Method for testing content of bound styrene

Abstract

The invention provides a method for testing the content of bound styrene. Comprising the following steps: based on a test value of a peak area ratio of 4-vinylcyclohexene to styrene of a cracking product of the BR and SSBR blend rubber, the content of bound styrene in SSBR standard rubber, the content of styrene in the BR and SSBR blend rubber obtained by testing by adopting an infrared spectrometer, a calibration curve, a first relational expression and a second standard curve, calculating the content of styrene in the BR and SSBR blend rubber, and calculating the content of styrene in the BR and SSBR blend rubber according to the calibration curve, the first relational expression and the second standard curve. The content of the combined styrene in the SSBR used in the combined rubber of the BR and the SSBR is reduced. Based on the method provided by the invention, the technical problem that the content of bound styrene in the SSBR used by the BR and SSBR blended glue cannot be given by an infrared spectrum technology in the prior art is solved.

Description

Technical Field

[0001] The invention relates to the field of rubber, in particular to a method for testing the content of combined styrene. Background Art

[0002] Butadiene styrene rubber (SBR) is a copolymer of butadiene and styrene. The rubber molecule chain has both the rigid structure of benzene rings and the flexible structure of butadiene. Compared with other rubbers, it has many excellent properties. According to the production method, butadiene styrene rubber is divided into emulsion-polymerized butadiene styrene rubber (ESBR) and solution-polymerized styrene butadiene rubber (SSBR). Due to the different polymerization methods, the microstructure of ESBR is relatively fixed, while SSBR is a copolymer obtained by anionic solution polymerization. The microstructure and macrostructure of the polymer can be adjusted according to the design requirements, such as the combined styrene content, vinyl content, glass transition temperature, branching degree, etc.

[0003] SBR is widely used in tire formulations alone or in combination with natural rubber, cis-PolybutadieneRubber (BR), etc. If the rubber formula contains both BR and SSBR, since both BR and SSBR contain three structures: cis-1,4-butadiene, trans-1,4-butadiene, and vinyl, the infrared spectroscopy technology can currently be used to test the total styrene content in the rubber, but the bound styrene content of SSBR itself cannot be given, and therefore the type of SSBR cannot be analyzed. Summary of the invention

[0004] The main purpose of the present invention is to provide a method for testing the bound styrene content, so as to solve the technical problem that the infrared spectroscopy technology in the prior art cannot give the bound styrene content in SSBR glue used as a combination of BR and SSBR.

[0005] In order to achieve the above object, according to one aspect of the present invention, a method for testing the content of styrene is provided, comprising the following steps:

[0006] A series of combined rubber standard rubbers with different BR and SSBR combined ratios are prepared by using a BR standard rubber and a SSBR standard rubber with known combined styrene content, and the styrene content of each combined rubber standard rubber is obtained based on the combined styrene content in the SSBR standard rubber and the combined ratio of BR and SSBR of each combined rubber standard rubber;

[0007] The absorbance of styrene in each combined rubber standard is tested by infrared spectrometer and normalized to obtain the normalized test value of the absorbance of styrene in each combined rubber standard; based on the styrene content in each combined rubber standard and the normalized test value of the absorbance of styrene in each combined rubber standard, a first standard curve of the styrene content in BR and SSBR combined rubber and the normalized absorbance of styrene in BR and SSBR combined rubber is constructed;

[0008] The peak area ratios of 4-vinylcyclohexene and styrene of the pyrolysis products of each combined rubber standard rubber are tested by pyrolysis gas chromatograph; based on the BR and SSBR combined ratio of each combined rubber standard rubber and the peak area ratios of 4-vinylcyclohexene and styrene of the pyrolysis products of each combined rubber standard rubber, a second standard curve of the combined ratio of BR and SSBR combined rubber and the peak area ratio of 4-vinylcyclohexene and styrene of the pyrolysis products of BR and SSBR combined rubber is constructed;

[0009] The absorbance of styrene in the blend of BR and SSBR is tested by infrared spectrometer and normalized to obtain a normalized test value of the absorbance of styrene in the blend of BR and SSBR, and the content of styrene in the blend of BR and SSBR is obtained based on the normalized test value of the absorbance of styrene in the blend of BR and SSBR and the first standard curve;

[0010] The peak area ratio of 4-vinylcyclohexene to styrene of the pyrolysis products of BR and SSBR blends was tested by pyrolysis gas chromatography.

[0011] Based on the ratio of the bound styrene content in the SSBR standard rubber to the bound styrene content in the SSBR rubber used in the blend of BR and SSBR, and the inverse relationship between the peak area ratio of the pyrolysis product of the blended rubber standard rubber to styrene and the peak area ratio of the pyrolysis product of the BR and SSBR blended rubber to styrene, a calibration curve is established to calibrate the test value of the peak area ratio of the pyrolysis product of the BR and SSBR blended rubber to styrene to obtain the calibration value of the peak area ratio of the pyrolysis product of the BR and SSBR blended rubber to styrene;

[0012] A first relationship is established based on the equation relationship between the ratio of the styrene content in the BR and SSBR blended rubber and the combined styrene content in the SSBR glue used in the BR and SSBR blended rubber and the proportion of the SSBR glue in the BR and SSBR blended rubber, and the inverse relationship between the combined ratio of the BR and SSBR blended rubber and the proportion of the SSBR glue in the BR and SSBR blended rubber;

[0013] Based on the test value of the peak area ratio of 4-vinylcyclohexene, the pyrolysis product of BR and SSBR blended rubber, to styrene, the bound styrene content in the SSBR standard rubber, the styrene content in the BR and SSBR blended rubber, the calibration curve, the first relationship and the second standard curve, the bound styrene content in the SSBR rubber used in the BR and SSBR blended rubber is obtained.

[0014] Furthermore, in terms of weight percentage, the content of styrene in each combined standard glue ranges from 2.5% to 25%.

[0015] Furthermore, in terms of weight percentage, the combined ratio of BR to SSBR of each combined rubber standard rubber ranges from (10:90) to (70:30).

[0016] Furthermore, before using an infrared spectrometer to test the absorbance of styrene in each combined rubber standard gum, and before using a pyrolysis gas chromatograph to test the peak area ratio of the pyrolysis product 4-vinylcyclohexene to styrene in each combined rubber standard gum, sample pretreatment is performed to remove small molecular organic matter in the combined rubber standard gum.

[0017] Furthermore, the sample pre-processing steps are as follows:

[0018] The combined rubber standard rubber is crushed and extracted with acetone at 85℃~95℃ for 6h~10h. After the extraction, the remaining rubber is taken out and dried at 70℃~90℃. The remaining rubber is then used to test the absorbance of styrene in the combined rubber standard rubber and the peak area ratio of the pyrolysis product 4-vinylcyclohexene and styrene of the combined rubber standard rubber.

[0019] Furthermore, the test conditions of the pyrolysis gas chromatograph include: pyrolysis temperature of 500°C to 600°C, needle temperature of 280°C to 300°C, injection port temperature of 270°C to 290°C, and FID temperature of 270°C to 290°C; the chromatographic column is SH-Rtx-5, and the column box temperature heating program is: initial temperature 40°C, maintained for 3 minutes, heating rate 10°C / min, heating to 270°C to 290°C, and maintained for 15 minutes.

[0020] Further, the absorbance of styrene in each combined glue standard glue is normalized according to formula (I);

[0021]

[0022] Among them, A 699 The absorption peak of styrene is 699 cm -1 The absorbance at the highest absorption peak nearby;

[0023] A 967 For trans-butadiene, the absorption peak is at 967 cm-1 The absorbance at the highest absorption peak nearby;

[0024] A 911 The absorption peak of vinyl is at 911 cm -1 The absorbance at the highest absorption peak nearby;

[0025] A 724 The absorption peak of cis-butadiene is 724 cm -1 The absorbance at the highest absorption peak nearby;

[0026] B 699 is the absorbance normalized to that of styrene.

[0027] Furthermore, the first standard curve is a linear standard curve shown in formula (II):

[0028] Y1=k1×B 699 +b1(II);

[0029] Wherein, Y1 is the styrene content in the blend of BR and SSBR;

[0030] B 699 is the normalized absorbance of styrene in the blend of BR and SSBR;

[0031] k1 and b1 are the slope and intercept respectively.

[0032] Furthermore, the second standard curve is a linear standard curve shown in formula (III):

[0033] Y2=k2×x'+b2(III);

[0034] Among them, Y2 is the ratio of BR and SSBR used in combination;

[0035] x' is the peak area ratio of 4-vinylcyclohexene and styrene, the pyrolysis products of BR and SSBR blends;

[0036] k2 and b2 are the slope and intercept respectively.

[0037] Further, the calibration curve is shown in formula (IV), and the first relationship is shown in formula (V);

[0038] x'=x / c×c x (IV);

[0039] K=Y1 / c x =1 / (1+Y2)(V);

[0040] Wherein, x is the measured value of the peak area ratio of 4-vinylcyclohexene to styrene, the pyrolysis product of BR and SSBR blend;

[0041] c is the bound styrene content in the SSBR standard rubber;

[0042] c x The combined styrene content in SSBR glue used for BR and SSBR glue;

[0043] K is the proportion of SSBR rubber in the blend of BR and SSBR;

[0044] Y1 is the styrene content in the blend of BR and SSBR.

[0045] By applying the technical solution of the present invention, the combined styrene content in the SSBR rubber used in the combined rubber of BR and SSBR is tested by combining infrared spectroscopy and pyrolysis gas chromatography, and the type of SSBR used in the combined rubber can be obtained through the combined styrene content of SSBR. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0047] Figure 1 shows the infrared spectrum of sample 1 in Example 1; and

[0048] Figure 2 The pyrolysis gas chromatogram of sample 1 in Example 1 is shown. DETAILED DESCRIPTION

[0049] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0050] As described in the background technology, the prior art uses infrared spectroscopy technology to test the total styrene content in the rubber material, but cannot provide the combined styrene content in the SSBR rubber used in combination with BR and SSBR. In order to solve the above problem, according to one aspect of the present invention, a method for testing the combined styrene content is provided, comprising the following steps:

[0051] A series of combined rubber standard rubbers with different BR and SSBR combined ratios are prepared by using a BR standard rubber and a SSBR standard rubber with known combined styrene content, and the styrene content of each combined rubber standard rubber is obtained based on the combined styrene content in the SSBR standard rubber and the combined ratio of BR and SSBR of each combined rubber standard rubber;

[0052] The absorbance of styrene in each combined rubber standard is tested by infrared spectrometer and normalized to obtain the normalized test value of the absorbance of styrene in each combined rubber standard; based on the styrene content in each combined rubber standard and the normalized test value of the absorbance of styrene in each combined rubber standard, a first standard curve of the styrene content in BR and SSBR combined rubber and the normalized absorbance of styrene in BR and SSBR combined rubber is constructed;

[0053] The peak area ratios of 4-vinylcyclohexene and styrene of the pyrolysis products of each combined rubber standard rubber are tested by pyrolysis gas chromatograph; based on the BR and SSBR combined ratio of each combined rubber standard rubber and the peak area ratios of 4-vinylcyclohexene and styrene of the pyrolysis products of each combined rubber standard rubber, a second standard curve of the combined ratio of BR and SSBR combined rubber and the peak area ratio of 4-vinylcyclohexene and styrene of the pyrolysis products of BR and SSBR combined rubber is constructed;

[0054] The absorbance of styrene in the blend of BR and SSBR is tested by infrared spectrometer and normalized to obtain a normalized test value of the absorbance of styrene in the blend of BR and SSBR, and the content of styrene in the blend of BR and SSBR is obtained based on the normalized test value of the absorbance of styrene in the blend of BR and SSBR and the first standard curve;

[0055] A pyrolysis gas chromatograph is used to test the peak area ratio of 4-vinylcyclohexene and styrene of the pyrolysis product of BR and SSBR blended rubber; based on the ratio of the bound styrene content in the SSBR standard rubber to the bound styrene content in the SSBR rubber used for the BR and SSBR blended rubber, and the inverse relationship between the peak area ratio of 4-vinylcyclohexene and styrene of the pyrolysis product of the blended rubber standard rubber and the peak area ratio of 4-vinylcyclohexene and styrene of the pyrolysis product of BR and SSBR blended rubber, a calibration curve is established to calibrate the test value of the peak area ratio of 4-vinylcyclohexene and styrene of the pyrolysis product of BR and SSBR blended rubber to obtain a calibration value of the peak area ratio of 4-vinylcyclohexene and styrene of the pyrolysis product of BR and SSBR blended rubber;

[0056] A first relationship is established based on the equation relationship between the ratio of the styrene content in the BR and SSBR blended rubber and the combined styrene content in the SSBR glue used in the BR and SSBR blended rubber and the proportion of the SSBR glue in the BR and SSBR blended rubber, and the inverse relationship between the combined ratio of the BR and SSBR blended rubber and the proportion of the SSBR glue in the BR and SSBR blended rubber;

[0057] Based on the test value of the peak area ratio of 4-vinylcyclohexene, the pyrolysis product of BR and SSBR blended rubber, to styrene, the bound styrene content in the SSBR standard rubber, the styrene content in the BR and SSBR blended rubber, the calibration curve, the first relationship and the second standard curve, the bound styrene content in the SSBR rubber used in the BR and SSBR blended rubber is obtained.

