CA1104138A - Preparation of acetylene-substituted polyimide oligomers - Google Patents
Preparation of acetylene-substituted polyimide oligomersInfo
- Publication number
- CA1104138A CA1104138A CA296,511A CA296511A CA1104138A CA 1104138 A CA1104138 A CA 1104138A CA 296511 A CA296511 A CA 296511A CA 1104138 A CA1104138 A CA 1104138A
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- CA
- Canada
- Prior art keywords
- acetylene
- polyimide
- accordance
- solvent
- substituted
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
- C08G73/00—Macromolecular compounds obtained by reactions forming a linkage containing nitrogen with or without oxygen or carbon in the main chain of the macromolecule, not provided for in groups C08G12/00 - C08G71/00
- C08G73/06—Polycondensates having nitrogen-containing heterocyclic rings in the main chain of the macromolecule
- C08G73/10—Polyimides; Polyester-imides; Polyamide-imides; Polyamide acids or similar polyimide precursors
- C08G73/1003—Preparatory processes
- C08G73/1007—Preparatory processes from tetracarboxylic acids or derivatives and diamines
- C08G73/101—Preparatory processes from tetracarboxylic acids or derivatives and diamines containing chain terminating or branching agents
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T428/00—Stock material or miscellaneous articles
- Y10T428/31504—Composite [nonstructural laminate]
- Y10T428/31721—Of polyimide
Abstract
PREPARATION OF ACETYLENE-SUBSTITUTED
POLYIMIDE OLIGOMERS
Abstract of the Disclosure An improved method is described for the preparation of certain acetylene-substituted polyimide oligomers which are substantially free of reaction solvent and thus do not fracture at use temperatures above 600°F. (316°C.). The acetylene-substituted polyimide oligomers are prepared by reacting an aromatic tetracarboxylic acid dianhydride such as benzophenone tetracarboxylic acid dianhydride with an aromatic diamino compound such as a diamino polyarylene ether in the presence of N-methyl-2-pyrrolidone (NMP) as a solvent to form a first reaction product which is in turn reacted with an aminoaryl-acetylene to form a solution of an acetylene-substituted polyamic acid oligomer in NMP. The polyamic acid oligomer is thereafter converted to the desired acetylene-terminated polyimide oligomer by heating in the continued presence of said N-methyl-2-pyrrolidone.
The N-methyl-2-pyrrolidone can then be removed by any suitable means such as by precipitation of the acetylene-substituted polyimide oligomer in a non-solvent such as ethanol.
POLYIMIDE OLIGOMERS
Abstract of the Disclosure An improved method is described for the preparation of certain acetylene-substituted polyimide oligomers which are substantially free of reaction solvent and thus do not fracture at use temperatures above 600°F. (316°C.). The acetylene-substituted polyimide oligomers are prepared by reacting an aromatic tetracarboxylic acid dianhydride such as benzophenone tetracarboxylic acid dianhydride with an aromatic diamino compound such as a diamino polyarylene ether in the presence of N-methyl-2-pyrrolidone (NMP) as a solvent to form a first reaction product which is in turn reacted with an aminoaryl-acetylene to form a solution of an acetylene-substituted polyamic acid oligomer in NMP. The polyamic acid oligomer is thereafter converted to the desired acetylene-terminated polyimide oligomer by heating in the continued presence of said N-methyl-2-pyrrolidone.
The N-methyl-2-pyrrolidone can then be removed by any suitable means such as by precipitation of the acetylene-substituted polyimide oligomer in a non-solvent such as ethanol.
Description
- Background of the Invention The prior art, notably U. S. Patent 3,845,018 to N. Bilow et al, and U. S. Patent 3,879,349, also to N. Bilow et al, disclose certain acetylene-substituted polyimide oligomers and describe methods for their preparation.
The polyimide oligomers are very useful as molding powders, coatings on wires or other substances, as adhesives, or as laminating resins. The ~inal product as taught in the '018 paten~, Column l, lines 50 et seq., has a very low void content as well as excellent thermal and physical properties.
A method of homopolymeri2ing the acetylene-substituted polyimide .. ,, . . - . .
r ~
3~3 oligomers described in the ~01~ patent can be found in the teachings of the ~349 patent referred to above.
The method of preparation of the acetylene-su~stituted polyimide oli~omers is described in the i018 patent and ls a multi~step procedure involving the initial reaction of an aromatic tetracarboxylic acid dianhydride such as benzophenone tetracarboxylic acid dianhydride with an aromatic diamine to form an anhydride-capped pol~amic acid, which is subsequently reacted with an aminoarylacetylene to produce an acetylene-terminated polyamic acid oligomer, which is then thermally con-verted to the desired acetylene-substituted polyimide oligomer.
The formation of the polyamic acid and acetylene-terminated oligomer occurs in the presence of a solvent, which in all of the working Examples in ~he cited art is dimethyl formamide.
In accordance with the teachings of the cited prior art, the dimethyl formamide solvent is removed before the conversion of the acetylene-terminated polyamic acid oligomer to the desired polyimide (see Col. 4 of the '018 reference, lines 31-33, and the working Examples). The solvent-free polyamic acid oligomer is then diluted with imidization agents such as acetic anhydride or a benæene-cresol mixture.
No reason is given for the removal of the DMF from the polyamic acid oligomer before imidization, but, an "imidization"
a~ent as noted is added, presumably to aid in the removal of the water of imidization and thus drive the reaction to comple-tion. When the imidization agent is benzene-cresol, the benzene is used to azeot ope with water. The function of the cresol is not specified by Bilow et àl in their patents. Since the DMF
is removed from the acetylene-capped oliyomers, the cresol is believed to function as a solvent for the oligomers to aid in the imidi~ation reaction. ~he acetic anhydride can serve as both a solvent and water removal agent. In any event, the separate 3~3 removal of DMF before imidization is an added burden on the process, especially since it is removed in a rotary evaporator requiring considerable energy input and time. The process of the present invention avoids the need for the removal of the reaction solvent before imidlza~ion and thus simplifies the reaction sequence. Further, the process of the present invention avoids the need for the addition of a reaction solvent such as cresol when a water-azeotroping agent such as benzene is added durlng irnidization.
It has also been found that when the teachings of the cited prior art references with regard to the preparation of the acetylene-substituted polyimide oligomers is followed using dimethyl formamide as the solvent, the resulting cured resin fractures at post-cure temperatures above about ~85F.
(252C.). The advantage of the acetylene-substituted polyimide oligomers is that on curing they have very low void contents, giving rise to excellent thermal and physical properties.
It has been found that the ability of the finally cured resin 20 to operate at high temperatures (over 485F. (252C.)) for extended periods of time is a direct function of the history of the post-cure temperatures to which the resin is subjected.
Thus if the finally cured resin is expected to perform well at temperatures in the 500 to 700F. (260 to 371C.) range, then post-curing of the resin must also occur at temperatures of about the same range. It has been found that when post-cure temperatures above about 485F. (252C.) are employed when DME' is used as the solvent in the preparation of the uncured acetylene-substituted polyimide oligomers, fracturing or blister-30 ing of the resin or laminates may occur. The reason for failurewas found to be the evolution of dimethyl formamide from the resin at temperatures exceeding 4~5F. (252C.), despite the fact that dimethyl formamide has a boiling point of about 302F.
3~
(150~C,) and thus should have been removed by simple distillation or evaporation earlier in the processing se~uence. It is theorized that somehow.the DMF solvent is coordinating or reacting with components of the acetylene-substituted polyimide oligomers and is not ~eing removed at the expected conditions as taught in the prior art. Extended drying time~ ca~not be employed, as this tends to prematurely cure the oligomers. Even if it were possible to extend th~ drying time, the dimethyl formamide may well not be removed since heating at 485F (252C) indicates no DMF was present in a gas stream being analyzed bv a pyrolysis-gas chromatography - mass spectrometr~ system.
It has now been discovered in accordance with the invention that N-methyl-2-pyrrolidone can ~e used as the solvent in the formation of t~e acetylene-su~stituted polyimide oligomers without the need for removal of the solvent prior to imidization.
Further, N-methyl-2-pyrrolidione can conveniently be removed from the reaction product despite its higher hoiling point of 392F (200C) so that cured resins perform well at elevated temperatures even on the order of 500 to 700F (288 to 371C) without fracturing for extended periods of tim~.
Thus according to the present invention, there is provided a process for the preparation of an acetyl~ne substituted polyimide oligomer which comprises reacting a stoichiometric excess of a dianhydride of an aromatic tetracarboxylic acid, or a lower alkyl diester of said aromatic tetracar~oxylic acid, with an aromatic diam.ine to form an anhydride-capped polyamic acid or acid-ester-capped analog in th~ presence of at least a sufficient amount of a solvent consisting essentially of N-methyl-2-pyrrolidone to form a 3Q solution at elevated temperatures; thereafter reacting said . . ., ~Y
3~
anhydride-capped polyamic acid or analog wi~h an aminoarylacety-lene compound in the presence of said solvent to produce an ace~ylene-terminated polyamic acid oligomer; converting said acetylene-terminated polyamic acid oligomer to the corresponding polyimide in the continued presenc~ of at least a portion of said solvent; and thereafter recover;ng the desired acetylene-substituted polyimide oligomers su~stantially free of said solvents.
