HEAT-RESISTANCE PROPERTIES OF POLY(P-PHENYLENE-2,6-BENZOBISOXAZOLE) FIBER

The high temperature properties of Poly(p-phenylene-2,6-benzobisoxazol e) (PBO) fiber are examined and compared with those of the p -Aramid f iber. In particular, the temperature dependence of tensile strength of the PBO fiber is reported for the first time. The PBO fiber has 100 d egrees C higher decomposition temperature than the p-Aramid fiber, and the amount of toxic gases in combustion is much smaller than the p -A ramid fiber. Although the relative strength decreased proportionally i n the range of room temperature to 500 degrees C, the PBO fiber has 40 % of the strength at room temperature even at a temperature of 500 deg rees C. After thermal treatment at 500 degrees C for 60 s, the PBO fib er retained 90% of its original strength. The PBO fiber is expected to substitute for asbestos, which is still used as a heat resistant cush ion material. (C) 1997 John Wiley & Sons, Inc.