[0058] Infrared spectroscopy is based on the vibration transition of molecules when they absorb infrared light. Different chemical structures absorb infrared light at different wavelengths (for example, for SSBR, the characteristic peak of styrene structure absorbing infrared light can be found at 699cm -1 Therefore, by measuring the absorbance of the sample at a specific wavelength, the content of a specific chemical structure in the sample can be determined. Based on the measurement of the characteristic absorption peaks of the styrene structure in a series of blended rubber standard rubbers with known styrene content, the relationship between the infrared spectrum absorbance and the styrene content can be established, that is, the first standard curve used to represent the relationship between the styrene content and the absorbance of styrene in BR and SSBR blended rubbers.

[0059] Pyrolysis gas chromatography (PY-GC) is an efficient technique for analyzing polymers and complex organic mixtures. The sample is pyrolyzed at high temperature, and the resulting pyrolysis products are separated and detected by gas chromatography. For BR and SSBR blends, 4-vinylcyclohexene and styrene in the pyrolysis products can be quantitatively analyzed, and their peak area ratios can reflect the blend ratio of BR to SSBR. Based on the peak area ratios of 4-vinylcyclohexene and styrene, the pyrolysis products of a series of blend standard gums with known BR and SSBR blend ratios, the relationship between the blend ratio of BR and SSBR blends and the peak area ratio of 4-vinylcyclohexene and styrene is constructed, i.e., the second standard curve.

[0060] Styrene-butadiene rubber is a synthetic rubber formed by copolymerization of two monomers, butadiene and styrene. Its molecular structure contains two basic units: butadiene units, which can form three different structures when polymerized, namely cis-1,4-butadiene structure, trans-1,4-butadiene structure and 1,2-butadiene structure (also known as vinyl structure); and styrene structural units, the molecular formula of styrene is C8H8, which copolymerizes with butadiene during polymerization to form styrene-butadiene copolymers.

[0061] Butadiene rubber, chemically known as poly-1,3-butadiene rubber, is a synthetic rubber made by the polymerization of butadiene (1,3-butadiene). Its structural units are mainly derived from butadiene monomers. Butadiene can be polymerized in three different ways to form the structural units of butadiene rubber: cis-1,4-butadiene structure, which is the most common structural unit in butadiene rubber, with a structural formula of -[-CH=CH-CH2-CH2-]-. During the polymerization process, the two carbon-carbon double bonds take a cis configuration to form a 1,4 addition polymer chain; trans-1,4-butadiene structure, with a structural formula of -[-CH=CH-CH2-CH2-]-. In the trans-configuration 1,4 addition polymerization, the hydrogen atoms on the double bond carbon atoms of butadiene are located on both sides of the chain, and the trans-1 ,4 structure rarely appears in high cis butadiene rubber, but its proportion is higher in low cis butadiene rubber. The content of trans 1,4 structure will directly affect the wear resistance and tear resistance of butadiene rubber; and 1,2-butadiene structure (ie vinyl structure), the structural formula is -[-CH2-CH=CH-CH2-]-. The proportion of this structure in butadiene rubber is usually low, but under certain specific conditions, such as solution styrene butadiene rubber (SSBR) prepared by solution polymerization, by adjusting the polymerization conditions, the proportion of vinyl units can be increased, thereby adjusting the properties of the rubber, such as increasing the modulus and improving the low-temperature performance.

[0062] The microstructure of the blend of BR and SSBR includes cis-1,4-butadiene structure, trans-1,4-butadiene structure, 1,2-butadiene structure and styrene structure, wherein the styrene content is the weight percentage of styrene in the total amount of the above four microstructures. The microstructure of the blend of BR and SSBR can be tested by infrared spectroscopy to obtain the styrene content in the blend of BR and SSBR.

[0063] Based on the test method of the present invention, by combining infrared spectroscopy and pyrolysis gas chromatography (PY-GC), the combined styrene content in the SSBR glue used in the SSBR glue used in the BR and SSBR combined glue can be accurately determined, and the type of SSBR used in the combined glue can be analyzed by the combined styrene content of SSBR, which is of great value for analyzing the type and performance of SSBR, and has universal applicability for various BR and SSBR combined glues. In addition, the infrared spectrometer and the pyrolysis gas chromatograph used in the determination process are both conventional testing equipment, which are simple to operate and convenient to test.

[0064] In some embodiments, the styrene content of each combined standard glue ranges from 2.5% to 25% by weight.

[0065] Based on the technical solution of the embodiment of the present invention, the content range of styrene in each blended rubber standard rubber is set between 2.5% and 21%. This range better covers the common content range of styrene in tire BR and SSBR blended rubber formulas, which helps to establish a wider applicability and conduct more accurate quantitative analysis later.

[0066] In some embodiments, the combined ratio of BR to SSBR of each combined rubber standard rubber is in the range of (10:90) to (70:30) by weight percentage.

[0067] Based on the technical solution of the embodiment of the present invention, the above-mentioned combined ratio of BR and SSBR is adopted, which covers the common range of combined ratios in tire BR and SSBR combined rubber formulas, and helps to establish a wider range of applicability.

[0068] In some embodiments, before using an infrared spectrometer to test the absorbance of styrene in each combined rubber standard gum, and before using a pyrolysis gas chromatograph to test the peak area ratio of the pyrolysis product 4-vinylcyclohexene to styrene of each combined rubber standard gum, sample pretreatment is performed to remove small molecular organic matter in the combined rubber standard gum to reduce the interference of small molecular organic matter on the measurement results of the infrared spectrum and the pyrolysis gas chromatograph.

