XPS STUDY OF THE HALOGENATION OF CARBON-BLACK .2. CHLORINATION

Three furnace carbon blacks, a thermal black, and an electrically conductive sample were submitted as received to chlorination, at 450 degrees C, with a mix of chlorine and carbon tetrachloride vapors. The treated samples were examined using chemical and spectroscopic (XPS) methods. The interpretation of the XPS spectra is facilitated by comparison with spectra of reference materials. XPS detects various types of carbon-chloride bonds formed essentially by addition or hydrogen substitution processes. The amount of fixed chlorine is dependent on the origin of the blacks, and there is no direct relationship between specific surface area and chlorine uptake. It is shown that chlorination is not limited to the external surface, nor is it to a sub-superficial layer. In fact, it proceeds inside the carbon black particles to a depth depending on their origin.