Synthesis of aromatic polyimides by a one-stage high-temperature polycondensation in solution

1968 ◽  
Vol 17 (6) ◽  
pp. 1331-1332 ◽  
Author(s):  
V. V. Korshak ◽  
S. V. Vinogradova ◽  
Ya. S. Vygodskii ◽  
B. N. Yudin
Keyword(s):  
High Temperature ◽  
Aromatic Polyimides ◽  
One Stage

Improving the Performance of High Temperature Piezopolymers for Magnetoelectric Applications

2013 ◽  
Vol 543 ◽  
pp. 439-442 ◽  
Author(s):  
Jon Gutiérrez ◽  
Andoni Lasheras ◽  
Jose Manuel Barandiaran ◽  
Jose Luis Vilas ◽  
Alberto Maceiras ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
High Performance ◽  
Polymeric Materials ◽  
Amorphous Polymers ◽  
Piezoelectric Response ◽  
Laminate Composites ◽  
Aromatic Polyimides ◽  
Orientation Polarization

Piezoelectricity in amorphous polymers is mainly due to the orientation polarization of the molecular dipoles. Aromatic polyimides are high-performance polymeric materials possessing large molecular dipoles. We already reported good magnetoelectric performance of laminate composites with Vitrovac 4040®as magnetostrictive component and the 2,6(b-CN)APB/ODPA (poli 2,6) polyimide as the piezoelectric. Although the piezoelectric response of this polyimide is good, its mechanical properties can be improved. To combine the best mechanical and piezoelectric response in the same polymer, copolyimides have been synthesized by reaction of the 4,4-oxydiphtalic anhydride (ODPA) with a mixture of 1,3-Bis-2-cyano-3-(3-aminophenoxy) phenoxybenzene (diamine 2CN) and 1,3-Bis (3-aminophenoxy) benzene (diamine 0CN). We present the piezoelectric, mechanical and ME performance of laminate composites of these copolyimides.

Comparative Study of Polyimides Containing Oxadiazole and Ether Groups

2009 ◽  
Vol 21 (5) ◽  
pp. 522-534 ◽  
Author(s):  
Maria Bruma ◽  
Mariana Dana Damaceanu ◽  
Peter Muller
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
High Temperature ◽  
Comparative Study ◽  
Aromatic Diamine ◽  
Polycondensation Reaction ◽  
Free Standing ◽  
Aromatic Polyimides ◽  
Film Forming ◽  
As Solubility

An aromatic diamine with a preformed oxadiazole ring and various dianhydrides with ether and other flexible or bulky groups, such as isopropylidene, hexafluoroisopropylidene, cyclohexylidene or fluorenylidene, were used in a polycondensation reaction at high temperature to produce poly(oxadiazole-ether-imide)s. The properties of these polymers such as solubility, film-forming ability, thermal stability and photoluminescence were studied and compared with those of related conventional aromatic polyimides. The mechanical properties of the free-standing films obtained from these polyimides were also investigated.

High-temperature reactive thermoplastic aromatic polyimides

1981 ◽  
Vol 26 (8) ◽  
pp. 2679-2691 ◽  
Author(s):  
Bruce A. Reinhardt ◽  
Fred E. Arnold
Keyword(s):  
High Temperature ◽  
Aromatic Polyimides

The effect of high temperature incubation upon the myocardial glycogen in the chick embryo

Development ◽  
1965 ◽  
Vol 14 (3) ◽  
pp. 273-280
Author(s):  
John M. Delphia ◽  
John Elliott
Keyword(s):  
High Temperature ◽  
Chick Embryo ◽  
Incubation Temperature ◽  
Growth Stages ◽  
Chick Embryos ◽  
One Stage ◽  
Accelerate Growth ◽  
Small Intestines ◽  
Incubation Temperatures

Numerous studies have shown that high temperature incubation for the chick embryo will accelerate growth. Ancel & Lallemand (1941) reported that, with incubation temperatures of 39·0 to 42·0°C. during the 3rd through the 6th day of incubation, 49·2 per cent, to 62·7 per cent, of the specimens expressed Coelosomia. This malformation is characterized by the eventration of the viscera through a body cleft. Delphia & Eveleth (1961) found that continuous incubation of chick embryos at 40·0°C. resulted in Coelosomia of the heart, liver, ventriculus and small intestines in 63 per cent, of the specimens. Further studies by Delphia (1963) indicated that, with a continuous incubation temperature of 40·0°C, the embryos were advanced in growth stages (Hamburger-Hamilton, 1951) by one stage and were 1·3 times heavier than normally incubated specimens at 8 days incubation. At this time (8 days incubation) coelosomia is demonstrated clearly.