[0069] In one embodiment, the sample pre-processing steps are as follows:

[0070] The combined rubber standard rubber is crushed and extracted with acetone at 85℃~95℃ for 6h~10h. After the extraction, the remaining rubber is taken out and dried at 70℃~90℃. The remaining rubber is then used to test the absorbance of styrene in the combined rubber standard rubber and the peak area ratio of the pyrolysis product 4-vinylcyclohexene and styrene of the combined rubber standard rubber.

[0071] Based on the technical solution of the embodiment of the present invention, the standard rubber sample is pre-treated, and the small molecular organic matter in the rubber is removed by high-temperature extraction in acetone, which has a simple process and high accuracy.

[0072] In some embodiments, the test conditions of the pyrolysis gas chromatograph include: a pyrolysis temperature of 500°C to 600°C, a needle temperature of 280°C to 300°C, an injection port temperature of 270°C to 290°C, and an FID temperature of 270°C to 290°C; the chromatographic column is SH-Rtx-5, and the column box temperature heating program is: initial temperature 40°C, maintained for 3 minutes, a heating rate of 10°C / min, heated to 270°C to 290°C, and maintained for 15 minutes, so as to fully release and accurately detect the pyrolysis products 4-vinylcyclohexene and styrene.

[0073] In some embodiments, the absorbance of styrene in each combined glue standard glue is normalized according to formula (I);

[0074]

[0075] Among them, A 699 The absorption peak of styrene is 699 cm -1 The absorbance at the highest absorption peak nearby;

[0076] A 967 For trans-butadiene, the absorption peak is at 967 cm -1 The absorbance at the highest absorption peak nearby;

[0077] A 911 The absorption peak of vinyl is at 911 cm -1 The absorbance at the highest absorption peak nearby;

[0078] A 724 The absorption peak of cis-butadiene is 724 cm -1 The absorbance at the highest absorption peak nearby;

[0079] B 699 is the absorbance normalized to that of styrene.

[0080] Based on the technical solution of the embodiment of the present invention, before constructing the first standard curve, the absorbance of styrene is subjected to the above normalization process, so that the absorbance data of styrene of the same sample are comparable under different sample test amounts.

[0081] In some embodiments, the first standard curve is a linear standard curve represented by formula (II):

[0082] Y1=k1×B 699 +b1(II);

[0083] Wherein, Y1 is the styrene content in the blend of BR and SSBR;

[0084] B 699 is the normalized absorbance of styrene in the blend of BR and SSBR;

[0085] k1 and b1 are the slope and intercept respectively.

[0086] Based on the technical solution of the embodiment of the present invention, based on the linear relationship established between the normalized styrene absorbance and the known styrene content, the slope k1 and the intercept b1 are obtained by fitting, which are used to predict the styrene content in BR and SSBR blends with high accuracy.

[0087] In some embodiments, the second standard curve is a linear standard curve represented by formula (III):

[0088] Y2=k2×x'+b2(III);

[0089] Among them, Y2 is the ratio of BR and SSBR used in combination;

[0090] x' is the peak area ratio of 4-vinylcyclohexene and styrene, the pyrolysis products of BR and SSBR blends;

[0091] k2 and b2 are the slope and intercept respectively.

[0092] Based on the technical solution of the embodiment of the present invention, the main qualitative substances of BR can be butadiene and 4-vinylcyclohexene, and the quantitative substance is preferably 4-vinylcyclohexene. The main qualitative substances of SSBR are butadiene and styrene, and the quantitative substance is preferably styrene. Based on the linear relationship between the test value x2 of the peak area ratio of 4-vinylcyclohexene to styrene obtained by the pyrolysis gas chromatograph and the known BR to SSBR combined ratio Y2, a second standard curve is established to predict the combined ratio of BR and SSBR combined rubber with high accuracy.

[0093] In one embodiment, the calibration curve is shown in formula (IV), and the first relationship is shown in formula (V);

[0094] x'=x / c×c x (IV);

[0095] K=Y1 / c x =1 / (1+Y2)(V);

[0096] Wherein, x is the measured value of the peak area ratio of 4-vinylcyclohexene to styrene, the pyrolysis product of BR and SSBR blend;

[0097] c is the bound styrene content in the SSBR standard rubber;

[0098] c x The combined styrene content in SSBR glue used for BR and SSBR glue;

[0099] K is the proportion of SSBR rubber in the blend of BR and SSBR;

[0100] Y1 is the styrene content in the blend of BR and SSBR.

[0101] Based on the technical solution of the embodiment of the present invention, when the linear standard curve shown in formula (III) is established, the combined rubber standard rubber is used, and the bound styrene content in the SSBR standard rubber is known. For example, when the linear standard curve is established using SSBR2557s with a bound styrene content of 25%, c is 25%. When the linear standard curve shown in formula (III) is applied to the calculation of the bound styrene content in the SSBR rubber used in the combined rubber of BR and SSBR, it is necessary to calibrate the test value of the peak area ratio of 4-vinylcyclohexene, a pyrolysis product of the combined rubber of BR and SSBR, to styrene (as shown in IV), and substitute the calibration value into the linear standard curve shown in formula (III) to obtain a more accurate calculation result; wherein, Y1 / c x , 1 / (1+Y2) represent the proportion of SSBR rubber in the blend of BR and SSBR respectively, so Y1 / c x The equation relationship between 1 / (1+Y2) and 1 / (1+Y2) is used to substitute the test value of the peak area ratio of 4-vinylcyclohexene to styrene of the pyrolysis product of BR and SSBR blend, the bound styrene content in the SSBR standard glue, and the styrene content in the BR and SSBR blend into the above formulas (III) to (V), and the bound styrene content c in the SSBR glue used in the BR and SSBR blend can be finally obtained. x .

