Influences of cryo-thermal cycling on the tensile properties of short carbon fiber/polyetherimide composites

The reliability of short fiber reinforced polymer composites is crucial for their successful applications in aerospace engineering with cryo-thermal cycling (CTC). This study investigates the influences of CTC on the tensile properties of short carbon fiber (SCF)/polyetherimide (PEI) composites at room temperature (25 °C) and elevated temperature (170 °C). First, SCF surfaces were coated by carbon nanotube-polydomaine (CNT-PDA) hybrid sizing, and then SCF/PEI composites were prepared via the facile injection molding technique. Impressively and unexpectedly, the tensile strength at 25 °C and 170 °C of SCF/PEI composites is all enhanced by the CTC exposure, attributing to the enhanced mechanical properties of PEI matrix and fiber/PEI interface bonding. In addition, CNT-PDA sizing and CTC exposure have a combined effect on improving the tensile properties of SCF/PEI composites at 25 °C and 170 °C. Overall, the SCF/PEI composites exhibit excellent mechanical properties under extreme service conditions, and are thus promising to serve in aerospace components.