CA1231793A - Thermosettable polymers - Google Patents
Thermosettable polymersInfo
- Publication number
- CA1231793A CA1231793A CA000481327A CA481327A CA1231793A CA 1231793 A CA1231793 A CA 1231793A CA 000481327 A CA000481327 A CA 000481327A CA 481327 A CA481327 A CA 481327A CA 1231793 A CA1231793 A CA 1231793A
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- CA
- Canada
- Prior art keywords
- group
- carbons
- prepolymer
- formula
- groups
- 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.)
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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
- C08G16/00—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00
- C08G16/02—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes
- C08G16/025—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes with heterocyclic organic compounds
- C08G16/0268—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes with heterocyclic organic compounds containing nitrogen in the ring
-
- 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
- C08G16/00—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00
- C08G16/02—Condensation polymers of aldehydes or ketones with monomers not provided for in the groups C08G4/00 - C08G14/00 of aldehydes
- C08G16/04—Chemically modified polycondensates
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
- C08J5/24—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs
- C08J5/241—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs using inorganic fibres
- C08J5/244—Impregnating materials with prepolymers which can be polymerised in situ, e.g. manufacture of prepregs using inorganic fibres using glass fibres
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2361/00—Characterised by the use of condensation polymers of aldehydes or ketones; Derivatives of such polymers
Abstract
Abstract of the Disclosure Heat resistant thermosetting prepolymers are prepared by reacting one or more methylated pyridines or pyrazines with one or more aromatic dialdehydes, and isopropenyl phenols. The prepolymers can be further reacted with bismaleimides to make prepolymers with lower cure temperatures and faster cure rates. The total number of methyl groups on the pyridine or pyrazine can vary from 2 to 4. The prepolymers are cured to produce heat resistant polymers and laminates with conventional fibers such as carbon fibers.
Description
i ~3 1 793 THERMOSETTING PREPOLYMERS PREPARED FROM AROMACTIC
DIALDEHYDES, ME~HYLATED PYRIDINES OR PYRAZINES, AND
ISOPROPENYL PHENOLS AND TO CURED COMPOSITES
PREPARED THEREFROM
This invention relates to thermosetting prepolymers prepared from methylated pyridines or pyrazines, aromatic dialdehydes, isopropenyl phenols, and with or without bismaleimides.
In the aerospace and/or aircraft industry there is a need for light weight fire resistant polymeric composites for interior and exterior use. A
recent development in this critical area was the discovery that composites based on polystyrylpyridines are useful in this field o endeavor. The key patents are outlined below.
It is known from U.S. patent 3,994,862 that polystyrylpyridine thermosetting prepolymers and cured polymers can be obtained by reacting methylated pyridines and aromatic dialdehydes.
U.S. patent 4,163,740 discloses the preparation of solutions of polystyrylpyridines in various organic solvents such as ethyl acetate, propanol, and methyl-ethylketone.
32,807-F -1-12317~3
DIALDEHYDES, ME~HYLATED PYRIDINES OR PYRAZINES, AND
ISOPROPENYL PHENOLS AND TO CURED COMPOSITES
PREPARED THEREFROM
This invention relates to thermosetting prepolymers prepared from methylated pyridines or pyrazines, aromatic dialdehydes, isopropenyl phenols, and with or without bismaleimides.
In the aerospace and/or aircraft industry there is a need for light weight fire resistant polymeric composites for interior and exterior use. A
recent development in this critical area was the discovery that composites based on polystyrylpyridines are useful in this field o endeavor. The key patents are outlined below.
It is known from U.S. patent 3,994,862 that polystyrylpyridine thermosetting prepolymers and cured polymers can be obtained by reacting methylated pyridines and aromatic dialdehydes.
U.S. patent 4,163,740 discloses the preparation of solutions of polystyrylpyridines in various organic solvents such as ethyl acetate, propanol, and methyl-ethylketone.
32,807-F -1-12317~3
2-IJ.S. patent 4,362,860 discloses related polystyrylpyridines terminated with vinyl pyridine.
This invention is directed to thermosetting prepolymers prepared by reacting (A) one or more aromatic 5 dialdehydes, (B) one or more azine compounds having the formula R R
~C--C_ C--C
R R
where Z is N, C-~3, C-CH2-CH3 or C-H
R is hydrogen, methyl, or e-thyl, whereby the total number of methyl groups substituted on the ring is in the range from 2-4, and (C) a member of the group consisting of (1) monomeric para or meta isopropenyl phenols having the formula R
H0 ~ C(CH3)=CH2 Rl wherein Rl is hydrogen or a group inert to the polymerization reaction such as hydroxy, halogen, 2S nitro, or amino groups, (2) dimers of said phenols, and
This invention is directed to thermosetting prepolymers prepared by reacting (A) one or more aromatic 5 dialdehydes, (B) one or more azine compounds having the formula R R
~C--C_ C--C
R R
where Z is N, C-~3, C-CH2-CH3 or C-H
R is hydrogen, methyl, or e-thyl, whereby the total number of methyl groups substituted on the ring is in the range from 2-4, and (C) a member of the group consisting of (1) monomeric para or meta isopropenyl phenols having the formula R
H0 ~ C(CH3)=CH2 Rl wherein Rl is hydrogen or a group inert to the polymerization reaction such as hydroxy, halogen, 2S nitro, or amino groups, (2) dimers of said phenols, and
(3) mixtures thereof.
