Advanced Materials Research Vol. 811

Abstract: This study concerned with colour fading of cotton fabric by plasma-induced ozone treatment. Cotton knitted fabrics were dyed with reactive dye of red colour with a depth of 0.5% and were subjected to ozneo generated by a plasma machine for colour fading. In order to investigate the colour properties of the plasma-induced ozone treated cotton fabric. The plasma-induced ozone treatment was conducted with different parameters: (i) air concentration = 10%, 30%, 50% and 70%; (ii) water content in fabric = 35% and 45% and (iii) treatment time = 10 minutes, 20 minutes and 30 minutes. After the plasma-induced ozone treatment, the colour properties of the fabric were measured by spectrophotometer under illuminant D₆₅ to obtain the CIE L*, CIE a* and CIE b* values.

Abstract: In this present investigation, the mechanical properties of industrial drawn copper wires have been studied by creep tests, tensile tests and hardness Vickers. The effect of prior heat treatments at 500°C for different time on the drawn wires behavior was the main goal of this investigation. We have found that these heat treatments influenced the creep behavior of drawn wires and recorded shape curves. The creep tests were applied under ambient atmosphere at 240 °C. The creep duration before rupture decreased with the prior heat treatment time. The creep tests results were confirmed by tensile tests. A relationship between the hardness and the ultimate tensile strength of this industrial material has been established. Optical and scanning electron microscopy observations have been also used. Cross section observations of the wire after tensile or creep-rupture tests have shown that the mechanism of rupture was mainly controlled by the void formation.

Abstract: Field dependent polaron transport in a conjugated polymer chain is studied numerically with local thermal fluctuations taken into account. Within a dynamical evolution method, a polaron moves from the left to the right side of the polymer chain in the presence of an applied electric field. Local lattice fluctuations are assumed to occur in a random way. The local thermal fluctuations are found to be equivalent to a potential barrier for the polaron. The range of the thermally disturbed region in the molecule and the effective temperature difference resulted from asymmetric thermal absorptions determine the height of the barrier. The intra-molecule polaron mobility obeys a logarithmic law in low electric field range provided that there exist asymmetric thermal absorptions within the molecule.

Abstract: t is found that the molecular weight of Hydroxy-terminated polybutadiene (HTPB) influences curing behaviors of HTPB/2,4-toluene diisocyanate (TDI) system and the mechanical properties of PBXs. Effects of the molecular weight of HTPB on the viscose viscosity,the cure time, and mechanical properties of polymer were studied by brookfield viscometer, hardness tester and tension test with the molecular weight of HTPB varying from 1500~4000.The experimental results show that the viscose viscosity increases slowly and the cure time is extended obviously,tensile strength decreases and elongation at break increases when the molecular weight of HTPB increases. Dynamic mechanical studies show that glass transition temperature and dynamic storage modulus decrease with the molecular weight of HTPB increasing.

Abstract: The objective of this work is the study of the mechanical stress influence on the structural evolution. In particular, we studied the initiation and the plasticity mechanisms propagation of a semicrystalline polymer at small scales. The material is polylactic acid (PLA) film with average molar mass of 199 kg/mole and a thickness of 200 μm. The lamellate morphology of this material is very heterogeneous: in given area and packages of different orientation plates, they are spherulites α and β which have a different mechanical behaviour on a lamellate scale.

Abstract: Hierarchical porous methylsilicone monoliths were prepared by filling monodisperse polystyrene microsphere (PS) as template and subsequently removing PS in selective solvent. The hierarchical porous structure can be tailored by adjusting the reactant ratio. The textural structure were investigated by the measurement of density, SEM observation, and N₂ desorption and adsorption isotherm and pore size distribution. The results showed the hierarchical porous methylsilicone materials with interconnected macropores and mesopores were lightweight and hydrophobic.

Abstract: Effective moduli of fiber-reinforced polymer matrix composites filled with nanoparticle considering the effect of linear change of interphase are presented in this paper. The three-phase inclusion problem for matrix-interface-particle is equivalent to the Eshelby two-phase inclusion problem. According to the result of the Eshelby inclusion problem, the effective modulus tensor of unit cell of equivalent particle is derived. The effective moduli of equivalent matrix are given based on Mori-Tanaka method. Using two fundamental equation of micromechanic theory, the three-dimensional bridged formulation of unidirectional composites is derived. The quantitative relationship between the macroscopic elastic parameters and the structural parameters of the fiber-reinforced polymer composites filled with nanoparticles is investigated. Effects of the thickness of interfacial layer, the particle size and the volume fraction of nanoparticles on the effective elastic moduli of the composites are also discussed.

Abstract: Recently, demand for environment protection and reduction of energy consumption has led to active development of technology to reduce the weight of transportation devices. Furthermore, due to the development of the ocean leisure industry, there is a increasing number of small shipbuilding including yacht using aluminum. However, there are a lot of problems to be solved in aluminum ship welding from the technological, economic and environmental perspectives. An alternative to solve these problems is the friction stir welding technique. But, inflow frictional heat is generated in case of friction stir welding of 6061-T6 alloy, and the crystalline structure grows, resulting in weak mechanical strength. Accordingly, this study is to improve the mechanical characteristics and corrosion resistance of FSWed 6061-T6 alloy through annealing heat treatment. This study compared the characteristics with time of heat treatment at a constant temperature for the annealing heat treatment. Results of electrochemical experiments, the stir zone in annealing time 60min. showed the low corrosion current density. Micro-Vickers hardness in 60min. presents the higher value than the other conditions.

Abstract: Conventional ships generated almost no cavitation erosion because they traveled at low speed. Thus, most ships have used painting, ICCP and sacrificial anode system. However, with the activation of international trading, and the increase of low-price, large-volume cargos, ships are becoming larger and faster. As a result, damages due to cavitations and corrosions have accelerated. Cavitation and erosion corrosions cause damages to materials by physical shock waves generated from the collapse of bubbles which are generated when the moving parts rotate in seawater. The stern in particular is exposed to more severe environment due to cavitation and high flow speed. When cavitation and electrochemical damages are combined with exposure to severe environment, it has serious impact on the life span of equipment. Therefore, this study investigated the electrochemical and cavitation characteristics in sea environment for Zn primer coating which is a pretreatment process of painting for rudders for ships. As a result, corrosion resistance improved, but erosion resistance did not.