Research On The Preparation And Flame-Retarding Performance Of Epoxy Modified With Expandable Graphite

In this paper, we research on the preparation and flame-retarding performance of Epoxy modified with expandable graphite. Flammabilities and thermal behaviors of added different usage of EG, added different size of the EG and added EG-APP of the cured resins were investigated by Limit Oxygen Index (LOI), Vertical Burning Test, Thermogravimetric Analysis (TGA).The flame-retardant mechanism of EG for epoxy resins was investigated by Scanning electron microscope (SEM).Results show that added EG of the cured resins, added EG-APP of the cured resins could improve of epoxy resins to a great extent respectively. When the add-on of EG(80mwsh) reaches 15wt%, the LOI of the cured resins increases from 20.2 to 29.4. When the add-on of EG(50mesh) reaches 15wt%, the LOI of the cured resins increases to 30.6. When the add-on of 7.5wt% EG(50mesh)-7.5wt%APP reaches 15wt%, the LOI of the cured resins increases to 37.2 and UL-94 reaches V-0 grade. EG(50mesh) have higher expansion ratio than EG(80mesh), when they are heated, EG(50mesh) can produce more compact and thick coal bed, so the retardant effectiveness will be better. In addition, with the addition of APP, the viscosity and compactness of the coal bed will be increased. The LOI value increases obviously, thermal decomposition rate is lowered and the thermo stability is enhanced, which suggests that EG/APP has synergistic flame-retarding function of compact, stable expandable charcoal layer.