Preparation of silica encapsulated carbon black with high thermal stability

A silica encapsulated carbon black has been prepared by a modified emulsion polymerization. After firing above 1000 °C, the product shows high oxidation resistance up to 1200 °C and good stability in frit glaze at 950 °C. The intrinsic mechanism for the high thermal stability is investigated by various techniques. SEM and TEM results show that carbon black nanoparticles are encapsulated by compact amorphous silica and an embedded structure is formed. XPS and FTIR analyses indicate that CSiO chemical bonds are present between carbon black and amorphous silica. The embedded structure with strong bonding can separate the carbon black from the outside, reduce the negative effects of mismatch in thermal expansion and thus improve the thermal stability of carbon black.