Use of TX100-dangled epoxy as a reactive noncovalent dispersant of vapor-grown carbon nanofibers in an aqueous solution

The dispersion of carbon nanotubes (CNTs) into individual particles or small bundles has remained a vexing problem that limits the use of the excellent properties of CNTs in composite applications. Noncovalent functionalization is an attractive option for changing the interfacial properties of nanotubes because it does not destroy the nanotube grapheme structure. In this study, a new reactive copolymer, epoxy-toluene diisocyanate-Triton X-100 (EP-TDI-TX100) was successfully synthesized, which is shown to be highly effective in dispersing vapor-grown carbon nanofibers (VGCNFs) into individual or small bundles, as evidenced by transmission electron microscopy (TEM) and UV–vis absorption spectra. The strong π–π interaction between VGCNFs and EP-TDI-TX100 was revealed by Raman spectra and the covalent reaction between curing agent was confirmed via Fourier transform infrared spectroscopy. For an effective dispersion, the optimum weight ratio of EP-TDI-TX100 to VGCNFs is 2:1. The maximum VGCNF concentration that can be homogeneously dispersed in an aqueous solution is approximately 0.64 mg/mL. The EP-TDI-TX100 molecules are adsorbed on the VGCNF surface and prevent reaggregation of VGCNFs, so that a colloidal stability of VGCNF dispersion can be maintained for 6 months.

Figure optionsDownload high-quality image (233 K)Download as PowerPoint slideHighlights
► We synthesized a reactive copolymer EP-TDI-TX100 for VGCNF dispersing.
► The dispersibility of VGCNFs with EP-TDI-TX100 was revealed by UV–vis spectroscopy.
► EP-TDI-TX100 has a higher dispersing capability for VGCNFs compared with TX100.
► EP-TDI-TX100-treated VGCNFs are uniformly dispersed in the water-based epoxy resin.