[0102] In addition to the bound styrene content in SSBR glue, the bound vinyl content in SSBR glue is also of great significance for analyzing the microstructure of SSBR glue. Vinyl content usually refers to the weight percentage of vinyl structure in butadiene structure (including 1,4-butadiene cis structure, 1,4-butadiene trans structure and vinyl structure). For example, the bound vinyl content in SSBR glue refers to the weight percentage of vinyl structure in SSBR glue to butadiene structure (including 1,4-butadiene cis structure, 1,4-butadiene trans structure and vinyl structure) in SSBR glue; the vinyl content in BR and SSBR blended rubber refers to the weight percentage of vinyl structure in BR and SSBR blended rubber to butadiene structure (including 1,4-butadiene cis structure, 1,4-butadiene trans structure and vinyl structure) in BR and SSBR blended rubber.

[0103] Butadiene rubber is divided into high-cis butadiene rubber and low-cis butadiene rubber, where "cis" refers to the connection mode of butadiene units in the polymer chain. In high-cis butadiene rubber, the cis-1,4-butadiene structure accounts for more than 98% of the polymer chain, while in low-cis butadiene rubber, the proportion of cis-1,4-butadiene structure is lower, and it may contain a higher trans-1,4-butadiene structure or vinyl structure. In some embodiments, the BR used in the combination of BR and SSBR is high-cis butadiene rubber (such as BR9000). When the vinyl content in the butadiene rubber is negligible, the combined vinyl content c in the SSBR rubber can be estimated using formula (VII): 乙烯基 .

[0104] c 乙烯基 =b×(100%-Y1) / (Y1 / c x ×100%-Y1)(VII)

[0105] Wherein, Y1 is the styrene content in the blend of BR and SSBR;

[0106] b is the vinyl content in the blend of BR and SSBR, which can be obtained by infrared spectroscopy.

[0107] c x The combined styrene content in SSBR glue used for BR and SSBR glue;

[0108] 100-Y1 represents the content of butadiene structure in the blend of BR and SSBR, b×(100-Y1) represents the weight percentage of vinyl structure in SSBR in the blend of BR and SSBR;

[0109] Y1 / c x It represents the proportion of SSBR rubber in the blend of BR and SSBR, (Y1 / c x ×100-Y1) represents the weight percentage of butadiene structure in SSBR in the blend of BR and SSBR.

[0110] In some embodiments, the vinyl content in the BR and SSBR blend can be obtained by infrared spectroscopy technology. Specifically, the following steps can be taken to obtain the vinyl content:

[0111] A series of combined rubber standard rubbers with different BR and SSBR combined ratios are prepared by using a BR standard rubber with a known combined vinyl content and a SSBR standard rubber with a known combined vinyl content, and the vinyl content in each combined rubber standard rubber and the vinyl content in each combined rubber standard rubber are calculated based on the combined vinyl content in the BR standard rubber, the combined vinyl content in the SBR standard rubber and the BR and SSBR combined ratio of each combined rubber standard rubber;

[0112] Using an infrared spectrometer to test the absorbance of vinyl in each combined rubber standard glue respectively and perform normalization processing to obtain normalized test values ​​of the absorbance of vinyl in each combined rubber standard glue, and constructing a third standard curve based on the vinyl content in each combined rubber standard glue and the normalized test values ​​of the absorbance of vinyl in each combined rubber standard glue;

[0113] The absorbance of vinyl in BR and SSBR blended rubber is obtained by infrared spectrometer and normalized to obtain the normalized test value of the absorbance of vinyl in BR and SSBR blended rubber. The vinyl content in BR and SSBR blended rubber is obtained based on the normalized test value of the absorbance of vinyl in BR and SSBR blended rubber and the first standard curve.

[0114] In one embodiment, the absorbance of the vinyl group in each combined glue standard glue is normalized according to formula (VIII);

[0115]

[0116] Among them, A 699 The absorption peak of styrene is 699 cm -1 The absorbance at the highest absorption peak nearby;

[0117] A 967 For trans-butadiene, the absorption peak is at 967 cm -1 The absorbance at the highest absorption peak nearby;

[0118] A 911 The absorption peak of vinyl is at 911 cm -1 The absorbance at the highest absorption peak nearby;

[0119] A 724 The absorption peak of cis-butadiene is 724 cm -1 The absorbance at the highest absorption peak nearby;

[0120] B 911 is the absorbance normalized to vinyl.

[0121] In one embodiment, the third standard curve is a linear standard curve represented by formula (IX):

[0122] Y3=k3×B 911 +b3(IX);

[0123] Wherein, Y3 is the vinyl content in the blend of BR and SSBR;

[0124] B 911 is the normalized absorbance of vinyl in BR and SSBR blends;

[0125] K3 and b3 are the slope and intercept respectively.

[0126] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0127] Example 1

[0128] A method for testing the content of styrene, comprising the following steps:

[0129] Step 1, prepare a series of combined rubber standard rubbers with combined ratios of BR9000 and SSBR2557s of 10 / 90, 20 / 80, 30 / 70, 40 / 60, 60 / 40, 70 / 30, 80 / 20 and 90 / 10 respectively; wherein the bound styrene content in SSBR2557s is 25%; based on the combined styrene content in SSBR2557s and the combined ratios of BR9000 and SSBR2557s of each combined rubber standard rubber, the styrene content in each combined rubber standard rubber is obtained to be in the range of 2.5% to 22.5%.

[0130] Step 2, sample pretreatment: Take 0.5g of the above-mentioned combined glue standard glue, cut it into thin strips, wrap it with quantitative filter paper, and extract it with acetone at 90℃ for 8h. After the extraction is completed, take out the remaining glue, place the remaining glue in an oven at 80℃ and dry it for 2h to obtain the combined glue standard glue sample, take it out and put it in a dryer for testing.

[0131] Step 3: Use Ge crystal ATR-FTIR at 4000cm -1 ~600cm -1 Infrared scanning is performed on each sample of the combined adhesive standard adhesive within the range, with a resolution of 4cm -1 The scanning times are 32 times, and the infrared spectra of each combined rubber standard rubber sample to be tested are obtained. Based on the infrared spectra of each combined rubber standard rubber sample to be tested, the absorbance of styrene, trans-butadiene, vinyl and cis-butadiene in each combined rubber standard rubber is obtained. Three different positions are selected on each sample for testing, and the absorbance test results are averaged.

