Functionalized Boron Nitride Nanosheets: A Thermally Rearranged Polymer Nanocomposite Membrane for Hydrogen Separation.

Amino functionalized boron nitride nanosheets (FBN) were incorporated into a crosslinked, thermally rearranged polyimide (XTR) to fabricate FBN-XTR nanocomposite membrane. The FBN-XTR membrane exhibited a small decrease in H2 permeability but demonstrated a remarkably increased H2 gas selectivity over other gases, compared with XTR. The XTR membrane heat-treated at 425 °C had a H2 permeability of 210 Barrers and a H2 /CH4 separation factor of 24.1, whereas the nanocomposite membrane with 1 wt % FBN exhibited a H2 permeability of 110 Barrers and H2 /CH4 separation factor of 275, an order of magnitude greater. At 1 wt % FBN loading, the FBN-XTR membrane showed three times higher tensile strength and 60 % higher elongation than pristine XTR membrane. In addition, FBN-XTR was found to be able to be readily processed into thin-film membranes for practical H2 separation applications.

Stress corrosion cracking and corrosion fatigue characterisation of MgZn1Ca0.3 (ZX10) in a simulated physiological environment.

Magnesium (Mg) alloys have attracted great attention as potential materials for biodegradable implants. It is essential that an implant material possesses adequate resistance to cracking/fracture under the simultaneous actions of corrosion and mechanical stresses, i.e., stress corrosion cracking (SCC) and/or corrosion fatigue (CF). This study investigates the deformation behaviour of a newly developed high-strength low-alloy Mg alloy, MgZn1Ca0.3 (ZX10), processed at two different extrusion temperatures of 325 and 400°C (named E325 and E400, respectively), under slow strain tensile and cyclic tension-compression loadings in air and modified simulated body fluid (m-SBF). Extrusion resulted in a bimodal grain size distribution with recrystallised grain sizes of 1.2 µm ± 0.8 µm and 7 ± 5 µm for E325 and E400, respectively. E325 possessed superior tensile and fatigue properties to E400 when tested in air. This is mainly attributed to a grain-boundary strengthening mechanism. However, both E325 and E400 were found to be susceptible to SCC at a strain rate of 3.1×10-7s-1 in m-SBF. Moreover, both E325 and E400 showed similar fatigue strength when tested in m-SBF. This is explained on the basis of crack initiation from localised corrosion following tests in m-SBF.

Carbon Nanotube/Alumina/Polyethersulfone Hybrid Hollow Fiber Membranes with Enhanced Mechanical and Anti-Fouling Properties.

Carbon nanotubes (CNTs) were incorporated into alumina/polyethersulfone hollow fibre membranes to enhance the mechanical property and the efficiency of water treatment. Results show that the incorporation of CNTs can greatly limit the formation of large surface pores, decrease the void size in support layers and improve the porosity and pore connectivity of alumina/polyethersulfone membranes. As a result of such morphology change and pore size change, both improved flux and rejection were achieved in such CNTs/alumina/polyethersulfone membranes. Moreover, the CNTs/alumina/PES membranes show higher antifouling ability and the flux recoveries after being fouled by bovine serum albumin (BSA) and humic acid were improved by 84.1% and 53.2% compared to the samples without CNT incorporation. Besides the improvement in water treatment performance, the incorporation of CNTs enhanced the tensile properties of inorganic/polymer membranes. Therefore, such CNTs/alumina/PES hollow fiber membranes are very promising candidates for good filter media in industry, considering their high efficiency and high mechanical properties.