Electron microscopy of high performance PBO and ABPBO polymers

Abstract

Recent developments in the synthesis and preparation of high molecular weight polymers have resulted in the generation of two new aromatic heterocyclic polymers with excellent mechanical properties. The polymers are the rigid rod poly-p-phenylene benzobisoxazole (PBO) and the flexible coil poly 2,5(6) benzoxazole (ABPBO). The purpose of this study was to characterize the morphology of PBO and ABPBO in as-spun (AS) and annealed (AN) conditions by the use of transmission electron microscopy (TEM) imaging and diffraction techniques, and to compare the results with other high performance polymers.Samples were prepared for TEM by detachment replication. A JEOL 100CX was operated at 120 kV. Dark field images were formed from the first, second, and third equatorial reflections in the case of PBO, and from the first and second equatorial reflections for ABPBO. In order to minimize beam damage artifacts, the areas of the sample used for dark field imaging were adjacent to those used for locating and focusing.