A novel siliconized epoxy matrix resin coating was developed by reacting diglycidyl ethers of bisphenol A (DGEBA) type epoxy resin with hydroxyl terminated polydimethylsiloxane modifier, using g-aminopropyltriethoxysilane crosslinker and dibutyltindilaurate catalyst. The siliconized epoxy resin was cured with 4, 4-diaminodiphenylmethane (DDM), DOPO-diamine (DOPO-2NH2), and Polyhedral oligomeric silsesquioxane amine (POSS-amine).

 The DOPO-diamine and POSS-amine cured epoxy and siliconized epoxy resins exhibit better flame retardant behaviour than DDM and cured resins. The thermal stability and flame retardant property of the cured epoxy resins were studied by thermal gravimetric analysis (TGA) and limiting oxygen index (LOI). The glass transition temperatures (Tg) were measured by differential scanning calorimetry (DSC) and the surface morphology was studied by scanning electron microscope (SEM). The heat deflection temperature (HDT) and moisture absorption studies were carried out as per ASTM standards. The thermal stability and flame retardant properties of the cured epoxy resins were found to be improved by the incorporation of both silicone and phosphorus into the epoxy skeleton. The synergistic effect of silicone and phosphorus enhanced the limiting oxygen index values that were observed for siliconized epoxy resins cured with phosphorus containing diamine compounds.

Key words: siliconized epoxy resin, epoxy resin, curatives, thermal stability, flame retardancy and limiting oxygen index

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