Effect of hydrogen bonding on the compressive strength of dihydroxypoly(p-phenylenebenzobisoxazole) fibers.

By the introduction of binary hydroxyl groups into poly(p-phenylenebenzoxazole) (PBO) macromolecular chains, a series of dihydroxypoly(p-phenylenebenzobisoxazole) (DHPBO) chains were prepared, and the effect of the hydroxyl groups on the axial compression property of DHPBO fibers was investigated. The variable-temperature Fourier transform infrared spectrum proved the existence of hydrogen bonds in DHPBO chains. Furthermore, the axial compression bending test showed that the introduction of hydroxyl groups into macromolecular chains apparently improved the compression resistance property of DHPBO fibers. Finally, a proposed arrangement of the hydrogen bonding in DHPBO fibers is presented.