Method for rapidly measuring polarity parameter of surface free energy of reinforcing filler for rubber

Abstract

The invention relates to a rubber material technology, in particular to a rapid determination method for a surface free energy polarity parameter of a reinforcing filler for rubber. The invention provides a method for rapidly measuring polarity parameters of surface free energy of a reinforcing filler for rubber, which comprises the following steps: preparing a filler chromatographic column, installing the filler chromatographic column in a chromatographic instrument column box, and setting a carrier gas flow and a column box temperature observation base line; after the base line is stable, specific substances are sequentially injected, and related adjustment retention time is recorded; calculating a logarithm value for adjusting retention time, making a linear graph and establishing a regression equation to obtain a slope and an intercept value; and calculating an equivalent carbon atom number and a Gibbs free energy polarity part of the polarity probe molecule, and further obtaining a surface free energy polarity parameter. Specific conditions and parameter selection in each step, such as packed column specification, carrier gas flow, polar probe molecule selection and the like, are explained, and specific steps for calculating the number of equivalent carbon atoms are elaborated in detail. According to the method, the process is simplified, and the determination efficiency is improved.

Description

Technical Field

[0001] The invention relates to rubber material technology, in particular to a method for quickly determining surface free energy polarity parameters of a rubber reinforcing filler. Background Art

[0002] Carbon black, white carbon black and other reinforcing fillers in the rubber industry can greatly improve the wear resistance, load-bearing capacity and puncture resistance of rubber industrial products such as tires. In the reinforcing function of fillers on rubber, the surface free energy of fillers belongs to the strength factor, while the morphological characteristics such as particle size and structure belong to the capacity factor of fillers. Therefore, from the perspective of reinforcement mechanism, the surface free energy of fillers belongs to the more basic and fundamental characteristics, which deeply affects the strength of the reinforcing function of fillers. However, although the surface free energy is crucial to the reinforcing function of fillers, it is not easy to characterize the surface free energy of fillers. At present, the relatively mature and reliable characterization method is inverse gas chromatography (IGC method for short). The conventional IGC method can determine the non-polar and polar parts of the surface free energy of fillers, but the test steps are quite cumbersome, requiring the measurement and recording of more than a dozen parameters, and as many as seven calculation formulas, and the test efficiency is low. Later, after a lot of experimental research and data analysis, scientists created a new mathematical model and successfully developed an efficient and fast IGC method for measuring the non-polar part of surface free energy (i.e. dispersion free energy), reducing the test parameters to 5 and shortening the test time to less than 4 hours.

[0003] At present, the conventional IGC method has a large test workload, and there are as many as 13 test parameters that need to be recorded and strictly controlled, including the mass of the filler in the chromatographic column g, the specific surface area of ​​the filler s, the column head pressure p i , outlet pressure p o , column temperature T C , room temperature T f , the saturated vapor pressure of water at room temperature corresponding to the measurement w , carrier gas flow rate D, air retention time t 空 , the retention time of n-pentane is t5, the retention time of n-hexadecane is t6, the retention time of n-heptane is t7, the retention time of polar probe molecules (such as acetone) is t 极性 Moreover, the calculation process of the conventional IGC method is very complicated, with a total of 13 calculation steps. Taking acetone as an example, the specific steps are:

[0004] The first step is to calculate the pressure correction factor j according to formula I, which is:

[0005]

[0006] In the second step, according to formula II, the adjusted retention volume V5 of n-pentane is calculated; where t r -t空 represents the adjusted retention time of the corresponding probe molecule, and formula II is:

[0007]

[0008] The third step is to calculate the adjusted retention volume V6 of n-hexadecane according to Formula II.

[0009] The fourth step is to calculate the adjusted retention volume V7 of n-heptane according to Formula II.

[0010] Step 5: Calculate the adjusted retention volume V of acetone in Formula II 丙酮 .

[0011] Step 6: Calculate the Gibbs free energy -ΔG5 of n-pentane according to Formula III. Formula III is:

[0012]

[0013] Step 7: Calculate the Gibbs free energy -ΔG6 of n-hexadecane according to formula III.