These thermosetting polymers are useful to make high temperature resistant composites wi-th, for example, fiber glass or carbon fibers. The advantage of this invention is that the prepolymers made herein cure at lower temperatures and faster than the known uncapped polystyrylpyridine prepolymers. Additionally, 32,807-F -2-1 2~ ~ ~93 the cured polymers obtained in accordance with the - methods described in this inven-tion posses superior ablative properties as seen by their very high char yields.
A preferred embodiment of the invention is to further react the prepolymer prepared above with a bismaleimide compound having the formula XC-C(O) C(O~-CX
il ,~N-Z-N ll XC-C(O) --C~O) CX
where Z is a divalent organic radical having at least two carbon atoms and selected from the group consisting of aliphatic groups, alicyclic groups, aromatic groups, and groups having at least two aryl residues or cyclohexyl residues bonded together by methylene, sulfonyl, or oxygen linkages or combinations thereof and X is independently hydrogen, halogen, an alkyl group of 1-4 carbons or an aryl group of 6;8 carbons.
The prepolymers of this invention are prepared by reacting alkylated azine compounds such as methyl pyridines and methyl pyrazines with aromatic dialdehydes in the presence of an acidic catalyst. After formation of oligomers, monomeric or dimeric isopropenyl phenols are added to cap the oligomers.
The azine compounds and the aldehydes are heated to a -temperature in the range from 130 to 230C, preferably in the range from 170 to 190C for a period of time from 0.5 to 6 hours and preferrably 1 to 2 hours. The reaction is conducted in the absence of oxygen and suitably with a nitrogen purge.
.
`_ 32,807-F -3-I ~ 3 1 7~3 Useful catalysts that can be used include, for example, sulfuric acid, hydrochloric acid, zinc chloride, acetic anhydride, aluminum trichloride, toluene disulfonic acid, trichloro acetic acid, and acetic acid. The catalysts are used in amounts from 0.5 to 20 weight percent based on the total weight of the reactants and preferrably in amounts from 2 to 5 weight percent. It is to be understood that the reaction can proceed in the absence of catalyst but the reaction time is much longer.
Examples of useful pyridines are 2,3-dimethyl pyridine, 2,~-dimethyl pyridine, 2,5-dimethyl pyridine, 2,6-di~ethyl pyridine, 3,4-dimethyl pyridine, 3,5-dimethyl pyridine, 3,5-dimethyl-2-ethyl pyridine, 2,3,~,6~tetramethyl pyridine, 2,3,5-tximethyll pyridine, 2,3,6-trimethyl pyridine, 2,4,5-trimethyl pyridine and 2,4,6-trimethyl pyridine.
Examples of useful mononuclear aromatic dialdehydes have the formula:
HC(O) ~ C(O)H
wherein X is independently hydrogen, chlorine, bromine, fluorine, or a monovalent hydrocarbon radical such as an alkyl group of 1-4 carbons, an aryl group of 6-8 carbons such as phenyl, tolyl, xylyl, an oxyalkyl group of 1-4 carbons or an oxyaryl group of 6-8 carbons.
Preferred compounds within the scope of the above formula are terephthalic aldehyde, phthalic aldehyde, and isophthalic aldehyde.
32,807-F -4~
I ~ 3 i 793 .5_ Examples of useful pyrazines are 2,5-dimethyl pyrazine, 2,3-dimethyl pyrazine, 2,5~dimethyl pyrazine, 2,3,5-trimethyl pyrazine and 2,3,5,6,-tetramethyl pyraæines.
