Synthesis and Characterization of Polymers Containing Rare Earth Metals

Abstract

Abstract Europium and terbium salts of methacrylic acid (MA) and octanoic acid (OCA) were prepared by a method similar to that described in the literature. Either Eu(MA)3 or Tb(MA)3 with three double bonds (C˭C) was used as a crosslinker containing rare earth metal ions, but the octanoic acid salts were used as additives. The salts were dissolved in methacrylic acid (<20%) and then copolymerized with methyl methacrylate (>80%) using AIBN (0.2 wt%) as initiator. The two types of polymers, one containing Eu(MA)3 or Tb(MA)3 and the other with Eu(OCA)3 or Tb(OCA)3, were synthesized by bulk copolymerization in molds made of two glass plates and characterized. The fluorescence spectroscopy of these polymers under ultraviolet/visible excitation light was investigated. The fluorescence excitation and emission spectra of the polymers showed the characteristic spectra of the free Eu3+ or Tb3+. The fluorescence intensity of the rare earth metal ions increased with increasing rare earth metal content. Fluorescence measurements for Eu(MA)3, Tb(MA)3, and Eu(OCA)3 polymers do not display fluorescence quenching behavior within the range of the rare earth metal content used in our experiments. But for Tb(OCA)3 polymers, this phenomenon was observed, illustrating that ionic aggregates exist in Tb(OCA)3 polymeric systems.