[0014] Step 8. Calculate the Gibbs free energy -ΔG7 of n-heptane according to formula III.

[0015] Step 9: Calculate the Gibbs free energy of acetone -ΔG according to Formula III 丙酮 .

[0016] The tenth step is to perform linear simulation with the molecular cross-sectional areas of n-pentane, n-hexadecane, and n-heptadecane (which can be obtained from English literature) as the horizontal coordinate and the Gibbs free energy of n-pentane, n-hexadecane, and n-heptadecane as the vertical coordinate to obtain the linear regression equation between the Gibbs free energy and the molecular cross-sectional area of ​​each n-alkane.

[0017] Step 11: Using the linear regression equation obtained in step 10, calculate the cross-sectional area of ​​the acetone molecule (abbreviated as α 丙酮 ) into the equation, and the nonpolar part of the Gibbs free energy of the acetone molecule is obtained.

[0018] Step 12: Calculate the polar part of the Gibbs free energy of the acetone molecule according to Formula IV Abbreviated as -ΔΔG 丙酮 , Formula IV is:

[0019]

[0020] Step 13: Calculate the surface free energy polarity parameter of acetone molecule according to formula V The formula V is:

[0021]

[0022] In summary, the conventional IGC method needs to go through the above 13 steps to obtain the surface free energy polarity parameters of the acetone molecule, and a total of 13 parameters involved, such as the column head pressure and the specific surface area of ​​the filler, need to be measured or recorded in advance, so the testing and calculation process is quite cumbersome. Summary of the invention

[0023] In order to completely solve the problem that the conventional inverse gas chromatography (IGC method) is complicated and inefficient in determining the surface free energy of fillers, especially the lack of a simple and efficient rapid determination method for the polar part of the surface free energy, the present invention proposes the following technical solutions:

[0024] A method for quickly determining the surface free energy polarity parameters of a rubber reinforcing filler, characterized in that it comprises the following steps:

[0025] S1: Prepare a chromatographic column for the filler to be tested, install the prepared chromatographic column into the column box of the chromatograph, start the chromatograph and set the carrier gas flow rate and column box temperature, and closely observe the baseline generated during the operation of the chromatograph;

[0026] S2: After the baseline is stable, inject 0.1-0.5ul of air, n-pentane, n-hexane, n-heptane, and polar probe molecules in sequence, and observe and record the retention times t5, t6, t7, and t8 of n-pentane, n-hexane, n-heptane, and polar probe molecules, respectively. 极性 , and the time when the air peak appears, the time when the air peak appears is taken as the dead time t 空 ;

[0027] S3: subtracting the dead time from the retention time of each of n-pentane, n-hexadecane and n-heptane to obtain the adjusted retention time t5′, t6′ and t7′ of each of n-pentane, n-hexadecane and n-heptane, respectively; calculating the logarithmic values ​​lnt5′, lnt6′ and lnt7′ of the adjusted retention time of each of n-pentane, n-hexadecane and n-heptane according to t5′, t6′ and t7′; establishing a linear regression equation based on lnt5′, lnt6′, lnt7′ and the carbon atom numbers of each of n-pentane, n-hexadecane and n-heptane, and calculating the slope and intercept of the linear regression equation;

[0028] S4: Calculate the equivalent number of carbon atoms n representing the polar probe molecule 等效 , according to n 等效 , the retention time t of the polar probe molecule recorded in S2 极性 , the slope value and intercept value of the linear regression equation in S3, and the polar part of the Gibbs free energy of the polar probe molecule -ΔΔG are calculated;

[0029] S5: When the surface free energy polarity parameter of the corresponding polar probe molecule is calculated using the polar part of the Gibbs free energy of the polar probe molecule in S4, the relevant expression is as follows:

[0030]

[0031] In the formula, I SP represents the surface free energy polarity parameter of polar probe molecule, N A represents Avogadro's constant, α 极性 Represents the molecular cross-sectional area of ​​the polar probe molecule.

