Polyamide nanocomposites containing hydrazide–hydrazone group reinforced with functionalized polyethyleneimine modified Mg(OH)₂ nanoparticles: Study on thermal properties, combustion resistance, and lead ion adsorption

Abstract Polyamide nanocomposites (PANC) were prepared from an aliphatic–aromatic polyamide (PA) containing hydrazide–hydrazone groups in the side chain, reinforced with functionalized polyethyleneimine (FPEI)/modified Mg(OH)₂ nanoparticles (FPMN). For this purpose, a new structure, aromatic diamine (DAHH), containing the hydrazide–hydrazone group, was synthesized, and used to synthesize PA by direct polycondensation. Also, polyethyleneimine (PEI) was structurally modified with salicylaldehyde for the modification of the surface of Mg(OH)₂ nanoparticles (MDH). The Field‐Emission Scanning Electron Microscopy and X‐ray diffraction results revealed that MDH were uniformly dispersed in nano‐size in the PA matrix. The thermogravimetric analysis results in both N₂ and air environments showed that PANC possesses higher thermal resistance than that of the neat PA. The 5% degradation temperature (T₅) of PANC containing 8 wt% of FPMN was obtained 40°C more than that of the pure PA in the N₂ environment. The microscale combustion calorimetry (MCC) results exhibited that the loading of FPMN into the PA matrix can efficiently increase the combustion resistance by decreasing the MCC parameters such as the heat release rate values. In addition, the lead ions adsorption efficiency of the prepared nanostructure materials was investigated, and the results exhibited that the adsorption data were obtained following the Langmuir isotherm model. The maximum adsorption efficiency was calculated to be 99.96% for PANC 8.