Morphology-controlled ZnO nanoarrays in situ grown on the basalt fiber surface for improving the interfacial properties of the high-performance thermoplastic composites

In this work, a biomimetic root-soil-like interfacial phase structure was constructed to improve the weak interfacial bonding of the fibers and resin based on the mechanical interlocking theory. Unidirectional basalt fiber (BF) reinforced high-temperature resistant thermoplastic poly(phthalazinone ether nitrile ketone) (PPENK, Tg=278 °C) composites with multiscale structures were prepared. By utilizing a whiskerization technique, the zinc oxide nanoarrays (ZnO-NAs) with controllable morphologies grown on the BF surface through a pyrolysis-hydrothermal method. The remarkable field emission properties of the ZnO-NAs allow for visually characterizing the interfacial phase structures. The flexural, interlaminar shear, and interfacial shear strengths of BF-ZnO-PEI-2/PPENK composite were increased by 43%, 65%, and 177%, respectively. Further investigations revealed that the flexural strength retention was 61% at 250°C, respectively. This study introduces a novel and viable approach to enhance the interfacial properties of BF-reinforced high-performance thermoplastic composites and expands their applications within high-temperature environments.