Ion-exchange Studies of Copolymer Derived from 4,4′-Biphenol

Abstract

A novel copolymer resin (4,4′-BP-4,4′-ODA-F-II) has been synthesized by condensation polymerization reaction of 4,4′-biphenol and 4,4′-oxydianiline using the linkage of formaldehyde in presence of acid catalyst. The resin composition was determined on the basis of elemental analysis. Solution viscosity measurements in dimethylformamide were carried out to ascertain the characteristic functions and constants. The number average molecular weight was determined by conductometric titration in non-aqueous medium. The copolymer resin was further characterized by UV-Visible, Infra-red and Nuclear magnetic resonance spectroscopy to confine the most probable structure of synthesized copolymer. Thermal analysis was carried out for studying the thermal degradation behavior and kinetic parameters. Thermal degradation curve depicts four decomposition steps after a loss of water molecule and has been discussed with minute details by applying Freeman-Carroll, Sharp-Wentworth and Coat-Redfern equations to evaluate the kinetic parameters i.e., activation energy (Ea), order of reaction (n) and frequency factor (z). The data from Freeman-Carroll method has been used to determine various thermodynamic parameters i.e., entropy change (ΔS), free energy change (ΔF) and apparent entropy (S*). This copolymer is proved to be a selective chelating ion exchanger for certain metal ions such as Fe3+, Cu2+, Hg+2, Ni2+, Co2+, Zn2+, Cd2+ and Pb2+. A batch equilibrium method was employed in the study of selectivity of metal ion uptake involving the measurements of distribution of a given metal ion between the copolymer sample and a solution containing the metal ion. The study was carried out over a wide pH range, shaking time and in media of various ionic strengths.