The Polymer Society of Korea

Abstract

Despite their excellent mechanical strength and thermal stability, epoxy resins are limited in advanced applications because of their intrinsic flammability. In this study, ammonium polyphosphate (APP) and pentaerythritol (PER) were microencapsulated via a TEOS-based sol–gel process to synthesize silica-microencapsulated intumescent flame retardant (MCIFR). The microcapsules were surface-functionalized with (3-aminopropyl)triethoxysilane (APTES) to enhance interfacial compatibility with an epoxy matrix. The MCIFR was physically dispersed into diglycidyl ether of bisphenol A (DGEBA) and cured with diaminodiphenylmethane (DDM) to fabricate hybrid epoxy composites. During combustion, the MCIFR containing composites formed an expanded char layer that effectively restricted heat and oxygen transfer, resulting in improved flame retardancy. The structure, thermal properties, and flame-retardant performance of the composites were evaluated using various analytical techniques.