Effect of carbon nanotube grafting on the wettability and average mechanical properties of carbon fiber/polymer multiscale composites

An experimental investigation is performed to relate the wetting behavior of unsized and carbon nanotube (CNT) grafted carbon fibers to the average mechanical properties of unsized and CNT grafted carbon fiber/polymer multiscale composites. Contact angle measurements and single fiber pull out tests show that the choice of polymer matrix plays a crucial role in determining whether the incorporation of CNTs on the fiber surface enhances or degrades the wettability and hence average mechanical properties of carbon fiber/polymer composites. CNT grafting leads to a significant improvement in interfacial shear strength as well as flexural and tensile response of carbon fiber/polymer composites with the epoxy resin. However, incorporation of CNTs on fiber surface has no significant effect on the average mechanical properties of carbon fiber/polyester composites. Moreover, it is recorded that the relative enhancement in properties after CNT grafting depends on the fiber orientation in CNT grafted carbon fiber/epoxy composites. POLYM. COMPOS., 39:E1184–E1195, 2018.