Examples of useful bismaleimides are N,N'-ethylene~ismaleimide, N,N'-ethylenebis-(2-methylmaleimide), N,N'-trimethylene bismaleimide, N,N'-tetramethylene bismaleimide, N,N'-hexamethylene bismaleimide, N,N'-1,4-cyclohexylene bismaleimide, N,N'-m phenylene bismaleimide, N,N'-p-phenylene bismaleimide, N,N'-2,4-tolylene bismaleimide, N,N'-2,6-tolylene bismaleimide, N,N'-(oxydi-p-phenylene)-bismaleimide, N,N'-(oxydi-p-phenylene)bis (2-methylmaleimide), N,N' (methylenedi-p-phenylene)-bismaleimicle, N,N'-(methylenedi-p-phenylene)--bis(2-methylmaleimide), N,N'-(methylenedi--p-phenylene~bis~2-phenylmaleimide), N,NI-(sulfonyldi-p-phenylene)bismaleimide, N,N'-(thiodi-p-phenylene)bismaleimide, N,N'-(dithiodi-p-phenylene)-bismaleimide, N,N'-(sulfonyldi-m-phenylene)-bismaleimid~, N,N'-(o,p-isopropylidenediphenylene)--bismaleimide, N,N'-(isopropylidenedi-p-phenylene)-bismaleimide, N,N'-(o,p cyclohexylidenediphenylene)-bismaleimide, N,N'-(m-xylene)bismaleimide, N,N'-(p-xylylene)bismaleimide, N,N'-(4,4-p-triphenylene)-bismaleimide, N,N'-(p-phenylenedioxydi-p-phenylene)-bismaleimide, N,N'-(methylenedi-p-phenylene)bis-(2,3-dichloromaleimide), and N,N'-(oxydi-p-phenylene)-bis(2-chloromaleimide).
The bismaleimides can be used in a weight ratio range of from one weight of maleimide to 4 of prepolymer and 4 weight units of maleimide -to one of prepolymer.
32,807-F -5-~3~93 The use of the bismaleimides in this invention gives prepolymers that cure at lower temperatures and at a faster rate.
It is to be understood that the foregoing reactants can be used alone or in combination as in an initial mixture of each or by the sequential addition during the reaction to achieve benefiçial results.
The molar ratio range of the aldehyde to the azine compounds can be from 0.2:1 to 4:1 and preferrably in the range of 0.66:1 to 1.5:1.
The molar ratio range of the isopropenyl phenol or dimers thereof to the azine compounds can be from 0.05:1 to 4:1 and preferably in the range of 0.2:1 to 1:1.
The prepolymer (oligomer or resin~ initially obtained is cured by press molding at a temperature range of 150 to 300C for a time of 1 to 8 hours. The resultant semicured polymer is further cured at a temperature range of 250 to 300C for a time of 2 to 10 hours to obtain the inal fire resistant molding.
Composites are made by adding heat resistant fibers to the prepolymer before the press molding.
Examples of useful heat resistant fibers to be used herein are graphite fibers, fiber glass, aramid fibers, and asbestos fibers.
The following examples are presented to further illustrate but not limit the invention.
32,807-F -6-Example 1:
174.6 grams (1.3 moles) of terephthalaldehyde and 163.5 (1.35 moles) of 2,4,6-trimethylpyridine were placed in a 500-cc glass resin kettle equipped with a mechanical stirrer, modified Dean-Start apparatus for collection of water, infrared heating lamps, thermometer, and nitrogen purge system. The resin kettle was purged with nitrogen for 5 minutes and the infrared lamps turned on. At a 90C pot temperature the terephthal-aldéhyde began to melt. The mechanical stirrer wasstarted and a 5 to 15-cc/min N2 purge maintained. At a 110C pot temperature 5 cc of concentrated sulfuric acid was added. The reaction mixture was heated to 150C for 1l~2 hours, collecting ~2 overhead. 43.0 grams (0.35 moles) of p-isopropenyl phenol was added and the reaction mixture maintained between 150 and 160C for 1~ hours. The reaction mixture was then cooled to room temperature, washed with acetone and methanol, filtered, and dried in a vacuum oven at 90C
and 30 inches of Hg vacuum (about 1600 Pa) for 45 minutes.
Prepolymer properties: Melting Point - 130-170C
IR-hydro~cy function - 3100-3600 cm Isopropenyl function - 885-900 cm 1 GPC - molecular weight - 900 Mn 2000 ~w .
12.5 grams of the prepolymer was compression molded at 204-220C and 500 psi ~3447 MPa) for 1 hour. The cured block sample obtained after pressing was post cured in an atmospheric oven at 240C for four hours. Properties of the cured material are as follows:
32,807-F -7-1 23 1 79~
Glass ~ransition Temperature (Tg) = 320C by DMA
Thermal Stability by Thermal Gravimetric Analysis (TGA) 5% wt loss in nitrogen and aix at 500C
75% char yield in ni-trogen ~ 950C
Example II
7.0 grams of N,N'-methylenedi~p~phenylenebis--maleimide was mixed with 7.0 grams o the prepolymer prepared as described in Example I. The prepolymer mixture was compression molded in a 2" x 2" (51x51 mml) plate at 180C and 500 psi (3447 MPa) for l hour. The cured copolymer block sample was post cured in an atmospheric oven at 240C for 4 hours~ Properties of the cured material are as follows:
Tg by DMA = 315C
Thermal stability (TGA) = 5% w-t loss in N2 = 460C
5% wt loss in air = 450C
63% char yield in N2 @ 950C.