The preparation of an acetylene-substituted polyimide oligomer in accordance with the invention occurs ~y a multi-step process involving the reaction of a stoichiometric excess o* an aromatic ~etracar~oxylic dianhydride, or a lower alkyl diester thereof, with an aromatic diamine to form an anhydride-capped polyamic acid or the corresponding acid-ester-capped analog in the presence of a sufficient amount of a solvent consisting essentially of N-methyl-2-pyrrolidone to form a solution at elevated temperatures of about 60C to about 17~C; thereafter - 4a -. ~ .
reacting the anhydride-~capped polyamic acid or analog with an aminoarylacetylene, such as aminophenylacetylene ! in the continued presence of NMP to produce an acetylene-substituted polyamic acid oligomer. The acetylene-substituted (terminated) polyamic acid oligomer is then converted at elevated temperatures, with or without a catalyst such as sulfuric acid and preferably by simple heating (thermally) to the corresponding polyimide in the continued presence of NMP. If an aromatic tetracarboxylic anhydride was employed in the initial reaction, then water is given off as a byproduct during the formation of the polyimide, On the other hand, if a lower alkyl diester of the aromatic tetra-carbo~ylic acid is employed initially, then, of course, an alcohol corresponding to the lowex alkyl group of the diester is evolved during formation of the polyimide. The water or alcohol byproduct is preferably continuously removed during the formation of the polyimide to aid, of course, in driving the reaction to completion.
A water-azeotroping agent such as benzene can be added to aid in the removal of the water of imidization. A portion of the NMP
could, optionally, be removed before the conversion of the poly-amic acid olig~mer, but sufficient NMP should remain for ease inhandling the oligomer during imidization. The presence of the NMP
during the imidization is not deleterious to the process and preferably remains in the reaction product to reduce the number of steps occurring in the formation of the desired acetylene-substituted polyimide oligomers which can thereafter be recovered substantially free of the NMP by methods well known in the art.
The recovered neat polyimide oligomers can be used to form molded articles under known conditions of curing. Laminates, for example glass laminates, or composites containing powdered metals or other materials can also be formed by curing at elevated temperatures of up to 485F. (252C.).
The precursors to the acetylene-substituted polyimide oligomers made by the process of this invention are known in ~ ~J'~ ~ 3~
the art, Preferred forms of the precursors and the polyimide oligomers are described in U. S. Patent 3,845,018 referred to above, issued to Norman Bilow et al on October 29, 1974. Thus the process of this invention is particularly directed to the preparation of an acetylene-substituted polyimide oligomer having the general structure:
Formula I
~ O O ` O O
1~ ~1 !1 11 ~C~ ~C ~ ~C~ ~C~ , HC - C - R'- - N ~R'\ N - R ~ - N Rl' N ~ Rl - C ~ CH
C C C C
ll ll ll ll O o n O O
wherein R is poly(arylene ether) or poly(arylene thioether)~
R' is arylene or diarylene ether, n is an average from 1 to about 10, and R" is ~ or ~ X_ ~ and X is C=O, CH2~ o~S2 ~ C(CF3)2 or a bond or acetylene substituted derivatives thereof.
The acetylene-substituted polyimide oligomers are prepared by a series of steps involving the preparation of intermediate "precursors" to the desired polyimlde oligomers.
Initially, a stoichiometric excess of an aromatic tetracarboxylic acid dianhydride, or a lower alkyl diester thereof, is reacted with an aromatic diamine to form an anhydride-capped polyamic acid or the corresponding acid - ester~capped analog in the presence of at least a sufficient amount of a solvent consisting essentlally of N-methyl-2-pyrrolidone (NMP) to form a solution at elevated temperatures.
Preferably the aromatic tetracarboxyllc acid dianhydride has the formula:
Formula II
O O
.. ..
/c~ /c o R" o C C
,. .. .
O O
where R" is ~ or ~ ~ and X is C=O, C~2, O, So2, -C(CF3)2 or a bond; where R" can contain pendent ethynyl groups.
The corresponding lower alkyl diester of Formula II
can be employed and is shown as Formula III below:
Formula III
O O
ll ll O C ~ , O
~ , ~
HO - C C - OH
o O
where R" is as defined and R"' is a lower alkyl group having from 1 to 4 carbon atoms such as methyl, ethyl, propyl or butyl and is preferably ethyl.
Examples o~ suitable compounds coming within the purview of Formulas II and III which can be ~mployed include, but are not limited to:
Formula II Compounds 3,3',4,4'ben20phenonetetracarboxylic dianhydride;
Pyromellitic dianhydride;
Bis(3,4-dicarboxyphenyl)methane dianhydride;
Bis(3,4-dicarboxyphenyl)ether dianhydride;
Bis(3,4-dicarboxyphenyl)sulfone dianhydride;
The polyimide oligomers are very useful as molding powders, coatings on wires or other substances, as adhesives, or as laminating resins. The ~inal product as taught in the '018 paten~, Column l, lines 50 et seq., has a very low void content as well as excellent thermal and physical properties.
A method of homopolymeri2ing the acetylene-substituted polyimide .. ,, . . - . .
r ~
3~3 oligomers described in the ~01~ patent can be found in the teachings of the ~349 patent referred to above.
The method of preparation of the acetylene-su~stituted polyimide oli~omers is described in the i018 patent and ls a multi~step procedure involving the initial reaction of an aromatic tetracarboxylic acid dianhydride such as benzophenone tetracarboxylic acid dianhydride with an aromatic diamine to form an anhydride-capped pol~amic acid, which is subsequently reacted with an aminoarylacetylene to produce an acetylene-terminated polyamic acid oligomer, which is then thermally con-verted to the desired acetylene-substituted polyimide oligomer.
The formation of the polyamic acid and acetylene-terminated oligomer occurs in the presence of a solvent, which in all of the working Examples in ~he cited art is dimethyl formamide.
In accordance with the teachings of the cited prior art, the dimethyl formamide solvent is removed before the conversion of the acetylene-terminated polyamic acid oligomer to the desired polyimide (see Col. 4 of the '018 reference, lines 31-33, and the working Examples). The solvent-free polyamic acid oligomer is then diluted with imidization agents such as acetic anhydride or a benæene-cresol mixture.
No reason is given for the removal of the DMF from the polyamic acid oligomer before imidization, but, an "imidization"
a~ent as noted is added, presumably to aid in the removal of the water of imidization and thus drive the reaction to comple-tion. When the imidization agent is benzene-cresol, the benzene is used to azeot ope with water. The function of the cresol is not specified by Bilow et àl in their patents. Since the DMF
is removed from the acetylene-capped oliyomers, the cresol is believed to function as a solvent for the oligomers to aid in the imidi~ation reaction. ~he acetic anhydride can serve as both a solvent and water removal agent. In any event, the separate 3~3 removal of DMF before imidization is an added burden on the process, especially since it is removed in a rotary evaporator requiring considerable energy input and time. The process of the present invention avoids the need for the removal of the reaction solvent before imidlza~ion and thus simplifies the reaction sequence. Further, the process of the present invention avoids the need for the addition of a reaction solvent such as cresol when a water-azeotroping agent such as benzene is added durlng irnidization.
It has also been found that when the teachings of the cited prior art references with regard to the preparation of the acetylene-substituted polyimide oligomers is followed using dimethyl formamide as the solvent, the resulting cured resin fractures at post-cure temperatures above about ~85F.
(252C.). The advantage of the acetylene-substituted polyimide oligomers is that on curing they have very low void contents, giving rise to excellent thermal and physical properties.
It has been found that the ability of the finally cured resin 20 to operate at high temperatures (over 485F. (252C.)) for extended periods of time is a direct function of the history of the post-cure temperatures to which the resin is subjected.
Thus if the finally cured resin is expected to perform well at temperatures in the 500 to 700F. (260 to 371C.) range, then post-curing of the resin must also occur at temperatures of about the same range. It has been found that when post-cure temperatures above about 485F. (252C.) are employed when DME' is used as the solvent in the preparation of the uncured acetylene-substituted polyimide oligomers, fracturing or blister-30 ing of the resin or laminates may occur. The reason for failurewas found to be the evolution of dimethyl formamide from the resin at temperatures exceeding 4~5F. (252C.), despite the fact that dimethyl formamide has a boiling point of about 302F.
3~
(150~C,) and thus should have been removed by simple distillation or evaporation earlier in the processing se~uence. It is theorized that somehow.the DMF solvent is coordinating or reacting with components of the acetylene-substituted polyimide oligomers and is not ~eing removed at the expected conditions as taught in the prior art. Extended drying time~ ca~not be employed, as this tends to prematurely cure the oligomers. Even if it were possible to extend th~ drying time, the dimethyl formamide may well not be removed since heating at 485F (252C) indicates no DMF was present in a gas stream being analyzed bv a pyrolysis-gas chromatography - mass spectrometr~ system.
It has now been discovered in accordance with the invention that N-methyl-2-pyrrolidone can ~e used as the solvent in the formation of t~e acetylene-su~stituted polyimide oligomers without the need for removal of the solvent prior to imidization.
Further, N-methyl-2-pyrrolidione can conveniently be removed from the reaction product despite its higher hoiling point of 392F (200C) so that cured resins perform well at elevated temperatures even on the order of 500 to 700F (288 to 371C) without fracturing for extended periods of tim~.
Thus according to the present invention, there is provided a process for the preparation of an acetyl~ne substituted polyimide oligomer which comprises reacting a stoichiometric excess of a dianhydride of an aromatic tetracarboxylic acid, or a lower alkyl diester of said aromatic tetracar~oxylic acid, with an aromatic diam.ine to form an anhydride-capped polyamic acid or acid-ester-capped analog in th~ presence of at least a sufficient amount of a solvent consisting essentially of N-methyl-2-pyrrolidone to form a 3Q solution at elevated temperatures; thereafter reacting said . . ., ~Y
3~
anhydride-capped polyamic acid or analog wi~h an aminoarylacety-lene compound in the presence of said solvent to produce an ace~ylene-terminated polyamic acid oligomer; converting said acetylene-terminated polyamic acid oligomer to the corresponding polyimide in the continued presenc~ of at least a portion of said solvent; and thereafter recover;ng the desired acetylene-substituted polyimide oligomers su~stantially free of said solvents.
