The advanced multifunctional filler has become one of the main challenges in developing high-performance polymer composites. In this study, the acid-treated multiwall carbon nanotubes (MWCNTs) were adhered to the surface of milled glass fiber under the combined effect of 3-aminopropyltriethyloxy silane and tetraethyl orthosilicate to fabricate a hierarchical fiber (MWCNTs-MGF). The morphologies of the hierarchical fibers were characterized using field-emission scanning electron microscope and transmission electron microscope, which showed evidence of a coating layer of MWCNTs on each fiber surface. The MWCNTs-MGF was employed as a multifunctional filler to prepare polyoxymethylene-based composites using a twin-screw extruder by melt blending. The obtained composites exhibited improved mechanical and thermal properties. The composite tensile strength and notched impact strength and Young's modulus increased by 10%, 32%, and 32%, respectively, as the MWCNTs-MGF content varies from 0 to 10 wt.%. Meanwhile, the reinforcing and toughing mechanisms of MWCNTs-MGF were also elaborated by analyzing the interfacial adhesion and fracture morphologies of the composites. Moreover, the study on thermal stability and crystallization behavior indicated that the polyoxymethylene/MWCNTs-MGF composites had higher thermal stability, crystallization temperature, and crystallinity as compared to the polymer matrix. The improvement of thermal stability originates from the unique surface structure of MWCNTs-MGF, while the increase in crystallization temperature and crystallinity is due to the strong heterogeneous nucleation ability of the hierarchical fibers.
High performance asymmetric supercapacitors with ultrahigh energy density based on hierarchical carbon nanotubes@NiO core–shell nanosheets and defect-introduced graphene sheets with hole structure
