Distribution of an antioxidant in polypropylene/ethylene-octene copolymer blends studied by atomic force microscopy-infrared.

In this work, the microscopic distribution of antioxidant 1010 (AT1010) in blends of isotactic polypropylene (iPP) with an ethylene-octene copolymer (POE) was investigated in situ using the atomic force microscopy-infrared (AFM-IR) technique. Pellets of an iPP/POE blend containing AT1010 at a mass ratio of 79.5 : 20 : 0.5 were extruded at different screw speeds, and were then injection-molded into plates. The domain size of the POE disperse phase in the pellets was about 1 µm, regardless of the screw speed, and remained unchanged in the injection molding. AFM-IR analyses revealed that AT1010 preferred to stay in the POE disperse phase rather than in the iPP matrix, with a concentration ratio of ∼1.2 in the extruded pellets independent of the screw speed, which was further increased to ∼1.5 in the molded plates. The preferred concentration of AT1010 in the POE was in line with its higher solubility in rubber than in iPP, and the enhanced partition of AT1010 in the molded plates was attributed to a longer processing time in the molten state than that for the extruded pellets, which was verified by AFM-IR analyses of pellets extruded with different residence times.

Carbon-based dots for the electrochemical production of hydrogen peroxide.

In this study, natural graphite was liquid exfoliated in the presence of single-layer carbon-based dots (CDs), which were used as intercalators. It was found that graphene of mainly single-layer has been obtained, on which lots of CDs were deposited. Combining the unique properties of these two materials, the CDs deposited on graphene (G/CDs) are proved to be outstanding catalysts for the electroreduction of oxygen to H2O2. The results from control experiments and density functional theory calculations demonstrated that the oxygen-containing functional groups on the CDs played a key role in the catalytic activity of the G/CDs.

Largely improved tensile properties of chitosan film via unique synergistic reinforcing effect of carbon nanotube and clay.

In this work, a great synergistic effect of 2D clay platelets and 1D carbon nanotubes (CNTs) on reinforcing chitosan matrix has been observed for the first time. With incorporation of 3 wt % clay and 0.4 wt % CNTs, the tensile strength and Young's modulus of the nanocomposites are significantly improved by about 171 and 124%, respectively, compared with neat chitosan. This could be understood as due to the formation of much jammed fillers network with 1D CNTs and 2D clay platelets combined together, as indicated by rheological measurement. Our work demonstrates a good example for the preparation of high performance polymer nanocomposites by using nanofillers of different dimension together.