Photosensitive and Optically Active Poly(amide-imide)s Based on N,N- (pyromellitoyl)-bis-L-amino acid and Dibenzalacetone Moiety in the Main Chain: Synthesis and Characterization

Six new photosensitive and optically active poly(amide-imide)s (PAIs) with good inherent viscosities based on N,N'-(pyromellitoyl)-bis-L-amino acid and dibenzalacetone moiety in the main chain were synthesized from the direct polycondensation reaction of N,N-(pyromellitoyl)-bis-L-amino acids 3a-f with 2,5-bis(4-aminobenzylidene)cyclopentanone 7 by two different methods such as direct polycondensation in a medium consisting of N-methyl-2-pyrrolidone (NMP)/triphenyl phosphite (TPP)/calcium chloride (CaCl2)/pyridine (py) and direct polycondensation in a tosyl chloride (TsCl)/pyridine (py)/N,N-dimethylformamide (DMF) system. Also, 2,5-bis(4-aminobenzylidene)cyclopentanone 7 was synthesized by using a two-step reaction. The polymerization reactions produced a series of photosensitive and optically active PAIs with high yield and good inherent viscosity. The resulted polymers were fully characterized by means of FTIR and 1H-NMR spectroscopy, elemental analyses, inherent viscosity, specific rotation, solubility tests and UV-Vis spectroscopy. Also thermal properties of the PAIs 8a-f were investigated using thermal gravimetric analysis(TGA) and derivative of thermogravimetric (DTG) analysis.