Modifications of rigid rod poly(1,4-phenylene-cis-benzobisoxazole) fibers by gas plasma treatments

The surface modifications of poly(1,4-phenylene-cis-benzobisoxazole) fibers by gas plasma treatments have been investigated in this paper. Oxygen, nitrogen, argon, and ammonia were regarded as inlet gas, respectively. After the plasma treatments, the effects on the morphology of the fiber surface, the tensile strength, the surface free energy, and the polymer crystallization behavior in the interface were carefully studied. The results showed that the total surface free energy of the fiber was increased by 35.3%, from 47.6 to 64.4 mJ/m², after the oxygen plasma treatment for 15 min. The increase has been 32.4% for N₂ plasma, 28.8% for argon plasma, and 28.6% for NH₃ plasma. The interfacial crystallization behavior of thermoplastic polyether ether ketone was also presented.