Optical properties of methacrylate ionomers crosslinked by Ti(IV) with various ligands

Six ionomers crosslinked by Ti ions having various ligands, i.e. methacryli c acid (MAA), acrylic acid (AA), crotonic acid (CA), vinylacetic acid (VAA) , 2-(methacryloyloxy) ethyl acetoacetate (MEA), and di (2-methacryloyloxyet hyl) phosphate (PMOE), were prepared and their optical properties were inve stigated. Each ionomer showed a characteristic absorption between ultraviol et and visible region depending on the kinds of the ligands. These absorpti ons were attributed to charge transfer between Ti4+ and the ligands. Solari zation was also observed for ionomers containing MAA or AA as ligands. Name ly, by sunlight irradiation Ti4+ was reduced to Ti3+ and the colors of the ionomers changed from pale yellow to black.