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A novel phosphorus, nitrogen-containing compound, poly(4, 4′-diaminodiphenyl methane phenyl dichlorophosphate) (PDMPD) with high thermal stability was synthesized. The PDMPD was then incorporated into polystyrene (PS) to be used as halogen-free flame retardant. Moreover, small amounts of two boron-containing compounds, Zinc borate (ZnB) and boron phosphate (BP) were combined with PDMPD,to explore effective flame-retardant formulations for PS. The flammability and the thermal properties of the composites were evaluated using limiting oxygen index (LOI) test, microscale combustion calorimeter (MCC) and thermogravimetric analysis (TGA) respectively. A Fourier transform infrared (FTIR) spectroscopy coupled with a thermogravimetric analyzer (TG-IR) was also used to study the gas phase from the degradation of PS composites. Furthermore, the char residues of the samples were investigated by scanning electron microscopy (SEM) and FTIR. The results showed that the incorporation of PDMPD can significantly decrease the flammability of virgin PS, and enhance the thermal stability at high temperature region, in both nitrogen and air atmosphere. A combination of PDMPD with small amounts of boron compounds can further decrease the flammability. [ABSTRACT FROM AUTHOR]

A series of flame retardant hybrids were prepared based on bisphenol A polycarbonate (PC), trisilanolphenyl-polyhedral oligomeric silsesquioxane (TPOSS) and oligomeric bisphenyl A bis(diphenyl phosphate) (BDP) by melt blending method. The thermal stability and flame retardant properties of the hybrids were investigated by thermogravimetry analysis and cone calorimeter. Combination TPOSS with BDP in the appropriate ratio enhanced the thermal stability and the flame retardant properties of the PC matrix. The char residues of the hybrids were investigated by scan electronic microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). The synergistic effect of BDP and TPOSS enhances the thermal stability and fire-resistance of the char layer which builds up on the surface of the burning polymer. [ABSTRACT FROM AUTHOR]