Ionic polymers based on tetrachloroferrate anions (FeCl 4 − ) have become one of the attractive functional materials due to their magnetic property. Series of polyvinyl chloride (PVC)-based ionic polymers ([PBCs][FeCl 4 ]) containing tetrachloroferrate anions were prepared by self-assembly using PVC , cholesteric pyridine-3,5-dicarbonate, 4,4 -bipyridine and FeCl 3 ·6H 2 O, and their liquid-crystalline (LC) behavior and magnetorheological (MR) effect were investigated in this study. The chemical structure, thermal properties and LC behavior were characterized by various equipment and instruments. The magnetic field response behavior, MR effect, and sedimentation stability were investigated by various technical methods. The [PBCs][FeCl 4 ] showed smectic A phase on heating and cooling cycles. The magnetorheological fluids (MRFs) were fabricated by the [PBCs][FeCl 4 ] polymers as suspended particles and silicone oil as carrier liquids, which presented a Bingham flow characteristics under an external magnetic field. For these [PBCs][FeCl 4 ]-based MRFs, both shear stress and magnetorheological effects increased with the increase of magnetic field strength, and it exhibited a maximum MR efficiency of 15.3 at 1.23 s −1 of shear rate under 80 kA/m of magnetic field strength. The MR effect of the [PBCs][FeCl 4 ]-based fluids was originated from a synergistic effect between the LC orientation of the mesogens and rearrangement of the FeCl 4 − anions when an external magnetic field was applied.
Li Cui,Shasha Li,Jin Kang,Caixia Yin,Yanxia Guo,Hongyan He,Fangqin Cheng
Effective separation of lithium isotopes ( 6 Li and 7 Li) is of great importance for the development of nuclear energy. Crown ethers (CEs) are widely used and reported separation systems, but the distribution coefficient of Li ( D Li ) is relatively low by CEs ( D Li , 10 − 2 –10 −5 ) and mainly depends on the anion type of Li salt. Herein, a novel and facile ion-pair strategy by introducing tetrachloridoferrate ([FeCl 4 ] − ) as counter anion is presented, which helps to overcome the Hofmeister bias and facilitates the efficient transfer of Li + from extremely hydrophilic chlorides. An exceptionally high D Li of 54 is achieved for benzo-15-crown-5 (B15C5), surpassing those of solvent extraction from solely Li salt aqueous solution. This strategy also demonstrates good separation performance of 6 Li/ 7 Li. The maximum 6 Li/ 7 Li separation factors ( α 6 L i / 7 L i ) of 1.038 and 1.049 are obtained for B15C5 and benzo-12-crown-4 (B12C4) in dichloroethane at 273 K. The highly efficient phase transfer of Li + can be attributed to the formation of stable [Li(B15C5)(H 2 O)][FeCl 4 ] or [Li(B12C4) 2 ][FeCl 4 ] ion pairs. Theoretical studies based on density functional theory (DFT) calculations suggest that the coordination and electrostatic environment of Li + plays an essential role in the separation of 6 Li/ 7 Li. Weakening the coordination and electrostatic interactions associated with Li + can facilitate the separation of 6 Li/ 7 Li. Additionally, B15C5 can be easily recycled by using ultra-pure water as the stripping solution. This work provides an industrially promising system for 6 Li/ 7 Li separation.
危险品化学品经营许可证（带存储）