Triphasic Oxygen Storage in Wet Nanoparticulate Polymer of Intrinsic Microporosity (PIM-1) on Platinum: An Electrochemical Investigation.

The triphasic interaction of gases with electrode surfaces immersed in aqueous electrolyte is crucial in electrochemical technologies (fuel cells, batteries, sensors). Some microporous materials modify this interaction locally via triphasic storage capacity for gases in aqueous environments linked to changes in apparent oxygen concentration and diffusivity (as well as activity and reactivity). Here, a nanoparticulate polymer of intrinsic microporosity (PIM-1) in aqueous electrolyte is shown to store oxygen gas and thereby enhance electrochemical signals for oxygen reduction in aqueous media. Oxygen reduction current transient data at platinum disk electrodes suggest that the reactivity of ambient oxygen in aqueous electrolyte (typically Doxygen = 2.8 × 10-9 m2 s-1; coxygen = 0.3 mM) is substantially modified (to approximately Dapp,oxygen = 1.6 (±0.3) × 10-12 m2 s-1; capp,oxygen = 50 (±5) mM) with important implications for triphasic electrode processes. The considerable apparent concentration of oxygen even for ambient oxygen levels is important. Potential applications in oxygen sensing, oxygen storage, oxygen catalysis, or applications associated with other types of gases are discussed.

Solar driven CO2 reduction with a molecularly engineered periodic mesoporous organosilica containing cobalt phthalocyanine.

A molecular cobalt phthalocyanine (CoPc) catalyst has been integrated in an ethylene-bridged periodic mesoporous organosilica (PMO) to fabricate a hybrid material, CoPc-PMO, that catalyses CO2 reduction to CO in a photocatalytic system using [Ru(bpy)3]2+ (bpy = 2,2'-bipyridine) as a photosensitizer and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH) as an electron donor. CoPc-PMO displays a Co-based turnover number (TONCO) of >6000 for CO evolution with >70% CO-selectivity after 4 h irradiation with UV-filtered simulated solar light, and a quantum yield of 1.95% at 467 nm towards CO. This system demonstrates a benchmark TONCO for immobilised CoPc-based catalysts towards visible light-driven CO2 reduction.

Spruce Bark-Extracted Lignin and Tannin-Based Bioresin-Adhesives: Effect of Curing Temperatures on the Thermal Properties of the Resins.

In this study, formaldehyde-free bioresin adhesives were synthesised from lignin and tannin, which were obtained from softwood bark. The extraction was done via organosolv treatment and hot water extraction, respectively. A non-volatile, non-toxic aldehyde, glyoxal, was used as a substitute for formaldehyde in order to modify the chemical structure of both the lignin and tannin. The glyoxal modification reaction was confirmed by ATR-FTIR spectroscopy. Three different resin formulations were prepared using modified lignin along with the modified tannin. The thermal properties of the modified lignin, tannin, and the bioresins were assessed by DSC and TGA. When the bioresins were cured at a high temperature (200 °C) by compression moulding, they exhibited higher thermal stability as well as an enhanced degree of cross-linking compared to the low temperature-cured bioresins. The thermal properties of the resins were strongly affected by the compositions of the resins as well as the curing temperatures.

Hydrophobic Shape-Memory Biocomposites from Tung-Oil-Based Bioresin and Onion-Skin-Derived Nanocellulose Networks.

The fabrication of smart biocomposites from sustainable resources that could replace today's petroleum-derived polymer materials is a growing field of research. Here, we report preparation of novel biocomposites using nanocellulose networks extracted from food residue (onion skin) and a vegetable oil-based bioresin. The resin was synthesized via the Diels-Alder reaction between furfuryl methacrylate and tung oil at various ratios of the components. The onion-skin-extracted cellulose nanofiber and cellulose nanocrystal networks were then impregnated with the resins yielding biocomposites that exhibited improved mechanical strength and higher storage modulus values. The properties of the resins, as well as biocomposites, were affected by the resin compositions. A 190-240-fold increase in mechanical strength was observed in the cellulose nanofiber (CNF) and cellulose nanocrystal (CNC)-reinforced biocomposites with low furfuryl methacrylate content. The biocomposites exhibited interesting shape-memory behavior with 80-96% shape recovery being observed after 7 creep cycles.

Synthesis and Properties of Thermosets from Tung Oil and Furfuryl Methacrylate.

This work focuses on the development of cross-linked polymer from a highly unsaturated vegetable oil, tung oil (TO) and a bio-based acrylate, furfuryl methacrylate (FMA). The presence of a high degree of unsaturated carbon-carbon bonding in TO makes it a suitable precursor for polymer synthesis. Using this advantage of TO, in this work, we have synthesised a cross-linked polymer from TO and FMA through free radical polymerisation followed by Diels-Alder (DA) reaction. Successful incorporation of both of the raw materials and the two chemical reactions was shown using Fourier-transform infrared (FTIR) and Raman spectroscopy. The development of cross-linked structure was analysed through thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA).