Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/91475
Title: Evolution of polyaniline structure during synthesis
Authors: Neoh, K.G. 
Kang, E.T. 
Tan, K.L. 
Keywords: FTi.r.
oxidative polymerization
polyanilines
spectroscopy
structure
synthesis
u.v.-vis.
X.p.s.
Issue Date: Sep-1993
Source: Neoh, K.G.,Kang, E.T.,Tan, K.L. (1993-09). Evolution of polyaniline structure during synthesis. Polymer 34 (18) : 3921-3928. ScholarBank@NUS Repository.
Abstract: The oxidative polymerization of aniline by (NH4)2S2O8 in dilute solutions of HClO4 or HCl of various concentrations was investigated. The reactions were terminated at various times and the solid products were isolated and analysed using Fourier transform infra-red and ultraviolet-visible absorption spectroscopy and X-ray photoelectron spectroscopy. The ultraviolet-visible absorption spectra of the reaction mixtures and the structure of the initial solid products indicate different initial reaction pathways and intermediates occurring under the conditions tested. At low acid concentrations, the solids that are initially precipitated out are salts of short-chain oligomers with the anions from the protonic acid as well as sulfate anions. In contrast, at low pH, the long-chain, para-disubstituted nature of the solid is evident at the initial stages and the counterions are predominantly supplied by the protonic acid. With decreasing acid concentration, although the polymerization rate decreases, a long-chain para-disubstituted polymer is ultimately obtained, albeit with an increase in the proportion of sulfate anions serving as counterions and in the amount of unprotonated imine units. A comparison of the thermal stability of the various polymers indicates a significantly lower decomposition temperature for the polymers obtained at low acid concentrations or short reaction time. © 1993.
Source Title: Polymer
URI: http://scholarbank.nus.edu.sg/handle/10635/91475
ISSN: 00323861
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

Page view(s)

16
checked on Feb 17, 2018

Google ScholarTM

Check


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.