Facile fabrication of hierarchically structured PBO-Ni(OH)2/NiOOH fibers for enhancing interfacial strength in PBO fiber/epoxy resin composites

A new hierarchical reinforcement was fabricated by depositing honeycomb-like Ni(OH)(2)/NiOOH coating onto poly(p-phenylene benzobisoxazole) (PBO) fibers using a facile chemical bath deposition (CBD) method. The crystal structure of Ni(OH)(2)/NiOOH deposited PBO fiber, denoted as PBO-Ni(OH)(2)/NiOOH, was characterized by X-ray diffractometer (XRD). Scanning electron microscopy (SEM) was employed to characterize the surface morphologies of PBO fibers and the de-bonding surface morphologies of their composites. Atomic force microscopy (AFM) and contact angle (CA) testing results demonstrated that the surface roughness (R-a) and wettability of PBO fibers increased obviously after Ni(OH)(2)/NiOOH deposition due to the unique honeycomb structure of the coating. Monofilament pull-out tests showed that the interfacial shear strength (IFSS) of PBO/epoxy composite increased by 46.3%. Moreover, the possible interfacial property enhancing reasons were explored. Thermogravimetric analysis (TGA) and hydro thermal aging tests revealed that PBO-Ni(OH)(2)/NiOOH had excellent thermal stability and hydrothermal aging resistance. Notably, the Ni(OH)(2)/NiOOH coating on the fiber surface can be easily reduced to Ni, resulting in a highly conductive PBO fiber. Our design starts from simple chemistry and inexpensive materials, and may offer a versatile and scalable method for fabricating hierarchical reinforcements. (C) 2016 Elsevier Ltd. All rights reserved.