| In addition to excellent properties of methylphenyl polysiloxane, the amino-modified methylphenyl polysiloxane has special reactivity because of the introduction of amino. Amino groups can generate the Schiff base structure by the reaction with carbonyl group. Since Schiff base can form complexes with metal ions, it occupies a very important position in coordination chemistry. Because of amino’s reactivity, Schiff base could be introduced on the silicone polymer so that it can be used to coordinated with metal ions to prepare functional silicone polymer materials with different properties. Since the N of -C=N and O of ortho group in Salicylidene Schiff base and 2-Carboxybenzaldehyde Schiff base can be both used as donor atoms, they have strong coordination ability and are easy to form stable complexes.Rare earth ions have unique luminescent properties. Schiff base ligands can effectively sensitize the luminescence of rare earth ions. The lanthanide-polysiloxane complexes with excellent luminescence properties can be obtained by the coordination of rare earth ions and Schiff base ligands, which combining the virtues of rare earth and silicone polymer, such as resistant heat, weather, easy processing, physical inertia, etc. It could be a new direction of the fluorescent materials.Compared with the conventional covalent cross-linking, polymer network formed by coordination cross-linking has sufficient strength to form materials. Harsh chemical environment isn’t necessary for the recombination of coordination bonds so that coordination cross-linking system can be used to design self-healing materials. Combing the flexibility of silicone polymeric chain and the coordination between Schiff base ligands with appropriate metal ions, the self-healing materials which have intelligent response to external condition can be prepared.In this paper, aminopropyl siloxane monomer and methyl phenyl cyclic siloxane were used as raw materials to obtain a series of aminopropyl modified polysiloxane, including side chains and terminated, by anionic catalytic bulk polymerization. Then the Schiff base functional polysiloxane were prepared by the reaction of aminopropyl modified silicone oil and salicylaldehyde, as well as 2-carboxybenzaldehyde. FT-IR,1H-NMR and UV-Vis were used to characteristic the structures of silicone oils and Schiff base polysiloxane.Four kinds of lanthanide (Ⅲ)-imined polysiloxane complexes had been prepared by the coordination reaction between Schiff base polysiloxane and lanthanides (Eu3+ or Tb3+). The complexes were characterized by FT-IR, H-NMR, UV-Vis, and fluorescence spectra. Studies showed that the ligands had already coordinated to lanthanides via N atom. The character fluorescence of Eu and Tb could be observed under ultraviolet light. Both the two kinds of Schiff base ligand had a better sensitization effect of Eu3+than that of Tb3+. And compared with salicylaldimine schiffbase ligand, the 2-carboxybenzaldehyde schiffbase ligand sensitizedthe fluorescence of rare earth ions more better.Using salicylaldiminato polysiloxane of different molecular weight as ligands, the Schiff base coordination polymer were prepared by the coordination with Cu2+, Co+, Fe+, respectively. The structures, thermal properties, mechanical properties, self-healing properties of these complexes were characterized by FT-IR and other test methods. The results showed that the coordination cross-linking between by Schiff base polysiloxane and metal ions (Cu2+, Co2+and Fe3+) could obtain the materials with certain mechanical properties. The self-healing effect of different complexes differs because of the different stability of coordination bonds. Cu(II) complexes and Fe(Ⅲ) complexes have good self-healing properties, while Co(II) complexes does not at low temperatures. Under the same conditions, the self-healing properties of Cu(Ⅱ) complexes is better than that of Fe(Ⅲ) complex. And the larger the molecular weight of the ligand molecule, the higher the ratio of ligand/metal ions, the lower healing efficiency would be. |
PDF Full Text Request