Bionic Multisilicon Copolymers Used As Novel Cross-Linking Agents for Preparing Anion Exchange Hybrid Membranes

摘要

Bionic multisilicon copolymers have long-main chains and many branched chains, and contain multifunctional groups of - N~+(CH3)3Cl~-and -Si(OCH3)3, which are similar to the stem, branch, fruit, and acetabula of a vine from bionic aspect, respectively. They have high flexibility, charge density, and cross-linking ability and thus can be used as novel cross-linking agents for preparing anion-exchange hybrid membranes. High content of -Si(OCH3)3 groups (68-78%) is suitable to enhance membrane stabilities. The membranesare stable in 65 C water up to 120 h and can keep integrity in 2 mol/L NaOH for 192 h. High content of -N~+(CH3)3Cl groups (42-55%) is suitable to enhance membrane electrical properties. The membranes have low membrane resistance (B_m, 0.59-0.94 Ω cm~2) and high diffusion dialysis performance. The acid (H~+) dialysis coefficients (U_H) are in the range of 0.007-0.075 m h~(-1) at room temperature and 0.015-0.115 m h~(-1) at 40 °C. The separation factor (S_(H/Fe)) can reach up to 43 at room temerature and 49 at 40 °C. All of the membranes are highly homogeneous, mechanically stable (21-31 MPa, 25-147%), and thermally stable (227-275 °C for halide form membranes, and 157-172 °C for OH~- form membranes). Hence, the investigation of multisilicon copolymers will give rise to a new developing field in material and membrane sciences.