Preparation and Characterization of R‐ <scp>ODA</scp> Polyimide‐Based Fibers

ABSTRACT Heat‐resistant fibers made of semi‐crystalline R‐ODA thermoplastic polyimide synthesized in our laboratory were produced by melt extrusion. Aiming a modification of mechanical properties, these fibers underwent high‐temperature orientation drawing to various draw ratios. Morphological structures of both the nascent R‐ODA powder and the fibers were examined using scanning electron microscopy. Wide‐angle X‐ray scattering showed that the polymer crystallized, and the crystallites' orientation depended on the filament orientation degree. Differential scanning calorimetry was employed to analyze thermal characteristics of R‐ODA‐based fibers. In addition, the mechanical properties of the polyimide fibers with different draw ratios were investigated.