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CN-121994670-A - Method for testing CTAB specific surface area of carbon black

CN121994670ACN 121994670 ACN121994670 ACN 121994670ACN-121994670-A

Abstract

The invention provides a method for testing the CTAB specific surface area of carbon black. The test method comprises the steps of sequentially carrying out first mixing and solid-liquid separation on a carbon black sample and a cetyltrimethylammonium bromide solution to obtain a first mixture, titrating the non-adsorbed cetyltrimethylammonium bromide in the first mixture to an end point by adopting a sodium dioctyl sulfosuccinate solution, recording the consumed volume, carrying out solid-liquid separation including centrifugation and multistage filtration, establishing a calculation formula of CTAB specific surface area of the carbon black sample as S= -S 0 ×（V 0 -V)/(b multiplied by m), carrying out the steps on a carbon black to-be-tested product with unknown CTAB specific surface area to obtain a volume test value of sodium dioctyl sulfosuccinate corresponding to the carbon black to-be-tested product, and substituting the volume test value and the mass into the calculation formula to calculate, thereby obtaining the CTAB specific surface area of the carbon black to-be-tested product. The test method is safe and reliable, is easy to operate, and has high accuracy and good repeatability of the test result.

Inventors

  • SHENG LIPING
  • ZHANG YANLING
  • LIU XUEJIAO

Assignees

  • 思通检测技术有限公司

Dates

Publication Date
20260508
Application Date
20260120

Claims (10)