The preparation of an acetylene-substituted polyimide oligomer in accordance with the invention occurs ~y a multi-step process involving the reaction of a stoichiometric excess o* an aromatic ~etracar~oxylic dianhydride, or a lower alkyl diester thereof, with an aromatic diamine to form an anhydride-capped polyamic acid or the corresponding acid-ester-capped analog in the presence of a sufficient amount of a solvent consisting essentially of N-methyl-2-pyrrolidone to form a solution at elevated temperatures of about 60C to about 17~C; thereafter - 4a -. ~ .
reacting the anhydride-~capped polyamic acid or analog with an aminoarylacetylene, such as aminophenylacetylene ! in the continued presence of NMP to produce an acetylene-substituted polyamic acid oligomer. The acetylene-substituted (terminated) polyamic acid oligomer is then converted at elevated temperatures, with or without a catalyst such as sulfuric acid and preferably by simple heating (thermally) to the corresponding polyimide in the continued presence of NMP. If an aromatic tetracarboxylic anhydride was employed in the initial reaction, then water is given off as a byproduct during the formation of the polyimide, On the other hand, if a lower alkyl diester of the aromatic tetra-carbo~ylic acid is employed initially, then, of course, an alcohol corresponding to the lowex alkyl group of the diester is evolved during formation of the polyimide. The water or alcohol byproduct is preferably continuously removed during the formation of the polyimide to aid, of course, in driving the reaction to completion.
A water-azeotroping agent such as benzene can be added to aid in the removal of the water of imidization. A portion of the NMP
could, optionally, be removed before the conversion of the poly-amic acid olig~mer, but sufficient NMP should remain for ease inhandling the oligomer during imidization. The presence of the NMP
during the imidization is not deleterious to the process and preferably remains in the reaction product to reduce the number of steps occurring in the formation of the desired acetylene-substituted polyimide oligomers which can thereafter be recovered substantially free of the NMP by methods well known in the art.
The recovered neat polyimide oligomers can be used to form molded articles under known conditions of curing. Laminates, for example glass laminates, or composites containing powdered metals or other materials can also be formed by curing at elevated temperatures of up to 485F. (252C.).
The precursors to the acetylene-substituted polyimide oligomers made by the process of this invention are known in ~ ~J'~ ~ 3~
the art, Preferred forms of the precursors and the polyimide oligomers are described in U. S. Patent 3,845,018 referred to above, issued to Norman Bilow et al on October 29, 1974. Thus the process of this invention is particularly directed to the preparation of an acetylene-substituted polyimide oligomer having the general structure:
Formula I
~ O O ` O O
1~ ~1 !1 11 ~C~ ~C ~ ~C~ ~C~ , HC - C - R'- - N ~R'\ N - R ~ - N Rl' N ~ Rl - C ~ CH
C C C C
ll ll ll ll O o n O O
wherein R is poly(arylene ether) or poly(arylene thioether)~
R' is arylene or diarylene ether, n is an average from 1 to about 10, and R" is ~ or ~ X_ ~ and X is C=O, CH2~ o~S2 ~ C(CF3)2 or a bond or acetylene substituted derivatives thereof.
The acetylene-substituted polyimide oligomers are prepared by a series of steps involving the preparation of intermediate "precursors" to the desired polyimlde oligomers.
Initially, a stoichiometric excess of an aromatic tetracarboxylic acid dianhydride, or a lower alkyl diester thereof, is reacted with an aromatic diamine to form an anhydride-capped polyamic acid or the corresponding acid - ester~capped analog in the presence of at least a sufficient amount of a solvent consisting essentlally of N-methyl-2-pyrrolidone (NMP) to form a solution at elevated temperatures.
Preferably the aromatic tetracarboxyllc acid dianhydride has the formula:
Formula II
O O
.. ..
/c~ /c o R" o C C
,. .. .
O O
where R" is ~ or ~ ~ and X is C=O, C~2, O, So2, -C(CF3)2 or a bond; where R" can contain pendent ethynyl groups.
The corresponding lower alkyl diester of Formula II
can be employed and is shown as Formula III below:
Formula III
O O
ll ll O C ~ , O
~ , ~
HO - C C - OH
o O
where R" is as defined and R"' is a lower alkyl group having from 1 to 4 carbon atoms such as methyl, ethyl, propyl or butyl and is preferably ethyl.
Examples o~ suitable compounds coming within the purview of Formulas II and III which can be ~mployed include, but are not limited to:
Formula II Compounds 3,3',4,4'ben20phenonetetracarboxylic dianhydride;
Pyromellitic dianhydride;
Bis(3,4-dicarboxyphenyl)methane dianhydride;
Bis(3,4-dicarboxyphenyl)ether dianhydride;
Bis(3,4-dicarboxyphenyl)sulfone dianhydride;
2,2-Bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride~
Formula III Compounds
Formula III Compounds
3~3~-dicarbomethoxy~4~4ibenzophenonedicarboxylic acid;
3,4'-dicarbomethoxy-3'4 benzophenonedicarboxylic acid;
3,4'-dicarbomethoxy-3'4 benzophenonedicarboxylic acid;
4,4'-dicarbomethoxy-3~3'benzophenonedicarboxylic acid;
3,3'-dicarboethoxy-4,4'benzophenonedicarboxylic acid;
3,4'-dicarbopropoxy-3',4benzophenonedicarboxylic acid;
2,5-dicarbome~hoxy terephthalic acid;
3,5-dicarbomethoxy isophthalic acid;
2,5-dicarboethoxy terephthalic acid;
3,5-dicarboethoxy isophthalic acid;
2,5-dicarbopropoxy terephthalic acid;
3,5-dicarbopropoxy isophthalic acid;
2,5-dicarbobutoxy terephthalic acid 3,5-dicarbobutoxy isophthalic acid, 3,3'-dicarbomethoxy-4,4'dicarboxydiph~nylether;
3,4'-dicarbomethoxy-3',4-dicarboxydiphensrlether;
4,4'-dicarbomethoxy-3,3'-dicarboxydiphenylether;
3,3'-dicarboethoxy-4,41-dicarboxydiphenylether;
3,3'-dicarbopropoxy-4,4'-dicarboxydiphenylether 3,41-dicarbobutoxy-3'4 -dicarboxydiphenylether;
3,3'-dicarbomethoxy-4,4'-dicarboxydiphenylsulfone;
3,4'-dicarobmethoxy-3'4- dicarboxydiphenylsulfone;
4,4'-dicarbomethoxy-3,3'-dicarboxydipllenylsulfone;
3,3'-dicarboeth~xy-4,4'-dicarboxydiphenylsulfone;
3,3'-dicarbopropoxy-4,4'-dicarboxydiphenylsulfone;
3,3'-dicarbobutoxy-4,4'-dicarboxydiphenylsul~one;
3,3'-dicarbomethoxy-4,4'~dicarboxydiphenylmethane;
3,4'-dicarbomethoxy-3'4 dicarboxydiphenylmethane;
4,4'-dicarbomethoxy-3,3'dicarboxydiphenylmethane;
3,3'-dicarboethoxy-4,4'-dicarboxydiphenylmethane;
3,3'-dicarbopropoxy-4,4'-dicarboxydiphenylmethane;
3,3'-dicarbobutoxy-4,4'-dicarboxydiphenylmethane;
3~
2~2-Bis(3-caxbomethoxy~4_carboxyphenyl)hexafluoropropane;
2-~3-carbomethoxy-4-carboxyphenyl~-2(3~-carboxy-4-carbomethoxy-phenyl),hexafluoropropane, 2,2-Bis(3-carboxy-4-carboxymethoxyphenyl)hexafluoroyropane.
The aromatic diamine to be reacted with the aromatic tetracarboxylic acid preferably has the formula:
Formula IV
. --H2N - R ~ NH2 where R is poly(arylene ether), diarylene ketone, diarylene methanej diarylene sulfone, poly~arylene thioether) or an acetylene-substituted derivative thereof.
In order to increase the tractability and solubility of the acetylene-substituted products of this invention, R will preferably contain two or more ether or thioether linkages between arylene radical~ and/or pendent aryl substituent~ on an aryl ether radical. Compounds of particular interest are those in which R corresponds to the following:
Formula V
,~X-~X~
m wherein X is O or S, Y is H or C-CH, m i~ a value from 0 to about 4, and the amino groups of Formula IV are meta or para to the ether or thioether linkages~
Norman Bilow et al in Column 2, line 67, of their U.S. patent 3,845,018 make reference to a description of a procedure useful in preparing diamino subst;tuted compounds corres-ponding to Formula V when Y is equal to C-CH ortho to an ether linkage. A modification of that procedure is used to substitute _ g _ . ~ .
3~
the C--CH meta to an ether linkage. In the modified procedure, the reaction may be exempli~ied by the following.
NaO ~ ONa Br ~NO2 2 5 , 2 5 02N ~ `¢~1' ¢~ N2 02N-- ~ ~ ~ 2 dil ~
CH3 02N - ~ ~ ~ NO2 C=O
Once the acetyl product is obtained, subsequent conversion to the diamino acetylenic substituted compound is achiev~d through the corresponding steps of the aforementioned, known procedure.
In compounds where m is 2 or more, the Y substituents may be the same or different. Compounds are preferred wherein the amino groups are in the meta positions because they have lower melting points and are more tractable and soluble than the corres-ponding para-substituted analogs. Representative compounds having pendant aryl groups are 3~3 7 -diamino-5-phenyl diphenyl ether, and 3,3'-diamino S-phenoxy diphenyl ether. Other typical diamines include 1-(3-aminophenoxy~-3-~4-aminophenoxy)benzene; 1,3-bis (3-aminophenoxy)benzene; and 1-(4-aminophenoxy)-3-~4-aminophenoxy) benzene. Particularly good results have been obtained with 1,3-bis(3-aminophenoxy)benzene in producîng acetylene-substituted polyimides which have good solubility and tractability~
--~0--. .. ~ ., .~.. ,.~ ,, ~ .
