Characterization of the effects of testing temperature on the interfacial shear strength of fiber/resin single-filament-composite

[Display omitted] •A validated PBO/EP single fiber pull-out test method is proposed.•The IFSS was found to have an inverse relationship with the test temperature.•The accuracy of single fiber pull-out was verified by COMSOL simulation results. In the micromechanical test of fiber-reinforced composites, single fiber pull-out test is the most widely used test method. However, for high performance fibers/matrix, different test equipment and sensor accuracy can affect the single fiber pull-out test results very much. In this study, an innovative single fiber pull-out test method is proposed for testing the interfacial shear strength (IFSS) of high performance fibers/resins at different temperatures. Single fiber pull-out test was carried out on PBO fiber/epoxy resin (EP) composites at room temperature and elevated temperature. The IFSS was found to have an inverse relationship with the test temperature. The IFSS value of PBO/EP decreased from 25.25 MPa at room temperature to 6.25 MPa as the temperature approached the glass transition temperature. COMSOL simulations showed that fiber pull-out with angular tilt exhibited better interfacial strength, demonstrating the validity of the method. The results of this paper provide ideas to study the effect of temperature on the mechanics of fiber-reinforced resin matrix composites and expand the way to design stiffer, stronger and more robust composites.