[0032] Preferably, in S1, when preparing a packed chromatographic column for the filler to be tested, the filler to be tested is filled into an empty packed column, and the inner diameter of the packed column is 2 to 5 mm, and the outer diameter is not limited.

[0033] Preferably, the filler to be tested is in powder form or particles smaller than 1 / 3 of the inner pore diameter of the filling column.

[0034] Preferably, the polar probe molecules in S2 need to be selected according to the filler to be tested.

[0035] Preferably, the polar probe molecule is acetone.

[0036] Preferably, in S3, when calculating the polar part of the Gibbs free energy -ΔΔG of the polar probe molecule, the relevant expression is as follows:

[0037] -ΔΔG=RT C {Lnt 极性 -n 等效 slope[Lnt(5,6,7),n(5,6,7)]-intercept[Lnt(5,6,7),n(5,6,7)]}

[0038] Where R represents the gas constant, T C Indicates the column temperature during the test; n 等效 Indicates the equivalent number of carbon atoms of the polar probe molecule. slope[Lnt(5,6,7),n(5,6,7)] indicates the slope of the linear regression equation of the logarithm of the adjusted retention time of n-pentaalkane, n-hexaalkane, and n-heptaalkane molecules and their respective carbon atom numbers. intercept[Lnt(5,6,7),n(5,6,7)] indicates the intercept of the linear regression equation of the logarithm of the adjusted retention time of n-pentaalkane, n-hexaalkane, and n-heptaalkane molecules and their respective carbon atom numbers. 极性 ' indicates the adjusted retention time of the polar probe molecule.

[0039] Preferably, when calculating the equivalent carbon atom number n of the polar probe molecule等效 The specific steps are as follows:

[0040] S41: Consult scientific literature to obtain the carbon atom number and cross-sectional area of ​​n-pentane, n-hexadecane, n-heptadecane, and polar probe molecules;

[0041] S42: Plotting with the carbon number of each of n-pentane, n-hexadecane and n-heptane as the abscissa and the molecular cross-sectional area of ​​each of n-pentane, n-hexadecane and n-heptane as the ordinate to obtain a linear graph and find a linear equation;

[0042] S43: Substitute the cross-sectional area of ​​the polar probe molecule into the equation of S42, and the number finally calculated is the equivalent carbon atom number n of the polar probe molecule 等效 .

[0043] The present invention introduces the equivalent carbon atom number n of the polar probe molecule into the rapid IGC method for determining the surface free energy polarity parameter. 等效 The concept of is as follows. First, the carbon atom number of n-alkane is taken as the horizontal coordinate and the molecular cross-sectional area of ​​n-alkane is taken as the vertical coordinate. After drawing a graph, it can be found that the molecular cross-sectional area of ​​each n-alkane is completely linearly related to its carbon atom number. After solving the linear regression equation, substituting the cross-sectional area of ​​the polar probe molecule into the equation can obtain a virtual carbon atom number. The virtual carbon atom number is the equivalent carbon atom number of the polar probe molecule. Its physical meaning is that the non-polar part of the Gibbs free energy of the adsorption and desorption process of the polar probe molecule on the filler surface is equivalent to the Gibbs free energy of adsorption and desorption of the n-alkane corresponding to the virtual carbon atom number.

[0044] The conventional IGC method uses a gas of known components to test the information of an unknown filler. That is, on a commonly used gas chromatograph, the chromatographic column is replaced, that is, the powder or small particle sample to be tested is loaded into the filling column (note that the filling mass and the specific surface area of ​​the filler must be determined in advance), and then the chromatographic column filled with fillers is installed on the gas chromatograph. Subsequently, the machine is turned on, the sample is injected, and the retention time of different probe molecules, the temperature of the chromatographic column, the pressure before the column, the pressure after the column and the carrier gas flow rate, a total of 13 parameters, are observed and recorded. Then, the principles of physical chemistry are used to calculate the adjusted retention volume, pressure correction factor, adsorption Gibbs free energy, and the polar part of the Gibbs free energy in turn, and finally the surface free energy polarity parameters are obtained.