Example III
Isopropenyl capped polystyrylpyridine powder from Example I and N,N'-methylenedi p-phenylenebis maleimide powder were blended together in a ratio of l/l by weight. 4.4 grams of this material was alternated with 3 7/8" squares of glass cloth in a mold which had a cavity of 4"x4"xl/8" ~102x102x3.2 mm). The glass cloth weighed between 2.92 and 2.96 grams per piece and seven pieces were used before the top plate o the mold was positioned in place. The mold was placed in a heated press and the resin was cured for 2 hours at 900 psi (6205 MPa) and 180C. A rigid, dark brown composite was obtained which did not support combustion when exposed to an open 1ame.
32,307-F -8-~3~7~3~
~693-3602 Example IV
153.5 grams (1.15 mole) of terephthalaldehyde and 103 grams (0.75 mole) of 2,3,5,6--tetramethylpyrazine were placed in a 500 cc glass resin kettle equipped with a mechanical stirrer, rnodified Dean-Stark apparatus for collection of water, infrare,d heating lamps, thermometer, and nitrogen purge system. ~he infrared lamps were turned on and a 5-10 cc/min nitrogen purge was initiated. At a 105C p-ot temperature the reactants had melted and the mechanical stirrer was started.
Approximately 5 cc of concentrated sulfuric acid was added and the reaction mixture was hea-ted to 160-170C
for 1 hour, collecting water overhead. The reaction mixture was then cooled to between 150 and 158C and 48.2 grams of para-isopropenyl phenol was added dropwise as a 50/50 b~ weight solution in acetone. The reaction mixture was maintained between 150 and 158C for 45 minutes before cooling to room temperature. The prepolymer was purified by dissolving in a 50/50 THF/acetone mixture and precipitating in water. The precipitated prepolymer was then filtered and dried in a vacuum oven.
- Prepolymer Properties: melting point = 175-185C
IR absorbtions = 3100-3~00 cm 1 Hydroxy 885-900 cm l Isopropenyl GPC wt. average mol. wt. = 4800 51.5 grams of the prepolymer was compression molded at a temperature between 210 and 230C and 500 psi (3447 MPa) for 1 hour in a 4"x4"xl/8" (lOlxlOlx3.1 mm) plate. The sample was then post cured at 230C for 12 hours in an atmospheric oven. Properties of the cured material are as follows:
_g_ . ~ ' .
~3~3 Glass transition temp. (Tg) = >380C by DSC
Thermal stability (TGA) = 67% char yield in nitrogen at 950C.
32,807-F -10-
These thermosetting polymers are useful to make high temperature resistant composites wi-th, for example, fiber glass or carbon fibers. The advantage of this invention is that the prepolymers made herein cure at lower temperatures and faster than the known uncapped polystyrylpyridine prepolymers. Additionally, 32,807-F -2-1 2~ ~ ~93 the cured polymers obtained in accordance with the - methods described in this inven-tion posses superior ablative properties as seen by their very high char yields.
A preferred embodiment of the invention is to further react the prepolymer prepared above with a bismaleimide compound having the formula XC-C(O) C(O~-CX
il ,~N-Z-N ll XC-C(O) --C~O) CX
where Z is a divalent organic radical having at least two carbon atoms and selected from the group consisting of aliphatic groups, alicyclic groups, aromatic groups, and groups having at least two aryl residues or cyclohexyl residues bonded together by methylene, sulfonyl, or oxygen linkages or combinations thereof and X is independently hydrogen, halogen, an alkyl group of 1-4 carbons or an aryl group of 6;8 carbons.
The prepolymers of this invention are prepared by reacting alkylated azine compounds such as methyl pyridines and methyl pyrazines with aromatic dialdehydes in the presence of an acidic catalyst. After formation of oligomers, monomeric or dimeric isopropenyl phenols are added to cap the oligomers.
The azine compounds and the aldehydes are heated to a -temperature in the range from 130 to 230C, preferably in the range from 170 to 190C for a period of time from 0.5 to 6 hours and preferrably 1 to 2 hours. The reaction is conducted in the absence of oxygen and suitably with a nitrogen purge.
.
`_ 32,807-F -3-I ~ 3 1 7~3 Useful catalysts that can be used include, for example, sulfuric acid, hydrochloric acid, zinc chloride, acetic anhydride, aluminum trichloride, toluene disulfonic acid, trichloro acetic acid, and acetic acid. The catalysts are used in amounts from 0.5 to 20 weight percent based on the total weight of the reactants and preferrably in amounts from 2 to 5 weight percent. It is to be understood that the reaction can proceed in the absence of catalyst but the reaction time is much longer.
