| 초록 |
Poly(P-phenylenebenzobisoxazole) (PBO) are rigid-rod molecules with extended chain conformation. Fibers processed from PBO have very high tensile strength and tensile modulus, but their performance under compression have been disappointing. Many researchers has been done in various ways to correct this problem. Binding the chains together by crosslinking or some other means would laterally stabilize the chain and thereby increase its resistance to buckling. As a result, the compressive strength of the fiber would increase. One of various ways is to convert phenylene into naphthalene. Fibers inverted phenylene into naphthalene from PBO are Poly(1,5-naphthalene-benzobisoxazole) (1,5-Naph-PBO) and Poly(2,6-naphthalene-benzobisoxazole) (2,6-Naph-PBO). The characteristic features of the X-ray diffraction pattern of 1,5- and 2,6-Naph-PBO fiber are the spotlike equatorial reflections and the diffuse reflections along the layer lines. Many types of the energetically stable models are structurally analyzed by an organized combination of two-dimensional X-ray data and computer simulation technique. The neighboring chains in the case of 1,5-Naph-PBO and 2,6-Naph-PBO are shifted by c/4 along the chain axis and assumed to arrange along the ıīo plane. |
