Synthesis of poly(p‐diphenylmethylterephthalamide) from recycled monomers

Abstract

Poly(p-diphenylmethylterephthalamide) or PMA was synthesized from the reaction between recycled terephthalic acid (TPA) and recycled 4,4Ј-methylenedianiline (MDA) in the presence of pyridine, triphenyl phosphite, and a solubilizing-aid agent. The reaction conditions used for this polymerization were determined from a model reaction using pure TPA and pure MDA as reactants. It was found that PMA with the highest % yield and molecular weight was obtained when the mixture of lithium chloride (LiCl) and calcium chloride (CaCl 2 ) were used as solubilizing-aid agents with a reaction time of 4 h. Recycled TPA with 92% purity was obtained from acid hydrolysis of waste PET bottles using sulfuric acid as a catalyst at 150°C for 5 h. Recycled MDA with 99% purity was obtained from aminolysis of rigid polyurethane foam scrap using diethylenetriamine as a degrading agent at 180°C for 70 min. PMAs prepared from recycled monomers exhibited thermal properties, which were comparable to those of PMA prepared from pure monomers. However, due to a possibility of several isomers present in recycled MDA, PMAs prepared from this monomer had lower melting points and thermal decomposition temperatures than those prepared from pure MDA.

Design of aromatic polyamides to modify cement performance under triaxial cyclic tests

“…[19] FTIR confirms the production of polyaramid bonds (Figure S1). [20] Amide function peaks consist of at least a strong sharp single band at 1640 cm −1 which relates to the C=O vibration (amide 1), and the second at 1540 cm −1 which relates to the combined motion of N-H bending and C-N stretching (amide II). [19] Solid-state nuclear magnetic resonance (SSNMR) spectroscopy confirms polymer mobility with peaks associated with the rigid aromatic groups and the flexible aliphatic group.…”