The carbon black disperser is mainly used to test the dispersion effect of carbon black in different media. It is commonly used in industries such as rubber, plastics, inks, coatings, etc. to evaluate the dispersion of carbon black in these materials. The dispersibility of carbon black directly affects the performance of the final product, including color, luster, wear resistance, aging resistance, etc.
The testing methods for carbon black dispersers generally include the following:
1. Dispersion Degree Test
Dispersion is an important indicator for evaluating the dispersion effect of carbon black in matrix materials. The testing method is usually determined by measuring the size and distribution of carbon black particles in the sample.
Method:
Mix carbon black with solvents (such as rubber matrix, ink solvent, etc.) and use a carbon black disperser to stir and disperse.
Observe the dispersed sample under a microscope and analyze the size and distribution of carbon black particles. The more evenly dispersed the particles, the better the dispersion effect.
The distribution of carbon black particles is measured using a particle size analyzer, usually using laser particle size analysis or resistance particle size analysis.
2. Dispersion Index
The dispersion index is a quantitative indicator for measuring the uniformity of carbon black dispersion. This testing method is usually determined by calculating the particle size distribution of carbon black particles and the standard deviation of the sample.
Method:
Mix carbon black and matrix using a disperser.
Obtain the particle size distribution of carbon black particles through laser particle size analyzer or image analysis software.
The dispersion index is calculated by the standard deviation of the distribution width and particle size of the particles. The smaller the index, the better the dispersion effect.
3. Visual Assessment
This is a simple testing method that usually uses artificial vision to observe the dispersion effect of carbon black and determine whether there is a significant agglomeration phenomenon.
Method:
Compare the mixed sample with the surface of the raw material and visually inspect the dispersion of carbon black. Standardized views usually display whether there are agglomeration, clumping, and other phenomena.
In some cases, using a microscope can provide a more detailed observation of the dispersed state.
4. Transmittance or Glossiness Measurement
Changes in transparency or glossiness are usually caused by uneven dispersion of carbon black particles. Transparency testing is commonly used in industries such as ink and coatings, while glossiness testing is commonly used for testing rubber and plastic products.
Method:
By measuring the transmittance of the sample, calculate its deviation from the standard sample (such as a completely dispersed sample). Low transparency usually indicates uneven dispersion of carbon black.
For glossiness testing, well dispersed carbon black will make the final product surface smoother and have higher glossiness, while the opposite will result in lower glossiness.
5. Dispersion Time Test
Dispersion time refers to the time it takes for carbon black to completely disperse into the matrix. This test can reflect the difficulty level of carbon black dispersion. The faster the dispersion, the easier it is for carbon black particles to disperse.
Method:
Run the sample on the disperser and record the time required for the dispersion of carbon black particles. Use appropriate tools such as viscometers and rotational shear rheometers to test the dispersion state of carbon black at different time points.
The shorter the time, the better the dispersion effect.
6. Particle Morphology and Aggregation Evaluation
This test evaluates the dispersion effect by observing the morphology and agglomeration of carbon black particles under a microscope.
Method:
Observe the dispersed carbon black particles using scanning electron microscopy (SEM) or transmission electron microscopy (TEM) to examine their morphology and the presence of particle agglomeration.
Agglomerated carbon black particles will appear as large irregular particles, while well dispersed samples will show uniform and independent particles.
7. Viscosity Measurement
The dispersion degree of carbon black affects the viscosity of materials, especially in inks, coatings, and rubber. Poor dispersion of carbon black can lead to higher viscosity. By measuring the viscosity of carbon black dispersions of different concentrations, the dispersion effect can be determined.
Method:
Measure the viscosity of carbon black solution at different speeds using a rotational viscometer (such as Brookfield viscometer) or rheometer. Well dispersed carbon black usually leads to lower viscosity, while carbon black with more severe agglomeration can lead to increased viscosity.
8. Laser Diffraction Method
Laser particle size analysis is a common high-precision method for measuring the dispersion state, which can accurately evaluate the particle size distribution of carbon black particles.
Method:
Add the carbon black sample to an appropriate solution and measure the particle size distribution of the carbon black particles using a laser particle size analyzer.
Samples with good dispersion exhibit a narrower particle size distribution, while samples with poor dispersion exhibit a wider particle size distribution.
summary
The testing methods of carbon black disperser mainly include dispersion testing, dispersion index, visual evaluation, transmittance/glossiness testing, dispersion time testing, particle morphology and agglomeration evaluation, viscosity measurement, and laser particle size analysis. Through these tests, the dispersion effect of carbon black can be comprehensively evaluated, providing a basis for subsequent product development.