Synthesis and characterization of novel aliphatic-aromatic polyamide/Fe3O4 nanocomposites containing pendent 9H-xanthene groups

New magnetic polyamide/Fe3O4 nanocomposites containing pendent 9H-xanthene were prepared via solution intercalation technique from polyamide 9 and Fe3O4 nanoparticle in a solution of N,N-dimethylacetamide. A new polyamide 9 as a source of polymeric matrix was synthesized by direct polycondensation reaction of 3,5-diamino-N-(4-(1,3,6,8-tetramethyl-9H-xanthen-9-yl)phenyl)benzamide (7) with adipic acid in a medium consisting of N-methyl-2-pyrrolidone, triphenyl phosphite, calcium chloride, and pyridine. The synthesized polyamide was characterized by Fourier transform infrared spectra, nuclear magnetic resonance, UV-vis, and photoluminescence spectroscopy. The structural and electronic properties of xanthene-based polyamide unit were studied by ab initio density functional theory method using the B3LYP/6-31G (d) level of theory. The highest occupied molecular orbital (HOMO), lowest unoccupied molecular orbital (LOMO) level energy, and band gap (Delta E=E-LUMO-E-HOMO) of the polyamide unit were calculated. Fe3O4 nanoparticles have been synthesized using a chemical co-precipitation route. Using a combination of dissolving the polymer and mixing Fe3O4 nanoparticles, we have demonstrated the formation of nanocomposites with uniform nanoparticle dispersion. The morphology, crystalline phase, thermal stability, and magnetization properties of the resultant materials were characterized by means of transmission electron microscope, X-ray diffraction, thermal gravimetric analysis, and vibrating sample magnetometer. The results indicated that the as-prepared nanocomposites exhibited superparamagnetic properties and improvements in the thermal stability compared to neat polyamide.