Utilizing a dianh~dride having Formula II a~ove and the diamine having Formula IU ~or illustration, the reaction proceeds to form an amic acid oligomer according to the following equation:
O O O O
,. " ,. .~
(n+l) O ~ R"~ /O ~ nH2N - R - NH2 ~~~ ~ c /R ~C OH
Oo O O
O O ~ O O
ll ll ll ll _ - R - NH - C\ /C - NH - - R - NH - C ,C\
HO - C C ~ OH R" O
ll ll ll ll _ O O m O
wherein n is one or greater, usually 1 to 15, and m is zero or greater.
The reaction of the aromatic tetracarboxylic acid, corresponding dianhydride or lower alkyl diester thereof with the aromatic diamine occurs at temperatures from 40to 180C., 20 preferably 70 to 160C.; reaction pressures of about atmos~
pheric, but higher pressures on the order of 1000 psig t6.9 MPa) can be employed if desired; and the reaction time is on the order of 10 to 300 minutes, more usually on the order of 30 to 150 minutes. Since both of the reactants tend to be solids, it is desirable to operate the process in the presence of a solvent, andin accordance with the subject invention, the solvent is NMP.
A sufficient amount of the solvent is employed to form a solution of the reactant at elevated temperatures where reaction occurs, 30 that is, temperatures on the order of 70 to 160C.
The anhydride-capped polyamic acid oligomers, or the corresponding ester-cappe~ analogs, are ~hen reacted with a compound having the formula:
~1~4~3~
Formula VI
~2N-Arylene-CcCH
wherein arylene is phenylene, naphthylene, or biphenylene.
It is preferred to use m-aminophenylacetylene, 3-amino-31ethynyl-biphenyl, 4-amino-3'-ethynylbiphenyl, or 3 amino-4'-ethynyl-diphenyl ether and the 3,3' and 4~4' ~ub~tituted analogs thereof because the meta substitutions provide oligomers with lower melting points, better solubility, and better melt flow properties. The anhydride-capped polyamic acid oligomer and an aminoarylacetylene compound are reacted in the presence of the NMP to produce an acetylene-terminated polyamic acid oligomer. The reaction occurs at elevated temperatures from about 40 to about 180Co ~ preferably at temperatures from 70 to 160C. The reaction pressure is again about atmospheric, but higher pressures can be used if desired, The reaction time is on the order of one to 16 hours, more usually about 2 to 12 hours. The aminoarylacetylenes represented by Formula VI above are known in the art and their preparation is described in Column 4, lines 41 et seq., of the Bilow et al U. S. Patent 3,845,018. For example, Bilow et al teach than an aromatic compound having both nitro and acetyl substituents is reacted, preferably under reflux, with dimethyl-formamide and phosphorus oxychloride to convert the acetyl radical to -C(Cl)=CHCH0. The reactio~ is exothermic, and external cooling is needed to keep it at approximately room temperature.
The ~-chloro-substituted aldehyde radical is converted to -C-CH
by refluxing a solution of the compound in dioxane and sodium hydroxide. The product is extracted with an organic solvent such as ether; the organic solution is dried; the solvent i6 removed; and the product recovered by vacuum distillation.
. ~, 3~
The nitro group is then converted to amino by refluxing an aqueous alcohol solution of the product with at least 6 moles of ferrous sulfate per mole of ni.tro compound. The product is removed by solvent extraction~ e.g. ether, and purified, e.g. by vacuum distillation. According to Bilow et al, the process is described in more detail in the same application Serial No. 347r 502 referred to above.
The product is a solution of an acetylene-terminated polyamic acid oligomer for the corresponding anhydride or ester analog depending on whether an acid anhydride or ester starting material was employed. This material represents a polyimide precursor in Formula VII below:
Formula VII
O O
\ /
HC--CR I ~ NH ~ C C ~ OR"~
11 ~1 O O _ n O O
.. ..
2 0 R "
R~ 0 ~ C \C ~ NH ~ R I ~ C~C~
ll ll O O
wherein R~ R~ / R~ and n are defined above, and R"' is H or lower alkyl, such as methyl, propyl, butyl and preferably ethyl.
R" and R may also contain pendent ethynyl groups~
To obtain the desired acetylene-substituted polyimide oligomers, it is now necessary to remove water if an aromatic tetracarboxylic dianhydride was employed, or to remove an alcohol if a lower alkyl diester of an aromatic tetracarboxylic acid was employed. Normally the imidization reactionoccurs thermally, although a catalyst can be added if desired, and it is preferred to add an imidization agent to aid in the azeotropic remoYal of wa~er and~or an alcohol.
In Column 4, lines 31 et seq., Bilow et al teach in their '018 patent referred to above that the dimethyl formamide solvent employed by Bilow et al is removed initially, and the polyamic acid is diluted with an imidization agent such as acetic anhydride or a benzene-cresol mixture. It is not clear why Bilow et al find it necessary to remove the dimethyl formamide solvent, but it has been found as will be noticed below in the working Examples that even when the dimethyl form-amide solvent is "removed" at this point, it is not fully removed, and portions of the dimethyl formamide appear to be chemically complexing or reacting and are evolved at higher post-cure temperatures resulting in fracturing of the products after curing.
It may be desirable to remove a portion of the NMP
solvent before the imidization reaction takes place, but this is simply a matter of convenience to the operator. The addition of an imidization agent is also optional and simply serves its normal engineering function to aid in the removal of b~product water or alcohol. Any well~known imidization agent can be employed such as benzene. It is preferred, of course, that the imidiæation occur thermally, and the tempera~ure at which imidization occurs is the reflu~ temperature necessary for the removal o~ the water and/or alcohol. The imidization reaction can, as is well known, be operated under higher temperatures if pressure operation i9 employed, but atmospheric operation is satisfactory. It ls also possible to remove the NMP before imidization and replace it with another solvent, but there is no advantage to do:ing this;
- 30 in fact, there is a definite disadvantage in having to maintain separate stores of different solvents.
3~
The acetylene-substituted polyimides made by the process of this invention are recovered by any suita~le technique.
For example, the NMP can be removed in a rotary evaporator followed by washing with absolute ethanol~ A preferred technique is to precipitate the polyimide oligomer by contacting a solution of the oligomer in NMP with an alcohol such as absolute ethanol followed by several washes ~ith absolute ethanol. The product is recovered by filtration or centrifugation and finally dried in an oven at 120C. under vacuum for 24 hours or longer.
The acetylene-substituted polyimides may be used neat to form molded articles, or the polyimide oligomers can be used to form laminates using, for example, a glass cloth, or the polyimide oligomers can be used to ~orm composites containing additives such as powdered metals. The polyimide oligomers are converted to a solid infusible product, e.g. molded article, by curing at elevated temperatures of up to 485F. (252C.) for time periods of 0.25 to 48 hours. The resulting laminates or composites have excellent physical properties, as noted by Bilow et al in their '018 patent. The properties of the product are improved by post-curing at temperatures above 485F.
(252C.) and usually temperatures from 50~ to 700F. ~260 to 371C.). The post curing time is normally from four to 48 hours.
The invention will be further described with reference to the following experimental work.
Example 1 To a solution of 3,3',4,4'-benzophellonetetracarbo~ylic acid dianhydride (BTDAj (lg.32 grams, 0.06 mole) in 165 ml of N-methyl-2-pyrrolidone heated at 150C. was added dropwise over a 45~minute period a solution of 1,3-bis(3-aminophenoxy)benzene (8.76 grams, 0.03 mole) in 75 ml of NMP. I'he mixture was heated for 50 minutes at 150 to 154C. and then a solution of 7.35 3L3~
qrams (0,063 mole~ of 3-aminophenylacetylene in 15 ml o~ NMP
was added all at once. A total of 32 ml o~ benæene was then added, and the reaction mixture was heated to 150 to 160C.
to reflux the ben~ene and remove the water of imidization as a water-benzene azeotrope into a Dean-Stark water trap. The total reaction time was ten hours. The total water removed was 3.5 ml; the benz ne and NMP solvents were removed at 80C, under vacuum on a rotary evaporator. The residue was washed with absolute ethanol u~ing a Waring blender, filtered, and then the same washing procedure was repeated twice more. The residue was dried in a vacuum oven for 24 hours at 120C.
The product yield was 31.5 grams, or 94.6~ of theoretical.
The product had a melting point range of 190 to 196C.
Fxample 2 -10~0 grams of a neat resin from Example 1 were molded into a disc having the dimensions 0.995" diameter x 0.575" thick (2.52 cm. dia. x 0.425cm. thick) after pre-cure for 45 minutes at 350F. (177C.). The molding conditions were 485F. (252C.) for 16 hours at 2000 psi (13.8 MPa). The disc was post-cured in two stages, as follows:
Stage 1 - 18 hours at 600F. (316C.) at atmospheric pressure;
Stage 2 - 24 hours at 700F. (371C.) at atmospheric pressure.
The post-cured sample showed no blistering or delimina~
tion, and the weight loss during post-curing was 2.02 percent, and the void content of the final product was found to be 1.06 percent.
~ e_e 3 The procedure of Example 2 was repeated, but a 50-50 isopropanol-methanol wash liquid was used. A yield of -16~
91.7 percent oligomer product was obtained. The weiyht loss during post-curing was 1.95%, and the void content of the final product was 1.19~.
Example 4 Example 3 was repeated, but isopropanol wash liquid was used. The properties of the product were substantially the same as in Example 2, except the yield was 93.8 percent.
The weight loss during post-curing was 1.~9 percent, and the void content of the final product was 0.86 percent.
Example S
Example 2 was repeated, except acetone was used as the wash liquid. The properties of the final product were substantially the same as in Example 2 except the yield was reduced to 72.6 percent. The weight loss and void content were 3.8~ and 2.19 percent, respectively.
Example 6 Example 2 was repeated except the wash liquid was water. The properties of the final product were substantially the same as in Example 2, except the yield was 99.6 percent.
The weigh~ loss and void content were 2.93 and 1.3 percent, respectively.
