Synthesis and characterization of linear, hyperbranched and dendritic poly(arylene ether amide)s through nitro displacement reaction

Abstract

Novel AB type monomers with one amide linkage, 4-nitro-3-trifluoromethyl-N-(4-hydroxyphenyl)benzamide (3) and 4-nitro-3-trifluoromethyl-N-(3-hydroxyphenyl)-benzamide (4) were synthesized and self-polymerized using nitro displacement reaction in the presence of potassium carbonate in DMSO. The synthesized polyamides showed the enhanced solubility without deterioration of thermal property. Four AB type monomers with two amide linkages, N-[4-(4-nitro-3-trifluoromethylbenzamido)]-N``(4-hydroxyphenyl)benzamide (7), N-[4-(4-nitro-3-trifluoromethylbenzamido)]-N``(3-hydroxyphenyl)benzamide (8), N-[3-(4-nitro-3-trifluoromethylbenzamido)]-N``(4-hydroxyphenyl)benzamide (9) and N-[3-(4-nitro-3-trifluoromethylbenzamido)]-N``(3-hydroxyphenyl)benzamide (10), were also synthesized and polymerized. The polyamides with two amide linkages per repeating unit were soluble in NMP and DMSO, but not in THF whereas the polyamides with one amide linkage per repeating unit were soluble in common organic solvents including THF. This solubility result indicates that the number of amide linkages is an important factor to control the solubility of aromatic polyamides. A series of AABB type poly(arylene ether amide)s having weight average molecular weight of 30,000 - 70,000 were prepared from N,N``-bis(4-nitro-3-trifluoromethylbenzoyl)-p-phenylenediamine (16) and N,N``-bis(4-nitro-3-trifluoromethylbenzoyl)-m-phenylenediamine (17) and several biphenol compounds. All the synthesized polyamides showed high glass transition temperature values above 213℃ and good solubility. Novel $AB_2$ type monomer containing one amide linkage, N-(3,5-dihydroxyphenyl)-4-nitro-3-trifluoromethyl-benzamide (20) was synthesized and polymerized under various conditions using nitro displacement reaction to produce hyperbranched poly(arylene ether amide)s. The synthesized hyperbranched poly(arylene ether amide)s are highly soluble in common organic solvents and their weight average molecular weights were in the range...