[0132] Step 4, normalizing the test value of the absorbance of styrene in each combined glue standard glue according to formula (I) to obtain the normalized test value of the absorbance of styrene in each combined glue standard glue, and then constructing a linear standard curve shown in formula (II) based on the styrene content in each combined glue standard glue and the normalized test value of the absorbance of styrene in each combined glue standard glue;

[0133]

[0134] Among them, A 699 The absorption peak of styrene is 699 cm-1 The absorbance at the highest absorption peak nearby;

[0135] A 967 For trans-butadiene, the absorption peak is at 967 cm -1 The absorbance at the highest absorption peak nearby;

[0136] A 911 The absorption peak of vinyl is at 911 cm -1 The absorbance at the highest absorption peak nearby;

[0137] A 724 The absorption peak of cis-butadiene is 724 cm -1 The absorbance at the highest absorption peak nearby;

[0138] B 699 is the normalized absorbance of styrene;

[0139] Y1=k1×B 699 +b1(II);

[0140] Wherein, Y1 is the styrene content in the blend of BR and SSBR;

[0141] B 699 is the normalized absorbance of styrene in the blend of BR and SSBR;

[0142] k1 and b1 are the slope and intercept respectively; the fitted k1 and b1 are 50.03 and 0 respectively, R 2 =0.998 (i.e. Y1 = 50.03 × B 699 ).

[0143] Step 5, using a pyrolysis gas chromatograph to test the pyrolysis gas chromatograms of each combined rubber standard rubber to be tested, and obtaining the peak area ratio of the pyrolysis product 4-vinylcyclohexene to styrene of each combined rubber standard rubber to be tested based on the pyrolysis gas chromatogram, and based on the BR and SSBR combined ratio of each combined rubber standard rubber and the peak area ratio of the pyrolysis product 4-vinylcyclohexene to styrene of each combined rubber standard rubber, construct a linear standard curve shown in formula (III);

[0144] Y2=k2×x'+b2(III);

[0145] Among them, Y2 is the ratio of BR and SSBR used in combination;

[0146] x' is the peak area ratio of 4-vinylcyclohexene and styrene, the pyrolysis products of BR and SSBR blends;

[0147] k2 and b2 are the slope and intercept, respectively. The fitted k2 and b2 are 1.8843 and -0.1682, respectively (i.e., Y2 = 1.8843x - 0.1682);

[0148] The test steps of the pyrolysis gas chromatograph are as follows: 0.05 mg of the combined rubber standard rubber sample to be tested is wrapped in a hot foil, placed in a pyrolyzer and tested to obtain the peak area ratio of the pyrolysis product 4-vinylcyclohexene to styrene of each combined rubber standard rubber sample to be tested;

[0149] The test conditions of the pyrolysis gas chromatograph are as follows: pyrolysis temperature of 590°C, needle temperature of 290°C, injection port temperature of 280°C, and FID temperature of 280°C; the chromatographic column is SH-Ttx-5, and the temperature rise program of the column box is as follows: initial temperature of 40°C, maintained for 3 min, heating rate of 10°C / min, heated to 280°C, maintained for 15 min; each sample is tested twice, and the peak area ratio of 4-vinylcyclohexene to styrene is averaged.

[0150] Step 6: Use Ge crystal ATR-FTIR at 4000cm -1 ~600cm -1 The sample high cis BR and SSBR blended rubber (specifically, BR9000 and SLR3402 were mixed at a blend ratio of 18 / 82, the theoretical content of bound styrene in SLR3402 was 15.0%, and the content of bound vinyl in SLR3402 was 30.0%, hereinafter referred to as sample 1) was subjected to infrared scanning at a resolution of 4 cm -1 , the number of scans is 32, and the infrared spectrum of sample 1 is obtained, as shown in Figure 1 As shown, among them, 699cm -1 、967cm -1 、911cm -11 、724cm -1 The absorption peak positions corresponding to the structures of styrene, trans-butadiene, vinyl and cis-butadiene respectively; the absorbance of styrene, trans-butadiene, vinyl and cis-butadiene in sample one is obtained based on the infrared spectrum of sample one, and three different positions on sample one are selected for testing, and the absorbance test results are averaged.

[0151] Step seven, normalize the test value of the absorbance of styrene in sample one (refer to step four for normalization) to obtain the normalized test value of the absorbance of styrene in sample one, calculate the styrene content in sample one based on the normalized test value of the absorbance of styrene in sample one and the linear standard curve shown in formula (II), test and calculate 5 times continuously, calculate the average value of 5 times as the styrene content in sample one, and use it to substitute into formula (V); wherein, the styrene content in sample one obtained by each calculation and the average value are shown in Table 1.

[0152] Step 8: Using a pyrolysis gas chromatograph to test the pyrolysis gas chromatogram of sample 1, as shown in FIG. Figure 2 As shown, wherein the retention times of 2.082min, 6.567min, and 7.908min correspond to the structures of butadiene, 4-vinylcyclohexene, and styrene, respectively; based on the pyrolysis gas chromatogram, the peak area ratio of 4-vinylcyclohexene to styrene of sample one is obtained (wherein, the test steps of the pyrolysis gas chromatography and the test conditions of the pyrolysis gas chromatograph refer to step five), the test is performed 5 times in a row, and the average value of the 5 times is calculated as the test value of the peak area ratio of the pyrolysis product 4-vinylcyclohexene to styrene of sample one, and is used to substitute into formula (IV); wherein the test values ​​and the average value of the peak area ratio of the pyrolysis product 4-vinylcyclohexene to styrene of sample one obtained each time are shown in Table 1.

[0153] Step nine, based on the ratio of the bound styrene content in the SSBR standard rubber to the bound styrene content in the SSBR rubber used for the blend of BR and SSBR, and the inverse relationship between the ratio of the peak area of ​​4-vinylcyclohexene and styrene of the pyrolysis product of the blended rubber standard rubber and the peak area of ​​4-vinylcyclohexene and styrene of the pyrolysis product of the blended rubber of BR and SSBR, a calibration curve shown in formula (IV) is established to calibrate the test value of the peak area ratio of 4-vinylcyclohexene and styrene of the pyrolysis product of the blended rubber of BR and SSBR, and obtain the calibration value of the peak area ratio of 4-vinylcyclohexene and styrene of the pyrolysis product of the blended rubber of BR and SSBR; based The first relationship shown in formula (V) is established by the equation relationship between the ratio of the styrene content in the BR and SSBR blended rubber and the bound styrene content in the SSBR rubber used in the BR and SSBR blended rubber and the proportion of SSBR rubber in the BR and SSBR blended rubber, and the inverse relationship between the combined ratio of BR and SSBR blended rubber and the proportion of SSBR rubber in the BR and SSBR blended rubber; the test value of the peak area ratio of the cracking product 4-vinylcyclohexene of sample one to styrene, the bound styrene content in the SSBR standard rubber, and the styrene content in sample one are substituted into formulas (III) to (V) to obtain the bound styrene content c in the SSBR rubber used in sample one. x :