Exam~le 7 To a solution of 55.1 grams (0.17 mole) of BTDA
in dry dimethyl formamide (500 ml), heated at 150 to 1S3C~, was added, drop-wise over a period of one hour, a room-tempera-ture solution of 25.0 grams (0.0856 mole) of 1,3-bis(3-amino-phenoxy)benzene in 250 ml o~ DMF. The mixture was heated at reflux for 2.0 hours, and then a solution of 3-aminophenyl acetylene (21.0 grams, 0.1795 mole) in DMF (100 ml) was added;
and the solution was heated at re1ux for an additional 4.0 hours after the addition. The DME solvent was removed on a rotary evaporator, and the residue was dissolved in hot (100C.) meta-cresol (500 ml)~ cooled~ and 250 ml of benzene was added, The mixture was heated at total reflux after adding a Dean-Stark water trap. After 3.0 hours, 1.2 ml of water was removed from the trap. The benzene - meta-cresol mixture was removed on the rotary evaporator until the total volume was approximately 250 ml. The slurry was precipitated and washed with 1000 ml of absolute ethanol, filtered, and then the procedure repeated twice again with 600 ml of fresh e~hanol using a Waring blender to insure good washing. The residue was dried in a vacuum oven for three hours at 120C. The product yield was 77.9 grams (82 percent).
Example 8 54.1 grams of a neat resin from Example 7 after pre-cure at 350F. (177C.) for 45 minutes was molded into a disc having the dimensions 2.239" diameter x 0.531" thick (5.686 cm. dia. x 1.349 cm. thick). The molding conditions were 2 hours at 485F. (252C.) and a pressure o~ 2000 psig (13.8 MPa). The molded product appeared to be of general good quality at this point. T e molded product was post-cured using the following schedule:
(1) 450-600F. (232-316C.) at 12.5F.
per hour;
(2) 600F. (316C.) for 24 hours;
(3) 600-700F. (316-371C.) at 5F.
per hour;
(4) 700E'. (371C.) for four hours; and
3,3'-dicarboethoxy-4,4'benzophenonedicarboxylic acid;
3,4'-dicarbopropoxy-3',4benzophenonedicarboxylic acid;
2,5-dicarbome~hoxy terephthalic acid;
3,5-dicarbomethoxy isophthalic acid;
2,5-dicarboethoxy terephthalic acid;
3,5-dicarboethoxy isophthalic acid;
2,5-dicarbopropoxy terephthalic acid;
3,5-dicarbopropoxy isophthalic acid;
2,5-dicarbobutoxy terephthalic acid 3,5-dicarbobutoxy isophthalic acid, 3,3'-dicarbomethoxy-4,4'dicarboxydiph~nylether;
3,4'-dicarbomethoxy-3',4-dicarboxydiphensrlether;
4,4'-dicarbomethoxy-3,3'-dicarboxydiphenylether;
3,3'-dicarboethoxy-4,41-dicarboxydiphenylether;
3,3'-dicarbopropoxy-4,4'-dicarboxydiphenylether 3,41-dicarbobutoxy-3'4 -dicarboxydiphenylether;
3,3'-dicarbomethoxy-4,4'-dicarboxydiphenylsulfone;
3,4'-dicarobmethoxy-3'4- dicarboxydiphenylsulfone;
4,4'-dicarbomethoxy-3,3'-dicarboxydipllenylsulfone;
3,3'-dicarboeth~xy-4,4'-dicarboxydiphenylsulfone;
3,3'-dicarbopropoxy-4,4'-dicarboxydiphenylsulfone;
3,3'-dicarbobutoxy-4,4'-dicarboxydiphenylsul~one;
3,3'-dicarbomethoxy-4,4'~dicarboxydiphenylmethane;
3,4'-dicarbomethoxy-3'4 dicarboxydiphenylmethane;
4,4'-dicarbomethoxy-3,3'dicarboxydiphenylmethane;
3,3'-dicarboethoxy-4,4'-dicarboxydiphenylmethane;
3,3'-dicarbopropoxy-4,4'-dicarboxydiphenylmethane;
3,3'-dicarbobutoxy-4,4'-dicarboxydiphenylmethane;
3~
2~2-Bis(3-caxbomethoxy~4_carboxyphenyl)hexafluoropropane;
2-~3-carbomethoxy-4-carboxyphenyl~-2(3~-carboxy-4-carbomethoxy-phenyl),hexafluoropropane, 2,2-Bis(3-carboxy-4-carboxymethoxyphenyl)hexafluoroyropane.
The aromatic diamine to be reacted with the aromatic tetracarboxylic acid preferably has the formula:
Formula IV
. --H2N - R ~ NH2 where R is poly(arylene ether), diarylene ketone, diarylene methanej diarylene sulfone, poly~arylene thioether) or an acetylene-substituted derivative thereof.
In order to increase the tractability and solubility of the acetylene-substituted products of this invention, R will preferably contain two or more ether or thioether linkages between arylene radical~ and/or pendent aryl substituent~ on an aryl ether radical. Compounds of particular interest are those in which R corresponds to the following:
Formula V
,~X-~X~
m wherein X is O or S, Y is H or C-CH, m i~ a value from 0 to about 4, and the amino groups of Formula IV are meta or para to the ether or thioether linkages~
Norman Bilow et al in Column 2, line 67, of their U.S. patent 3,845,018 make reference to a description of a procedure useful in preparing diamino subst;tuted compounds corres-ponding to Formula V when Y is equal to C-CH ortho to an ether linkage. A modification of that procedure is used to substitute _ g _ . ~ .
3~
the C--CH meta to an ether linkage. In the modified procedure, the reaction may be exempli~ied by the following.
NaO ~ ONa Br ~NO2 2 5 , 2 5 02N ~ `¢~1' ¢~ N2 02N-- ~ ~ ~ 2 dil ~
CH3 02N - ~ ~ ~ NO2 C=O
Once the acetyl product is obtained, subsequent conversion to the diamino acetylenic substituted compound is achiev~d through the corresponding steps of the aforementioned, known procedure.
In compounds where m is 2 or more, the Y substituents may be the same or different. Compounds are preferred wherein the amino groups are in the meta positions because they have lower melting points and are more tractable and soluble than the corres-ponding para-substituted analogs. Representative compounds having pendant aryl groups are 3~3 7 -diamino-5-phenyl diphenyl ether, and 3,3'-diamino S-phenoxy diphenyl ether. Other typical diamines include 1-(3-aminophenoxy~-3-~4-aminophenoxy)benzene; 1,3-bis (3-aminophenoxy)benzene; and 1-(4-aminophenoxy)-3-~4-aminophenoxy) benzene. Particularly good results have been obtained with 1,3-bis(3-aminophenoxy)benzene in producîng acetylene-substituted polyimides which have good solubility and tractability~
--~0--. .. ~ ., .~.. ,.~ ,, ~ .
Utilizing a dianh~dride having Formula II a~ove and the diamine having Formula IU ~or illustration, the reaction proceeds to form an amic acid oligomer according to the following equation:
O O O O
,. " ,. .~
(n+l) O ~ R"~ /O ~ nH2N - R - NH2 ~~~ ~ c /R ~C OH
Oo O O
O O ~ O O
ll ll ll ll _ - R - NH - C\ /C - NH - - R - NH - C ,C\
HO - C C ~ OH R" O
ll ll ll ll _ O O m O
wherein n is one or greater, usually 1 to 15, and m is zero or greater.
The reaction of the aromatic tetracarboxylic acid, corresponding dianhydride or lower alkyl diester thereof with the aromatic diamine occurs at temperatures from 40to 180C., 20 preferably 70 to 160C.; reaction pressures of about atmos~
pheric, but higher pressures on the order of 1000 psig t6.9 MPa) can be employed if desired; and the reaction time is on the order of 10 to 300 minutes, more usually on the order of 30 to 150 minutes. Since both of the reactants tend to be solids, it is desirable to operate the process in the presence of a solvent, andin accordance with the subject invention, the solvent is NMP.
A sufficient amount of the solvent is employed to form a solution of the reactant at elevated temperatures where reaction occurs, 30 that is, temperatures on the order of 70 to 160C.
The anhydride-capped polyamic acid oligomers, or the corresponding ester-cappe~ analogs, are ~hen reacted with a compound having the formula:
~1~4~3~
Formula VI
~2N-Arylene-CcCH
wherein arylene is phenylene, naphthylene, or biphenylene.
It is preferred to use m-aminophenylacetylene, 3-amino-31ethynyl-biphenyl, 4-amino-3'-ethynylbiphenyl, or 3 amino-4'-ethynyl-diphenyl ether and the 3,3' and 4~4' ~ub~tituted analogs thereof because the meta substitutions provide oligomers with lower melting points, better solubility, and better melt flow properties. The anhydride-capped polyamic acid oligomer and an aminoarylacetylene compound are reacted in the presence of the NMP to produce an acetylene-terminated polyamic acid oligomer. The reaction occurs at elevated temperatures from about 40 to about 180Co ~ preferably at temperatures from 70 to 160C. The reaction pressure is again about atmospheric, but higher pressures can be used if desired, The reaction time is on the order of one to 16 hours, more usually about 2 to 12 hours. The aminoarylacetylenes represented by Formula VI above are known in the art and their preparation is described in Column 4, lines 41 et seq., of the Bilow et al U. S. Patent 3,845,018. For example, Bilow et al teach than an aromatic compound having both nitro and acetyl substituents is reacted, preferably under reflux, with dimethyl-formamide and phosphorus oxychloride to convert the acetyl radical to -C(Cl)=CHCH0. The reactio~ is exothermic, and external cooling is needed to keep it at approximately room temperature.
The ~-chloro-substituted aldehyde radical is converted to -C-CH
by refluxing a solution of the compound in dioxane and sodium hydroxide. The product is extracted with an organic solvent such as ether; the organic solution is dried; the solvent i6 removed; and the product recovered by vacuum distillation.
