Synthesis and characterization of new polyamideimides with a highly flexible soft block

Five new polyamideimides (PAI) were synthesized from five diacid chlorides with preformed imide rings and a telechelic alpha,omega-diamino-polyoxyethy lene (Jeffamine JFA ED600). The diacid chloride monomers could be obtained in high yields (77-92%) from chlorinating the corresponding diacids which w ere obtained from the reaction of trimellitic anhydride with aromatic diami nes (1,4-phenylene diamine; 2,2-bis(4-aminophenyl)methane; 2,2-bis(4-aminop henyl)propane; 4,4'-oxydianiline and 1,1-bis(4-aminophenyl)cyclohexane). Th e telechelic monomers were characterized by FTIR and IH-NMR. After a few pr eliminary experiments aimed at optimizing the polymerization conditions for particularly poorly soluble diacid chlorides, five new PAI were synthesize d with inherent viscosities in the range of 0.35-0.65 dL/g. Their character ization by transmission FTIR and by advanced NMR techniques, including hete ronuclear 2D NMR, fully confirmed their chemical structure as shown by the complete assignments of their H-1 and C-13-NMR spectra. Compared with other PAI described in the literature, these polymers proved to be much more sen sitive towards polar organic solvents even showing significant solubilities in chloroform and tetrahydrofuran. These materials enabled the casting of transparent films which were very tough in the dry state. However, and as f urther evidenced by a DSC investigation, their phase separation is usually not sufficient to provide a very strong physical crosslinking by the aggreg ation of the polymer hard blocks. Consequently, their physical crosslinking would have to be significantly improved for preventing the material failur e in highly solvating media and open the way for new performances in membra ne separation systems. (C) 1999 John Wiley & Sons, Inc.