Fang-Chang Tsai

Carbon Nanotube Industrial Applications

Since carbon nanotube was discovered by S. Ijima in 1991, it has become one of the main academic research subjects. Carbon nanotube is the thinnest tube human can make presently. It has advantages in lightweight, high strength, high toughness, flexibility, high surface area, high thermal conductivity, good electric conductivity and chemical stability. Carbon nanotube can be applied to manufacture smaller transistors or electronic devices. Samsung Korea has made carbon nanotube into Field Emission Display. When the technology is matured and the cost is reduced, it will replace traditional bulky cathode ray tube (CRT) screen. Carbon nanotube has high toughness, so it can be made into highstrength composite with other materials. Thus, carbon nanotube is a material with high economic value and very worth researching. Besides, carbon nanotube has both conductor and semiconductor properties. Therefore, for electronic circuit, the semiconductor property of carbon nanotube enables its application to field emission transistor (FET) gate electrode, which has 100 times higher electric conductivity than silicon semiconductor when voltage is applied and 1000 times higher operational frequency than current Complementary MetalOxide Semiconductor (CMOS). The conductor property makes carbon nanotube have similar thermal conductivity to diamond and superior current carrying capacity to copper and gold. For the application of display, its long-term reliability is very excellent [Iijima, 1991, Lee et. al., 1977]. In order to create new material systems with superior properties, various nanoparticle morphologies have been used as reinforcing fillers in elastomeric matrices. These nanometerscale reinforcing particles include spherical particles such as silica or titania [McCarthy et. al., 1997, Kohjiya et. al., 2005], platelets such as layered silicates [Osman et. al., 2001, Joly et. al., 2002, Varghese & Karger-Kocsis, 2003, Kim et. al., 2004, Arroyo et. al., 2003, Bala et. al., 2004, Jeon et. al., 2004], carbon [Gauthier et. al., 2005] or clay fibers [Bokobza & Chauvin, 2005] and multiwall or singlewall carbon nanotubes[Barraza et.

Adsorptive removal of acid orange 7 from aqueous solution with metal–organic framework material, iron (III) trimesate

AbstractIn this paper, a highly porous metal–organic framework (MOF) based on iron (III) trimesate (MIL-100 (Fe)) was applied to the adsorption of a harmful anionic dye, acid orange 7 (AO7), from aqueous solution. The influences of various factors on the adsorption as well as adsorption kinetics and isotherms were investigated. It was found that a relatively low pH value was favorable for the adsorption. The high dosage of the adsorbent led to a high decolorization rate, but a low adsorption quantity. The adsorption kinetics obeyed the pseudo-second-order kinetic model and the adsorption isotherms followed the Langmuir mode. The driving force of the adsorption was an entropy effect rather than an enthalpy change. The adsorption mechanism may be explained with a simple electrostatic interaction between AO7 aqueous solution and the adsorbent. The adsorption capacities of MIL-100 (Fe) are much higher than those of an activated carbon. Finally, it can be suggested that (MOFs) having high porosity and large po...

Investigation of the oxygen depletion properties of low density polyethylene resins filled with thermally stable oxygen scavengers

