Heat resistance properties of poly(p-phenylene-2,6-benzobisoxazole) fiber

The high temperature properties of Poly(p-phenylene-2,6-benzobisoxazole) (PBO) fiber are examined and compared with those of the p-Aramid fiber. In particular, the temperature dependence of tensile strength of the PBO fiber is reported for the first time. The PBO fiber has 100°C higher decomposition temperature than the p-Aramid fiber, and the amount of toxic gases in combustion is much smaller than the p-Aramid fiber. Although the relative strength decreased proportionally in the range of room temperature to 500°C, the PBO fiber has 40% of the strength at room temperature even at a temperature of 500°C. After thermal treatment at 500°C for 60 s, the PBO fiber retained 90% of its original strength. The PBO fiber is expected to substitute for asbestos, which is still used as a heat resistant cushion material. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:1031–1036, 1997