High temperature composites

Miscellaneous Applications. Ben2otrifluoride derivatives have been incorporated into polymers for different appHcations. 2,4-Dichloroben2otrifluoride or 2,3,5,6-tetrafluoroben2otrifluoride [651-80-9] have been condensed with bisphenol A [80-05-7] to give ben2otrifluoride aryl ether semipermeable gas membranes (336,337). 3,5-Diaminoben2otrifluoride [368-53-6] and aromatic dianhydrides form polyimide resins for high temperature composites (qv) and adhesives (qv), as well as in the electronics industry (338,339). 

Halogenated intermediates based on chlorendic anhydride and alkoxylated, brominated bisphenol are quite stable and are used extensively in flame-retarded high temperature compositions, but brominated aUcychcs, such as dibromotetrahydrophthahc resin, are rapidly dehydrohalogenated at lower temperatures. 

Coolant flow and temperatures (in and out) low flow and high temperature. Composition of proeess and effluent streams. 

The synthesis, physical and mechanical properties of thermally curable oligomers primarily for use as high temperature composite matrices are reviewed. High temperature in this context is defined as having usable mechanical properties at 177°C and higher. 

Savadogo, O. 2004. Emerging membranes for electrochemical systems—Part 11. High-temperature composite membranes for polymer electrolyte fuel cell (PEFC) applications. Journal of Power Sources 127 135-161. 

Following these patent disclosures, research organizations involved in air-craft/aerospace material developments recognized the potential of thermosetting imide oligomers as resins for high temperature composites and adhesives. 

Other applications include rotomolded tanks and containers for the storage of corrosive chemicals, such as nitric or hydrochloric acid. Extruded sheets can be thermoformed into various parts, such as battery cases for heart pacemakers.58 ECTFE film is used as release sheet in the fabrication of high-temperature composites for aerospace applications. Braided cable jackets made from monofilament strands are used in military and commercial aircraft as a protective sleeve for cables.59... 

Y. Yildirim, E. Gobina and R. Hughes, An Experimental Evaluation of High-Temperature Composite Membrane Systems for Propane Dehydrogenation J. Membrane Sci., 135 107-15 (1997). 

Igniter composition used with pyrotechnic devices that is loaded in direct contact with main pyrotechnic charge. Pyrotechnic first fire composition compounded to produce high temperature. Composition must be readily ignitible, and be capable of igniting the underlying pyrotechnic charge. 

Fig. 12.5 Schematic of flexible load train developed at Southern Research Institute for high temperature composite testing.

Fig. 12.7 Schematic of edge-loaded gripping system developed at the University of Michigan for high temperature composite testing.

As a result, those workers who are trying to develop self-lubricating materials for these high temperatures are looking at much more exotic and much less efficient lubricants, such as the calcium fluoride/barium fluoride eutectic and silver used in the NASA PS200 and PM212 high-temperature composites ... 

Nadler, M. P. Thermal Degradation Study of IM7/DMBZ-15 High Temperature Composite by TGA/FTIR Technical Paper NAWCWD-TP-8568, Naval Air Warfare Center, Weapons Division, China Lake, CA 93555, Research Dept., September 2003. 

In the study of the structure, i.e. the ionic composition of the investigated molten electrolyte, the physico-chemical analysis, based on the results of measurements of phase equilibrium, density, surface tension, viscosity, and electric conductivity of melts, combined with X-ray phase analysis and IR, respectively, Raman spectroscopy of quenched melts, is used. In the last two measurements, it may be assumed that the high temperature composition is at least qualitatively conserved after quenching. In the investigation of the structure of the electrolytes, the so-called chemical approach is used. 

Catalysis has also had a major impact on the functional and specialty chemicals businesses, providing lower cost routes and higher performance materials than would have otherwise been possible. Major examples are from polymer syntheses including Ziegler-Natta, anionic, cationic polymerization processes, for formation of polyolefins, ABS resins, polyesters and other synthetic materials. Future materials areas include high temperature composites, electronic materials and conducting organics. 

Based on the literature survey, no membranes or MEAs reported so far can achieve all the above required goals. This research is directed at developing novel high-temperature, composite proton exchange membrane-electrolyte assemblies for PEMFC for building applications. 

Other tetraketones have also been used in the preparation of PQs. The PQs have proven to be one of the better high temperature polymers with respect to both stability and potential application. The PQs are also one of the three most highly developed systems—the others being benzimidazoles and oxadiazoles. The interest in the PQs increased considerably after the development in 1967 of the soluble phenylated polyquinoxaline (PPQ). PQs are stable to 550°C and are used for high-temperature composites and adhesives. 

A solder resistant high-temperature composition that does not suffer from this drawback has been developed. The blend is composed of poly-(arylene ether) (PAE), PPS, and GFs. The PAE has an intrinsic viscosity (IV) less than or equal to about 0.15 dlg as determined in chloroform at 25°C. The use of the low IV PAE permits improved blending, which leads to improved high-temperature properties. Homopolymers of PAE are those containing 2,6-dimethylphenylene ether units. Suitable copolymers include random copolymers containing, for example, 2,6-dimethylphenylene ether units. In combination with 2,3,6-trimethyl-l,4-phenylene ether units or alternatively, copolymers derived from the copolymerization of 2,6-dimethylphenol with 2,3,6-trimethylphenol. Partially crosslinked PPS, as well as mixtures of branched and linear PPS, may be used in the high-temperature compositions. 

The composition advantageously displays a thermal resistance effective to withstand the high temperatures encountered in a reflowing oven. Further, the high-temperature compositions more closely match the thermal shrinkage of PBT, which is presently used in solder connector applications. 

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