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High Modulus (high + modulus)
Selected AbstractsMorphology and High Modulus of Laminated Ultra-Drawn Polyethylene Films with Biaxial Orientation Prepared by Microwave HeatingMACROMOLECULAR MATERIALS & ENGINEERING, Issue 7 2007Mami Azuma Abstract To improve the poor mechanical properties of uniaxially ultra-drawn films along the transverse direction, lamination of two ultrahigh molecular weight polyethylene/ethylene dimethylaminoethyl methacrylate copolymer blend films was carried out in the rectangular elongation direction by a microwave heating method. The characteristics of the successful laminated films were analyzed theoretically and experimentally. The original orientation of the crystallites for the blend films was maintained perfectly after lamination, and the preferential directions intersected each other. The Young's modulus increased symmetrically with respect to the 45 ° direction. This is the first report concerning a drastic improvement of the Young's modulus in the transverse direction for films ultra-drawn along one direction. [source] Preparation and thermal properties of bismaleimide blends based on hydroxyphenyl maleimidePOLYMER INTERNATIONAL, Issue 8 2005BS Rao Abstract N -(4-hydroxyphenyl)maleimide was melt-blended with the glycidyl ether of bisphenol-A and various mole percentages of 4, 4,-(diaminodiphenylsulfone) bismaleimide. The cure behaviour of the resins was evaluated by differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA). The blends showed distinct reductions in the onset of cure (To) and peak exothermic (Texo) temperatures. The blends cured at low temperatures exhibited glass transition temperatures (Tgs) higher than the cure temperatures. The cured blends showed high moduli, glass transition temperatures in excess of 250 °C and good thermal stabilities up to 400 °C. Copyright © 2005 Society of Chemical Industry [source] Solid-state polymerization of melt-spun poly(ethylene terephthalate) fibers and their tensile propertiesJOURNAL OF APPLIED POLYMER SCIENCE, Issue 3 2007Sachiko Nitta Abstract The production of high modulus and high strength poly(ethylene terephthalate) fibers was examined by using commercially available melt-spun fibers with normal molecular weight (intrinsic viscosity = 0.6 dL/g). First, molecular weight of as-spun fibers was increased up to 2.20 dL/g by a solid-state polymerization, keeping the original shape of as-spun fibers. Second, the polymerized as-spun fibers were drawn by a conventional tensile drawing. The achieved tensile modulus and strength of as-drawn fibers (without heat setting) were 20.0 and 1.1 GPa, respectively. A heat setting was carried out for the as-drawn fibers. Tensile properties of the treated fibers were greatly affected by the condition of the heat setting. This was related to the increase of sample crystallinity and molecular degradation during the treatments. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 1791,1797, 2007 [source] The discovery of polymer-clay hybridsJOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 4 2004Masaya Kawasumi Abstract The first successful example of a polymer-clay hybrid was nylon-clay hybrid (NCH), which is a nano-meter-sized composite of nylon-6 and 1-nm-thick exfoliated aluminosilicate layers of the clay mineral. NCH was found and developed at Toyota Central Research and Development Laboratories over 17 years ago. The NCH containing a few weight percentages of clay exhibits superior properties such as high modulus, high strength, and good gas-barrier properties. The key for the discovery of NCH was the polymerization of a nylon monomer in the interlayer space of the clay. This highlight presents the development of NCH from its discovery to its commercialization. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 819,824, 2004 [source] Novel Polymer Electrolyte Membrane, Based on Pyridine Containing Poly(ether sulfone), for Application in High-Temperature Fuel CellsMACROMOLECULAR RAPID COMMUNICATIONS, Issue 21 2005Elefterios K. Pefkianakis Abstract Summary: Novel poly(aryl ether sulfone) copolymers containing 2,5-biphenylpyridine and tetramethyl biphenyl moieties were synthesized by polycondensation of 4-fluorophenyl sulfone with 2,5-(4,,4, dihydroxy biphenyl)pyridine and tetramethyl biphenyl diol. Copolymers with different molecular weights and different monomer compositions were obtained. These copolymers exhibit excellent film-forming properties, mechanical integrity, and high modulus up to 250,°C, high glass transition temperatures (above 280,°C) as well as high thermal stability up to 400,°C. In addition to the above properties required for PEMFC application, this novel material shows high oxidative stability and acid doping ability, enabling proton conductivity in the range of 10,2 S,·,cm,1 above 130,°C. Synthesis of copolymers with high acid uptake and ionic conductivity. [source] Mechanical Properties of a Single Electrospun Fiber and Its StructuresMACROMOLECULAR RAPID COMMUNICATIONS, Issue 9 2005Shu-Ying Gu Abstract Summary: A method to measure the Young's modulus of a single electrospun polyacrylonitrile (PAN) fiber is reported. The Young's modulus can be calculated from the force-displacement curves obtained by the bending of a single fiber attached to an atomic force microscopy (AFM) cantilever. It is suggested that the high modulus of electrospun fibers is caused by the orientation of molecular chains, which is confirmed by wide-angle X-ray diffraction (WAXD) measurements. The