The thermal stability, oxygen depletion and tensile properties of low density polyethylene (LDPE) resins filled with ascorbic acid (Vc), sodium ascorbate (SA), iron (Fe) and modified iron (MFe) oxygen scavengers were systematically investigated. Thermogravimetric analysis (TGA) results clearly suggest that the thermal stability of SA powder and L95(SA)5 specimen is significantly better than that of Vc powder and L95(Vc)5 specimen, respectively. The oxygen depletion efficiency of L95(SA)5 is significantly better than that of L95(Vc)5, L95(Fe)5 and L95(MFe)5 specimens, although the virgin SA powders exhibit worse oxygen depletion efficiency than Vc, Fe or MFe powders before melt blending. Moreover, at a fixed weight ratio of Vc (or SA) to MFe of the oxygen scavenger compounds, the oxygen depletion efficiency of L95[SAx(MFe)y]5 series specimens is always significantly better than that of L95[Vcx(MFe)y]5 series specimens. In fact, at weight ratios of Vc/MFe and SA/MFe higher than 3/7 and 5/5, respectively, the residual oxygen concentration values present in the airtight flask of L95[Vcx(MFe)y]5 and L95[SAx(MFe)y]5 series samples at any time are even lower than those of the L95(Vc)5 and L95(SA)5 specimens, respectively. Further tensile experiments show that the tensile properties of the L95[SAx(MFe)y]5 series samples are always higher than those of the corresponding L95[Vcx(MFe)y]5 series samples with the same loadings of oxygen scavenger compounds, respectively. In order to understand these interesting thermal stability, oxygen depletion and tensile properties of these LDPE oxygen-scavenging plastics, scanning electron microscope and energy dispersive X-rays analysis of the compositions on the surfaces of L95[SAx(MFe)y]5 and L95[Vcx(MFe)y]5 series samples were performed. Possible reasons accounting for these interesting properties of these LDPE oxygen-scavenging plastics are proposed.

Adsorption of Methylene Blue on Multi-Walled Carbon Nanotubes in Sodium Alginate Gel Beads

Surface water contamination by pollutants is common in highly industrialized countries due to direct discharge of industrial effluents into bodies of water or precipitation of air-borne pollutants into surface water [Murakamia et. al., 2008]. Dyes from the pollutants released along with industrial effluents are easily detected because of their inherently high visibility, meaning that concentrations as low as 0.005 mg/L can easily be detected and capture the at‐ tention of the public and the authorities [Ray et. al., 2003, Ray et. al., 2002]. Apart from the aesthetic problems caused by dyes, the greatest environmental concern with dyes is their ab‐ sorption and reflection of sunlight entering the water, which interferes with the growth of bacteria, such that bacteria levels are insufficient to biologically degrade impurities in the water [Pierce, 1994. Ledakowicz et. al., 2001]. Methylene blue (MB) and methyl violet are two common dyes that have been shown to induce harmful effects on living organisms dur‐ ing short periods of exposure [Hameed et. al., 2009]. Oral ingestion of MB results in a burn‐ ing sensation and may cause nausea, vomiting, diarrhea, and gastritis. The accidental consumption of large dose induces abdominal and chest pain, severe headache, profuse sweating, mental confusion, painful micturation, and methemoglobinemia [Yasemin et. al., 2006]. Inhalation of methyl violet may cause irritation to the respiratory tract, vomiting, di‐ arrhea, pain, headaches, and dizziness; long-term exposure may cause damage to the mu‐ cous membranes and gastrointestinal tract [Allen & Koumanova, 2005]. The majority of dyes

Effects of compound curing agent on the thermo-mechanical properties and structure of epoxy asphalt

Abstract Epoxy asphalt curing system was prepared by sebacic acid compound with methyl-tetrahydrophthalic anhydride (MeTHPA) or Tung oil anhydride (TOA). Tensile strength, penetration, differential scanning calorimetry, dynamic mechanical thermal analysis, torn section microscopy photographs and scanning electron microscope analysis were utilised to investigate the mechanical properties, thermodynamic behaviour and micro-structure of epoxy asphalt curing systems under different curing agents. The results showed that in the presence of compound curing agent, the tensile strength and surface hardness of the epoxy asphalt curing system effectively improved, the induction period of the curing reaction decreased, the curing reaction mechanism turned to one-step reaction from two-step reaction, the Tg of asphalt phase and epoxy phase could simultaneously increase, and high-temperature damping performance also improved, but the particle size of asphalt dispersed in epoxy resin becomes uneven, while the curing system becomes semi-brittle from toughness. Compared to TOA, the effects of MeTHPA on such performance were more obvious.