[0154] x'=x / c×cx (IV);

[0155] K=Y1 / c x =1 / (1+Y2)(V);

[0156] Wherein, x is the measured value of the peak area ratio of 4-vinylcyclohexene to styrene, the pyrolysis product of BR and SSBR blend;

[0157] c is the bound styrene content in the SSBR standard rubber;

[0158] c x The combined styrene content in SSBR glue used for BR and SSBR glue;

[0159] K is the proportion of SSBR rubber in the blend of BR and SSBR;

[0160] Y1 is the styrene content in the blend of BR and SSBR.

[0161] Specifically, the test value of the peak area ratio of the pyrolysis product 4-vinylcyclohexene to styrene of sample 1, 0.310, the bound styrene content of the SSBR standard rubber, 25%, and the styrene content of sample 1, 13.1%, are substituted into formulas (III) to (V) to obtain:

[0162] y = 1.8843 × (0.3106 / 25% × c x )-0.1682;

[0163] 13.1% / c x =1 / (1+y);

[0164] Calculate the bound styrene content c in the SSBR rubber used in sample 1 x The absolute deviation from the theoretical value of 15.0% for the bound styrene content in SLR3402 is within 1%.

[0165] The BR used in sample 1 is high cis-butyl rubber. When the vinyl content in cis-butyl rubber is negligible, the bound vinyl content c in SSBR can be estimated using formula (VII): 乙烯基 .

[0166] c 乙烯基 =b×(100%-Y1) / (Y1 / c x ×100%-Y1)(VII)

[0167] Wherein b is 25.5%, which is obtained by infrared spectroscopy technology and will not be described in detail here;

[0168] Set Y1 to 13.1%, c xSubstituting into formula (VII) we get c = 15.7% and b = 25.5%. 乙烯基 =25.5%×(100%-13.1%) / (13.1% / 15.7%×100%-13.1%)=0.315=31.5%, thus obtaining the combined vinyl content of the SSBR glue used in sample 1 is 31.5%, which is within 2% of the absolute deviation from the theoretical value of 30.0% of the combined vinyl content in SLR3402.

[0169] Table 1

[0170]

[0171] Example 2

[0172] The only difference from Example 1 is that the test sample 1 in step 6 is replaced by the test sample BR9000 and SSBR2550H vulcanized rubber, wherein the theoretical value of the combined styrene content in SSBR2550H is 25.0%, the theoretical value of the combined vinyl content in SSBR2550H is 47.0%, and the ratio of BR9000 and SSBR2550H is 20 / 80).

[0173] The styrene content in the vulcanized rubber of BR9000 and SSBR2550H is 20.3%, the vinyl content in the vulcanized rubber of BR9000 and SSBR2550H is 35.6%, and the peak area ratio of the cracking product 4-vinylcyclohexene to styrene in the vulcanized rubber of BR and SSBR is 0.2234. Substituting 20.3%, 0.2234 and 25% into formulas (III) to (V), the combined styrene content c of SSBR2550H used in the vulcanized rubber of BR9000 and SSBR2550H is further calculated. x Substituting 20.3%, 25.7% and 35.6% into formula (VII), we obtain a combined vinyl content of 48.2% in SSBR2550H vulcanized with BR9000 and SSBR2550.

[0174] Embodiment 3-8

[0175] The difference from Example 1 is that the sample 1 to be tested in step 6 is replaced by BR9000 and NS616 (wherein the theoretical value of the combined styrene content in NS616 is 21.0%, and the theoretical value of the combined vinyl content in NS616 is 63.0%), and the ratios are 10 / 90, 20 / 80, 30 / 70, 40 / 60, 60 / 40, 70 / 30, 80 / 20, 90 / 10, respectively, and the BR and SSBR rubber samples are respectively referred to as sample 10 / 90, sample 20 / 80, sample 30 / 70, sample 40 / 60, sample 60 / 40, sample 70 / 30, sample 80 / 20, and sample 90 / 10;

[0176] Among them, the obtained styrene content in each sample to be tested, the vinyl content in each sample to be tested, and the peak area ratio of the cracking product 4-vinylcyclohexene to styrene of each sample to be tested are shown in Table 2; the further calculated combined styrene content in SSBR used for each sample to be tested (i.e., the calculated value of the combined styrene content in SSBR) and the combined vinyl content in SSBR used for each sample to be tested (i.e., the calculated value of the combined vinyl content in SSBR) are shown in Table 3.

[0177] Table 2

[0178]

[0179] Table 3

[0180]

[0181] As can be seen from Table 3, the absolute deviations of the calculated values ​​of the combined styrene content in NS616 used in each sample to be tested (20.4% to 21.8%) and the theoretical value (21%) are all within ±1%, and the absolute deviations of the calculated values ​​of the combined vinyl content in NS616 used in each sample to be tested (60.6% to 63.6%) and the theoretical value (63%) are all within ±5%. The test method for the styrene content based on the embodiment of the present invention has a high accuracy.

