Deformation Micromechanics in Rigid Rod Fibres and Composites

The relationship between structure and mechanical properties in as-spun and heat-treated high modulus poly(p-phenylene benzobisoxazole) (PBO) fibres has been examined using a combination of electron microscopy mechanical testing, and Raman microscopy. The structure of the fibres has been determined by obtaining longitudinal sections and electron diffraction from skin and core regions. Well-defined intense Raman siectra werf obtained from individual fibres and three main bands at 1280cm−1, 1540cm−1 and 1615cm−1 have been indentified. It is shown that shifts in Raman bands during straining are a direct reflection of molecular deformation within the fibres.