Examples of useful pyridines are 2,3-dimethyl pyridine, 2,~-dimethyl pyridine, 2,5-dimethyl pyridine, 2,6-di~ethyl pyridine, 3,4-dimethyl pyridine, 3,5-dimethyl pyridine, 3,5-dimethyl-2-ethyl pyridine, 2,3,~,6~tetramethyl pyridine, 2,3,5-tximethyll pyridine, 2,3,6-trimethyl pyridine, 2,4,5-trimethyl pyridine and 2,4,6-trimethyl pyridine.
Examples of useful mononuclear aromatic dialdehydes have the formula:
HC(O) ~ C(O)H
wherein X is independently hydrogen, chlorine, bromine, fluorine, or a monovalent hydrocarbon radical such as an alkyl group of 1-4 carbons, an aryl group of 6-8 carbons such as phenyl, tolyl, xylyl, an oxyalkyl group of 1-4 carbons or an oxyaryl group of 6-8 carbons.
Preferred compounds within the scope of the above formula are terephthalic aldehyde, phthalic aldehyde, and isophthalic aldehyde.
32,807-F -4~
I ~ 3 i 793 .5_ Examples of useful pyrazines are 2,5-dimethyl pyrazine, 2,3-dimethyl pyrazine, 2,5~dimethyl pyrazine, 2,3,5-trimethyl pyrazine and 2,3,5,6,-tetramethyl pyraæines.
Examples of useful bismaleimides are N,N'-ethylene~ismaleimide, N,N'-ethylenebis-(2-methylmaleimide), N,N'-trimethylene bismaleimide, N,N'-tetramethylene bismaleimide, N,N'-hexamethylene bismaleimide, N,N'-1,4-cyclohexylene bismaleimide, N,N'-m phenylene bismaleimide, N,N'-p-phenylene bismaleimide, N,N'-2,4-tolylene bismaleimide, N,N'-2,6-tolylene bismaleimide, N,N'-(oxydi-p-phenylene)-bismaleimide, N,N'-(oxydi-p-phenylene)bis (2-methylmaleimide), N,N' (methylenedi-p-phenylene)-bismaleimicle, N,N'-(methylenedi-p-phenylene)--bis(2-methylmaleimide), N,N'-(methylenedi--p-phenylene~bis~2-phenylmaleimide), N,NI-(sulfonyldi-p-phenylene)bismaleimide, N,N'-(thiodi-p-phenylene)bismaleimide, N,N'-(dithiodi-p-phenylene)-bismaleimide, N,N'-(sulfonyldi-m-phenylene)-bismaleimid~, N,N'-(o,p-isopropylidenediphenylene)--bismaleimide, N,N'-(isopropylidenedi-p-phenylene)-bismaleimide, N,N'-(o,p cyclohexylidenediphenylene)-bismaleimide, N,N'-(m-xylene)bismaleimide, N,N'-(p-xylylene)bismaleimide, N,N'-(4,4-p-triphenylene)-bismaleimide, N,N'-(p-phenylenedioxydi-p-phenylene)-bismaleimide, N,N'-(methylenedi-p-phenylene)bis-(2,3-dichloromaleimide), and N,N'-(oxydi-p-phenylene)-bis(2-chloromaleimide).
The bismaleimides can be used in a weight ratio range of from one weight of maleimide to 4 of prepolymer and 4 weight units of maleimide -to one of prepolymer.
32,807-F -5-~3~93 The use of the bismaleimides in this invention gives prepolymers that cure at lower temperatures and at a faster rate.
It is to be understood that the foregoing reactants can be used alone or in combination as in an initial mixture of each or by the sequential addition during the reaction to achieve benefiçial results.
The molar ratio range of the aldehyde to the azine compounds can be from 0.2:1 to 4:1 and preferrably in the range of 0.66:1 to 1.5:1.
The molar ratio range of the isopropenyl phenol or dimers thereof to the azine compounds can be from 0.05:1 to 4:1 and preferably in the range of 0.2:1 to 1:1.
The prepolymer (oligomer or resin~ initially obtained is cured by press molding at a temperature range of 150 to 300C for a time of 1 to 8 hours. The resultant semicured polymer is further cured at a temperature range of 250 to 300C for a time of 2 to 10 hours to obtain the inal fire resistant molding.
Composites are made by adding heat resistant fibers to the prepolymer before the press molding.
Examples of useful heat resistant fibers to be used herein are graphite fibers, fiber glass, aramid fibers, and asbestos fibers.
The following examples are presented to further illustrate but not limit the invention.
