Noncovalent Surface Functionalization of Multi-walled Carbon Nanotubes with Polyhedral Oligomeric Silsesquioxane Nanoparticles Based on CH- Interactions
One-pot chain walking copolymerization of ethylene and polyhedral oligomeric silsesquioxane (POSS) monomer was first performed at 0.1 MPa/35℃ with a Pd-diimine catalyst to synthesize hyperbranched polyethylene covalently tethered with multiple POSS nanoparticles (HBPE@POSS).The resulting HBPE@POSS was then used to functionalize multi-walled carbon nanotubes (MWCNTs) under the assistance of ultrasonication in tetrahydrofuran (THF) and chloroform
respectively.The structure and POSS portion of the HBPE@POSS were characterized via proton nuclear magnetic resonance (1H-NMR)
gel permeation chromatography (GPC)
thermogravimetric analysis (TGA) and wide-angled X-ray diffraction (WAXD) techniques
respectively.Further
the dispersibility
morphology and aggregate state of HBPE@POSS functionalized MWCNTs
and noncovant interactions between MWCNTs and HBPE@POSS as well
are investigated through UV-Vis absorbance spectroscopy
transmittance electron microscopy (TEM)
WAXD
Fourier-transformed infrared (FTIR) spectroscopy and TGA techniques
respectively.It is testified that POSS can be covalently introduced into hyperbranched polyethylene with a portion of 39.0 wt% in the HBPE@POSS.The HBPE@POSS is found to effectively debundle/solubilize MWCNTs both in THF and chloroform
giving stable MWCNTs solutions with concentrations up to 987 mg/L in THF and 511 mg/L in chloroform.Also
it is found that POSS of certain portion can be irreversibly adsorbed onto MWCNTs by means of the noncovalent CH- interactions between MWCNTs and HBPE@POSS.It is expected that more inorganic nanoparticles (INPs) can be introduced onto CNTs through this method
thus leading to a novel strategy for surface functionalization of CNTs with INPs.