  1. 1. A method for testing the CTAB specific surface area of carbon black, comprising: Step S1, sequentially carrying out first mixing and solid-liquid separation on a carbon black sample and a cetyl trimethyl ammonium bromide solution to obtain a first mixture, titrating the non-adsorbed cetyl trimethyl ammonium bromide in the first mixture to an end point by adopting a sodium dioctyl sulfosuccinate solution, and recording the volume of the consumed sodium dioctyl sulfosuccinate solution; Step S2, when the carbon black sample is n industrial reference carbon blacks with different masses and known CTAB specific surface areas, the industrial reference carbon blacks pass through the step S1 to obtain the volume test values of the dioctyl sodium sulfosuccinate solutions corresponding to the industrial reference carbon blacks, the mass of the industrial reference carbon blacks is taken as an abscissa, the volume test values of the dioctyl sodium sulfosuccinate solutions are taken as an ordinate, and a calibration curve is drawn to obtain a linear regression equation, wherein n is more than or equal to 3; step S3, a calculation formula of CTAB specific surface area of the carbon black sample is established as S= -S 0 ×（V 0 -V)/(b multiplied by m), wherein S 0 is a CTAB specific surface area standard value of industrial reference carbon black, V 0 is a longitudinal intercept of the calibration curve, b is a slope of the calibration curve, V is a volume of consumed sodium dioctyl sulfosuccinate corresponding to the carbon black sample, and m is a mass of the carbon black sample; and S4, when the carbon black sample is a carbon black to-be-detected product with unknown CTAB specific surface area, the carbon black to-be-detected product passes through the step S1 to obtain a volume test value of sodium dioctyl sulfosuccinate corresponding to the carbon black to-be-detected product, and the volume test value of the sodium dioctyl sulfosuccinate and the mass of the carbon black to-be-detected product are substituted into the calculation formula in the step S3 to calculate, so that the CTAB specific surface area of the carbon black to-be-detected product is obtained.
  2. 2. The test method according to claim 1, wherein in the step S1, the carbon black sample is a dried carbon black sample, the drying temperature is 125 ℃, and the drying time is 1-3 hours; The ratio of the mass of the dried carbon black sample to the volume of the cetyltrimethylammonium bromide solution was 0.01g/mL; and/or, the molar concentration of the cetyltrimethylammonium bromide solution is 0.01mol/L; And/or the molar concentration of the dioctyl sodium sulfosuccinate solution is 0.0022mol/L.
  3. 3. The test method according to claim 1 or 2, wherein in the step S1, the first mixing mode is oscillation, the first mixing time is 30-45 min, and the frequency of the oscillation is 200-300 r/min; And/or the step S1 further comprises adding a titration auxiliary solution and water into the first mixture to perform titration, wherein the volume ratio of the first mixture to the titration auxiliary solution to the water is 5:15:15-40, and the titration auxiliary solution is octyl phenyl polyoxyethylene ether solution; And/or monitoring the moment of the end point by using a turbidity meter, and recording the volume of the consumed dioctyl sodium sulfosuccinate solution.
  4. 4. A test method according to any one of claims 1 to 3, wherein in step S1, the centrifugation time is 20 to 60min, and the rotational speed of the centrifugation is 4000 to 9000r/min.
  5. 5. The method according to any one of claims 1 to 4, wherein the filtration is performed using a filter membrane having a pore size that decreases in order with an increasing number of filtration steps, and/or a pore size of 0.05 to 0.25 μm, and a pressure of 0.1 to 0.5mpa.
  6. 6. The test method according to claim 5, wherein the multi-stage filtration comprises a first stage filtration, a second stage filtration and a third stage filtration performed in this order, wherein the first stage filtration is performed by using a filter membrane having a pore size of 0.22 to 0.25 μm, the second stage filtration is performed by using a filter membrane having a pore size of 0.1 to 0.15 μm, and the third stage filtration is performed by using a filter membrane having a pore size of 0.05 to 0.08 μm.
  7. 7. The method according to any one of claims 1 to 6, wherein in the step S2, the mass of the industrial reference carbon black is 0.1 to 1.5g, and/or the n is 3 to 8.
  8. 8. The test method according to any one of claims 1 to 7, wherein in the step S3, the industrial reference carbon black is of model ITRB and/or IRC4#, when the industrial reference carbon black is of model ITRB, the S 0 is 83.0 x10 3 m 2 /kg, and when the industrial reference carbon black is of model IRC4#, the S 0 is 78.5 x10 3 m 2 /kg; And/or V 0 is 22.102-22.502, and b is-15.050 to-15.554.
  9. 9. The method according to any one of claims 1 to 8, wherein in the step S4, the brand of the carbon black to be measured is selected from any one or more of N100 series, N200 series, N300 series, N500 series, N600 series and N700 series, the NSA specific surface area of the carbon black to be measured is 20 x 10 3 ~151×10 3 m 2 /kg, and the mass of the carbon black to be measured is 0.28 to 1.37g.
  10. 10. The test method according to claim 9, wherein when the brand of the carbon black to be tested is N100 series and the NSA specific surface area of the N100 series is 125 x 10 3 ~151×10 3 m 2 /kg, the mass of the carbon black to be tested is 0.28 to 0.32g; And/or when the brand of the carbon black to be measured is N200 series and the NSA specific surface area of the N200 series is 97 multiplied by 10 3 ~129×10 3 m 2 /kg, the mass of the carbon black to be measured is 0.33-0.37 g; And/or when the brand of the carbon black to be measured is N300 series and the NSA specific surface area of the N300 series is 75 multiplied by 10 3 ~103×10 3 m 2 /kg, the mass of the carbon black to be measured is 0.38-0.42 g; and/or when the brand of the carbon black to be measured is N500 series or N600 series, and the NSA specific surface areas of the N500 series and the N600 series are respectively and independently 27 multiplied by 10 3 ~45×10 3 m 2 /kg, the mass of the carbon black to be measured is 0.88-0.92 g; and/or when the brand of the carbon black to be measured is N700 series and the NSA specific surface area of the N700 series is 20 multiplied by 10 3 ~39×10 3 m 2 /kg, the mass of the carbon black to be measured is 1.33-1.37 g.

