摘要:
An aromatic ether oligomer or polyaromatic ether comprising the formula: O—Arn; wherein Ar is an independently selected divalent aromatic radical; formed by reacting a dihydroxyaromatic with a dihaloaromatic; and wherein the reaction is performed in the presence of a copper compound and cesium carbonate. The polyaromatic ether is formed when neither the dihydroxyaromatic nor the dihaloaromatic is present in an excess amount. The aromatic ether oligomer is formed by using an excess of either dihydroxyaromatic or dihaloaromatic. A phthalonitrile monomer comprising the formula: formed by reacting a 3- or 4-nitrophthalonitrile with a hydroxy-terminated aromatic ether oligomer. A thermoset formed by curing the phthalonitrile monomer. Processes for forming all the above.
摘要:
A carbon nanotube composition and method of making the same. The composition is made by: heating a precursor composition under a non-oxidizing or reducing atmosphere to form a carbon composition of carbon nanotubes and amorphous carbon; and calcining the carbon composition in the presence of oxygen to oxidize and vaporize the amorphous carbon without oxidizing the carbon nanotubes. The precursor composition includes a mixture or complex of a transition metal compound and an organic compound that chars at elevated temperatures.
摘要:
A crosslinked polymer and process of making it are disclosed. A copolymer having at least one alkyne group, carborane group, and alkylsiloxane group is reacted with a siloxane crosslinker in a hydrosilation reaction. This produces a crosslinked polymer where the crosslink sites are reacted alkyne groups.
摘要:
A cyanate ester system is disclosed. An aryl ether oligomer may be made from a dihydroxyaromatic compound and a dihaloaromatic compound in the presence of a base. The oligomer is then reacted with a cyanide compound in the presence of a base to form the cyanate ester shown below. The cyanate ester may then be cross-linked to a thermoset having triazine ring cross-links.
摘要:
An aromatic ether oligomer or polyaromatic ether comprising the formula: wherein Ar is an independently selected divalent aromatic radical; formed by reacting a dihydroxyaromatic with a dihaloaromatic; and wherein the reaction is performed in the presence of a copper compound and cesium carbonate. The polyaromatic ether is formed when neither the dihydroxyaromatic nor the dihaloaromatic is present in an excess amount. The aromatic ether oligomer is formed by using an excess of either dihydroxyaromatic or dihaloaromatic. A phthalonitrile monomer comprising the formula: formed by reacting a 3- or 4-nitrophthalonitrile with a hydroxy-terminated aromatic ether oligomer. A thermoset formed by curing the phthalonitrile monomer. Processes for forming all the above.
摘要:
The present invention provides for a composition comprising: a composition formed by heating to a temperature of from about 300° C. and above a mixture of: an organometallic composition and an aromatic-acetylene containing compound; and wherein said organometallic composition comprises the formula: wherein A is selected from the group consisting of H, and wherein M is a metal; wherein Rx and Ry are independently selected from the group consisting of an aromatic, a substituted aromatic group and combinations thereof; wherein m, s and z are ≧0; wherein m and s are independently determined in each repeating unit; wherein said aromatic-acetylene containing composition is 1,2,4,5-tetrakis(phenylethynyl)benzene, 1,2,4-tris(phenylethynyl)benzene or 1,3,5-tris(phenylethynyl)benzene; and wherein said organometallic composition and said aromatic-acetylene composition are molar mix proportions of between 1 and 99 of said organometallic composition and between 99 and 1 of said aromatic-acetylene composition.
摘要:
A transition metal-containing ceramic made by the process comprising the step of pyrolyzing an organometallic linear polymer containing at least one metallocenylene unit, at least one silyl or siloxyl unit, and at least one acetylene unit to form a ceramic; where the ceramic has a ceramic yield of at least about 75% by weight. A transition metal-containing ceramic made by the process comprising the steps of: forming an organometallic linear polymer containing at least one metallocenylene, at least one silyl or siloxyl unit, and at least one acetylene unit; crosslinking said linear polymer through the acetylene units, thereby forming a thermoset; and pyrolyzing said thermoset to form a ceramic; where the ceramic has a ceramic yield of at least about 75% by weight.
摘要:
An aromatic ether oligomer or polyaromatic ether comprising the formula: wherein Ar is an independently selected divalent aromatic radical; formed by reacting a dihydroxyaromatic with a dihaloaromatic; and wherein the reaction is performed in the presence of a copper compound and cesium carbonate. The polyaromatic ether is formed when neither the dihydroxyaromatic nor the dihaloaromatic is present in an excess amount. The aromatic ether oligomer is formed by using an excess of either dihydroxyaromatic or dihaloaromatic. A phthalonitrile monomer comprising the formula: formed by reacting a 3- or 4-nitrophthalonitrile with a hydroxy-terminated aromatic ether oligomer. A thermoset formed by curing the phthalonitrile monomer. Processes for forming all the above.
摘要:
Transition metal-containing ceramic or carbonaeous material are formed from novel linear polymers containing a random distribution of repeating acetylenic units, organotransition metal complexes, siloxane, boron, silicon, and/or carborane-siloxane units. The precursor thermosets are formed by crosslinking of the linear polymers through the acetylenic units in the polymer backbone. The ceramics may also be formed directly by pyrolysis of the linear polymers. The preceramic polymers are potentially useful for fabricating ceramic fibers and composite materials having enhanced strength, hardness and toughness as well as superior mechanical, optical, electrical and/or magnetic properties.