Thermally Stable Poled Polymers: Highly Efficient Heteroaromatic Chromophores In High Temperature Polyimides

1993 ◽  
Vol 328 ◽  
Author(s):  
Alex K-Y. Jen ◽  
K. Y. Wong ◽  
V. Pushkara Rao ◽  
K. Drost ◽  
Y. M. Cai ◽  
...  
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Functional Groups ◽  
Optical Activity ◽  
Nonlinear Optical ◽  
Temporal Stability ◽  
Thermally Stable ◽  
Electro Optic ◽  
Recent Developments

ABSTRACTIn this paper, we report our recent developments in achieving thermally stable polyimides that possess large second order nonlinear optical activity. We have developed several classes of novel chromophores based on the combination of efficient thiophene conjugating units and novel electron-donating and electron-accepting functional groups. Through these developments, we have synthesized chromophores that possess non-resonant βμ values as high as 9,100 × 10−48 esu measured at 1.9 μm. These chromophores also possess improved thermal and chemical stabilities. The incorporation of these chromophores in high temperature polyimides produces E-O Materials with high linear electro-optic coefficients (in excess of 15 pm/V at 1.3 μm) and long-term temporal stability at an elevated temperature of 150°C for more than 800 hours.

Highly Active and Thermally Stable Ctlromophores and Polymers for Electro-Optic Applications

1995 ◽  
Vol 392 ◽  
Author(s):  
Alex K-Y. Jen ◽  
Tian-An Chen ◽  
Varanasi Pushkara Rao ◽  
Yong-Ming Cai ◽  
Yue-Jin Liu ◽  
...  
Keyword(s):  
High Temperature ◽  
Nonlinear Optical ◽  
Thermally Stable ◽  
Highly Active ◽  
Electro Optic ◽  
Nlo Chromophores

AbstractWe have developed two new classes of highly active and thermally stable nonlinear optical (NLO) chromophores based on the use of efficient thiophene conjugating units, a N,N-diphenylamino electron-donating group, and a 1,1′-dicyanovinyl substituted electron-accepting group. We have also developed a facile and generally applicable method to functionalize NLO chromophores onto high temperature polymers to demonstrate both high electro-optic (E-O) coefficients and long-term alignment stability at 100 °C.

Microstructural characterization of a rapidly solidified Al-Fe-V-Si alloy for elevated temperature applications

1988 ◽  
Vol 46 ◽  
pp. 550-551
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Grain Growth ◽  
Volume Fraction ◽  
Microstructural Characterization ◽  
Second Phase ◽  
Microstructural Stability ◽  
Elevated Temperature Strength ◽  
Temperature Applications

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.

Developments in Cyclic Analysis and High Temperature Design

2005 ◽  
Author(s):  
Peter Carter ◽  
Douglas L. Marriott
Keyword(s):  
High Temperature ◽  
Power Systems ◽  
Creep Damage ◽  
Limit Load ◽  
Cyclic Stress ◽  
Research Literature ◽  
Stress Classification ◽  
Analysis Technique ◽  
Recent Developments

Design for cyclic loading is emerging as a key question for next generation power systems. Recent developments in techniques for cyclic stress analysis have significant implications for high temperature design. In the same way that limit load analysis is now being used to overcome the difficulties and guesswork of stress classification for steady primary loads, so shakedown and ratcheting analysis can eliminate the more difficult problems of stress classification for cyclic loads. The paper shows how reference stresses defined for shakedown and ratcheting provide rapid and conservative information for design against rupture and creep damage, deformation and strain accumulation, and ratcheting. These techniques will provide additional insights to designers and are likely to augment rather than replace, existing options. These ideas have existed in the research literature for some time, but have now become more accessible by the general industry with a new analysis technique in a commercial finite element code. Examples are given which demonstrate the methodology for nozzles having non-thermal secondary stresses, and prediction of long-term distortion in thermal shock problems.

Multi-Functional Device Applications of Nonlinear Optical Polymer Materials.

1989 ◽  
Vol 175 ◽  
Author(s):  
R. Lytel ◽  
G.F. Lipscomb
Keyword(s):  
Nonlinear Optical ◽  
Polymer Materials ◽  
Functional Roles ◽  
Optical Polymer ◽  
Field Operation ◽  
Electro Optic ◽  
Recent Developments ◽  
Device Applications ◽  
Nonlinear Optical Polymer ◽  
Practical Field

AbstractRecent developments in the application of electro-optic polymer materials to perform multi-functional roles in integrated optic device applications are summarized and future requirements for practical field operation are discussed.

Poled Polyimides for Thermally Stable Electro-Optic Materials

1992 ◽  
Vol 247 ◽  
Author(s):  
J. W. Wu ◽  
J. F. Valley ◽  
M. Stiller ◽  
S. Ermer ◽  
E. S. Binkley ◽  
...  
Keyword(s):  
Electric Field ◽  
Nonlinear Optical ◽  
Room Temperature ◽  
Curing Process ◽  
Thermally Stable ◽  
Excellent Thermal Stability ◽  
Electro Optic ◽  
Poling Temperature ◽  
Electric Field Poling ◽  
Thermal Stability Of

ABSTRACTUsing polyimide as host in a guest-host electro-optic (EO) thin film a thermally stable poled electro-optic response is demonstrated at temperatures at 150 °C and 300 °C. Electric field poling during curing process including imidization (170 -230 °C) and densification (340 -380 °C) accounts for the highly thermally stable EO response. As a room temperature curing process, chemical imidization is employed as a novel curing process. Dehydration occurring through imidization of the polyamic acid is completed chemically after poling rather than thermally during poling. After thermal aging at 155 °C (above the poling temperature) chemically imidized samples retain over 30% of their original poling induced EO signal while similarly poled samples, which have not been chemically imidized, produce a null EO response. For a class of polyimides possessing aliphatic structure, the thermoplastic behavior of cured guest-host polyimide system allowed the electric field poling at temperatures above the glass transition temperature (Tg). One example of polyimide doped with 10% nonlinear optical molecules exhibits Tg near 200 °C, leading to an excellent thermal stability of the poled EO response with a depoling knee-temperature of 150°C.