. ~, 3~
The nitro group is then converted to amino by refluxing an aqueous alcohol solution of the product with at least 6 moles of ferrous sulfate per mole of ni.tro compound. The product is removed by solvent extraction~ e.g. ether, and purified, e.g. by vacuum distillation. According to Bilow et al, the process is described in more detail in the same application Serial No. 347r 502 referred to above.
The product is a solution of an acetylene-terminated polyamic acid oligomer for the corresponding anhydride or ester analog depending on whether an acid anhydride or ester starting material was employed. This material represents a polyimide precursor in Formula VII below:
Formula VII
O O
\ /
HC--CR I ~ NH ~ C C ~ OR"~
11 ~1 O O _ n O O
.. ..
2 0 R "
R~ 0 ~ C \C ~ NH ~ R I ~ C~C~
ll ll O O
wherein R~ R~ / R~ and n are defined above, and R"' is H or lower alkyl, such as methyl, propyl, butyl and preferably ethyl.
R" and R may also contain pendent ethynyl groups~
To obtain the desired acetylene-substituted polyimide oligomers, it is now necessary to remove water if an aromatic tetracarboxylic dianhydride was employed, or to remove an alcohol if a lower alkyl diester of an aromatic tetracarboxylic acid was employed. Normally the imidization reactionoccurs thermally, although a catalyst can be added if desired, and it is preferred to add an imidization agent to aid in the azeotropic remoYal of wa~er and~or an alcohol.
In Column 4, lines 31 et seq., Bilow et al teach in their '018 patent referred to above that the dimethyl formamide solvent employed by Bilow et al is removed initially, and the polyamic acid is diluted with an imidization agent such as acetic anhydride or a benzene-cresol mixture. It is not clear why Bilow et al find it necessary to remove the dimethyl formamide solvent, but it has been found as will be noticed below in the working Examples that even when the dimethyl form-amide solvent is "removed" at this point, it is not fully removed, and portions of the dimethyl formamide appear to be chemically complexing or reacting and are evolved at higher post-cure temperatures resulting in fracturing of the products after curing.
It may be desirable to remove a portion of the NMP
solvent before the imidization reaction takes place, but this is simply a matter of convenience to the operator. The addition of an imidization agent is also optional and simply serves its normal engineering function to aid in the removal of b~product water or alcohol. Any well~known imidization agent can be employed such as benzene. It is preferred, of course, that the imidiæation occur thermally, and the tempera~ure at which imidization occurs is the reflu~ temperature necessary for the removal o~ the water and/or alcohol. The imidization reaction can, as is well known, be operated under higher temperatures if pressure operation i9 employed, but atmospheric operation is satisfactory. It ls also possible to remove the NMP before imidization and replace it with another solvent, but there is no advantage to do:ing this;
- 30 in fact, there is a definite disadvantage in having to maintain separate stores of different solvents.
3~
The acetylene-substituted polyimides made by the process of this invention are recovered by any suita~le technique.
For example, the NMP can be removed in a rotary evaporator followed by washing with absolute ethanol~ A preferred technique is to precipitate the polyimide oligomer by contacting a solution of the oligomer in NMP with an alcohol such as absolute ethanol followed by several washes ~ith absolute ethanol. The product is recovered by filtration or centrifugation and finally dried in an oven at 120C. under vacuum for 24 hours or longer.
The acetylene-substituted polyimides may be used neat to form molded articles, or the polyimide oligomers can be used to form laminates using, for example, a glass cloth, or the polyimide oligomers can be used to ~orm composites containing additives such as powdered metals. The polyimide oligomers are converted to a solid infusible product, e.g. molded article, by curing at elevated temperatures of up to 485F. (252C.) for time periods of 0.25 to 48 hours. The resulting laminates or composites have excellent physical properties, as noted by Bilow et al in their '018 patent. The properties of the product are improved by post-curing at temperatures above 485F.
(252C.) and usually temperatures from 50~ to 700F. ~260 to 371C.). The post curing time is normally from four to 48 hours.
The invention will be further described with reference to the following experimental work.
Example 1 To a solution of 3,3',4,4'-benzophellonetetracarbo~ylic acid dianhydride (BTDAj (lg.32 grams, 0.06 mole) in 165 ml of N-methyl-2-pyrrolidone heated at 150C. was added dropwise over a 45~minute period a solution of 1,3-bis(3-aminophenoxy)benzene (8.76 grams, 0.03 mole) in 75 ml of NMP. I'he mixture was heated for 50 minutes at 150 to 154C. and then a solution of 7.35 3L3~
qrams (0,063 mole~ of 3-aminophenylacetylene in 15 ml o~ NMP
was added all at once. A total of 32 ml o~ benæene was then added, and the reaction mixture was heated to 150 to 160C.
to reflux the ben~ene and remove the water of imidization as a water-benzene azeotrope into a Dean-Stark water trap. The total reaction time was ten hours. The total water removed was 3.5 ml; the benz ne and NMP solvents were removed at 80C, under vacuum on a rotary evaporator. The residue was washed with absolute ethanol u~ing a Waring blender, filtered, and then the same washing procedure was repeated twice more. The residue was dried in a vacuum oven for 24 hours at 120C.
The product yield was 31.5 grams, or 94.6~ of theoretical.
The product had a melting point range of 190 to 196C.
Fxample 2 -10~0 grams of a neat resin from Example 1 were molded into a disc having the dimensions 0.995" diameter x 0.575" thick (2.52 cm. dia. x 0.425cm. thick) after pre-cure for 45 minutes at 350F. (177C.). The molding conditions were 485F. (252C.) for 16 hours at 2000 psi (13.8 MPa). The disc was post-cured in two stages, as follows:
Stage 1 - 18 hours at 600F. (316C.) at atmospheric pressure;
Stage 2 - 24 hours at 700F. (371C.) at atmospheric pressure.
The post-cured sample showed no blistering or delimina~
tion, and the weight loss during post-curing was 2.02 percent, and the void content of the final product was found to be 1.06 percent.
~ e_e 3 The procedure of Example 2 was repeated, but a 50-50 isopropanol-methanol wash liquid was used. A yield of -16~
91.7 percent oligomer product was obtained. The weiyht loss during post-curing was 1.95%, and the void content of the final product was 1.19~.
Example 4 Example 3 was repeated, but isopropanol wash liquid was used. The properties of the product were substantially the same as in Example 2, except the yield was 93.8 percent.
The weight loss during post-curing was 1.~9 percent, and the void content of the final product was 0.86 percent.
Example S
Example 2 was repeated, except acetone was used as the wash liquid. The properties of the final product were substantially the same as in Example 2 except the yield was reduced to 72.6 percent. The weight loss and void content were 3.8~ and 2.19 percent, respectively.
Example 6 Example 2 was repeated except the wash liquid was water. The properties of the final product were substantially the same as in Example 2, except the yield was 99.6 percent.
The weigh~ loss and void content were 2.93 and 1.3 percent, respectively.
Exam~le 7 To a solution of 55.1 grams (0.17 mole) of BTDA
in dry dimethyl formamide (500 ml), heated at 150 to 1S3C~, was added, drop-wise over a period of one hour, a room-tempera-ture solution of 25.0 grams (0.0856 mole) of 1,3-bis(3-amino-phenoxy)benzene in 250 ml o~ DMF. The mixture was heated at reflux for 2.0 hours, and then a solution of 3-aminophenyl acetylene (21.0 grams, 0.1795 mole) in DMF (100 ml) was added;
and the solution was heated at re1ux for an additional 4.0 hours after the addition. The DME solvent was removed on a rotary evaporator, and the residue was dissolved in hot (100C.) meta-cresol (500 ml)~ cooled~ and 250 ml of benzene was added, The mixture was heated at total reflux after adding a Dean-Stark water trap. After 3.0 hours, 1.2 ml of water was removed from the trap. The benzene - meta-cresol mixture was removed on the rotary evaporator until the total volume was approximately 250 ml. The slurry was precipitated and washed with 1000 ml of absolute ethanol, filtered, and then the procedure repeated twice again with 600 ml of fresh e~hanol using a Waring blender to insure good washing. The residue was dried in a vacuum oven for three hours at 120C. The product yield was 77.9 grams (82 percent).
Example 8 54.1 grams of a neat resin from Example 7 after pre-cure at 350F. (177C.) for 45 minutes was molded into a disc having the dimensions 2.239" diameter x 0.531" thick (5.686 cm. dia. x 1.349 cm. thick). The molding conditions were 2 hours at 485F. (252C.) and a pressure o~ 2000 psig (13.8 MPa). The molded product appeared to be of general good quality at this point. T e molded product was post-cured using the following schedule:
(1) 450-600F. (232-316C.) at 12.5F.
per hour;
(2) 600F. (316C.) for 24 hours;
(3) 600-700F. (316-371C.) at 5F.
per hour;
(4) 700E'. (371C.) for four hours; and
(5) allowed to cool at room temperature.
The void content was 4.2 percent, and the weight loss was 3.74percent. The sample showed blistering, delamination and swelling. The sample was cut in half, and small delaminations -18~
were noted throughout the centerO This indicated that volatile products or decomposition was taking place during the post~cure.
The neat resin from Example 2 above and Example 7 above were both examined using a pyrolysis-gas chromatographic-mass spectrometry procedure at 350F. (177C.) pre-cure tempera-ture; 485F. (252C.) (the molding temperature), and then at 700F. (371C.) (the maximum cure temperature). In each case the sample was heated to the indicated temperature in a stream of helium. The heated stream is then directed to a gas chromatograph which separates the components. The components are then identified in the mass spectrometer. The heating time at each temperature is four minutes. Residual D~F and meta-cresol were detected at 350F. (177C.) from the sample from Example 7, and NMP was noted from the resin from Example 2 at 350F.(177C.). No volatile products were noted at tempera-tures of 485F,(252C.) for the resin from either Example 2 or Example 7. However, at 700F. (371C.) DMF was again detected from the resin from Example 7, but no volatile products were noted when using the process of this invention, which is the resin from Example 2 above.