[0182] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for testing the content of styrene, characterized in that: The steps include: A series of combined rubber standard rubbers with different BR and SSBR combined ratios are prepared by using a BR standard rubber and a SSBR standard rubber with known combined styrene content, and the styrene content in each combined rubber standard rubber is obtained based on the combined styrene content in the SSBR standard rubber and the BR and SSBR combined ratio of each combined rubber standard rubber; The absorbance of styrene in each of the combined rubber standard glues is tested by infrared spectrometer and normalized to obtain the normalized test value of the absorbance of styrene in each of the combined rubber standard glues; based on the styrene content in each of the combined rubber standard glues and the normalized test value of the absorbance of styrene in each of the combined rubber standard glues, a first standard curve of the styrene content in BR and SSBR combined rubbers and the normalized absorbance of styrene in BR and SSBR combined rubbers is constructed; The peak area ratios of 4-vinylcyclohexene and styrene of the pyrolysis products of each of the combined rubber standard rubbers are tested by a pyrolysis gas chromatograph; based on the BR and SSBR combined ratio of each of the combined rubber standard rubbers and the peak area ratios of 4-vinylcyclohexene and styrene of the pyrolysis products of each of the combined rubber standard rubbers, a second standard curve of the combined ratio of BR and SSBR combined rubber and the peak area ratio of 4-vinylcyclohexene and styrene of the pyrolysis products of BR and SSBR combined rubber is constructed; The infrared spectrometer is used to test the absorbance of styrene in the BR and SSBR blend rubber and normalize the absorbance of styrene in the BR and SSBR blend rubber to obtain a normalized test value of the absorbance of styrene in the BR and SSBR blend rubber, and the styrene content in the BR and SSBR blend rubber is obtained based on the normalized test value of the absorbance of styrene in the BR and SSBR blend rubber and the first standard curve; The pyrolysis gas chromatograph is used to test the peak area ratio of 4-vinylcyclohexene to styrene of the pyrolysis product of the BR and SSBR blend; Based on the ratio of the bound styrene content in the SSBR standard rubber to the bound styrene content in the SSBR rubber used for the BR and SSBR blend, and the inverse relationship between the peak area ratio of the pyrolysis product 4-vinylcyclohexene of the blended rubber standard rubber to styrene and the peak area ratio of the pyrolysis product 4-vinylcyclohexene of the BR and SSBR blended rubber to styrene, a calibration curve is established to calibrate the test value of the peak area ratio of the pyrolysis product 4-vinylcyclohexene of the BR and SSBR blended rubber to styrene, and obtain the calibration value of the peak area ratio of the pyrolysis product 4-vinylcyclohexene of the BR and SSBR blended rubber to styrene; A first relationship is established based on the equation relationship between the ratio of the styrene content in the BR and SSBR blended rubber to the combined styrene content in the SSBR glue used in the BR and SSBR blended rubber and the proportion of the SSBR glue in the BR and SSBR blended rubber, and the inverse relationship between the combined ratio of the BR and SSBR blended rubber and the proportion of the SSBR glue in the BR and SSBR blended rubber; Based on the test value of the peak area ratio of the pyrolysis product 4-vinylcyclohexene to styrene in the BR and SSBR blend, the bound styrene content in the SSBR standard glue, the styrene content in the BR and SSBR blend, the calibration curve, the first relationship and the second standard curve, the bound styrene content in the SSBR glue used in the BR and SSBR blend is obtained.

2. The method for testing the bound styrene content according to claim 1, characterized in that: In terms of weight percentage, the content of styrene in each of the combined standard glues ranges from 2.5% to 25%.

3. The method for testing the bound styrene content according to claim 1, characterized in that: In terms of weight percentage, the combined ratio of BR and SSBR in each of the combined rubber standard rubbers ranges from (10:90) to (70:30).

4. The method for testing the bound styrene content according to claim 1, characterized in that: Before using the infrared spectrometer to test the absorbance of styrene in each of the combined rubber standard gums, and before using the pyrolysis gas chromatograph to test the peak area ratio of the pyrolysis product 4-vinylcyclohexene to styrene in each of the combined rubber standard gums, sample pretreatment is performed to remove small molecular organic matter in the combined rubber standard gums.

5. The method for testing the bound styrene content according to claim 4, characterized in that: The sample pre-treatment steps are as follows: The combined rubber standard rubber is crushed and extracted with acetone at 85°C to 95°C for 6h to 10h. After the extraction, the remaining rubber is taken out and dried at 70°C to 90°C. The remaining rubber is then used to test the absorbance of styrene in the combined rubber standard rubber and the peak area ratio of the cleavage product 4-vinylcyclohexene to styrene in the combined rubber standard rubber.

6. The method for testing the bound styrene content according to claim 1, characterized in that: The test conditions of the pyrolysis gas chromatograph include: a pyrolysis temperature of 500°C to 600°C, a needle temperature of 280°C to 300°C, an injection port temperature of 270°C to 290°C, and an FID temperature of 270°C to 290°C; the chromatographic column is SH-Ttx-5, and the temperature rise program of the column box temperature is: an initial temperature of 40°C, maintained for 3 minutes, a heating rate of 10°C / min, and the temperature is increased to 270°C to 290°C and maintained for 15 minutes.

7. The method for testing the bound styrene content according to any one of claims 1 to 6, characterized in that: The absorbance of the styrene in each of the combined glue standard glues is normalized according to formula (I); Among them, A 699 The absorption peak of styrene is 699 cm -1 The absorbance at the highest absorption peak nearby; A 967 The absorption peak of trans-butadiene is 967 cm -1 The absorbance at the highest absorption peak nearby; A 911 The absorption peak of vinyl is at 911 cm -1 The absorbance at the highest absorption peak nearby; A 724 The absorption peak of cis-butadiene is 724 cm -1 The absorbance at the highest absorption peak nearby; B 699 is the absorbance normalized to that of styrene.

8. The method for testing the bound styrene content according to claim 7, characterized in that: The first standard curve is a linear standard curve shown in formula (II): Y1=k1×B 699 +b1(II); Wherein, Y1 is the styrene content in the blend of BR and SSBR; B 699 is the normalized absorbance of styrene in the blend of BR and SSBR; k1 and b1 are the slope and intercept respectively.

9. The method for testing the bound styrene content according to any one of claims 1 to 6, characterized in that: The second standard curve is a linear standard curve shown in formula (III): Y2=k2×x'+b2(III); Among them, Y2 is the ratio of BR and SSBR used in combination; x' is the peak area ratio of 4-vinylcyclohexene and styrene, the pyrolysis products of BR and SSBR blends; k2 and b2 are the slope and intercept respectively.

10. The method for testing the bound styrene content according to claim 9, characterized in that: The calibration curve is shown in formula (IV), and the first relationship is shown in formula (V); x'=x / c×c x (IV); K=Y1 / c x =1 / (1+Y2)(V); Wherein, x is the measured value of the peak area ratio of 4-vinylcyclohexene to styrene, the pyrolysis product of BR and SSBR blend; c is the bound styrene content in the SSBR standard rubber; c x The combined styrene content in SSBR glue used for BR and SSBR glue; K is the proportion of SSBR rubber in the blend of BR and SSBR; Y1 is the styrene content in the blend of BR and SSBR.

Images