Epoxy Modified Polymethylpenylsiloxane Emulsions for Oil Agent in Carbon Fibers Production with Different Epoxy Content to Improve the Thermal Stability and Decrease the Surface Tension

A series of epoxy modified polymethylpenylsiloxane (EPMPS) emulsions for oil agent in carbon fibers production were synthesized with EPMPS resins and non-ionic emulsifier by phase inversion emulsification. The EPMPS resins with different epoxy content were prepared by non-hydrolytic sol–gel method. The influence of epoxy content on the chemical structure, molecular weight, surface tension and thermal stability of EPMPS resins were investigated by Fourier transform infrared (FTIR), gel permeation chromatography (GPC), contact angle meter and thermogravimetric analysis (TGA), respectively. The properties of EPMPS emulsions and their effects on polyacrylonitrile (PAN) precursor were investigated by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). It was found that the increase of epoxy content not only obviously decreased the molecular weight and surface tension of EPMPS, but also conduced to the processing of PAN precursor. With the decreasing of surface tension, the oil agent was easier to spread and film on the surface of PAN precursors. In addition, the TGA curves showed that the EPMPS resins had good thermal stability at low temperature and can be completed volatilized under high temperature conditions. Hence, the EPMPS emulsions could be used as oil agent for PAN precursors.