It appears that DMF, unlike NMP, is either chemically reacting with the oligomer or is forming a coordination compound which is stable to temperatures of above 485F. (252C.).
The evolution of DMF was identified as the material which was causing the blistering and delamination of molded products in the 485 to 700F. (252 to 371C.) range. This is the tempera-ture range required for post-curing for optimum high temperature stability.
Resort may be had to such variations and modifica-tions as fall within the spirit of the invention and the scope of the appetlded claims.
The void content was 4.2 percent, and the weight loss was 3.74percent. The sample showed blistering, delamination and swelling. The sample was cut in half, and small delaminations -18~
were noted throughout the centerO This indicated that volatile products or decomposition was taking place during the post~cure.
The neat resin from Example 2 above and Example 7 above were both examined using a pyrolysis-gas chromatographic-mass spectrometry procedure at 350F. (177C.) pre-cure tempera-ture; 485F. (252C.) (the molding temperature), and then at 700F. (371C.) (the maximum cure temperature). In each case the sample was heated to the indicated temperature in a stream of helium. The heated stream is then directed to a gas chromatograph which separates the components. The components are then identified in the mass spectrometer. The heating time at each temperature is four minutes. Residual D~F and meta-cresol were detected at 350F. (177C.) from the sample from Example 7, and NMP was noted from the resin from Example 2 at 350F.(177C.). No volatile products were noted at tempera-tures of 485F,(252C.) for the resin from either Example 2 or Example 7. However, at 700F. (371C.) DMF was again detected from the resin from Example 7, but no volatile products were noted when using the process of this invention, which is the resin from Example 2 above.
It appears that DMF, unlike NMP, is either chemically reacting with the oligomer or is forming a coordination compound which is stable to temperatures of above 485F. (252C.).
The evolution of DMF was identified as the material which was causing the blistering and delamination of molded products in the 485 to 700F. (252 to 371C.) range. This is the tempera-ture range required for post-curing for optimum high temperature stability.
Resort may be had to such variations and modifica-tions as fall within the spirit of the invention and the scope of the appetlded claims.
Claims (22)
1. A process for the preparation of an acetylene-substituted polyimide oligomer which comprises reacting a stoichiometric excess of a dianhydride of an aromatic tetracarboxylic acid, or a lower alkyl diester of said aromatic tetracarboxylic acid, with an aromatic diamine to form an anhydride-capped polyamic acid or acid-ester-capped analog in the presence of at least a sufficient amount of a solvent consisting essentially of N-methyl-2-pyrrolidone to form a solution at elevated temperatures;
thereafter reacting said anhydride-capped polyamic acid or analog with an aminoarylacetylene compound in the presence of said solvent to produce an acetylene-terminated polyamic acid oligomer;
converting said acetylene-terminated polyamic acid oligomer to the corresponding polyimide in the continued presence of at least a portion of said solvent;
and thereafter recovering the desired acetylene-substituted polyimide oligomers substantially free of said solvents.
thereafter reacting said anhydride-capped polyamic acid or analog with an aminoarylacetylene compound in the presence of said solvent to produce an acetylene-terminated polyamic acid oligomer;
converting said acetylene-terminated polyamic acid oligomer to the corresponding polyimide in the continued presence of at least a portion of said solvent;
and thereafter recovering the desired acetylene-substituted polyimide oligomers substantially free of said solvents.
2. A process in accordance with claim l wherein said acetylene-substituted polyimide oligomers are recovered at a temperature less than the minimum melting point of said polyimide oligomers.
3. A process in accordance with claim 2 wherein said acetylene-substituted polyimide oligomers are recovered at a temperature of less than 185°C.
4. A process in accordance with claim 3 wherein a tetra-carboxylic acid anhydride is employed wherein the aromatic diamine is a polyarylene ether diamine, wherein the aminoarylacetylene is aminophenyl acetylene and wherein water is continuously removed during the conversion of said polyamic acid to said polyimide.
5. A process for the preparation of an acetylene-substituted polyimide oligomer having the following general structure:
wherein R is poly(arylene ether) or poly(arylene thioether), R' is arylene or diarylene ether, n is an average from 1 to about 10, and R" is or and X is C=O, CH2, O, SO2, -?(CF3)2 or a bond, which process comprises:
reacting a stoichiometric excess of (i) an aromatic tetracarboxylic acid dianhydride having the formula:
where R" is as defined above;
(ii) a lower alkyl diester of an aromatic tetra-carboxylic acid having the formula:
where R" is as defined above and R"' is a lower alkyl group having from 1 to 4 carbon atoms;
with a compound having the formula:
where R is poly(arylene ether), diarylene ketone, diarylene methane, diarylene sulfone, poly(arylene thioether) or an acetylene-substituted derivative thereof;
in the presence of at least a sufficient amount of a solvent consisting essentially of N-methyl-2-pyrrolidone ("NMP") to form a solution at elevated temperatures to form an anhydride-capped polyamic acid or the acid-ester-capped analog;
thereafter reacting said anhydride-capped polyamic acid or analog in the continued presence of NMP with an amino-arylacetylene compound having the formula:
H2N - R' - C ? CH
where R' is phenylene, phenoxyphenylene, naphthylene, or biphenylene to produce an acetylene-substituted polyamic acid oligomer having the formula:
where R, R', R" and n are as defined above, and R"' is H or a lower alkyl having from one to four carbon atoms and R and R"
may contain pendent ethynyl groups;
converting said acetylene-substituted polyamic acid oligomer to the corresponding polyimide in the continued presence of at least a portion of said solvent;
and thereafter recovering the desired acetylene-substituted polyimide oligomers substantially free of said solvent.
wherein R is poly(arylene ether) or poly(arylene thioether), R' is arylene or diarylene ether, n is an average from 1 to about 10, and R" is or and X is C=O, CH2, O, SO2, -?(CF3)2 or a bond, which process comprises:
reacting a stoichiometric excess of (i) an aromatic tetracarboxylic acid dianhydride having the formula:
where R" is as defined above;
(ii) a lower alkyl diester of an aromatic tetra-carboxylic acid having the formula:
where R" is as defined above and R"' is a lower alkyl group having from 1 to 4 carbon atoms;
with a compound having the formula:
where R is poly(arylene ether), diarylene ketone, diarylene methane, diarylene sulfone, poly(arylene thioether) or an acetylene-substituted derivative thereof;
in the presence of at least a sufficient amount of a solvent consisting essentially of N-methyl-2-pyrrolidone ("NMP") to form a solution at elevated temperatures to form an anhydride-capped polyamic acid or the acid-ester-capped analog;
thereafter reacting said anhydride-capped polyamic acid or analog in the continued presence of NMP with an amino-arylacetylene compound having the formula:
H2N - R' - C ? CH
where R' is phenylene, phenoxyphenylene, naphthylene, or biphenylene to produce an acetylene-substituted polyamic acid oligomer having the formula:
where R, R', R" and n are as defined above, and R"' is H or a lower alkyl having from one to four carbon atoms and R and R"
may contain pendent ethynyl groups;
converting said acetylene-substituted polyamic acid oligomer to the corresponding polyimide in the continued presence of at least a portion of said solvent;
and thereafter recovering the desired acetylene-substituted polyimide oligomers substantially free of said solvent.
6. A process in accordance with claim 5 wherein said acetylene-substituted polyimide oligomers are recovered at a temperature less than the minimum melting point of said polyimide oligomers.
7. A process in accordance with claim 6 wherein said acetylene-substituted polyimide oligomers are recovered at a temperature of less than 185°C.
8. A process in accordance with claim 5 wherein water or an alcohol is continuously removed during the conversion of said polyamic acid to said polyimide.
9. A process in accordance with claim 5 wherein an aromatic tetracarboxylic acid dianhydride is employed having from one to two aromatic rings and wherein water is continuously removed during the conversion of said polyamic acid to said polyimide.
10. A process in accordance with claim 9 wherein an azeo-troping agent is added to aid in the removal of the water of imidization.
11. A process in accordance with claim 10 wherein the azeotroping agent is benzene.
12. A process in accordance with claim 11 wherein the polyimide reaction product is treated to first remove the azeotroping agent and the solution of the polyimide in NMP is contacted with a sufficient amount of a non-solvent to result in precipitation of the polyimide in a filterable solid form.
13. A process in accordance with claim 12 wherein the non-solvent is selected from the group consisting of aliphatic alcohols having from one to four carbon atoms and water, or mixtures thereof.
14. A process in accordance with claim 13 wherein the non-solvent is absolute ethanol.
15. A process in accordance with claim 14 wherein said precipitated polyimide is recovered and dried at a temperature less than the minimum melting point of said polyimide.
16. A process in accordance with claim 5 wherein said aromatic tetracarboxylic dianhydride or lower alkyl diester has from one to two aromatic rings and wherein the diamine is a polyarylene ether and wherein the aminoarylacetylene has a single ring.
17. A process in accordance with claim 16 wherein the aromatic tetracarboxylic acid, corresponding dianhydride or lower alkyl diester has two rings and wherein no ring has more than two acid groups.
18. A process in accordance with claim 17 wherein the aromatic tetracarboxylic acid dianhydride is 3,3'-4,4'benzo-phenonetetracarboxylic acid dianhydride.
19. A process in accordance with claim 18 wherein the polyarylene ether is 1,3-bis(3-aminophenoxy)benzene.
20. A process in accordance with claim 19 wherein the aminophenylacetylene is 3-aminophenylacetylene.
21. A process for the preparation of acetylene-substituted polyimide oligomers which when cured as laminates and composites do not fracture on heating to temperatures in excess of 485°F.
