A new type of cation-exchange polymeric microspheres with pendant methylenethiol groups

Synthesis and characterization of the new styrene microspheres with pendant methylenethiol groups are presented. At the first stage, the polymeric matrices were obtained by the suspension-emulsion polymerization of monomers: styrene (St) with 2,3-(2-hydroxy-3-methacryloyloxypropoxy)naphthalene (NAF.DM) or (bis[4(2-hydroxy-3-methacryloyloxypropoxy)phenyl]sulfide (BES.DM) or divinylbenzene (DVB). At the second stage, the modification of the sythesized matrices was performed as follows: the matrices were reacted with paraformaldehyde in the presence of hydrochloric acid forming chloromethyl derivatives. Next, by reaction with thiourea, a thiouronium salt was obtained, and then the hydrolysis with NaOH solution and acidification with HCl were carried out. Finally, microspheres with -CH2SH groups on their surface were obtained. The -SH group content (elemental analysis), thermal properties (thermogravimetric analysis), Fourier transform infrared as well as the swelling characteristics of the functional microspheres were examined. The surface texture was also visualized by the atomic force microscopy (AFM) method. The obtained polymers were screened towards sorption of Cu(II) ions. It was found that a better correlation between the experimental Cu(II) uptake and the theoretical curves predicted by the Langmuir or Freundlich models is obtained in the case of the DVB-St-SH polymer. In the case of the BES.DM-St-SH and 2,3-NAF-St-SH ones, the Freundlich model corresponded quite well to the experimental data. Copyright (c) 2013 John Wiley & Sons, Ltd.