Effect of heat treatment on the structure and properties of poly(2,6-benzothiazole) (ABPBT) and poly(2,5-benzoxazole) (ABPBO)

Poly(2,6-benzothiazole) (ABPBT), poly(2,5-benzoxazole) (ABPBO) were synthesized and their fibers were prepared by dry-jet wet-spinning technique. The effect of heat treatment on the structure and properties of the fibers/films were studied in detail by the measurements using Fourier transform infrared (FTIR), scanning electron microscope (SEM), wide-angle X-ray diffraction (WAXD) and Instron tensile tester. The results not only showed that heat treatment had a significant effect on the macrostructure and microstructure of fibers, making fibers more regular and improving their mechanical properties, but also indicated that there was a suitable range of heat treatment conditions. (C) 2000 Kluwer Academic Publishers.