(252°C.) for extended periods of time, which comprises:
reacting a stoichiometric excess of an aromatic tetracarboxylic acid dianhydride or a lower alkyl diester thereof, with an aromatic diamine to form an anhydride-capped polyamic acid or the corresponding acid-ester-capped analog in the presence of at least a sufficient amount of a solvent consisting essentially of N-methyl-2-pyrrolidone to form a solution at elevated temperatures;
thereafter reacting said anhydride-capped polyamic acid or analog with an aminoarylacetylene compound in the presence of said solvent to produce an acetylene-terminated polyamic acid oligomer;
thermally converting said acetylene-terminated polyamic acid oligomer to the corresponding polyimide in the continued presence of said solvent;
thereafter recovering the desired acetylene-substituted polyimide oligomers substantially free of said solvent;
forming a molded article from the neat polyimide oligomers, a laminate or a composite from said recovered polyimide oligomers by curing at elevated temperatures of up to 485°F. (252°C.);
and post-curing said cured molded article, laminate or composite at a temperature in excess of 485°F. (252°C.).
(252°C.) for extended periods of time, which comprises:
reacting a stoichiometric excess of an aromatic tetracarboxylic acid dianhydride or a lower alkyl diester thereof, with an aromatic diamine to form an anhydride-capped polyamic acid or the corresponding acid-ester-capped analog in the presence of at least a sufficient amount of a solvent consisting essentially of N-methyl-2-pyrrolidone to form a solution at elevated temperatures;
thereafter reacting said anhydride-capped polyamic acid or analog with an aminoarylacetylene compound in the presence of said solvent to produce an acetylene-terminated polyamic acid oligomer;
thermally converting said acetylene-terminated polyamic acid oligomer to the corresponding polyimide in the continued presence of said solvent;
thereafter recovering the desired acetylene-substituted polyimide oligomers substantially free of said solvent;
forming a molded article from the neat polyimide oligomers, a laminate or a composite from said recovered polyimide oligomers by curing at elevated temperatures of up to 485°F. (252°C.);
and post-curing said cured molded article, laminate or composite at a temperature in excess of 485°F. (252°C.).
22. A process in accordance with claim 21 wherein the post-curing temperature is from 485°F. to 700°F. (252°C; to 371°C.) # # #
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US782,001 | 1977-03-28 | ||
| US05/782,001 US4097456A (en) | 1977-03-28 | 1977-03-28 | Preparation of acetylene-substituted polyimide oligomers and polyimide polymers |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1104138A true CA1104138A (en) | 1981-06-30 |
Family
ID=25124617
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA296,511A Expired CA1104138A (en) | 1977-03-28 | 1978-02-09 | Preparation of acetylene-substituted polyimide oligomers |
Country Status (9)
| Country | Link |
|---|---|
| US (1) | US4097456A (en) |
| JP (1) | JPS53119865A (en) |
| BE (1) | BE865366A (en) |
| CA (1) | CA1104138A (en) |
| DE (1) | DE2812276A1 (en) |
| FR (1) | FR2385759A1 (en) |
| GB (1) | GB1602002A (en) |
| IT (1) | IT1096153B (en) |
| NL (1) | NL7803272A (en) |
Families Citing this family (34)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4337110A (en) * | 1977-05-09 | 1982-06-29 | Gulf Oil Corporation | Laminates prepared from solutions of resins containing amic acid groups |
| USRE30922E (en) * | 1979-04-05 | 1982-05-04 | Gulf Oil Corporation | Vinyl end-capped polyimide oligomers |
| US4206106A (en) * | 1979-04-05 | 1980-06-03 | Gulf Oil Corporation | Vinyl end-capped polyimide oligomers |
| WO1981001293A1 (en) * | 1979-11-05 | 1981-05-14 | Hughes Aircraft Co | Acetylene terminated imide oligomers having improved solubilities and lower melting points |
| US4321198A (en) * | 1980-01-25 | 1982-03-23 | Plastics Engineering Company | Polyimide derivatives having acetylenic amic acid groups |
| US4316845A (en) * | 1980-01-25 | 1982-02-23 | Plastics Engineering Company | Polyimide derivatives having terminal acetylenic groups |
| US4431792A (en) * | 1980-10-23 | 1984-02-14 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Thermoset-thermoplastic aromatic polyamide containing N-propargyl groups |
| US4395540A (en) * | 1980-10-23 | 1983-07-26 | The United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration | Thermoset-thermoplastic aromatic polyamide containing N-propargyl groups |
| US4367329A (en) * | 1981-05-20 | 1983-01-04 | The United States Of America As Represented By The Secretary Of The Air Force | Polyaromatic amides having acetylene groupings curable by Diels-Alder cycloaddition |
| US4661604A (en) * | 1981-06-16 | 1987-04-28 | Trw, Inc. | Monofunctional crosslinking imidophenols |
| US4438273A (en) * | 1981-07-24 | 1984-03-20 | Hughes Aircraft Company | Isoimide containing oligomers |
| US5693741A (en) | 1988-03-15 | 1997-12-02 | The Boeing Company | Liquid molding compounds |
| US5521014A (en) * | 1981-11-13 | 1996-05-28 | The Boeing Company | Extended multidimensional ether or ester oligomers |
| US5512676A (en) | 1987-09-03 | 1996-04-30 | The Boeing Company | Extended amideimide hub for multidimensional oligomers |
| US5705598A (en) | 1985-04-23 | 1998-01-06 | The Boeing Company | Polyester sulfone oligomers and blends |
| US5210213A (en) | 1983-06-17 | 1993-05-11 | The Boeing Company | Dimensional, crosslinkable oligomers |
| US5969079A (en) | 1985-09-05 | 1999-10-19 | The Boeing Company | Oligomers with multiple chemically functional end caps |
| US4536559A (en) * | 1983-06-17 | 1985-08-20 | The Boeing Company | Thermally stable polyimide polysulfone compositions for composite structures |
| US5516876A (en) * | 1983-09-27 | 1996-05-14 | The Boeing Company | Polyimide oligomers and blends |
| US4584364A (en) * | 1984-02-06 | 1986-04-22 | The Boeing Company | Phenolic-capped imide sulfone resins |
| US4871475A (en) * | 1985-10-07 | 1989-10-03 | The Boeing Company | Polysulfone and polyethersulfone oligomers |
| US4476184A (en) * | 1983-08-09 | 1984-10-09 | The Boeing Company | Thermally stable polysulfone compositions for composite structures |
| US4622383A (en) * | 1983-11-30 | 1986-11-11 | International Business Machines Corporation | Method for the fractionation of reactive terminated polymerizable oligomers |
| US5618907A (en) | 1985-04-23 | 1997-04-08 | The Boeing Company | Thallium catalyzed multidimensional ester oligomers |
| US5610317A (en) | 1985-09-05 | 1997-03-11 | The Boeing Company | Multiple chemically functional end cap monomers |
| US4663425A (en) * | 1985-12-10 | 1987-05-05 | The United States Of America As Represented By The Secretary Of The Air Force | Ethynyl-containing aromatic polyamide resin |
| US4752642A (en) * | 1985-12-10 | 1988-06-21 | The United States Of America As Represented By The Secretary Of The Air Force | Ethynyl-containing aromatic polyamide resin |
| JPS6317242A (en) * | 1986-07-09 | 1988-01-25 | Sumitomo Electric Ind Ltd | Production of optical fiber |
| US4898754A (en) * | 1986-09-30 | 1990-02-06 | The Boeing Company | Poly(amide-imide) prepreg and composite processing |
| US5817744A (en) | 1988-03-14 | 1998-10-06 | The Boeing Company | Phenylethynyl capped imides |
| JPH0739451B2 (en) * | 1988-08-30 | 1995-05-01 | 宇部興産株式会社 | End-modified imide oligomer composition |
| US5322920A (en) * | 1990-07-25 | 1994-06-21 | Kanegafuchi Kagaku Kogyo Kabushiki Kaisha | Thermosetting esterimide oligomer and its production method |
| JPH04342786A (en) * | 1991-05-17 | 1992-11-30 | Kanebo Nsc Ltd | Heat-resistant adhesive material |
| US5239049A (en) * | 1991-12-16 | 1993-08-24 | Olin Corporation | Selected poly(dianhydrides) compounds, selected poly(amic acid) compounds, and selected poly(imide) compounds |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3845018A (en) * | 1973-04-03 | 1974-10-29 | Hughes Aircraft Co | Acetylene substituted polyamide oligomers |
| US3998786A (en) * | 1973-05-25 | 1976-12-21 | University Of Notre Dame Du Lac | Process for preparing aromatic polyimides, polyimides prepared thereby |
| US3897395A (en) * | 1973-05-25 | 1975-07-29 | Univ Notre Dame Du Lac | Process for chain-extending unsaturated terminated polyimides and products prepared therefrom |
| US3879349A (en) * | 1973-11-12 | 1975-04-22 | Hughes Aircraft Co | Homopolymerization of acetylene substituted polyimide polymers |
-
1977
- 1977-03-28 US US05/782,001 patent/US4097456A/en not_active Expired - Lifetime
-
1978
- 1978-02-09 CA CA296,511A patent/CA1104138A/en not_active Expired
- 1978-03-02 GB GB8260/78A patent/GB1602002A/en not_active Expired
- 1978-03-21 DE DE19782812276 patent/DE2812276A1/en not_active Withdrawn
- 1978-03-24 IT IT2162178A patent/IT1096153B/en active
- 1978-03-24 FR FR7808767A patent/FR2385759A1/en not_active Withdrawn
- 1978-03-28 BE BE186311A patent/BE865366A/en unknown
- 1978-03-28 NL NL7803272A patent/NL7803272A/en not_active Application Discontinuation
- 1978-03-28 JP JP3496778A patent/JPS53119865A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE2812276A1 (en) | 1978-10-05 |
| US4097456A (en) | 1978-06-27 |
| GB1602002A (en) | 1981-11-04 |
| FR2385759A1 (en) | 1978-10-27 |
| IT7821621A0 (en) | 1978-03-24 |
| IT1096153B (en) | 1985-08-17 |
| BE865366A (en) | 1978-09-28 |
| NL7803272A (en) | 1978-10-02 |
| JPS53119865A (en) | 1978-10-19 |
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