, and drying to obtain the hydrogenated styrene butadiene rubber sample.

3. The testing method according to claim 2, characterized in that: The solid content of the hydrogenated styrene-butadiene rubber solution is 10-20%.

4. The testing method according to claim 2, characterized in that: The base film includes a polytetrafluoroethylene film.

5. The testing method according to claim 2, characterized in that: The drying time is 10 to 20 minutes.

6. The testing method according to claim 2, characterized in that: The drying temperature is 100-110°C.

7. The testing method according to claim 1, characterized in that: The infrared spectrum test in step (1) is an attenuated total reflection infrared spectrum test.

8. The testing method according to claim 1, characterized in that: The infrared spectrum test in step (1) is performed using a Fourier transform infrared spectrometer.

9. The testing method according to any one of claims 1 to 8, characterized in that: The scanning wavelength of the infrared spectrum test in step (1) is 1100-600 cm -1 .

10. The testing method according to claim 1, characterized in that: The testing method comprises the following steps: (1) Spreading a hydrogenated styrene butadiene rubber solution having a solid content of 10 to 20% on a polytetrafluoroethylene film, and drying at 100 to 110° C. for 10 to 20 minutes to obtain a hydrogenated styrene butadiene rubber sample having a thickness of 0.01 to 0.05 mm; (2) Using a Fourier transform infrared spectrometer to perform an attenuated total reflection infrared spectrum scanning test on the hydrogenated styrene butadiene rubber sample obtained in step (1), the scanning wavelength is 1100-600 cm -1 , obtaining the absorbance of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene in the hydrogenated styrene-butadiene rubber sample; (3) Substituting the absorbances of 1,2-butadiene, cis-1,4-butadiene and trans-1,4-butadiene obtained in step (2) into formula I for calculation, the mass percentage of cis-1,4-butadiene in the hydrogenated styrene butadiene rubber sample is obtained; (4) Substituting the mass percentage of cis-1,4-butadiene obtained in step (3) into formula II for calculation to obtain the detection result of the hydrogenation degree of the hydrogenated styrene-butadiene rubber; X=(Wt 顺1,4 +28.056) / 1.2407 Formula II; In Formula I and Formula II, Wt 顺1,4 Represents the mass percentage of cis-1,4-butadiene, A 1,2 represents the absorbance of 1,2-butadiene, A 顺1,4 represents the absorbance of cis-1,4-butadiene, A 反1,4 represents the absorbance of trans-1,4-butadiene, and X represents the degree of hydrogenation; In the infrared spectrum test, at a wave number of 756 cm -1 The corrected peak height corresponding to cis-1,4-butadiene is read at the position of 909 cm -1 The corrected peak height corresponding to 1,2-butadiene was read at the position of 966 cm -1 The corrected peak height corresponding to the corrected value is read at the position of trans-1,4-butadiene.

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