What's the difference between gas phase white carbon black and precipitation white carbon black?

"The difference between gas-phase white carbon black and precipitation white carbon black? A: they use different raw materials and production processes Gas-phase white carbon black has high purity, small particle size and high structure, while precipitation white carbon black has high ion content and water content due to the limitations of its production process In addition, their appearance and surface chemical properties are also different The following is the specific chemical reaction equation of the two: precipitated white carbon black: fumed white carbon black: the factors that affect the properties of high temperature vulcanized silicone rubber? A: the factors that affect the properties of silicone rubber are the specific surface area, dosage and surface treatment of fumed white carbon black (the water content of white carbon black can affect its reinforcement, rheology and transparency, etc.) How to determine the hydroxyl group on the surface of white carbon black? A: the silicon hydroxyl number on the surface of silica is generally determined by infrared, lithium reagent and Karl Fisher reagent In addition, thermogravimetry can also be used The weight loss of silica can be divided into three stages: the first stage is room temperature - 190 ℃, the loss of free adsorbed water, the second stage is 190-917 ℃, the loss of adsorbed water forming hydrogen bond with silicon hydroxyl, and the third stage is 917-1320 ℃, What is lost is the water formed by condensation of hydroxyl groups According to the weight loss data, the number of surface hydroxyl groups can be calculated, and the test unit is generally expressed in (PCS / Nm2) The surface treatment of fumed silica and the type of treatment agent? A: the surface treatment of fumed silica is to use certain chemicals to react with the hydroxyl groups on the surface of silica through certain processes, so that the treatment agent can be connected to the surface of silica in the form of chemical bond to obtain permanent surface properties Generally, the treatment methods include heating the white carbon black together with the treatment agent to make the treatment agent boil (also called wet process) and contacting and reacting the dry white carbon black pretreatment agent with steam (also called dry process) At present, most of the foreign companies adopt dry continuous treatment The disadvantage of wet method is that the separation and purification of products are difficult, the cost is high, and the pollution is serious The surface treatment agents used generally include organosilicon compounds, alcohols, amines and polymer grafting modification.