[0045] The rapid IGC method also uses known gas components to determine the characteristics of unknown fillers, and also requires filling the sample to be tested into the chromatographic column, but the differences are: ① there is no need to determine the filling mass and specific surface area of ​​the sample to be tested in advance; ② there is no need to record parameters such as the pre-column pressure, post-column pressure and carrier gas flow rate, but only needs to record the retention time of different probe molecules and the chromatographic column temperature; ③ there is no need to calculate the adjusted retention volume, pressure correction factor and adsorption Gibbs free energy of each probe molecule, but the calculation formula re-derived by the newly established mathematical model is used to directly obtain the polar part of the Gibbs free energy, and then the surface free energy polarity parameters can be obtained.

[0046] The beneficial effects of the present invention are:

[0047] 1. Compared with the conventional IGC method, the present invention does not require the prior determination of the filling mass and specific surface area of ​​the sample to be tested.

[0048] 2. Compared with the conventional IGC method, the present invention does not need to record parameters such as column pre-pressure, column post-pressure and carrier gas flow rate, but only needs to record the retention time of different probe molecules and the chromatographic column temperature.

[0049] 3. Compared with the conventional IGC method, the present invention does not need to calculate the adjusted retention volume, pressure correction factor and adsorption Gibbs free energy of each probe molecule, but directly calculates the polar part of the Gibbs free energy using the calculation formula re-derived by the newly established mathematical model, and then obtains the surface free energy polarity parameter.

[0050] 4. The present invention simplifies the measurement steps, reduces the parameters required for measurement and recording, and provides a relatively fast measurement method for the polar part of surface free energy. Moreover, the calculation process of the invention is scientific and reasonable, and the accuracy of the measurement results is improved by establishing a linear regression equation. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 The figure is a schematic diagram of the steps of the method for quickly determining the surface free energy polarity parameters of the rubber reinforcing filler of the present invention. DETAILED DESCRIPTION

[0052] Example 1

[0053] A method for quickly determining the surface free energy polarity parameters of a rubber reinforcing filler comprises the following steps:

[0054] S1: Prepare a packed chromatographic column for the filler to be tested. When preparing a packed chromatographic column for the filler to be tested, fill the filler to be tested into an empty packed column. The inner diameter of the packed column is 2 to 5 mm, and the outer diameter is not limited. The filler to be tested is in powder form or particles smaller than one-third of the inner hole diameter of the packed column. Then install the prepared chromatographic column into the column box of the chromatograph, start the chromatograph and set the carrier gas flow rate and the column box temperature. When setting the carrier gas flow rate, the carrier gas flow rate is between 10 ml / min and 100 ml / min. Then closely observe the baseline generated during the operation of the chromatograph.

[0055] S2: After the baseline is stable, inject 0.1-0.5ul of air, n-pentane, n-hexane, n-heptane, and polar probe molecules in sequence. The polar probe molecules need to be selected according to the filler to be tested, and acetone is generally used. Then observe and record the retention times t5, t6, t7, t8 of n-pentane, n-hexane, n-heptane, and polar probe molecules. 极性 ; and subtract the dead time t 空 (time of air peak) and then the adjusted retention time of each alkane and polar probe molecule, i.e., t5′, t5′ and t5′, was obtained.

[0056] t6, t7, t 极性 ;

[0057] S3: According to t5′, t6′, and t7′, the logarithmic values ​​of the adjusted retention time of n-pentane, n-hexadecane, and n-heptane, lnt5′, lnt6′, and lnt7′, respectively, are calculated, wherein lnt5′ represents the logarithmic value of the adjusted retention time of n-pentane, lnt6′ represents the logarithmic value of the adjusted retention time of n-hexadecane, and lnt7′ represents the logarithmic value of the adjusted retention time of n-heptane. A linear regression equation is established based on lnt5′, lnt6′, lnt7′ and the carbon atom numbers of n-pentane, n-hexadecane, and n-heptane, and the slope and intercept values ​​of the linear regression equation are calculated;

[0058] S4: Calculate the equivalent number of carbon atoms n representing the polar probe molecule 等效 , the specific steps are as follows:

[0059] S41: Obtain the carbon atom number and cross-sectional area of ​​each of n-pentane, n-hexadecane, n-heptadecane, and the polar probe molecule by measurement or table lookup;

[0060] S42: Plotting with the carbon number of each of n-pentane, n-hexadecane and n-heptane as the abscissa and the molecular cross-sectional area of ​​each of n-pentane, n-hexadecane and n-heptane as the ordinate to obtain a linear graph and obtain a linear regression equation;

[0061] S43: Substitute the cross-sectional area of ​​the polar probe molecule into the equation, and the number finally calculated is the equivalent carbon atom number n of the polar probe molecule. 等效 .

[0062] In obtaining the equivalent carbon number n of the polar probe molecule 等效 Finally, the polar part of the Gibbs free energy of the polar probe molecule -ΔΔG needs to be calculated; the relevant expression is as follows:

[0063] -ΔΔG=RT C {Lnt 极性 -n 等效 slope[Lnt(5,6,7),n(5,6,7)]-intercept[Lnt(5,6,7),n(5,6,7)]}

[0064] Where R represents the gas constant, T C Indicates the column temperature during the test; n 等效 represents the equivalent carbon atom number of the polar probe molecule, intercept[Lnt(5,6,7),n(5,6,7)] represents the intercept value of the linear regression equation of the logarithm of the adjusted retention time of n-pentane, n-hexadecane, and n-heptadecane molecules and their respective carbon atom numbers, slope[Lnt(5,6,7),n(5,6,7)] represents the slope value of the linear regression equation of the logarithm of the adjusted retention time of n-pentane, n-hexadecane, and n-heptadecane molecules and their respective carbon atom numbers, t 极性 ' indicates the adjusted retention time of the polar probe molecule.

[0065] S5: When the surface free energy polarity parameter of the corresponding polar probe molecule is calculated using the polar part of the Gibbs free energy of the polar probe molecule in S4, the relevant expression is as follows:

[0066]

[0067] In the formula, I SP represents the surface free energy polarity parameter of polar probe molecule, N A represents Avogadro's constant, α 极性 Represents the molecular cross-sectional area of ​​the polar probe molecule.

[0068] Example 2

[0069] Taking furnace carbon black N375 as an example, acetone is used as the polar probe molecule, and the steps are as follows:

[0070] S1: Prepare a packed chromatographic column for the filler furnace carbon black N375 to be tested. When preparing a packed chromatographic column for the filler to be tested, fill the filler to be tested into an empty packed column. The inner diameter of the packed column is 2 to 5 mm, and the outer diameter is not limited. The filler to be tested is in powder form or particles less than one-third of the inner diameter of the packed column. Then install the prepared chromatographic column into the column box of the chromatograph, start the chromatograph and set the carrier gas flow rate and the column box temperature. When setting the carrier gas flow rate, the carrier gas flow rate is between 10 ml / min and 100 ml / min. Then closely observe the baseline generated during the operation of the chromatograph.

[0071] S2: After the baseline is stable, inject 0.1-0.5ul of air, n-pentane, n-hexane, n-heptane, and polar probe molecules in sequence. The polar probe molecules need to be selected according to the filler to be tested, and acetone is generally used. Then observe and record the retention times t5, t6, t7, t8 of n-pentane, n-hexane, n-heptane, and polar probe molecules. 极性 ; and after deducting the dead time (time of the air peak), the adjusted retention time of each alkane and polar probe molecule was obtained, namely t5′, t6′, t7′, t 极性 ′; that is, t5′=t5-t 空气 , and so on.

[0072] S3: According to t5′, t6′, t7′, the logarithmic values ​​of the adjusted retention time of n-pentane, n-hexadecane, and n-heptane, lnt5′, lnt6′, and lnt7′, respectively, are calculated, wherein lnt5′ represents the logarithmic value of the adjusted retention time of n-pentane, lnt6′ represents the logarithmic value of the adjusted retention time of n-hexadecane, and lnt7′ represents the logarithmic value of the adjusted retention time of n-heptane. Create a table in Excel, write two columns of data in the Excel table, the first column is the logarithmic values ​​of the adjusted retention time of n-pentane, n-hexadecane, and n-heptane, respectively, lnt5′, lnt6′, and lnt7′, and the second column is the number of carbon atoms of n-pentane, n-hexadecane, and n-heptane, respectively, and then use the formula provided by Excel to obtain the slope value and intercept value of the linear regression equation of these two columns of data.

