Effect of Environmental Degradation on Shear Properties of PPS /Carbon Fiber Composites

Advanced thermoplastic composites are an alternative to thermoset composites in many aeronautical applications owing to their superior properties. Among the thermoplastic matrix, PPS (poly phenylene sulfide) stands out due to its structural characteristics. The objective of this study is to evaluate the influence of environmental conditioning on the shear behavior of PPS / carbon fiber composites. Samples of this material have been conditioned in saline water solution, in hygrothermal conditioning and under UV radiation. After conditionings the specimens were evaluated by interlaminar shear strength (ILSS) and Iosipescu shear test methods. The environmental conditioning reduced the interlaminar shear stress (ILSS) of conditioned composites in comparison with non-conditioned composites tested with the same method (58.4 +/- 1.9 MPa). The ILSS decreased by ca. 14 and 3%, respectively, after hygrothermal conditioning and saline water solution. Moreover, the values of interlaminar shear stress under UV radiation decreased by 2, 11 and 9% after exposure times of 300, 600 and 900 hours, respectively. The non-conditioned composites tested with the losipescu method (109.2 +/- 0.4 MPa) also had ILSS decreasing with environmental conditioning: the values decreased 6% after hygrothermal conditioning and 12% after saline water solution. The UV radiation exposure led to a decrease of 6, 10 and 14% following exposures during 300, 600 and 900 hours, respectively.