Sericin cocoon bio-compatibilizer for reactive blending of thermoplastic cassava starch

Cassava starch was blended with glycerol to prepare thermoplastic starch (TPS). Thermoplastic starch was premixed with sericin (TPSS) by solution mixing and then melt-blended with polyethylene grafted maleic anhydride (PEMAH). The effect of sericin on the mechanical properties, morphology, thermal properties, rheology, and reaction mechanism was investigated. The tensile strength and elongation at break of the TPSS10/PEMAH blend were improved to 12.2 MPa and 100.4%, respectively. The TPS/PEMAH morphology presented polyethylene grafted maleic anhydride particles (2 μm) dispersed in the thermoplastic starch matrix, which decreased in size to approximately 200 nm when 5% sericin was used. The melting temperature of polyethylene grafted maleic anhydride (121 °C) decreased to 111 °C because of the small crystal size of the polyethylene grafted maleic anhydride phase. The viscosity of TPS/PEMAH increased with increasing sericin content because of the chain extension. Fourier-transform infrared spectroscopy confirmed the reaction between the amino groups of sericin and the maleic anhydride groups of polyethylene grafted maleic anhydride. This reaction reduced the interfacial tension between thermoplastic starch and polyethylene grafted maleic anhydride, which improved the compatibility, mechanical properties, and morphology of the blend.

Sericin cocoon bio-compatibilizer for reactive blending of thermoplastic cassava starch

Cassava starch was blended with glycerol to prepare thermoplastic starch (TPS). TPS was premixed with sericin (TPSS) by solution mixing and then melt-blended with polyethylene grafted maleic anhydride (PEMAH). The effect of sericin on the mechanical properties, morphology, thermal properties, rheology, and reaction mechanism was investigated. The tensile strength and elongation at break of the TPSS10/PEMAH blend were improved to 12.2 MPa and 100.4%, respectively. The TPS/PEMAH morphology presented PEMAH particles (2 µm) dispersed in the TPS matrix, which decreased in size to approximately 200 nm when 5% sericin was used. The melting temperature of PEMAH (121°C) decreased to 111°C because of the small crystal size of the PEMAH phase. The viscosity of TPS/PEMAH increased with increasing sericin content because of the chain extension. Fourier-transform infrared spectroscopy (FTIR) confirmed the reaction between the amino groups of sericin and the maleic anhydride groups of PEMAH. This reaction reduced the interfacial tension between TPS and PEMAH, which improved the compatibility, mechanical properties, and morphology of the blend.

Porous intermetallic Ni2XAl (X = Ti or Zr) nanoparticles prepared from oxide precursors

Chemical synthesis of porous intermetallic Ni2XAl (X = Ti or Zr) nanoparticles with small crystal size (24–34 nm) and high surface area (10–71 m2 g−1).

Photocatalytic Degradation of Paraquat Dichloride using TiO2-Fe Nano Powder under Visible and Sunlight Irradiation

Paraquat dichloride, is an active herbicide with the chemical formula [(C6H7N2)]Cl2, and in the last decade became the most widely used agricultural pesticide in Indonesia. It has an important role in oil palm plantations but recently appeared many problems and caused environmental pollution. In this research, the photodegradation of paraquat herbicide using TiO2-Fe nanopowder was investigated. The TiO2-Fe catalyst was prepared by the sol-gel method and characterized using XRD and DRS. The characterization results showed that Fe as a dopant on TiO2 produced a small crystal size. This condition can increase the performance of photocatalysis from the area of UV to visible light. Degradation of paraquat dichloride is carried out under visible and sunlight irradiation to significantly increase photocatalytic activity. Decreasing of paraquat content was observed for every 15 minutes and measured by spectrophotometer UV-Vis. The addition of 0.5 gram of TiO2-Fe catalyst to 50 mL of sample solution increased the degradation percent by 98.4% for 75 minutes with a concentration of Fe3+ 10% (w/w). These results indicate that the presence of Fe dopants on TiO2 can increase the photocatalytic activity of nano TiO2 particles from UV light to visible light.

Large plasticity in magnesium mediated by pyramidal dislocations

Lightweight magnesium alloys are attractive as structural materials for improving energy efficiency in applications such as weight reduction of transportation vehicles. One major obstacle for widespread applications is the limited ductility of magnesium, which has been attributed to 〈c+a〉 dislocations failing to accommodate plastic strain. We demonstrate, using in situ transmission electron microscope mechanical testing, that 〈c+a〉 dislocations of various characters can accommodate considerable plasticity through gliding on pyramidal planes. We found that submicrometer-size magnesium samples exhibit high plasticity that is far greater than for their bulk counterparts. Small crystal size usually brings high stress, which in turn activates more 〈c+a〉 dislocations in magnesium to accommodate plasticity, leading to both high strength and good plasticity.

Preparation of Black Phosphorus by the Mechanical Ball Milling Method and its Characterization

In this paper, red phosphorus successfully turned to black phosphorus by the mechanical ball milling method. The samples were analyzed by the X-ray diffraction (XRD) method and by high resolution transmission electron microscopy (HRTEM). The XRD result showed that the black phosphorus obtained had small crystal size and a small, amorphous, broadly diffused peak of red phosphorus. The HRTEM analysis showed that the grain size of most of the black phosphorus was small (about 3-5nm). The electron diffraction pattern and the d-spacing on HRTEM correspond well to the characteristic peaks of black phosphorus, such as {111}, {021} and {151}. In some areas, the grain size of black phosphorus was large (about 20-50nm) and contained many defects in crystals. This showed that initially, the amorphous red phosphorus turned into black phosphorus nanocrystals under the action of mechanical milling. Subsequently, the grains were refined and became tiny grains under the action of a large number of edge dislocations in the crystals. During analysis of the TEM, the small size crystals of black phosphorus were rapidly non-crystallized and seriously damaged by electron irradiation. Therefore only the big grains were left after 30 minutes of irradiation.

Vanadium, V – a new native element mineral from the Colima volcano, State of Colima, Mexico, and implications for fumarole gas composition

Vanadium, V, is a new mineral found in sublimates of high-temperature fumaroles of the Colima volcano, Mexico. The mineral precipitates over a narrow temperature range of 550–680°C, and occurs in association with colimaite (K3VS4) and shcherbinaite (V2O5). Native vanadium was been found on the inner wall of an inserted silica tube and subsequently in the adjacent rock of the Z3 fumarole. Vanadium forms smooth, irregular to flattened crystals, 5–20 μm in diameter. Smaller irregular crystals have also been observed in silica tubes. Due to its small crystal size, its physical properties (hardness, cleavage and density) could not be determined. An EDS spectrum indicated the presence of V, Fe, Al and Ti with an empirical formula calculated on the basis of EPMA analyses of V0.86Fe0.09Al0.04Ti0.01. Gandolfi and glancing-angle X-ray diffraction data showed that the microcrystals were body-centred cubic, space group Im3̄m, a = 3.022(3) Å, V = 27.60 (5) Å3, Z = 2. The five strongest calculated diffraction lines are [ d spacings in Å, (I) (hkl)]: 2.1411 (100)(110), 1.5126 (12)(200), 1.2301 (19)(211), 0.9565 (8)(310) and 8.8090 (11)(321). The calculated density is 6.033 g cm–3. Thermochemical modelling was used to explain why very oxidized gas at Colima precipitates V-bearing minerals and some native elements (vanadium and gold). Vanadium, is the second newly recognized mineral species (after colimaite) collected from an active fumarole in this volcanic crater. The mineral and its name have been approved by the CNMNC (IMA 2012-021a).