Description

Method for testing CTAB specific surface area of carbon black Technical Field The invention relates to the technical field of rubber, in particular to a method for testing CTAB specific surface area of carbon black. Background Carbon black is a reinforcing agent and a coloring agent commonly used for tires, and the characterization of carbon black raw materials and recovered carbon black is of great significance. The reinforcing effect of carbon black on rubber generally considers the accessibility of the surface of carbon black aggregate to rubber molecules, and accessibility is mainly influenced by the fact that on one hand, carbon black aggregate has micropores with smaller size, but rubber molecular chains cannot enter the micropores, and on the other hand, the surface of the carbon black aggregate is rough, and larger rubber molecular chains cannot contact the concave surface of the rough surface, so that the concave surface of the rough surface of the carbon black and the inside of the carbon black hole cannot play a role in reinforcing. Thus, the use of cetyltrimethylammonium bromide (CTAB) adsorption surface area can characterize the smooth surface area of the carbon black, thereby more effectively reflecting the reinforcing properties of the carbon black. The principle of testing the smooth specific surface area of carbon black by the CTAB method is that the CTAB molecules are quite large and cannot be adsorbed on the inner surfaces of micropores of the carbon black, so that the CTAB specific surface area can reflect the effective contact area of the carbon black and rubber molecules. The isothermal adsorption line of carbon black in aqueous CTAB solution has a longer flat section of single molecule adsorption layer. The adsorption of CTAB by carbon black is not affected by tar-like substances or functional groups containing hydrogen, oxygen and the like on the surface of the CTAB, and the adsorption can be quickly balanced by a mechanical stirring or ultrasonic vibration method. After filtering off the colloidal dispersion of carbon black, the amount of unadsorbed CTAB was titrated with sodium dioctyl sulfosuccinate (OT). Experimental results the CTAB specific surface area was determined for either an industrial colored reference carbon black ITRB or an industrial reference carbon black (irc4 #). However, the existing method for testing the CTAB specific surface area of the carbon black has the problems that the repeatability of test results is poor, the carbon black and the CTAB solution are difficult to separate, formaldehyde solution is required to be added in the preparation of the OT standard solution, and the environment and personnel are easy to be damaged. Therefore, there is a need to develop a new carbon black CTAB specific surface area test method. Disclosure of Invention The invention mainly aims to provide a method for testing the CTAB specific surface area of carbon black, which aims to solve the problems that in the prior art, the CTAB specific surface area of carbon black is difficult to separate from a CTAB solution, so that the repeatability of a test result is poor, and an OT standard solution is not environment-friendly. In order to achieve the above object, according to one aspect of the present invention, there is provided a method for testing a CTAB specific surface area of carbon black, the method comprising the steps of S1, subjecting a carbon black sample and a cetyltrimethylammonium bromide solution to a first mixing and a solid-liquid separation in order to obtain a first mixture; titration of non-adsorbed cetyltrimethylammonium bromide in a first mixture by adopting a sodium dioctyl sulfosuccinate solution until the end point, recording the volume of the consumed sodium dioctyl sulfosuccinate solution, solid-liquid separation comprising sequentially performing centrifugation and filtration, wherein the filtration is multistage filtration, the sodium dioctyl sulfosuccinate solution is sodium dioctyl sulfosuccinate and water, step S2, when a carbon black sample is n industrial reference carbon blacks with different qualities and known CTAB specific surface area, the industrial reference carbon black passes through step S1 to obtain the volume test value of the sodium dioctyl sulfosuccinate solution corresponding to the industrial reference carbon black, the mass of the industrial reference carbon black is taken as an abscissa, a calibration curve is drawn by taking the volume test value of the sodium dioctyl sulfosuccinate solution as an ordinate, a linear regression equation is obtained, the linear regression equation is y=bx+V 0, wherein n is more than or equal to 3, step S3, a calculation formula for establishing the B specific surface area of the carbon black sample is S= -S 0×（V0 -V b x m, wherein S 0 is the industrial reference carbon black, the mass of the industrial reference carbon black is CTAB specific surface area is CTAB, the mass of the calibration curve is