communication will provide a basic understanding of the relationship between mechanical properties and structures of electrospun fibers. A PAN fiber was attached to a contact mode cantilever to facilitate the measurement of force-displacement curves and Young's modulus. [source] Wear and microstructural characteristics of spray atomized zircon sand reinforced LM13 alloy.MATERIALWISSENSCHAFT UND WERKSTOFFTECHNIK, Issue 7 2010Verschleiß- und Gefügecharakteristik von sprühkompaktierter mit Zirkoniumsand verstärkter LM13 Legierung Verbundwerkstoff; Aluminiummatrix; Sprühkompaktieren; Verschleißverhalten Abstract The requirement of the high performance light weight materials demands the development of varieties of materials within the economical range to get it commercialized. Light weight aluminium alloys are used in several structural applications like automotive, aerospace, defense industry and other fields of engineering. The ceramic particle reinforced aluminium metal matrix composites (AMCs) have emerged as a suitable candidate for commercial applications. A variety of processing routes have been adopted to manufacture AMCs. In the present work LM13 alloy reinforced with zircon sand is formed via spray forming. During experimentation a self prepared convergent-divergent nozzle is used for inert gas atomization of the melt which is subsequently deposited on copper substrate placed vertically below the atomizer. The zircon sand particles are injected in the atomization zone by external injectors aligned perpendicular to the gas atomization axis. Zircon sand has been found to have new promising economical commercial candidate due to its easy availability and good mechanical properties like high hardness, high modulus of elasticity and good thermal stability. The microhardness of cast alloy and spray formed composite shows that the spray formed zircon sand reinforced composite has higher hardness. Also the lower wear rate has been observed in case of the zircon sand reinforced AMC as compared to LM13 alloy. This behaviour is further analyzed in light of microstructural features of the spray deposited composite using optical and scanning electron microscope (SEM). A comparative study of this material (LM13/Zircon sand) with the parent alloy (LM13) is presented in this work. [source] Tailoring viscoelastic and mechanical properties of the foamed blends of EVA and various ethylene-styrene interpolymersPOLYMER COMPOSITES, Issue 3 2003I-Chun Liu Foamed materials (EVA/ESI) have been prepared from blends of ethylene-vinyl acetate copolymer (EVA) and ethylene-styrene interpolymers (ESI) in the presence of various amounts of dicumyl peroxide (DCP). Four ESIs of different compositions were employed in this study; their styrene contents ranged from 30 to 73 wt% and their Tg ranged from ,2 to 33°C. It has been found that microcellular morphology, degree of crosslinking and expansion ratio were strongly affected by the DCP concentration and the type of ESI employed. A minimum degree of crosslinking was required for making good foams and the same degree of crosslinking could be achieved by employing a smaller amount of DCP for an EVA/ESI blend having a higher styrene content. In contrast to other EVA blends, such as EVA/LDPE, these EVA/ESI blends exhibited no existence of any optimum DCP concentration, and the , glass transition temperatures of the foams varied with the ESI type, covering a wide span from 0°C to 37°C. Therefore, it was possible to tailor the Tg of an EVA/ESI blend by choosing an appropriate type of ESI. Furthermore, by correctly tailoring the Tg, the EVA/ESI foam could be made into a rubbery material with a custom-designed damping factor. Tensile strength and modulus of the EVA/ESI foams increased generally with an increase in the styrene content, with the exception that ESIs with very low styrene content will confer on the blend a high modulus at small strain and a large elongation at break. [source] Compatibilized poly(ether imide)/LCP blends: drawing ability and mechanical properties of the ribbonsPOLYMERS FOR ADVANCED TECHNOLOGIES, Issue 7 2002F. J. Vallejo Abstract The effects of the addition of polyarylate (PAr) on the drawing ability of poly(ether imide) (PEI)/Rodrun liquid-crystalline 5000 (Ro LC5000) (Ro) blends and on the mechanical properties of their ribbons were studied. The compatibilizing effect of the PAr led to an increase in the drawing ability of the blends, as seen by the fact that the maximum Ro content compatible with the drawing process increased from 15 to 30%. This may lead to new applications in the field of gas barrier materials. The presence of PAr also led to an increase in the adhesion between the two phases of the blends and consequent improved ductility. However, the very high modulus of elasticity and tensile strength in the direction of orientation (up to three-fold those of the matrix) due to the less developed fibrillation were smaller than the corresponding values before compatibilization. These very large modulus of elasticity and tensile strength values and those perpendicular to the direction of orientation, which were similar to those of the matrix, led to a high anisotropy in the extruded ribbons that increased with the draw ratio (DR) and the Ro contents. The high mechanical properties of the ribbons may be used and the anisotropy diminished by layering the ribbons in, and perpendicular to, the direction of orientation, according to the expected external load. Copyright © 2002 John Wiley & Sons, Ltd. [source] | ||||||||||