One-Stage High Temperature Catalytic Synthesis of Star-Shaped Oligoimides by (В4+АВ) Scheme

2019 ◽  
Vol 61 (2) ◽  
pp. 148-154 ◽  
Author(s):  
A. Yu. Tsegelskaya ◽  
A. E. Soldatova ◽  
G. K. Semenova ◽  
M. D. Dutov ◽  
I. G. Abramov ◽  
...  
Keyword(s):  
High Temperature ◽  
Catalytic Synthesis ◽  
One Stage

Influence of Thermo-Mechanical Processing on the Microstructure of Beryllia Dispersed Nickel Alloys

1973 ◽  
Vol 31 ◽  
pp. 184-185
Author(s):  
M.S. Grewal ◽  
S.A. Sastri ◽  
N.J. Grant
Keyword(s):  
High Temperature ◽  
Nickel Alloys ◽  
Thermomechanical Processing ◽  
Cold Work ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Mechanical Processing ◽  
Uniform Dispersion ◽  
Oxide Particles ◽  
Nickel Base

Currently there is a great interest in developing nickel base alloys with fine and uniform dispersion of stable oxide particles, for high temperature applications. It is well known that the high temperature strength and stability of an oxide dispersed alloy can be greatly improved by appropriate thermomechanical processing, but the mechanism of this strengthening effect is not well understood. This investigation was undertaken to study the dislocation substructures formed in beryllia dispersed nickel alloys as a function of cold work both with and without intermediate anneals. Two alloys, one Ni-lv/oBeo and other Ni-4.5Mo-30Co-2v/oBeo were investigated. The influence of the substructures produced by Thermo-Mechanical Processing (TMP) on the high temperature creep properties of these alloys was also evaluated.

Application of TEM to Deformation, Wear, and Fracture of Ceramics

1974 ◽  
Vol 32 ◽  
pp. 472-473
Author(s):  
B. J. Hockey
Keyword(s):  
Wear Resistance ◽  
High Temperature ◽  
Mechanical Behavior ◽  
Brittle Materials ◽  
High Temperature Strength ◽  
Wide Range ◽  
Corrosive Environments ◽  
Further Development

Ceramics, such as Al2O3 and SiC have numerous current and potential uses in applications where high temperature strength, hardness, and wear resistance are required often in corrosive environments. These materials are, however, highly anisotropic and brittle, so that their mechanical behavior is often unpredictable. The further development of these materials will require a better understanding of the basic mechanisms controlling deformation, wear, and fracture.The purpose of this talk is to describe applications of TEM to the study of the deformation, wear, and fracture of Al2O3. Similar studies are currently being conducted on SiC and the techniques involved should be applicable to a wide range of hard, brittle materials.

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

Effect of Improved ThO2 Particle Dispersion in Nickel on High-Temperature Strength

1970 ◽  
Vol 28 ◽  
pp. 444-445
Author(s):  
E. R. Kimmel ◽  
H. L. Anthony ◽  
W. Scheithauer
Keyword(s):  
High Temperature ◽  
Metal Matrix ◽  
Oxide Particle ◽  
Oxide Phase ◽  
Dislocation Motion ◽  
Particle Dispersion ◽  
High Temperature Strength ◽  
Strengthening Effect ◽  
Oxide Particles ◽  
The Stability

The strengthening effect at high temperature produced by a dispersed oxide phase in a metal matrix is seemingly dependent on at least two major contributors: oxide particle size and spatial distribution, and stability of the worked microstructure. These two are strongly interrelated. The stability of the microstructure is produced by polygonization of the worked structure forming low angle cell boundaries which become anchored by the dispersed oxide particles. The effect of the particles on strength is therefore twofold, in that they stabilize the worked microstructure and also hinder dislocation motion during loading.

Sign in / Sign up

Export Citation Format

Share Document