Synthesis and Properties of High Thermally Stable and Organosoluble Poly(pyridine imide)s with Pendent Diethylaminophenyl Groups

A novel diamine monomer 4-(4-diethylaminophenyl)-2,6-bis(4-aminophenyl)pyridine (APAP) was successfully synthesized, and then a series of poly(pyridine imide)s was prepared from APAP with five commercial dianhydrides: pyromellitic dianhydride (PMDA), 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA), 4,4-oxydiphthalic anhydride (ODPA), 3,3,4,4-benzophenone tetracarboxylic dianhydride (BTDA), and 4,4-(hexafluoroisopropylidene)diphthalic anhydride (6FDA) via a two-step solution polycondensation method. The structure of APAP was characterized by FT-IR, NMR, and MS. The resulting polymers have good solubility in polar solvents, such as NMP, DMF, and DMSO. Furthermore, they exhibited outstanding thermal stability. The glass transition temperature (T-g) of polymers range from 326 to 346 degrees C, and the temperature at 5 % and 10 % weight loss in the range of 527 degrees C to 570 degrees C and 550 degrees C to 601 degrees C, respectively. Moreover, they also presented excellent hydrophobicity with contact angels in the range of 88.4 degrees to 94.0 degrees.