Carbon black surface area definition - Database & Sql Blog Articles

Carbon black is a fine particulate material formed during the incomplete combustion of carbon-based fuels such as coal, petroleum, and biomass. Once released into the atmosphere, it absorbs sunlight and reduces the amount of solar radiation that reaches the Earth's surface. It is a black, powdery substance created through the partial combustion or pyrolysis of hydrocarbons in a controlled gas-phase environment. Its primary composition is elemental carbon, with small amounts of oxygen, hydrogen, and sulfur present. The particles of carbon black are generally spherical in shape, ranging in size from 10 to 500 micrometers. Many of these particles tend to aggregate, forming three-dimensional structures that resemble bonds or fibrous networks. In the rubber industry, carbon black is widely used as a reinforcing agent and filler, enhancing the mechanical properties of the rubber compound. As one of the oldest industrial materials, carbon black has been utilized for centuries across various applications, including rubber, paint, and ink production. One of the key properties used to classify and identify different types of carbon black is its surface area. This is typically measured using gas adsorption methods, with the most common being the low-temperature nitrogen adsorption method (BET method). The BET technique provides an accurate measurement of the total surface area, including both external and internal surfaces. In recent years, macromolecular adsorption techniques like CTAB (Cetyl Trimethyl Ammonium Bromide) have also gained attention. Unlike nitrogen, which can penetrate micropores, CTAB molecules are larger and cannot enter these pores, thus measuring only the external surface area. For most rubber-grade carbon blacks, which are non-porous, the results from BET and CTAB methods are often similar. However, for some pigment-grade carbon blacks, the difference between the two methods reflects the degree of porosity or roughness on the surface. Another commonly used method is the iodine absorption test, which is simple and fast but can be influenced by the oxidation level of the carbon black surface. When determining the specific surface area of carbon black, the BET method measures the total surface area (NSA), which includes both the outer surface area (STSA) and the inner surface of micropores. These micropores typically range in size from 2 to 50 nm. For rubber reinforcement applications, since rubber molecules are too large to enter the micropores, the external surface area becomes more critical in evaluating the performance of carbon black. The CTAB method was introduced in 1971 as an alternative approach to measure the external surface area. However, due to the size of CTAB molecules (approximately 61.6 angstroms), they cannot access the micropores, making this method suitable for measuring only the accessible external surface. Some carbon black particles may have medium-sized pores, ranging from 20 to 500 angstroms. In such cases, CTAB molecules can penetrate, while rubber molecules still cannot. Despite this, the CTAB method is not widely accepted due to its manual nature and lower accuracy. Additionally, the stability of the CTAB solution over time significantly affects the test results, requiring periodic preparation and calibration. To address these challenges, the t-method was developed in 1965 by J.H. de Boer. This method calculates the external surface area based on the statistical thickness of the adsorption layer. By plotting the relationship between the adsorbed nitrogen volume and the thickness of the adsorption layer, the external surface area can be determined accurately. Today, the national standard GB/T 10722-2003 outlines the procedure for determining the total and external surface areas of carbon black using the nitrogen adsorption method. Advanced instruments like the Jingbo Gaobo dual-site surface area analyzer are designed to meet these standards, offering high repeatability (1.5%) and precision, making them ideal for the carbon black industry.

Harvester Guide Rail

Harvester Guide Rail,Harvester Conveyor Belts,Manure Spreader Accessories,Heavy Duty Clutch Plates

Changzhou Youeryou Trading Co., Ltd. , https://www.farmpartssupplier.com