Study on synthesis of novel soluble aromatic polyamides with pendant cyano groups

A series of novel soluble aromatic polyamides with pendant cyano groups were synthesized by low temperature polycondensation of aromatic diamines with a new monomer 2,6-bis(4-chloroformylphenoxy)benzonitrile (ClPOBN) in the presence of N,N-dimethylacetamide (DMAC) as the solvent and tertiary amines as the absorbent of HCl. The properties and structures of obtained polymers were characterized by means of FTIR, TG, and elemental analysis. Structures of prepared polymers are as expected. TG studies show that the polymers had excellent thermal stability as measured by 5% weight loss temperatures in nitrogen (409–438 °C).They are soluble in aprotic polar organic solvents such as N-methyl pyrrolidone (NMP), dimethyl sulphoxide (DMSO) and N,N-dimethylformamides (DMF) and are swelled in common solvents, such as CHCl_3, ethylene dichloride (DCE), CH₂Cl₂, tetrahydrofuran (THF), etc. Their thin films which cast from DMF had tensile strength of 79–93 MPa, Young’s moduli of 1.7–2.6 GP, elongation at break of 9–15%, indicating they are strong in mechanical properties.