Structure characterization, reactivity, and thermal properties of new cyclic phosphine oxide epoxy resin containing tetra-oxirane rings

A new type of epoxy resin, which contained cyclic phosphine oxide and tetra‐oxirane rings in the main chain, was synthesized. The structure of the new type of epoxy resin was confirmed by elemental analyses (EA), infrared (IR) spectroscopy, and 1H nuclear magnetic resonance (NMR) and 13C‐NMR spectroscopies. In addition, compositions of the new synthesized cyclic phosphine oxide epoxy resin (TGCAO) with three curing agents, for example, bis(3‐aminophenyl)ethylphosphine oxide (BEMP), 4,4′‐diaminodiphenylmethane (DDM), and 4,4′‐diaminodiphenylsulfone (DDS) were used for making a comparison of its curing reactivity, heat, and flame retardancy with those of Epon 828 and DEN438. The reactivities were measured by differential scanning calorimetry. Through the evaluation of thermal gravimetric analysis, those polymers, which were obtained through the curing reactions between the new epoxy resin and three curing agents (BEMP, DDM, and DDS), also demonstrated adequate thermal propeties, as well as a high char yield. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 68: 1397–1409, 1998