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

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-10phosphaphenanthrene-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