Polydiphenylamine/zeolite y composites and electrical conductivity responses toward halogenated hydrocarbons

Abstract

Composites of polydiphenylamine (D-PDPA) and zeolite Y with H+ as the cation (Y-H+) have been fabricated to be used as a sensing material towards non-halogenated and halogenated solvents (hexane, dichloromethane, 1, 2-dichloroethane, chloroform). These composites are toxic towards human and environment and are widely used as solvents in various industries. Polydiphenylamine, zeolite Y, and their composites are characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, particle size analysis, surface area, and pore size analysis. The effects of the Si/Al ratio, zeolite content, and vapor concentrations are investigated. The electrical conductivity sensitivity of the composites towards the solvents is higher than the pristine D-PDPA by ~1 order of magnitude. The composites can discriminate a non-halogenated solvent from halogenated solvents. They possess maximum electrical conductivity sensitivity values towards dichloromethane, but the composites do not respond to hexane. Generally, the sensitivity of the composites increases with increasing zeolite content and vapor concentration. The interactions between the composites and the vapors are investigated by FT-IR spectroscopy and UV-Vis spectroscopy. A mechanism for the interaction between the composites and the solvents is proposed. © 2013.