Synthesis and Characterization of Polyarylenepyromellitimides and Mechanical and Thermal Properties of Their Fibres

Abstract

<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">Polypyromellitimides based on 4, 4'-diaminobenzanilide (DAB), 2, 5-bis (<i>p</i>-aminophenyl)-1, 3, 4-oxadiazole (ODZ), 4, 4'diaminodiphenyl ether (E) and bis(3-aminophenyl) methylphosphine oxide (DAP) were synthesized and characterized by IR spectroscopy. Fibres were spun from a DMF solution of the corresponding polyamide-acid by wet spinning and cyclodehydrated to polyimide by chemical means. The 'as-spun' fibres had low tenacity and modulus. Fibres based on DAB and ODZ diamines had higher modulus than those based on E. A decrease in the mechanical properties of fibres was observed by heat-ageing at 200°C for several hours or on UV irradiation.</span>