A Comparative Investigation of Surface Modification of Carbon Black and Silica by Plasma Polymerization

Abstract

Abstract Carbon black and silica are widely used active fillers in the rubber industry to improve the physical and dynamic properties of rubbers. The surface energy difference between rubbers and these active fillers is large, which has a negative influence on the stability of their dispersion in the rubber matrix and on the distribution in blends of different rubbers. Reduction of the surface energy of carbon black and silica is aimed for by modifying their surfaces. Plasma polymerization is utilized to modify the surface of carbon black and silica by depositing a thin film over its surface. The modified fillers are characterized using thermogravimetric analysis (TGA), x-ray photoelectron spectroscopy (XPS) and time of flight secondary ion mass spectroscopy (ToF-SIMS). The studies show that carbon black and silica behave differently towards surface modification by plasma polymerization. The difference in behavior of carbon black and silica is related to the availability of active sites on their surface during exposure to the plasma atmosphere. In this paper the mechanistic aspects of surface modification by plasma polymerization are also discussed.