Production of NiAl-layered double hydroxide intercalated with bio-safe amino acid containing organic dianion and its utilization in formation of LDH/poly(amide-imide) nanocomposites
Novel Ni-Al layered double hydroxide (LDH) intercalated with bio-active amino acid containing dicarboxylate was synthesized via co-precipitation reaction of Ni(NO3)2. 6H2O, Al(NO3)3. 9H2O and N,N′-(pyromellitoyl)-bis-L-phenylalanine under ultrasonic irradiation. The X-ray diffraction (XRD) results of the organo-modified LDH show that the dianion are intercalated in the interlayer region of LDH and expanded the interlayer distance. An optically active and organo-soluble poly(amide-imide) was prepared by the direct step-growth polymerization of L-phenylalanine based diacid and 3,5-diamino-N-(4-hydroxyphenyl)benzamide in the presence of molten tetra-butylammonium bromide as a green solvent. Then nanocomposite materials built from the assembly of L-phenylalanine amino acid containing polymer and two-dimensional organo-modified LDH were synthesized by solution intercalation method. The structures and morphology of the synthesized materials were investigated by XRD, Fourier transform infrared spectra, field emission scanning electron microscope (FE-SEM) and transmission electron microscopy (TEM) techniques. The thermal properties of the modified LDH and the resulting nanocomposites were studied by thermogravimetry analysis techniques and the results showed improved in the thermal properties of the nanocomposites in comparison with the neat polymer. The FE-SEM, TEM and XRD results revealed a coexistence of exfoliated and intercalated modified LDH in polymer matrix.