32,807-F -6-Example 1:
174.6 grams (1.3 moles) of terephthalaldehyde and 163.5 (1.35 moles) of 2,4,6-trimethylpyridine were placed in a 500-cc glass resin kettle equipped with a mechanical stirrer, modified Dean-Start apparatus for collection of water, infrared heating lamps, thermometer, and nitrogen purge system. The resin kettle was purged with nitrogen for 5 minutes and the infrared lamps turned on. At a 90C pot temperature the terephthal-aldéhyde began to melt. The mechanical stirrer wasstarted and a 5 to 15-cc/min N2 purge maintained. At a 110C pot temperature 5 cc of concentrated sulfuric acid was added. The reaction mixture was heated to 150C for 1l~2 hours, collecting ~2 overhead. 43.0 grams (0.35 moles) of p-isopropenyl phenol was added and the reaction mixture maintained between 150 and 160C for 1~ hours. The reaction mixture was then cooled to room temperature, washed with acetone and methanol, filtered, and dried in a vacuum oven at 90C
and 30 inches of Hg vacuum (about 1600 Pa) for 45 minutes.
Prepolymer properties: Melting Point - 130-170C
IR-hydro~cy function - 3100-3600 cm Isopropenyl function - 885-900 cm 1 GPC - molecular weight - 900 Mn 2000 ~w .
12.5 grams of the prepolymer was compression molded at 204-220C and 500 psi ~3447 MPa) for 1 hour. The cured block sample obtained after pressing was post cured in an atmospheric oven at 240C for four hours. Properties of the cured material are as follows:
32,807-F -7-1 23 1 79~
Glass ~ransition Temperature (Tg) = 320C by DMA
Thermal Stability by Thermal Gravimetric Analysis (TGA) 5% wt loss in nitrogen and aix at 500C
75% char yield in ni-trogen ~ 950C
Example II
7.0 grams of N,N'-methylenedi~p~phenylenebis--maleimide was mixed with 7.0 grams o the prepolymer prepared as described in Example I. The prepolymer mixture was compression molded in a 2" x 2" (51x51 mml) plate at 180C and 500 psi (3447 MPa) for l hour. The cured copolymer block sample was post cured in an atmospheric oven at 240C for 4 hours~ Properties of the cured material are as follows:
Tg by DMA = 315C
Thermal stability (TGA) = 5% w-t loss in N2 = 460C
5% wt loss in air = 450C
63% char yield in N2 @ 950C.
Example III
Isopropenyl capped polystyrylpyridine powder from Example I and N,N'-methylenedi p-phenylenebis maleimide powder were blended together in a ratio of l/l by weight. 4.4 grams of this material was alternated with 3 7/8" squares of glass cloth in a mold which had a cavity of 4"x4"xl/8" ~102x102x3.2 mm). The glass cloth weighed between 2.92 and 2.96 grams per piece and seven pieces were used before the top plate o the mold was positioned in place. The mold was placed in a heated press and the resin was cured for 2 hours at 900 psi (6205 MPa) and 180C. A rigid, dark brown composite was obtained which did not support combustion when exposed to an open 1ame.
32,307-F -8-~3~7~3~
~693-3602 Example IV
153.5 grams (1.15 mole) of terephthalaldehyde and 103 grams (0.75 mole) of 2,3,5,6--tetramethylpyrazine were placed in a 500 cc glass resin kettle equipped with a mechanical stirrer, rnodified Dean-Stark apparatus for collection of water, infrare,d heating lamps, thermometer, and nitrogen purge system. ~he infrared lamps were turned on and a 5-10 cc/min nitrogen purge was initiated. At a 105C p-ot temperature the reactants had melted and the mechanical stirrer was started.
Approximately 5 cc of concentrated sulfuric acid was added and the reaction mixture was hea-ted to 160-170C
for 1 hour, collecting water overhead. The reaction mixture was then cooled to between 150 and 158C and 48.2 grams of para-isopropenyl phenol was added dropwise as a 50/50 b~ weight solution in acetone. The reaction mixture was maintained between 150 and 158C for 45 minutes before cooling to room temperature. The prepolymer was purified by dissolving in a 50/50 THF/acetone mixture and precipitating in water. The precipitated prepolymer was then filtered and dried in a vacuum oven.
- Prepolymer Properties: melting point = 175-185C
IR absorbtions = 3100-3~00 cm 1 Hydroxy 885-900 cm l Isopropenyl GPC wt. average mol. wt. = 4800 51.5 grams of the prepolymer was compression molded at a temperature between 210 and 230C and 500 psi (3447 MPa) for 1 hour in a 4"x4"xl/8" (lOlxlOlx3.1 mm) plate. The sample was then post cured at 230C for 12 hours in an atmospheric oven. Properties of the cured material are as follows:
_g_ . ~ ' .
~3~3 Glass transition temp. (Tg) = >380C by DSC
Thermal stability (TGA) = 67% char yield in nitrogen at 950C.