[0073] S4: Calculate the equivalent number of carbon atoms n representing the polar probe molecule 等效 , the specific steps are as follows:

[0074] S41: Consult scientific literature to obtain the carbon atom number and cross-sectional area of ​​n-pentane, n-hexadecane, n-heptadecane, and polar probe molecules;

[0075] S42: Plotting with the carbon number of each of n-pentane, n-hexadecane and n-heptane as the abscissa and the molecular cross-sectional area of ​​each of n-pentane, n-hexadecane and n-heptane as the ordinate to obtain a linear graph and obtain a linear regression equation;

[0076] S43: Substitute the cross-sectional area of ​​the polar probe molecule into the equation, and the number finally calculated is the equivalent carbon atom number n of the polar probe molecule. 等效 .

[0077] In obtaining the equivalent carbon number n of the polar probe molecule 等效 Finally, the polar part of the Gibbs free energy of the polar probe molecule -ΔΔG needs to be calculated; the relevant expression is as follows:

[0078] -ΔΔG=RT C {Lnt 极性 -n 等效 slope[Lnt(5,6,7),n(5,6,7)]-intercept[Lnt(5,6,7),n(5,6,7)]}

[0079] Where R represents the gas constant, T C Indicates the column temperature during the test; n 等效 represents the equivalent carbon atom number of the polar probe molecule, intercept[Lnt(5,6,7),n(5,6,7)] represents the intercept value of the linear regression equation of the logarithm of the adjusted retention time of n-pentane, n-hexadecane, and n-heptadecane molecules and their respective carbon atom numbers, slope[Lnt(5,6,7),n(5,6,7)] represents the slope value of the linear regression equation of the logarithm of the adjusted retention time of n-pentane, n-hexadecane, and n-heptadecane molecules and their respective carbon atom numbers, t 极性 ' indicates the adjusted retention time of the polar probe molecule.

[0080] S5: When the surface free energy polarity parameter of the corresponding polar probe molecule is calculated using the polar part of the Gibbs free energy of the polar probe molecule in S4, the relevant expression is as follows:

[0081]

[0082] In the formula, I SP represents the surface free energy polarity parameter of polar probe molecule, N A represents Avogadro's constant, α 极性 Represents the molecular cross-sectional area of ​​the polar probe molecule.

[0083] Example 3

[0084] Taking furnace carbon black N375 as an example and acetone as a polar probe molecule, the following embodiments and comparative examples were obtained by using the rapid determination method for the surface free energy polarity parameters of a rubber reinforcing filler of the present invention and the conventional IGC method.

[0085] S1: First, sieve out small carbon black particles in the range of 30-60 mesh, and then load them into an empty stainless steel chromatographic column with an inner diameter of 2 mm and an outer diameter of 3 mm. The two ends of the column are sealed with quartz wool and steel wire respectively;

[0086] S2: Install the prepared chromatographic column containing the sample to be tested on the GC-17C chromatograph, first turn on the carrier gas, adjust the flow rate to about 9.7ml / min, then turn on the computer and chromatograph, and set the column box temperature to 180℃;

[0087] S3: After the temperature of the column box is stable, open the workstation software, start the baseline, and turn on the hydrogen and air at the same time, adjust the flow rate and ignition, and observe the baseline trend. The experiment can be carried out only after the baseline is flat;

[0088] S4: After the baseline is flattened, start injecting samples, and use a 0.5ul microinjector to inject air, n-pentane, n-hexadecane, n-heptadecane, and acetone probe molecules respectively;

[0089] S5: Observe the chromatographic peaks, record the peak time (retention time) of each probe molecule, and subtract the time of the air peak (dead time) from each chromatographic peak to obtain the adjusted retention time of all probe molecules;

[0090] S6: Using the linear regression equation between the cross-sectional area of ​​n-alkane molecules and their carbon number, the equivalent carbon number of acetone is obtained as 2.20588. This parameter is the only equivalent carbon number of acetone, so it can be determined before testing.

