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Deformation Temperature (deformation + temperature)

Distribution by Scientific Domains

Polymers and Materials Science	83%

Selected Abstracts

Transparent carbon nanotube field emission devices for display and lamp

PHYSICA STATUS SOLIDI (A) APPLICATIONS AND MATERIALS SCIENCE, Issue 6 2007
Yousuk Cho
Abstract A new, simple method to fabricate transparent carbon nanotube field emission devices is developed. The highly graphitized, single wall carbon nanotubes (SWNTs) are attached to an Sn/ITO glass by the arc discharge method. Post-heat treatments of the sample below the deformation temperature of soda-lime glass form a Sn,SWNT composite, and the nanotubes form good mechanical adhesion and electrical contact with the substrates. When the composite is oxidized in air below 400 °C, the Sn particles change to a transparent oxide form. The emission current density of the heat-treated SWNT,Sn composite is about 1 mA/cm2 at an electric field of 3 V/,m. The emission current density of the SWNT,SnOx composite is similar. However, at a higher oxidation temperature, the emitter shows more stable emission property and longer life time. The transparency of the emitter can be useful in the design of emitter devices. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Properties and strain hardening character of polyethylene terephthalate containing Isosorbide

POLYMER ENGINEERING & SCIENCE, Issue 3 2009
Ramesh M. Gohil
Polyethylene terephthalate containing Isosorbide (PEIT) polymers made from renewable corn-derived Isosorbide monomer exhibit a wide range of glass transition temperatures (80,180°C) and are therefore able to be used in many applications. Stress,strain curves for high Isosorbide content copolymers show strain softening, which impairs the molecular orientation during orientation of films and bottles. It is therefore necessary to find ways to modify deformation behavior of PEIT copolymers. Deformation characteristics of PEIT and other polyesters have been evaluated to define stretching parameters and necessary composition for making oriented bottles for hot fill applications. In the presence of polymeric nucleating agents, (polymeric ionomers or polyesters containing sodium ions), strain-hardening parameters become almost temperature- independent below solid state deformation temperature of 125°C. We developed a methodology to achieve molecular orientation comparable with films and articles made by conventional processing of poly(ethylene terephthalate), PET. Polyesters containing sodium ions are efficient nucleating agents for PEIT, and their required concentration is dependent on deformation temperature. Both strain hardening and stress at 250% strain depend on the concentration of nucleating agents and deformation temperatures. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers [source]

Shape memory effect of poly(methylene-1,3-cyclopentane) and its copolymer with polyethylene

POLYMER INTERNATIONAL, Issue 4 2002
Han Mo Jeong
Abstract Poly(methylene-1,3-cyclopentane) (PMCP) cyclopolymerized from 1,5-hexadiene by metallocene catalyst, rac -(ethylenebis(1-indenyl))Zr(N(CH3)2)2 is partially crystalline and has a value of elongation at break of more than 400% in the temperature range 25,85,°C. The shape memory effect of PMCP with moderate molecular weight is enhanced by sequentially polymerized polyethylene segments, the crystalline phase of which seems to strengthen the fixed structure which memorizes the original shape. The glass transition temperature or melting temperature of PMCP can be selectively used as shape recovery temperature when an appropriate deformation temperature is chosen. © 2002 Society of Chemical Industry [source]

Superplastic Behavior of Fine-Grained ,-Silicon Nitride Material under Compression

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 4 2000
Guo-Dong Zhan
The deformation behavior of a hot-pressed, fine-grained ,-Si3N4 ceramic was investigated in the temperature range 1450°,1650°C, under compression, and the results for strain rate and temperature dependence of the flow stress are presented here. The present results show that the material is capable of high rates of deformation (,10,4,10,3 s,1) within a wide range of deformation temperatures and under a pressure of 5,100 MPa; no strain hardening occurs in the material, even at slow deformation rates, because of its stable microstructure; Newtonian flow occurs, with a stress exponent of approximately unity; and the material has activation energy values for flow in the range 344,410 kJ·mol,1. Grain-boundary sliding and grain rotation, accommodated by viscous flow, might be the mechanisms of superplasticity for the present material. [source]