Pbo Fiber Statistical Strength In The Composite Application

PBO ( poly (p-phenylene-2,6-benzobisoxazole) ) fiber, because of its excellent mechanics, heat-resistance function and fire-retardant property, has been used in many fields include military and public. It has the ability to compare with high-powered C-fiber and is called super fiber of 21 century.This kind of new fiber is placed in the stage of beginning in our country and there is not enough information of its properties. A integrated research about PBO single fiber, fiber tow and unidirectional composites is done and gets some useful datum. These information and datum can offer necessary support for the design of PBO fiber composites in the future.Based on Weibull / weakest link model, the statistic average strength and its distribution of four different length PBO single fibers were researched. The results point out the method that the tensile strength changed with length and are checked up by using Kolmogorov examination to prove the correctness of using Weibull distribution. From the experiment, the equation to forecast the strength of PBO fiber is deduced. Subsequently, the 5cm PBO fibers are treated with six different chemical medium in ambient temperature 100h. The effects on their strength and strength dispersity were studied to evaluate the property of resistance to chemical reagents and their surfaces are observed by using SEM. HCL and H2SO4 have very big influence and different break mechanisms on PBO fiber.Through the average strength and parameter B , the properties of fiber tow and composites can be forecasted. Compared with the forecasted value and true value, the result is that the way to made fiber tow and composites is pivotal to their properties. The average tensile strength of PBO fiber tow made through a good way is high to out 28% than forecasted value, up to 5GPa. But a good method to make epoxy resin/PBO fiber unidirectional composites is not found now. From the SEM, the unidirectional composites' section can be observed. The interface character andpermeation degree have great effects on the performance of PBO fiber composites. The resin can well permeate PBO fiber if using prepreg, but the interface is still weak. At last, the influence brought by interface character on PBO fiber unidirectional composites is analyzed by DMA.