United Technologies Corporation

University of Connecticut

National Center for Manufacturing Sciences

US Government As Represented by the Secretary of the Army

Daniel A Scola

John Henry Vontell, Sr

Ruth H Pater

James P Bell

Jengli Liang

Jude O Iroh

Richard Thomas Grannells

Christopher Dennis Simone

Marvin C Cheney, Jr

David J Parker

Samuel Huang

Eleonora Vaccaro

Xiaomei Fang

A series of low melting and low viscosity phenylethynyl end-capped polyimides (PETIs) possessed of long term thermal and mechanical stability useful as films, melt coatings, adhesives, matrix and RTM resins and particular as coatings for optical fibers and phenylethynyl end-capped bismides blended with PETIs are disclosed. Processes for their production including: 1) modification of PETI-5 oligomer by molecular weight adjustments by blending with reactive low melting phenylethynyl end-capped imide monomers, 2) modification of the PETI-5 backbone structure with other diamine components, and 3) modification of the PETI-5 backbone with bulky fluorinated groups are also disclosed.

Low viscosity melt processable high temperature polyimides

Polyamides, polyesters, and polyamideesters are efficiently synthesized in a microwave process with precise temperature control. Compared to conventional thermal polymerizations, the microwave process takes less time and produces polymers with equivalent or superior physical properties.

Microwave synthesis of polyamides, polyesters, and polyamideesters

A high-performance printed wiring board assembly is disclosed which utilizes a substrate component having a reinforcement material. The substrate has a glass fabric reinforcement embedded in a condensation-reacted and thermally-crosslinked nadic end-capped polyimide resin. There are electrically conductive lamina current pathways directly adhered to the substrate. There are high-temperature soldered or metallurgically bonded connections that electrically join conductor leads of electrical devices to the lamina current pathways.

Printed wiring board assembly with a substrate having a glass fabric reinforced, condensation reacted and thermally crosslinked nadic end-capped polyimide resin

A method of manufacturing a high-performance printed wiring board assembly, and the resulting product, utilize a substrate component that has a reinforcement material embedded in a condensation-reacted and thermally-crosslinked nadic end-capped polyimide resin electrically conductive lamina component pathways directly adhered to the substrate component resin and high-temperature soldered or otherwise attached connections that electrically join the conductor leads of included electrical devices to the lamina component conductive pathways.

Printed wiring board assemblies

In accordance with the present invention, electropolymerization in a substantially aqueous solution is used to form thick (e.g. greater than 2 microns or 30 weight %) and thermally stable coatings of thermoplastic materials onto electrically conductive filler materials (e.g. rods, plates, fibers). In a first preferred embodiment, the thick thermoplastic matrix comprises a copolymer of 3-carboxyphenyl meleimde and styrene. In a second preferred embodiment, cyclic (and preferably aromatic) N-substituted methacrylamide monomers are electropolymerized onto electrically conductive (e.g., graphite) filler (e.g., fibers, plates, film or cloth) to form a novel polymer composite exhibiting high Tg as well as a controlled degree of cross-linking which can prevent flow at high temperature. This invention is particularly will suited for direct preparation of thermoplastic prepregs containing commercially available bundles of graphite fibers. These prepregs are then molded under heat and pressure so as to form a thermoplastic matrix composite with good fiber distribution, uniformity and high temperature resistance.

Thermoplastic composites formed by electropolymerization of

In accordance with the present invention, electropolymerization in a substantially aqueous solution is used to form thick (e.g. greater than 2 microns or 30 weight %) and thermally stable coatings of thermoplastic materials onto electrically conductive filler materials (e.g. rods, plates, fibers). In a first preferred embodiment, the thick thermoplastic matrix comprises a copolymer of 3-carboxyphenyl maleimide and styrene. In a second preferred embodiment, cyclic (and preferably aromatic) N-substituted methacrylamide monomers are electropolymerized onto electrically conductive (e.g., graphite) filler (e.g., fibers, plates, film or cloth) to form a novel polymer composite exhibiting high Tg as well as a controlled degree of cross-linking which can prevent flow at high temperature. This invention is particularly well suited for direct preparation of thermoplastic prepregs containing commercially available bundles of graphite fibers. These prepregs are then molded under heat and pressure so as to form a thermoplastic matrix composite with good fiber distribution, uniformity and high temperature resistance.

Electropolymerization method and product

A pretreatment process for fabricating polyimide composites from prepreg, thereby reducing the formation of void producing or blister producing gases at elevated temperatures during a subsequent post cure cycle. The pretreatment process includes heating a prepreg to an elevated temperature and holding at said temperature for a period of time sufficient to achieve complete imidization of the prepreg but such that the material is still processable. Processes are also disclosed for the subsequent cure of the prepreg to form thermoplastic high temperature fiber reinforced composites.

