Interfacial Shear Strength (IFSS) and Absorbed Energy Versus Temperature in Carbon Fiber-Thermoplastic Composites via Single Fiber Pullout Testing

Single-fiber micromechanical experiments are often conducted to obtain interface properties between the matrix and fiber in fiber reinforced composites. This study investigates the apparent interfacial shear strength in AS4/polypropylene composites using the single fiber pullout test at sub-ambient, ambient, and elevated temperatures. Fiber failure surfaces are examined (using scanning electron microscopy) to identify the failure mechanisms present and embedded length of the fiber. The results indicate a higher IFSS at low temperatures than at elevated temperatures. Specific energies associated with debonding frictional sliding are also shown to be inversely temperature dependent. The failure mode transitions from cohesive failure in the matrix at room temperature and elevated temperatures to interfacial failure at the lowest temperature. This experimental setup and results will help to understand the temperature dependent failure mechanisms in polymer composite systems across a range of temperatures.