Yufei Wang,Shuanjin Wang,Min Xiao,Shuqin Song,Dongmei Han,Michael A. Hickner,Yuezhong Meng
Novel sulfonated poly (fluorenyl ether ketone) with pendant quaternary ammonium groups (SPFEKA) was successfully synthesized by one-pot copolymerization of bis(4-fluoro-3-sulfophenyl)sulfone disodium salt, 4,4′-difluorobenzophenone, bisphenol fluorene and 2,2′-dimethylaminemethylene-9,9′-bis(4-hydroxyphenyl) fluorene (DABPF). The chemical structures were confirmed by FT-IR, and 1 H NMR. The thermal properties were fully investigated by TGA . The synthesized copolymers SPFEKAs are soluble in aprotic solvents, and can be cast into membranes on a glass plate from their N,N′-dimethylacetamide (DMAc) solution. A new kind of amphoteric ion exchange membrane (AIEM) was obtained by immersed SPFEKA into 1 M sulfuric acid. The proton conductivities of these membranes are comparable to the most reported sulfonated polymers under the same conditions. The permeability of vanadium ions in vanadium redox flow battery (VRB) was effectively suppressed by introducing quaternary ammonium groups for Donnan exclusion effect . AIEM-20% possess a only 4.4% vanadium ion permeability of Nafion 115. Cell performance tests showed that the VRB assembled with AIEM-20% shows the highest coulombic efficiency (CE) at the current density of 50 mA/cm 2 , because of its lowest VO 2+ permeability. In conclusion, these ionomers could be promising candidates for ion-exchange membranes for VRB applications.
Xing Ming,Qing Liu,Miaomiao Wang,Yongqing Cai,Binmeng Chen,Zongjin Li
Chloride-induced corrosion in reinforced concrete is a primary durability issue that causes large economic loss every year. To improve the intrinsic chloride binding capacity and realize a favorable corrosion protection of cement-based materials are thus crucial to prolong the service life of concrete structures. Here, alumina nano particles (ANPs) were incorporated to improve the chloride binding capacity of cement pastes in chloride solutions and the anti-corrosion performance of mortars under accelerated corrosion process. The ANPs facilitated the formation of alumino-ferrite-mono (AFm)-type phases, thereby improved the content of chemically bound chlorides. Solution calcium (Ca) ions benefited the chloride captured by calcium-(alumino-)silicate-hydrates (C-(A-)S-H) in the assistance of ANPs, especially at high initial chloride concentrations , and further evoked a pH-related chloride binding response. Moreover, the enhanced corrosion resistance was finally realized by incorporating appropriate amount of ANPs because of the filling and chemical effects induced low permeability of mortars. In general, the ANPs possess dual functions in the aspects of chloride binding and corrosion inhibition . These findings are expected to advance the design of high-durable cement-based materials serviced in the marine environment.
危险品化学品经营许可证（带存储）