Method for fabricating thermoplastic high temperature polymer graphite

A fluorinated condensation copolyimide has repeating polymer units that include: ##STR1## in which X and Y are diamines. The copolyimide can be made by reacting a 3F-monomer and a 6F-monomer with an aromatic or aliphatic diamine. The 3F-monomer includes 4,4'-(2,2,2-trifluoro-1-phenylethylidene) diphthalic anhydride, a dialkylester of 4,4'-(2,2,2-trifluoro-1-phenylethylidene) diphthalic anhydride, 4,4'-(2,2,2-trifluoro-1-phenylethylidene) diphthalic acid, or mixtures thereof. The 6F-monomer includes 4,4'-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene] diphthalic anhydride, a dialkylester of 4,4'-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene] diphthalic anhydride, 4,4'-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene] diphthalic acid, or mixtures thereof.

Fluorinated condensation copolyimides

A high temperature fluorinated polyimide is made by forming a solution that includes a 3F-monomer and an aromatic or aliphatic diamine such that the solution has a ratio of 3F-monomer to diamine of greater than 1.05. The 3F-monomer is 4,4'-(2,2,2-trifluoro-1-phenylethylidene) diphthalic anhydride, a dialkylester of 4,4'-(2,2,2-trifluoro-1-phenylethylidene) diphthalic anhydride, 4,4'-(2,2,2-trifluoro-1-phenylethylidene) diphthalic acid, or mixtures thereof. The solution is mixed so the 3F-monomer reacts with the diamine to form a 3F-polyimide.

High temperature 3f-polyimides

Cyclic (and preferably aromatic) N-substituted methacrylamide monomers are electropolymerized onto electrically conductive (e.g., graphite) filler (e.g., fibers, plates, film or cloth) to form a novel polymer composite exhibiting high Tg as well as a controlled degree of cross-linking which can prevent flow at high temperature.

Process for forming methacrylamide polymer prepreg composite by

A polyimide resin or composite may be pretreated by heating a reaction mixture that initially includes an aromatic diamine monomer, an end cap monomer, and an aromatic dianhydride monomer to a temperature between about 250.degree. C. and about 300.degree. C. for a period sufficient to completely imidize the reaction mixture to an imide resin without substantial crosslinking. A crosslinked reinforced polyimide composite article may be fabricated by heating a plurality of prepregs to a first temperature between about 250.degree. C. and about 300.degree. C. for a first period sufficient to completely imidize the prepreg without substantial crosslinking. Each prepreg has a plurality of reinforcing fibers and a reaction mixture. The prepregs are stacked in a desired orientation to form a laminated structure before or after heating to the first temperature and further heated at a superatmospheric pressure to a second temperature for a second period to form a crosslinked reinforced polyimide composite article by consolidating the prepregs and crosslinking the imide resin in the prepreg.

Fabricating crosslinked polyimide high temperature composites and resins

A method for making a fiber reinforced crosslinked polyimide matrix composite article that is substantially free of internal voids and surface blisters is disclosed. The method includes heating a fiber prepreg under vacuum to remove volatile impurities and volatile reaction products from the prepreg and subsequently curing the prepreg to form the article.

Method for making a fiber reinforced crosslinked polyimide matrix

Fluorinated aromatic hydrocarbons including fluorinated aromatic carboxylic acids fluorinated aromatic dianhydrides and fluorinated aromatic dialkyl esters that serve as precursor monomers for high temperature fluorinated polyimides. The fluorinated aromatic carboxylic acid monomer comprises: ##STR1## wherein X is hydrogen, carboxyl, sulfonic acid, hydroxy, alkyl, halogen or nitro and hydrates of said acids. The fluorinated aromatic dianhydride monomer comprises: ##STR2## wherein x is hydrogen, carboxyl, sulfonic acid, hydroxy, alkyl, halogen or nitro. The fluorinated aromatic dialkyl ester monomer comprises: ##STR3## wherein X is hydrogen, carboxyl, sulfonic acid, hydroxy, alkyl, halogen or nitro and Y is an alkyl group and hydrates of said esters.

Monomers for high temperature fluorinated polyimides

A microcrack resistant graphite fiber reinforced high temperature resin matrix composite laminate is disclosed. The laminate comprises layers having the fiber reinforcement in parallel alignment within each layer. The layers are arranged such that the fibers are oriented at 0.degree. and 90.degree. (.+-.10.degree.) in alternating layers. The specific number of plies per layer is selected so as to produce microcrack resistance. A method for making a microcrack resistant graphite fiber reinforced high temperature resin matrix composite laminate is also disclosed.

Microcrack resistant fiber reinforced resin matrix composite laminates

High temperature fluorinated polyimides having repeating polymer units comprising ##STR1## wherein X is diamine. Typically, these polyimides are the copolymerization product of about 3 mole % to about 42 mole % nadic esters; about 39 mole % to about 49 mole % diamine; and about 17 mole % to about 48 mole % 4,4'9(2,2,2-trifluoro-1-phenylethylidene)-bipthalic tetra carboxylic acid dialkylester. These polimides provide the high strength properties at high temperatures yet they can be processed into solid polymers, fibers, films and composites at low temperatures and pressures.

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Glastonbury, CT, United States of America

Daniel A Scola