Novel heterocyclic semi-aromatic polyamides: synthesis and characterization

摘要

Novel heterocyclic aliphatic-aromatic polyamides (PAs) with enhanced flame retardancy, thermal stability, and solubility in organic solvents were synthesized from a polycondensation reaction of 4-aryl-2,6-bis(4-aminophenyl)pyridine 4a-c with adipic acid 5. Diamine monomers 4a-c containing a pyridine ring bearing different kinds of aromatic type pendant groups on its 4-position were synthesized and characterized by FTIR and NMR spectroscopy. The resulting PAs were characterized by Fourier transform infrared spectra, nuclear magnetic resonance ( 1 H NMR), size exclusion chromatogra- phy, thermogravimetric analysis, differential scanning calorimetric, and microscale combustion calorimeter. The polymers showed good flame retardancy, thermal stability, and very good solubility in polar aprotic solvents. In the presence of bromide, PA 6c showed good flame retardancy, reflecting the decrease in heat release rate and the total heat release while the char yield of the PA was higher than two other polymers.