A highly efficient phenylphosphonate based flame retardant epoxy resin (FREP) was firstly prepared from phenylphosphonic dichloride (PPDCl) and allylamine (AA). Functionalized graphite nanoplatelets (fGNPs) fillers were then performed to fabricate the fGNPs/FREP nanocomposites via mixing followed by casting method. The thermally conductive coefficient (l), thermal diffusivity (a), flame retardancy, electrical conductivities and thermal stabilities of the fGNPs/FREP nanocomposites were all enhanced with the increasing addition of fGNPs fillers. The l and a value of the fGNPs/FREP nanocomposite with 30 wt% fGNPs fillers was increased to 1.487 W/mK and 0.990 mm2/s, about 7 times and 6 times for that of pure FREP matrix (0.234 W/mK and 0.170 mm2/s), respectively. And the corresponding electrical con ductivity was also increased to 5.0 x 10 4 S/cm, far better than that of pure FREP matrix (1.0 x 10 12 S/ cm). In comparison with that of pure FREP, the THR and TSP value of the fGNPs/FREP nanocomposite with 15 wt% fGNPs fillers was decreased by 37% and 32%, respectively, char yield was increased by 13%, and LOI value was increased from 31% to 37%. However, the peak of heat release rate of the fGNPs/FREP nano composite became worse due to its high thermal conductivity. Nanoindentation revealed that there was negligible influence of fGNPs fillers on the hardness values and Young's modulus of the fGNPs/FREP nanocomposites.

In this study, a superefficiently flame-retardant bioplastic poly­(lactic acid) was developed by incorporating gas–solid biphase flame-retardant N,N′-diallyl-P-phenylphosphonicdiamide (P-AA), into PLA matrix. The flame retardancy of PLA/P-AA was investigated by limiting oxygen index (LOI), vertical burning test (UL94), and cone calorimeter test. Surprisingly, it was noted that only 0.5 wt % loading of P-AA increased LOI value of PLA from 20.5 to 28.4 and passed UL 94 V-0 rating at 3.2 mm thickness. In order to understand the effect of P-AA on the thermal decomposition behavior of PLA, a comprehensive study was investigated in this paper, including (i) adopting modified Coats–Redfern method to study the thermal decomposition kinetics of PLA and PLA/P-AA systems, and (ii) characterizing the evolved gaseous products and the residues in the condensed phase by thermogravimetry linked Fourier transform infrared spectroscopy (TGA–FTIR) and variable temperature Fourier transform infrared spectroscopy (VT-FTIR) techniques, respectively. Moreover, tensile properties of PLA and PLA/P-AA were studied.

This work aimed to investigate the effect of two types of phosphorus-containing flame retardants (P-FRs) with different chemical surroundings (phenylphosphonate-based (PO-Ph) and phenylphosphoric-based (PO-OPh)) on the flameretardant efficiency for diglycidyl ester of bisphenol-A type epoxy (EP) resin. The two series of P-FRs which were named as FPx and FPOx (x=1, 2 and 3), respectively, showed reactivity with epoxy group that was examined by differential scanning calorimetric (DSC) and variable temperatures FTIR spectrum (VT-FTIR). A comparative study between the FPx and FPOx (x=1, 2 and 3) contaning flame-retardamt epoxy was carried out via investigating their flammability, thermal stability and mechanical properties. The most significant difference on flame retardancy between them was that FPx (x=1, 2 and 3) endowed EP with V-0 rating in UL 94 test at 5 wt% loading, while FPOx (x=1, 2 and 3) showed no rating at such loading. Importantly, it is found that there was almost 10 times difference in the flame-retardant efficiency for epoxy resin between FPx and FPOx, though they had similar chemically molecular structures. Moreover, TGA-FTIR and TGA-MS coupling techniques (TGA, thermalgravimetric analysis; MS, mass spectroscopy) were employed to study the thermal decomposition of FP1 and FPO1; the impacts of FP1 and FPO1 on the thermal decomposition of EP were studied by TGA-FTIR as well. Furthermore, an online temperature detection experiment was designed to collect the temperatures by thermocouple and infrared thermometers, respectively in the UL 94 test. Based on the above results, the flame-retardant mechanisms of FP1 and FPO1 in EP were discussed. In addition, the impact of P-FRs on mechanical properties of EP was studied by means of tensile test and dynamic mechanical analysis .

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