Preparation, flame retardancy, and thermal degradation of epoxy thermosets modified with phosphorous/nitrogen-containing glycidyl derivative

Phosphorus/nitrogen-containing advanced epoxy resins were obtained by chain-extension of the diglycidyl ether of bisphenol-A epoxy (DGEBA) resin with phosphorus-modified triglycidyl isocyanurate (TGICP). The structure of TGICP was characterized by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). Differential scanning calorimetry revealed that the EP/TGICP composites possessed higher glass transition temperatures than that of phosphorus free EP. The thermal stability and flame retardant properties of the epoxy resin/TGICP systems were investigated by thermogravimetric analysis (TGA), limiting oxygen index (LOI), and vertical burning test (UL-94) test. When the TGICP content was 10 wt%, the LOI value of epoxy resin system was as high as 35.0% and it can obtain the V-0 grade in UL-94 protocol. From microscale combustion calorimetry (MCC) measurement, it was found that the addition of TGICP reduced the value of peak heat release rate and total heat release. The thermal degradation process of EP and EP/TGICP composite was monitored by real time FTIR. Moreover, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to explore the morphology and chemical components of the char residues. Copyright (C) 2010 John Wiley & Sons, Ltd.