Novel aromatic and aromatic-aliphatic poly(thiourea-amide)s for the extraction of toxic heavy metal ions

Abstract

A series of novel aromatic and aromaticaliphatic diamines [isophthaloyl bis(3-(3-aminophenyl)thiourea), terephthaloyl bis(3-(3-aminophenyl)thiourea), adipoyl bis(3-(3-aminophenyl)thiourea), sebacoyl bis(3-(3-aminophenyl)thiourea)] were synthesized starting from the dinitro compounds. Spectroscopic and elemental analyses were carried out for the structure elucidation of the monomers. Three series of poly(thiourea-amide)s (PTAMs) bearing C=S groups were prepared through the condensation of new diamines with the diacid chlorides such as isophthaloyl, terephthaloyl and adipoyl chloride. The ensuing PTAMs were characterized using FTIR, H-1-NMR and C-13-NMR techniques. Physical properties of the polymers such as solution miscibility, crystallinity, solution viscosity, molecular weight, and thermal properties were measured. Consequently, good organosolubility of these polymers was experiential in amide solvents as DMAc, DMF, DMSO and NMP. Moreover, PTAMs exhibited eta(inh) in the range of 0.92-1.56 dL/g and GPC measurements revealed M-w around 607 x 10(2)-851 x 10(2). DSC served to envisage the glass transition temperatures (T-g) of poly(thiourea-amide)s located between 232 and 258 degrees C and the initial decomposition temperatures (T-0) probed by thermogravimetry were in the range of 305-419 degrees C. Structure-property relationship of these polymers was also studied. Eventually, solid-liquid extraction tests of the selected poly(thiourea-amide)s systems revealed excellent results because these polymers show nearly 100% elimination of lead and mercury cations from water media. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012