Resin-V: Synthesis and Physicochemical Studies of a Biphenol–Guanidine–Formaldehyde Terpolymer Resin Manjusha M. Jadhao, 1 Sandeep Kumar, 1 L. J. Paliwal, 2 N. S. Bhave, 2 Sarfaraz Alam 1 1 Defence Materials and Stores Research and Development Establishment, G. T. Road, Kanpur 208013, India 2 Department of Chemistry, Rashtrasant Tukdoji Maharaj Nagpur University, Nagpur 440010 ,India Received 19 September 2008; accepted 14 November 2009 DOI 10.1002/app.32084 Published online 10 June 2010 in Wiley InterScience (www.interscience.wiley.com). ABSTRACT: A terpolymer resin was synthesized by the condensation of 2,2 0 -dihydroxybiphenyl with guanidine and formaldehyde in the presence of 2M HCl as a catalyst. The resin obtained was characterized on the basis of ele- mental analysis, infrared spectroscopy, NMR spectroscopy, ultraviolet–visible spectroscopy, and thermogravimetric analysis/differential thermal analysis. The number-average molecular weight was determined by nonaqueous conduc- tometric titration. A thermal study of the resin was carried out to determine its mode of decomposition, activation energy, order of reaction, frequency factor, entropy change, free energy, and apparent entropy change. The Freeman– Carroll and Sharp–Wentworth methods were applied for the calculation of the kinetic parameters, and the data from the Freeman–Carroll method were used to determine vari- ous thermodynamic parameters. The chelation ion-exchange properties of this resin were studied for Fe 3þ , Cu 2þ , Ni 2þ , Co 2þ , Zn 2þ , Cd 2þ , and Pb 2þ ions. A batch equilibrium method was used in the study of the selectivity of the metal- ion uptake that involved the measurements of the distribu- tion of a given metal ion between the polymer sample and a solution containing the metal ion. The study was carried out over a wide pH range and in media of various ionic strengths. The terpolymer showed a higher selectivity for Fe 3þ ions than for the other metal ions in this study. V C 2010 Wiley Periodicals, Inc. J Appl Polym Sci 118: 1969–1978, 2010 Key words: degree of polymerization (DP); infrared spectroscopy; ion exchangers; NMR; thermogravimetric analysis (TGA) INTRODUCTION Polymer science continues to play an important role in the development of new and improved ion- exchange resins. The main object of the research on ion-exchange and chelating resins is to prepare func- tionalized polymers that can provide flexible work- ing conditions together with good stability and a high capacity for selective metal ions. 1,2 These resins, possessing chelating groups, may be used in chro- matographic separations of certain metal ions and in the recovery and removal of traces of certain metal- lic ions from a high concentration of other electro- lytes. 3,4 Phenolformaldehyde resins are widely used in different branches of industry. The introduction to their composition of functional groups, such as amino, sulfo, and carboxyl groups, improves the sorption properties of ion exchangers and imparts to them selectivity. 5,6 Many terpolymers derived from phenol derivatives have been found to posses selec- tive chelating ion-exchange properties. 7–9 The phenol aminoformaldehyde resin Yarrezin B, usually used for the extraction of ions of heavy nonferrous metals (zinc, lead, copper, cadmium, etc.), is produced in the Russian Federation. The resin based on 7-alkyl-8- hydroxyquinoline (Kelex 100 or Lix 26) is used to remove copper and gallium and to separate ions of toxic heavy metals from solutions of Ni(II), Cu(II), Zn(II), Cd(II), and Hg(II). 10 Lenka and coworkers 11–13 reported the ion-exchange properties of 2,4-dinitro- phenylhydrazone of 2-hydroxyacetophenone/formal- dehyde resin, semicarbazone, and oximes of 2- hydroxyacetophenone-substituted benzoic acid/ formaldehyde. 11–13 In the literature, few resins con- taining guanidine functional groups have been reported; 14,15 they play an important role as a com- plexing agent, an ion exchanger, and so on. Guani- dine is also used as an accelerator and increases the ultimate strength of a material, 16 whereas biphenol- containing polymers exhibit renowned applications in optical data storage and heat- and fire-resistant properties. 17,18 Cataneseu et al. 19 studied the synthe- sis and characterization of terpolymers derived from 4,4 0 -dihydroxyazobenzene and 4,4 0 -dihydroxybi- phenyl with various 2-dihalo monomers, namely, 1,3-dibromopropane, bis(2-chloroethyl) ether, 1,6- dichlorohexane, and 2,2-bis(chloromethyl)oxetone, by phase-transfer catalysis in liquid–liquid systems. Jeong et al. 20 examined the miscibility and shape- memory effect of segmented thermoplastic polyur- ethane with a poly(caprolactone)-based soft segment and hexamethylene isocyanate/1,4-butanediol/4,4 0 - Correspondence to: M. M. Jadhao (manju_poly@yahoo. com). Journal of Applied Polymer Science, Vol. 118, 1969–1978 (2010) V C 2010 Wiley Periodicals, Inc.