Study on Epoxy Molding Compounds Modified by Novel Phosphorus-Containing Flame Retardant and OMMT

Abstract

In electronic packaging, epoxy molding compounds are frequently used for encapsulation and are required of flame retardancy, having a low total emission of heat and toxic fume when exposed to an ignition source, and having a high thermal stability. The article is on research of halogen-free flame-retardant modified epoxy molding compounds for electronic packaging. A phosphorus containing organic flame retardant is used as a novel reactive flame retardant intermediate named 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO), which is synthesized firstly by reacting phosphorous trichloride to o-phenylphenol with ZnCl2 as a catalyst, then hydrolysis and cyclization. The chemical structure of the obtained DOPO is characterized with IR, 1H, and so on. And it is used as the flame retardant to modify diglycidyl ether of bisphenol A (DGEBA) to prepare phosphorus containing epoxy resin. The mixture of glycidyl ether of cresol formaldehyde novolac and the phosphorus containing epoxy resin/montmorillonite nanocomposites is prepared at the presence of catalytic center between the galleries of the montmorillonite. With phenol novolac as a curing agent and at exist of a catalyst, the prepared nanocomposites is fully cured. Thermal properties of cured epoxy nanocomposites are characterized by using a thermogravimetry analysis (TGA) measurement. The flame retardancy of the nanocomposites is tested in UL-94 vertical test and limiting oxygen index (LOI). The results show that the epoxy molding compounds have excellent performances for the application in electronic packaging.