Synthesis and properties of tetrapolyamides containing 4,4′-methylenedianiline moiety

A series of tetrapolyamides were synthesized by low temperature solution polycondensation of terephthaloyl dichloride with 1,2-dihydro-2-(4-aminophenyl)-4-[4-(4-aminophenonxyl) phenyl]-phthalazin-1-one (DHPZ-DA),4,4'-methylenedianiline (MDA) and p-phenylene diamine(PPD). The synthesized polyamides were characterized by FTIR and H-1-NMR. The polymers exhibited inherent viscosities of 1.24 similar to 2.32 dL/g and some were soluble in several organic solvents such as N-methyl pyrrolidone, N, N-dimethylacetamide and N, N-dimethylformamide, when the three kinds of diamines were in proper ratios. These polymers had glass transition temperatures above 301 degrees C and 5 % weight loss above 438 degrees C in nitrogen. Some polyamide films were prepared from their NMP solutions and had tensile strength of 64 similar to 72 MPa, elongation at break of 4.9% similar to 8.1 % and tensile modulus of 1.7 similar to 2.1 GPa. The results showed that these polyamides showed the combination of excellent thermal properties, solubility and mechanical properties.