Study On PBO Fiber Compress Strength Modification And Light Aging

Poly(p-phenylene benzobisozazole) fiber with high strength, high modulus, and high thermal stability is the typical representative of the new generation fibers. PBO is the rigid-rod polymer with the low interaction force in the molecular and the low compressive strength. At the same time, PBO is easy to age at the condition of exposure in UV (Ultraviolet) so as to affect the mechanical strength. In this paper,γ-Co⁶⁰ irradiation is applied to modify PBO fiber to improve the compressive strength effectively. Besides, to study the PBO light aging phenomena, the PBO fibers were exposed in different gaseous mediums and different light sources for clarifying the chemical structure evolution and mechanism during the light aging process based on different characterization methods. At last, various light stabilizers were used to improve the PBO properties and reduce the light aging phenomena of PBO.In the study of PBO fiber compress strength modification, the optimized parameters of modification process for better PBO compressive strength were achieved based on experiments at different conditions (such as various modification agents, irradiation degree, concentration of modification agents and the resin content of composites). The results showed that the compressive strength of PBO composite can be significantly improved by the coupling use of modification agent andγ-Co60 irradiation. The chemicophysical properties of modified PBO fibers'surface were characterized by XRD, IR, and SEM.In the study of PBO fiber light aging research, the pattern of aged PBO in different environments was observed and analyzed by AFM. The single fiber tensile-strength test was applied in the study of mechanical properties of aged PBO fibers at natural condition and different mediums. The results showed that the fiber aged in the oxygen medium has the most decrease of properties. According to the phenomena, the PBO fibers aged in the oxygen medium were further characterized by XPS, XRD and IR which can provide the information on the structure change of light aged PBO.Finally, three kinds of light stabilizing agents: Chimassorb944FD,Tinuvin622LD and Tinuvin770DF were chosen to improve the PBO properties with the aid of plasma treatment. The aging rate of PBO fiber was slowed in the condition of plasma and light stabilizing agent treatments, and the PBO fiber modified by Tinuvin770DF stabilizer has the best tensile-strength.