Hughes Aircraft Company

USA As Represented by Secretary of the Navy

Lockheed Corporation

Abraham L Landis

Thomas K Dougherty

Kreisler S Lau

Norman Bilow

Arthur B Naselow

Leroy J Miller

Randy E Cameron

Kreusler S Lau

Polymer-ceramic networks in which the polymer chain is anchored in a cera network are formed from compounds of the formula ##STR1## where X is R', OR', OH, H, Cl, or Br,

Substituted silyl-terminated compounds and polymers thereof

Semi-interpenetrating polymer networks having improved processibility and compatibility are prepared by combining a linear polymer comprised of a thermoplastic polyisoimide and a short chain thermosetting polymer in the form of a cross-linkable oligomer comprised of a thermosetting imide or isoimide oligomer containing unsaturated terminal groups, e.g., an acetylene-, a maleimide-, a nadimide- or a benzocyclobutene-terminated imide or isoimide oligomer. In the resulting blend at least one of the diamine and dianhydride moieties of the structural backbone unit of the polyisoimide and of the cross-linkable oligomer are the same, and preferably both of the components of the blend have the same structural backbone unit. An example of a preferred semi-interpenetrating polymer network is the combination of (1) the polyisoimide produced by reaction of benzophenonetetracarboxylic dianhydride (BTDA) with 1,3-bis (3-amino-phenoxy)benzene (APB) to form the polyamic acid precursor, followed by cyclodehydration thereof, and (2) the acetylene-terminated isoimide oligomer containing BTDA-APB backbone units and marketed as Thermid IP-600 by National Starch Company. Upon curing such semi-interpenetrating network or blend, a polymer having high toughness and high modulus is obtained.

Processible polyimide blends

Solution blending of (a) a conductive polymer containing carbon-nitrogen linkages, such as polyaniline, having an organic group or an inorganic group, e.g., derived from an anhydride or an aromatic multisulfonic acid, covalently linked to nitrogen atoms of the polymer and (b) a malemide, particularly a bismalemide, e.g., the bismaleimide prepared by reacting 1,3 bis (3 aminophenoxybenzene) with 2 units of maleic anhydride, or a bismaleimide terminated oligomer, in a suitable solvent. On removal of solvent and heating to cure the bismaleimide, a continuous phase blend of the conductive polymer and the bismaleimide is formed, having good electrical conductivity and strength. The solution blend can be applied as a coating on a substrate or can be processed to a powder which can be compressed into parts. The conductive blend can be melted and cured without the evolution of volatiles.

Conductive polymer-maleimide blends and method of producing same

Polyimide polymers having a relatively low dielectric constant and good solvent resistance, are formed by polymerization of a polyimide oligomer having the formula ##STR1## wherein R is selected from the group consisting of: --C.tbd.CH,

Hexafluoroisopropylidene-containing polyimide oligomers and polymers

Polymer-ceramic networks in which the polymer chain is anchored in a ceramic network are formed from compounds of the formula ##STR1## where X is R', OR', OH, H, Cl, or Br,

A solar cell having an active surface protected by a free-standing film, said film having the recurring repeating unit: ##STR1## where R is: ##STR2## said film having a molecular weight of at least about 25,000.

Solar cell coated with high molecular weight polyimide

A solvent polycondensation process of preparing polyimides of high molecular weight from dianhydrides and relatively unreactive diamines, where the reaction is carried out in a cresol as a solvent.

Method of preparing high molecular weight polyimide, product and use

A copolymer formed from an isoimide oligomer and another compound, such as an aryl sulfone, each of which has reactive functional terminal groups, such as ethylenic or acetylenic groups. The isoimide oligomer is soluble in the other compound, unreactive with the compound below a certain temperature and forms a liquid blend therewith. Upon heating the liquid blend above that certain temperature, the terminal groups on the isoimide oligomer and the other compound react with each other to form a copolymer. The liquid blends may be used to form encapsulants, coatings, films, and resin matrices for composites to provide resins with excellent high temperature properties.

Copolymers utilizing isoimides and method of preparing same

Processes for forming a class of relatively low molecular-weight oligomers containing at least one isoimide group and terminal groups capable of undergoing an addition polymerization reaction are provided. These oligomers are characterized by excellent solubility in common solvents and a melting temperature considerably lower than their cure temperature, thus enabling the oligomers to be formed into cured polymers more slowly and at lower temperatures, all without the evolution of deleterious gases. The process for forming these oligomers includes the formation of a polyamic acid and dehydration thereof under specified conditions to effect cyclization of the polyamic acid to form the isoimide-containing oligomer, without the formation of undesired side-reaction products.

Process for preparing isoimide containing oligomers

A class of relatively low molecular-weight oligomers containing at least one isoimide group and terminal groups capable of undergoing an addition polymerization reaction are provided. These oligomers are characterized by excellent solubility in common solvents and a melting temperature considerably lower than their cure temperature, thus enabling the oligomers to be formed into cured polymers more slowly and at lower temperatures, all without the evolution of deleterious gases. The oligomers of the present invention may be formed by reacting an aromatic dianhydride with an aromatic diamine, followed by reaction with a monoanhydride. The resulting product is dehydrated to form the isoimide-containing oligomer.

Isoimide containing oligomers

A class of relatively low molecular-weight oligomers containing at least one isoimide group and terminal groups capable of undergoing an addition polymerization reaction are provided. These oligomers are characterized by excellent solubility in common solvents and a melting temperature considerably lower than their cure temperature, thus enabling the oligomers to be formed into cured polymers more slowly and at lower temperatures, all without the evolution of deleterious gases. The oligomers of the present invention may be formed by reacting an aromatic dianhydride with an aromatic diamine, followed by reaction with a functional mono-amine. The resulting product is then dehydrated to form the isoimide-containing oligomer.

A class of relatively low molecular-weight oligomers containing at least one isoimide group and terminal groups capable of undergoing an addition polymerization reaction. The oligomers of the present invention are characterized by excellent solubility in common solvents and a melting temperature considerably lower than their cure temperature, thus enabling the oligomers to be formed into cured polymers more slowly and at lower temperatures, all without the evolution of deletrious gases.

Improved diimide and polyimide oligomers containing phenylacetylene terminal groups have been produced which melt at low temperatures and are curable into useful laminating resins, molding compounds and matrix resins. These oligomers are analogous to diimides and polyimides made from conventional dianhydrides, such as benzophenonetetracarboxylic dianhydride or pyromellitic dianhydride.

Acetylene terminated imide oligomers which melt at low temperatures

The present invention is directed to a novel class of polynitrile (polycyano) substituted polyimide oligomers and the polyamic acid or ester precursors thereof. The nitrile groups on the oligomers allow the compounds to be cured through addition reactions which result in little or no outgassing. In addition, these oligomers are curable with heat in the presence of catalysts such as those which induce cyano trimerizations. The fully cured polyimides derived from these oligomers have excellent thermal and mechanical properties at high temperatures.

Growing community of inventors

Northridge, CA, United States of America

Abraham L Landis