32,807-F -10-
Claims (7)
1. A thermosetting prepolymer prepared from (A) one or more aromatic dialdehydes, (B) one or more azine compounds having the formula where Z is N, C-CH3, or C-CH2-CH3, or C-H
R is hydrogen, methyl, or ethyl, whereby the total number of methyl groups substituted on the ring is in the range from 2-4, and (C) a member of the group consisting of (1) monomeric para or meta isopropenyl phenols having the formula wherein R1 is hydrogen, or a group inert to the polymerization reaction, (2) dimers of said phenols, and (3) mixtures thereof.
R is hydrogen, methyl, or ethyl, whereby the total number of methyl groups substituted on the ring is in the range from 2-4, and (C) a member of the group consisting of (1) monomeric para or meta isopropenyl phenols having the formula wherein R1 is hydrogen, or a group inert to the polymerization reaction, (2) dimers of said phenols, and (3) mixtures thereof.
2. The prepolymer of Claim 1 wherein said azine compound is 2,4,6-trimethyl pyridine, 2,6-dimethyl pyridine, or a mixture thereof.
3. The prepolymer of Claim 1 wherein said azine compound is 2,5-dimethyl pyrazine, 2,3,5,6-tetra-methyl pyrazine, or a mixture thereof.
4. The prepolymer of Claim 1 wherein said dialdehyde has the formula wherein X is independently hydrogen, chlorine, bromine, fluorine, or a monovalent hydrocarbon radical such as an alkyl group of 1-4 carbons, an aryl group of 6-8 carbons such as phenyl, tolyl, xylyl, an oxyalkyl group of 1-4 carbons or an oxyaryl group of 6-8 carbons.
5. The thermosetting prepolymer which comprises the product of Claim 1 further reacted with a bismaleimide compound having the formula where Z is a divalent organic radical having at least two carbon atoms and selected from the group consisting of aliphatic groups, alicyclic groups, aromatic groups, and groups having at least two aryl residues or cyclohexyl residues bonded together by methylene, sulfonyl, or oxygen linkages or combinations thereof and X is independently hydrogen, halogen, an alkyl group of 1-4 carbons or an aryl group of 6-8 carbons.
6. A cured composite which comprises the product obtained by heat curing the product of Claim 1 with heat resistant fibers.
7. The cured composite of Claim 6 wherein the heat curing is conducted at a temperature in the range from 150 to 300°C for a time sufficient to obtain a cure.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US609,156 | 1984-05-11 | ||
| US06/609,156 US4500690A (en) | 1984-05-11 | 1984-05-11 | Thermosetting polymers from aromatic aldehydes, azines and isopropenyl phenols |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1231793A true CA1231793A (en) | 1988-01-19 |
Family
ID=24439573
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000481327A Expired CA1231793A (en) | 1984-05-11 | 1985-05-10 | Thermosettable polymers |
Country Status (12)
| Country | Link |
|---|---|
| US (1) | US4500690A (en) |
| EP (1) | EP0182865A4 (en) |
| JP (2) | JPS61500619A (en) |
| AU (1) | AU566620B2 (en) |
| BR (1) | BR8506739A (en) |
| CA (1) | CA1231793A (en) |
| DK (1) | DK12886D0 (en) |
| ES (1) | ES8702933A1 (en) |
| IL (1) | IL75163A (en) |
| NO (1) | NO860078L (en) |
| WO (1) | WO1985005366A1 (en) |
| ZA (1) | ZA853558B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2551761B1 (en) * | 1983-09-12 | 1985-10-18 | Poudres & Explosifs Ste Nale | POLYSTYRYLPYRIDINE RESINS WITH IMPROVED TENACITY AND COMPOSITE MATERIAL COMPRISING SUCH RESINS |
| FR2551763B1 (en) * | 1983-09-13 | 1987-01-02 | Onera (Off Nat Aerospatiale) | NOVEL, ACCELERALLY CURED THERMOSETTING POLYMERS AND PREPOLYMERS RESULTING FROM POLYCONDENSATION OF PYRIDINE DERIVATIVES AND AROMATIC DIALDEHYDES AND THE ADDITION OF A PHENOLIC COMPOUND |
| US4500690A (en) * | 1984-05-11 | 1985-02-19 | The Dow Chemical Company | Thermosetting polymers from aromatic aldehydes, azines and isopropenyl phenols |
| US4543388A (en) * | 1984-05-17 | 1985-09-24 | The Dow Chemical Company | Thermosettable polymers or prepolymers prepared from polymethylated pyrazines and aromatic polyaldehydes and cured products therefrom |
