Effect Of Heat-treatment On The Structure And Performance Of PBO Fibers

Poly (p-phenylene benzobisoxazole)(PBO) fibers, because of its hightensile strength, high modulus, high heat-resisting, can be used as reinforcementin advanced composites and has great potential applications in the fields ofaerospace, military and general industry. However, because of its smooth surfaceand inactivity chemical, PBO fibers have a low interfacial adhesion with the resin,which greatly affect its applications. So far，many researches still focus on thesurface treatment of PBO fibers to get a good interfacial properties and perfectmechanical properties.Heat treatment is another treatment technique of PBO fibers and has beenapplied in the preparation of PBO fibers reinforced polymer-based composites.But it is still not totally clear that which properties of the PBO fibers are affectedby heat treatment and how the heat treatment on PBO fibers affected the loadtransfer mechanism and energy dissipation in polymer-based composites.In this study, the PBO fibers were heat treated at air or nitrogen atmosphere,different temperatures (500℃~800℃, Temperature range:50℃), differenttimes(10s,20s,30s). After heat treatment experiments, use various testinginstruments to determine the influence of heat-treatment on PBO fibers’properties and surface appearance. Determination of tensile properties wasanalyzed by single fiber drawing test. Scanning Electron Microscope was used towatch the changes of treated PBO fibers’surface appearance. Thermogravimetricanalysis was used to measure the decomposition temperature of treated PBOfibers. Contact Angle Meter was used to characterize fibers’wetting property.The result shows that: When the temperature of heat-treatment was belowthe decomposition temperature, the degree of crystallinity and mechanicalstrength were enhanced while the surface wettability of fiber was also advanced.After been heat-treatment at air atmosphere and650℃, the interfacial shear of PBO/EP composite was increased48.77%than untreated fiber, while the tensilestrength was decreased24.73%. But at nitrogen atmosphere and700℃, theinterfacial shear of PBO/EP composite was increased47.53%than untreated fiber,while the tensile strength was decreased22.06%.