Preparation and characterization of optically active poly (amide-imide)/TiO2 bionanocomposites containing Ntrimellitylimido-L- isoleucine linkages: Using ionic liquid and ultrasonic irradiation

In the present investigation, novel poly(amide-imide)/TiO₂ bionanocomposites containing L-isoleucine moiety in the main chain were prepared via a simple and inexpensive ultrasonic irradiation process. Poly(amide-imide) as a source of polymer was synthesized by direct polycondensation reaction of N-trimellitylimido-L-isoleucine with 4,4′-diaminodiphenylsulfone in the tetrabutyl ammonium bromide/triphenyl phosphite as a green solvent system. Due to the high surface energy and tendency for agglomeration, the surface of TiO₂ nanoparticles was modified with γ-aminopropyltriethoxyl silane. The resulting hybrid bionanocomposites were fully characterized by FT-IR spectroscopy, UV–vis spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy (TEM) and thermogravimetric analysis. Through TEM photographs, it can be found that the surface modified TiO₂ nanoparticles with diametric size of less than 40 nm, uniformly dispersed in the obtained PAI matrix.