Synthesis and characterization of UHMWPE nanocomposite fibers containing carbon nanotubes coated with a PVP surfactant layer

Ultra-high-molecular-weight polyethylene (UHMWPE) nanocomposite fibers were fabricated using solution spinning, consisting of surface modified single-walled carbon nanotubes (SWCNTs) embedded into the fiber matrix. The SWCNTs were modified using polyvinylpyrrolidone (PVP) noncovalent functionalization process, which acts as a surfactant and has the ability to enhance the dispersion of CNTs in the base polymer matrix by reducing aggregation and promoting interfacial adhesion with the fiber polymer matrix. Tensile testing of fibers containing PVP-coated SWCNTs showed substantial improvements in the tensile strength and fracture strain by 125% and 137%, respectively, compared to fibers containing pristine CNTs. The amount of PVP coated onto the surfaces of CNTs was determined to be about 32.5% using thermogravimetric analysis (TGA). Differential scanning calorimetry (DSC) analysis of the nanocomposite fibers showed significant increase in crystallinity and upshift in the melting point compared to that of neat UHMWPE fibers. Fourier transform infrared spectroscopy (FTIR) analysis showed the presence of characteristic absorbance bands of PVP functional groups (CN @ 1289 cm(-1) and CO @ 1651 cm(-1)) on the modified CNTs. Scanning electron microscopy (SEM) imaging of modified CNTs and nanocomposite fibers showed an increase in average tube diameter and reduced aggregate formation compared to pristine CNTs, indicating the successful coating of the nanotubes with PVP. Preferential alignment of the modified CNTs along the direction of fiber extrusion and crack bridging of the fiber by nanotubes were also observed. POLYM. COMPOS., 39:E1025-E1033, 2018. (c) 2017 Society of Plastics Engineers