Janus molecules: large second-order nonlinear optical performance, good temporal stability, excellent thermal stability and spherical structure with optimized dendrimer structure

2018 ◽  
Vol 2 (7) ◽  
pp. 1374-1382 ◽  
Author(s):  
Pengyu Chen ◽  
Huanyu Zhang ◽  
Mengmeng Han ◽  
Ziyao Cheng ◽  
Qian Peng ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Nonlinear Optical ◽  
Temporal Stability ◽  
Second Order ◽  
Optical Performance ◽  
Excellent Thermal Stability ◽  
Good Thermal Stability ◽  
Spherical Structure ◽  
Electro Optic

A Janus molecule J2 containing five FTC moieties exhibited good thermal stability, excellent electro-optic performance and good temporal stability.

Visco-Elastic FEM Stress Analysis of Bolted Flange Connections With PTFE-Blended Gaskets Under Elevated Temperature

2012 ◽  
Author(s):  
Koji Sato ◽  
Shinya Kurokawa ◽  
Toshiyuki Sawa
Keyword(s):  
High Temperature ◽  
Elevated Temperature ◽  
Fluid Temperature ◽  
Long Term Conditions ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Strain Relationship ◽  
Bolted Flange ◽  
Relationship Of

Bolted flange connections with gaskets have been used under high temperature and long-term conditions. Sometimes leakage accidents occur from the gasket interfaces due to the creep and relaxation phenomena. In the present paper, the changes of the gasket stress in bolted flange connections under high temperature conditions for a long-term are analyzed using FEM calculations taking into account the gasket temperature dependency. The gaskets used are PTFE-blended (V#GF300). It’s shown that the effect of the temperature on the stress-strain relationship of the gasket is substantial. The changes in the gasket stress of the connections for 12 months are analyzed using the FEM. The effects of nominal diameter of flanges, retightening and the fluid temperature (20 to 300 °C) on the change of gasket stress in the connections under elevated temperature are examined using the FEM calculations. It is found that the reduction in the gasket stress is over 40%. In addition, experiments to measure the axial bolt force were carried out. The calculated results are in a fairly good agreement with the experimental results. The results reveal that the long-term behavior of the bolted flange connections can be estimated in our study. Discussion is made on the effects of the bolt preload and retightening on the reduction of the gasket stress and the sealing performance.

Approaches to High Temperature Contacts to Silicon Carbide

1996 ◽  
Vol 423 ◽  
Author(s):  
J. M. Delucca ◽  
S. E. Mohney
Keyword(s):  
Silicon Carbide ◽  
High Temperature ◽  
Elevated Temperature ◽  
Transition Metal ◽  
Phase Equilibria ◽  
Periodic Table ◽  
Electrical Characteristics ◽  
Thermally Stable ◽  
Silicon Carbon ◽  
Metallurgical Reactions

AbstractMetallurgical reactions between contacts and SiC can alter the electrical characteristics of the contacts, either beneficially or detrimentally. Simultaneously, consumption of the underlying SiC epilayer takes place. During prolonged operation at elevated temperature, contacts that are not in thermodynamic equilibrium with SiC may continue to react with it. For this reason, interest in thermally stable carbide and silicide contacts to SiC has been growing. To select appropriate carbides or silicides for further study, however, knowledge of the transition metal-silicon-carbon (TM-Si-C) phase equilibria is required. A significant body of literature on the TM-Si-C systems exists and should therefore be examined in the context of electronic applications. In this paper, phase equilibria for representative TM-Si-C systems are presented, trends in these systems with respect to temperature and position of the metal in the periodic table are discussed, and attractive carbide and silicide contacts and processing schemes for thermally stable contacts are highlighted.

Side Chain Polymers for Electro-Optic Applications

1991 ◽  
Vol 228 ◽  
Author(s):  
Ronald N. DeMartino ◽  
Diane E. Allen ◽  
Richard Keosian ◽  
Garo Khanarian ◽  
David R. Haas
Keyword(s):  
Mechanical Properties ◽  
Optical Activity ◽  
Molecular Basis ◽  
Molecular Design ◽  
Polymeric Materials ◽  
Side Chain ◽  
New Materials ◽  
Electro Optic ◽  
Recent Developments ◽  
Nlo Materials

ABSTRACTOrganic and polymeric materials have emerged in recent years as candidates for advanced device and systems applications. This interest has arisen from the promise of extraordinary optical, structural, and mechanical properties of certain organic materials, and from the fundamental success of molecular design performed to create new materials.Our approach to the problem is to develop an understanding of the molecular basis of non-linear optical activity, incorporate the most promising candidates into tractable polymers, and evaluate these materials in device format. This paper will review some of the recent developments in the NLO materials effort at Hoechst Celanese.

Enhanced High-Temperature Long-Term Stability of Polymer Solar Cells with a Thermally Stable TiOx Interlayer

2009 ◽  
Vol 113 (39) ◽  
pp. 17268-17273 ◽  
Author(s):  
Dong Hwan Wang ◽  
Sang Hyuk Im ◽  
Hang Ken Lee ◽  
O Ok Park ◽  
Jong Hyeok Park
Keyword(s):  
Solar Cells ◽  
High Temperature ◽  
Polymer Solar Cells ◽  
Thermally Stable ◽  
Term Stability ◽  
Long Term Stability
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