[0091] S7: According to the following calculation steps, the surface free energy polarity parameters of the N375 carbon black for the polar probe molecule acetone can be obtained in three steps;

[0092] (1) Calculate the logarithmic values ​​of the adjusted retention time of n-pentane, n-hexadecane, and n-heptane, i.e., lnt5′, lnt6′, and lnt7′, respectively; and calculate the logarithmic value of the adjusted retention time of acetone, lnt 丙酮 ′;

[0093] (2) The polar part of the Gibbs free energy is calculated using the new formula below:

[0094] -ΔΔG=RT C {Lnt 极性 -n 等效 slope[Lnt(5,6,7),n(5,6,7)]-intercept[Lnt(5,6,7),n(5,6,7)]};

[0095] (3) Finally, calculate the surface free energy polarity parameter,

[0096] After substituting various parameters, the surface free energy polarity parameter of N375 carbon black corresponding to the acetone probe molecule is 9.33×10 -2 J / m 2 .

[0097] Table 1 shows the molecular surface free energy polarity related parameters measured by the rapid determination method for surface free energy polarity parameters of a rubber reinforcing filler mentioned above in the present invention, with furnace carbon black N375 as the filler to be tested and acetone as the polarity probe:

[0098] Table 1 Surface free energy polarity parameters determined by the method of the present invention

[0099]

[0100]

[0101] Comparative Example 1

[0102] Table 2 shows the surface free energy polarity related parameters measured by conventional IGC method with furnace carbon black N375 as the filler to be tested and acetone as the polarity probe:

[0103] Table 2 Surface free energy polarity parameters determined by conventional IGC method

[0104]

[0105]

[0106] In summary, the measurement results obtained by the two test methods of Example 1 and Comparative Example 1 are the same. However, since the parameters that need to be tested and recorded by the rapid IGC method are reduced from 13 in the conventional IGC method to 6, the calculation steps during data processing are reduced from 13 to only 5, and the calculation process is simpler, the experimental workload and calculation load are greatly reduced, which is obviously more efficient and convenient.

[0107] On the basis of overcoming the rapid characterization method of dispersion free energy, the present invention successfully developed a rapid IGC method that can accurately and rapidly determine the surface free energy polarity parameters by reconstructing the mathematical model and using mathematical tools such as calculus, after more in-depth theoretical research and practical tests. The newly developed rapid IGC method reduces the recording parameters that need to be controlled and tested from 13 to 6, and the calculation steps from 13 to 5, eliminating the large amount of test time required for characterizing many parameters such as carrier gas flow rate, column front pressure, nitrogen adsorption specific surface area of ​​the sample and sample filling weight, and the test time is shortened from about 30 hours to less than 4 hours.

