What are the performance indicators of carbon black?

Particle size

The particle size of carbon black represents the original particle size of carbon black. It is tested by an electron microscope and is the average value of a certain number of particle sizes.

Tinting power

Also known as tinting intensity. It is the coloring ability of carbon black when white or colored pigments are mixed with carbon black. That is, the degree to which carbon black increases the light absorption of the mixture. It is usually expressed as a percentage and can be measured by measuring the carbon black dilute colorant using a blackness reflectometer.

Specific surface area

The specific surface area of carbon black refers to the total surface area of carbon black particles per unit mass or unit volume, and the unit is m2/g. Specific surface area, like particle size, is one of the basic properties of carbon black. Generally speaking, the specific surface area of carbon black with a relatively smooth surface (such as carbon black for rubber) is inversely proportional to the particle size, that is, the smaller the particle size, the greater the specific surface area, and vice versa. Therefore, if carbon black particles are assumed to be spherical, the specific surface area can be calculated from the particle size data.

The specific surface integral of carbon black is the external specific surface area (or smooth specific surface area), the internal specific surface area (or the specific surface area within the pores) and the total specific surface area. The total specific surface area is equal to the sum of the external specific surface area and the internal specific surface area. There are many methods to measure the specific surface area. Commonly used methods include nitrogen adsorption method (BET method), iodine absorption value method, CTAB method (macromolecule adsorption method), t value method and electron microscope method.

DBP absorption value

The structure of carbon black can be measured using DBP (dibutyl phthalate) absorption. According to experience, in low-structure pigment carbon black, the DBP absorption value per 100g of carbon black should not be higher than 70ml; while in high-structure pigment carbon black, the DBP absorption value per 100g of carbon black should not be less than 110ml. Medium structure carbon black is somewhere in between. The structure has a substantial impact on the applicability of pigment black.

PH value

The pH value is related to the number of surface functional groups. Furnace carbon black has few surface functional groups and a small amount of soluble salts, so the carbon black itself is mostly neutral or alkaline. In order to improve the viscosity, stability and fluidity of carbon black, some pigmented carbon blacks can be surface treated to change the number of surface functional groups to become acidic.

Density

The weight of carbon black per unit volume is: (g/L), which represents the size of the space occupied by various types of carbon black. The larger the granulation size, the greater the density, and vice versa. The granulation size has an important impact on the carbon black. The dispersion has an impact.