Abstract
In this study, a commercial epoxy resin was mixed with a phosphorus-containing oligomer and thermally cross-linked using a mixture of two aliphatic amines as curing agents. The miscibility and the influence of the phosphorus-containing oligomer on the characteristics of epoxy thermosets were investigated by scanning electron microscopy (SEM), thermogravimetric analysis, differential scanning calorimetry, and dynamic mechanical analysis. SEM revealed that phosphorus-containing oligomer was well dispersed into the epoxy matrix. Dynamic mechanical analysis indicated an increase in storage modulus as the phosphorus-containing oligomer content loaded into epoxy matrix increased. Thermogravimetric analysis showed that the onset temperature of phosphorus-containing epoxy thermosets and the peak corresponding to the temperature of decomposition decreased compared with the ones corresponding to the neat epoxy system, whereas the char yield increased with the increase in phosphorus content added into the epoxy networks. To better understand the mechanism of action of phosphorus-containing epoxy thermosets, the char residue was investigated by SEM and energy-dispersive X-ray spectroscopy. (C) 2014 Wiley Periodicals, Inc.