Claims

1. A method for rapidly determining the surface free energy polarity parameters of a rubber reinforcing filler, characterized in that: The following steps are involved: S1: Prepare a chromatographic column for the filler to be tested, install the prepared chromatographic column into the column box of the chromatograph, start the chromatograph and set the carrier gas flow rate and column box temperature, and observe the baseline generated during the operation of the chromatograph; S2: After the baseline is stable, inject 0.1-0.5ul of air, n-pentane, n-hexane, n-heptane, and polar probe molecules in sequence, and observe and record the retention times t5, t6, t7, and t8 of n-pentane, n-hexane, n-heptane, and polar probe molecules, respectively. 极性 The time when the air peak appears is taken as the dead time t 空 ; S3: Subtract the dead time from the retention time of n-pentane, n-hexadecane and n-heptane to obtain the adjusted retention time t5′, t6′ and t7′ of n-pentane, n-hexadecane and n-heptane, i.e., t5′=t5-t 空气 , and the rest are analogous, the logarithmic values ​​of the adjusted retention time of n-pentane, n-hexadecane, and n-heptane, lnt5′, lnt6′, and lnt7′, respectively, are calculated based on t5′, t6′, and t7′, a linear regression equation is established based on lnt5′, lnt6′, and lnt7′ and the carbon atom numbers of n-pentane, n-hexadecane, and n-heptane, respectively, and the slope value and intercept value of the linear regression equation are calculated; S4: Calculate the equivalent number of carbon atoms n representing the polar probe molecule 等效 , according to n 等效 , the adjusted retention time t of the polar probe molecule recorded in S2 极性 ′, that is, t 极性 ′=t 极性 -t 空气 , the slope and intercept values ​​of the linear regression equation calculated in S3 are used to calculate the polar part of the Gibbs free energy of the polar probe molecule -ΔΔG. The relevant expression is as follows: -ΔΔG=RT C {Lnt 极性 -n 等效 slope[Lnt(5,6,7),n(5,6,7)]-intercept[Lnt(5,6,7),n(5,6,7)]}; Where R represents the gas constant, T C Indicates the column temperature during the test; n 等效 represents the equivalent number of carbon atoms of the polar probe molecule, slope[Lnt(5,6,7),n(5,6,7)] represents the slope of the linear regression equation of the logarithm of the adjusted retention time of n-pentane, n-hexadecane, and n-heptane molecules and their respective carbon atoms, intercept[Lnt(5,6,7),n(5,6,7)] represents the intercept of the linear regression equation of the logarithm of the adjusted retention time of n-pentane, n-hexadecane, and n-heptane molecules and their respective carbon atoms, Lnt 极性 represents the adjusted retention time t of the polar probe molecule 极性 The logarithm of ′. S5: When the surface free energy polarity parameter of the corresponding polar probe molecule is calculated using the polar part of the Gibbs free energy of the polar probe molecule in S4, the relevant expression is as follows: In the formula, I SP represents the surface free energy polarity parameter of polar probe molecule, N A represents Avogadro's constant, α 极性 Represents the molecular cross-sectional area of ​​the polar probe molecule.

2. The method for rapidly determining the surface free energy polarity parameter of a rubber reinforcing filler according to claim 1, characterized in that: In the above S1, when preparing a packed chromatographic column for the filler to be tested, the filler to be tested is filled into an empty packed column. The inner diameter of the packed column is 2 to 5 mm, and the outer diameter is not limited.

3. The method for rapidly determining the surface free energy polarity parameter of a rubber reinforcing filler according to claim 1, characterized in that: In the above S1, the filler to be tested is in powder form or particles smaller than one third of the diameter of the inner hole of the filling column.

4. The method for rapidly determining the surface free energy polarity parameter of a rubber reinforcing filler according to claim 1, characterized in that: In the above-mentioned S1, when setting the carrier gas flow rate, the carrier gas flow rate is between 10 ml / min and 100 ml / min.

5. The method for rapidly determining the surface free energy polarity parameter of a rubber reinforcing filler according to claim 1, characterized in that: The polar probe molecules in S2 need to be selected according to the filler to be tested.

6. The method for rapidly determining the surface free energy polarity parameter of a rubber reinforcing filler according to claim 5, characterized in that: The polar probe molecule is any one of acetone, ethanol and acetonitrile.

7. The method for rapidly determining the surface free energy polarity parameters of a rubber reinforcing filler according to claim 1, characterized in that: In calculating the equivalent number of carbon atoms n of the polar probe molecule 等效 The specific steps are as follows: S41: Consult scientific literature to obtain the carbon atom number and cross-sectional area of ​​n-pentane, n-hexadecane, n-heptadecane, and polar probe molecules; S42: Plotting with the carbon number of each of n-pentane, n-hexadecane and n-heptane as the abscissa and the molecular cross-sectional area of ​​each of n-pentane, n-hexadecane and n-heptane as the ordinate to obtain a linear graph and find a linear equation; S43: Substitute the cross-sectional area of ​​the polar probe molecule into the linear equation of S42, and the number finally calculated is the equivalent carbon atom number n of the polar probe molecule 等效 .

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