Carbon black is the colorant, anti ultraviolet aging agent and anti-static agent of plastics. With the development of plastic industry, carbon black is used more and more in plastic industry. From ordinary daily plastic to high-grade engineering plastic, carbon black is indispensable. Compared with carbon black used in rubber industry, carbon black used in plastics is not much, but it has a great impact on the performance of plastics. Therefore, the performance requirements of carbon black used in plastics are more stringent. Different plastic products for different purposes have different requirements on the performance of carbon black. Now carbon black should be used as an introduction in plastics.
Physical properties of carbon black particles
Transmission electron microscope with automatic image analysis technology can be used to test the particle size, aggregate size, shape and distribution of carbon black. When transmission electron microscopy is applied to multiple images of carbon black aggregates, the three-dimensional structure of the aggregates can be seen. By rotating the collective structure of carbon black with the goniometer on the transmission electron microscope, it can be found that the appearance of the collective is different at different angles.
We can build three-dimensional images of aggregates through the images of aggregates from different angles. In a word, we can see that the aggregate with high structure carbon black is bigger and more complex than that with low structure carbon black by rotating. At the same magnification, the images tested by TEM and the 3D images simulated by computer are shown in Figure 1. From the simulation image on the right, although the image is two-dimensional, we can clearly feel the three-dimensional image of the aggregate; and through observation, we can understand the spatial relationship between carbon black particles. In addition, such model images can be rotated as needed to observe and measure carbon black aggregates. With the development of 3D image analysis technology, the future 3D analysis technology will give a satisfactory explanation of how the aggregate structure affects the application performance.
Dispersion stability of carbon black
The purpose of carbon black dispersion is to meet the customer's requirements for the performance of plastic products; however, the dispersion and stability of carbon black sometimes can not meet the requirements, which will affect the performance of plastic products. Let's analyze some common problems.
(1) "Flocculation", "coarsening" and "agglomeration" are common dispersion problems in pigment paste. They are caused by Brownian motion between carbon black particles. To achieve ideal dispersion, it depends on the improvement of dispersion equipment, the application of additives and the application of other technologies.
(2) The dispersion of pigment paste is not good, which leads to the decrease of blackness, brown color and poor luster of plastic products. These problems can be solved by increasing the dispersion, adjusting the filling amount of carbon black, increasing the mixing time and improving the mixing conditions.
(3) The high viscosity of plastics is related to the excessive addition of carbon black, which may lead to overheating of plastics. High temperature will cause adverse reactions to thermosensitive polymers, resulting in overheating of the system, resulting in gel production, and will also reduce the dispersion quality and stability of the carbon black.
Therefore, reducing the amount of carbon black or controlling the appropriate temperature is helpful to reduce the problem. With the development of plastic industry, the requirement of carbon black is higher and higher. As a carbon black production enterprise, we must keep pace with the development of plastic industry, make continuous innovation in the quality, product performance and application performance of carbon black, so that the quality of carbon black can better meet the development needs of plastic industry.
