Synthesis and electric properties of polyethylene glycol-modified fly ash floating bead/polyaniline composites

Abstract

Fly ash floating bead (FAFB) was modified by the nonionic surfactant polyethylene glycol (PEG) under various concentrations to improve its hydrophobility, and then PEG modified FAFB composited with polyaniline (FAFB-PEG/PAn) by emulsion polymerization method using different feed ratios of FAFB-PEG. The chemical structure, phase structure, microstructure, conductivity, and dielectric properties were studied by FT-IR, XRD, SEM, four-probe technique, and LCR digital bridge, respectively. It was demonstrated that the optimal concentration of PEG was 1 mol/L and the corresponding grafting ratio was 1.42 %. The phase structure of FAFB was not destroyed after modification by PEG, while the surface became smoother and could be coated by PAn successfully according to SEM technique. Compared to that of dodecylbenzenesulfonic acid doped PAn (PAn-DBSA), the conductivity of FAFB-PEG/PAn was decreased by 10-100 times after introduction of various amounts of FAFB-PEG, especially the value could be decreased to 0.01 S cm-1 if 50 wt% of FAFB-PEG was provided. Additionally, the dielectric constant and loss factor of FAFB-PEG/PAn composites gradually decreased with increasing amount of FAFB-PEG in the frequency range of 100 KHz-2 MHz, namely, the dielectric constant could be still kept at 500 and correspondingly the loss factor decreased to 4.7 at 100 KHz if 50 wt% of FAFB-PEG was provided. The leaking current phenomenon derived from PAn-DBSA could also be weakened by FAFB-PEG.