Surface Treated Montmorillonite: Structural and Thermal Properties of Chiral Poly(Amide-Imide)/Organoclay Bionanocomposites Containing Natural Amino Acids

This work concerns the preparation of novel optically active nanocomposite materials derived from Cloisite Na⁺ clay, which has been functionalized by protonated l-methionine amino acid as a swelling agent for sufficient compatibilization with the poly(amide-imide) (PAI) matrix. The polymer chains were formed from the polycondensation reaction of N,N′-(pyromellitoyl)-bis-phenylalanine diacid chloride with 4,4′-diaminodiphenylether. Interaction between the two phases was established by modifying the PAI chains with amine end groups and free acid groups of the organoclay (OC). The effect of OC dispersion and the interaction between OC and PAI chains on the properties of resulting bionanocomposite material was studied using Fourier transform infrared spectroscopy, X-ray diffraction (XRD), transmission electron microscopy, field emission scanning electron microscopy and thermogravimetric analysis techniques. The XRD pattern and morphological investigation revealed the formation of intercalated and exfoliated OC platelets in the matrix. Because of the existence of naturally occurring amino acids as biological chiral resources, it is predictable that these materials may be potentially biodegradable and biocompatible.