| US4575542A (en) * | 1985-04-23 | 1986-03-11 | The Dow Chemical Company | Thermosettable polystyrylpyridine prepolymer terminated with ethylenically unsaturated groups and cured products therefrom |
| US4540745A (en) * | 1984-07-19 | 1985-09-10 | The Dow Chemical Company | Allyl styryl pyridines and pyrazines and polymers thereof |
| US4539377A (en) * | 1984-07-19 | 1985-09-03 | The Dow Chemical Company | Alkenylphenylglycidyl ether capped hydroxystyryl pyridines (pyrazines) and polymers thereof |
| DE3587534T2 (en) * | 1984-10-15 | 1994-01-05 | Sumitomo Chemical Co | Thermosetting resin composition. |
| US4831137A (en) * | 1985-04-23 | 1989-05-16 | The Dow Chemical Company | Reaction products of pteridine and 4-isopropenyl-1-cyclohexene-1-carboxaldehyde |
| US4755600A (en) * | 1985-04-23 | 1988-07-05 | The Dow Chemical Company | Reaction products of pyrazine, pyridine, quinoline and quinoxaline derivatives and 4-isopropenyl-1-cyclohexene-1-carboxaldehyde |
| US4629770A (en) * | 1985-04-23 | 1986-12-16 | The Dow Chemical Company | Thermosettable polystyrylpyrazine polymers terminated with ethylenically unsaturated groups and cured products therefrom |
| US4613663A (en) * | 1985-09-19 | 1986-09-23 | The Dow Chemical Company | Thermoplastic and thermosettable products prepared by reacting nitrogen-containing heterocyclic compounds with aromatic aldehydes |
| US4736035A (en) * | 1986-04-04 | 1988-04-05 | The Dow Chemical Company | Heterocyclic styryl compounds and resins prepared therefrom |
| DE102007041796A1 (en) * | 2007-08-30 | 2009-03-05 | Ami Agrolinz Melamine International Gmbh | Processes and apparatus for preparing pre-condensed resin solutions |
| JP5643167B2 (en) * | 2011-09-02 | 2014-12-17 | 株式会社ダイセル | Crosslinkable composition |
Family Cites Families (17)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE749268C (en) * | 1941-11-07 | 1944-11-20 | Process for the production of synthetic resins from coal tar bases | |
| US2631140A (en) * | 1951-07-19 | 1953-03-10 | Universal Oil Prod Co | Modified phenolic resins |
| US2843566A (en) * | 1953-11-03 | 1958-07-15 | Pittsburgh Plate Glass Co | Alkenylphenol-aldehyde |
| DE1121331B (en) * | 1957-03-22 | 1962-01-04 | Teerverwertung Gmbh | Process for the production of rapidly hardening, optionally hardening-delayed resols by softening |
| US2948702A (en) * | 1957-05-14 | 1960-08-09 | Pittsburgh Plate Glass Co | Coating compositions containing alkenyl phenol-aldehyde resins and structures prepared therefrom |
| US3294746A (en) * | 1962-03-08 | 1966-12-27 | Union Carbide Corp | Polycarbonates from dimers of alkenyl phenols |
| US3516971A (en) * | 1966-11-09 | 1970-06-23 | Webb James E | Aromatic diamine-aromatic dialdehyde high - molecular - weight schiff - base polymers prepared in a monofunctional schiff-base |
| US3526611A (en) * | 1966-11-09 | 1970-09-01 | Webb James E | Synthesis of polymeric schiff bases by schiff-base exchange reactions |
| US3651012A (en) * | 1969-04-25 | 1972-03-21 | Gen Electric | Novel bis-imide compositions and polymers therefrom |
| FR2261296B1 (en) * | 1974-02-14 | 1978-09-29 | Onera (Off Nat Aerospatiale) | |
| US4179429A (en) * | 1975-10-22 | 1979-12-18 | Mitsui Toatsu Chemicals Incorporated | Laminates prepared from resol-type phenol resins |
| FR2378052A1 (en) * | 1977-01-25 | 1978-08-18 | Poudres & Explosifs Ste Nale | PROCESS FOR THE PREPARATION OF POLYSTYRYLPYRIDINE |
| US4320043A (en) * | 1981-01-12 | 1982-03-16 | The Quaker Oats Company | Furfuryl alcohol-dialdehyde foundry binders |
| US4362860A (en) * | 1981-11-02 | 1982-12-07 | Rockwell International Corporation | Addition curing polystyryl pyridine |
| FR2551763B1 (en) * | 1983-09-13 | 1987-01-02 | Onera (Off Nat Aerospatiale) | NOVEL, ACCELERALLY CURED THERMOSETTING POLYMERS AND PREPOLYMERS RESULTING FROM POLYCONDENSATION OF PYRIDINE DERIVATIVES AND AROMATIC DIALDEHYDES AND THE ADDITION OF A PHENOLIC COMPOUND |
| US4515938A (en) * | 1984-03-12 | 1985-05-07 | The Dow Chemical Company | Hydroxystyrylazapolymers |
| US4500690A (en) * | 1984-05-11 | 1985-02-19 | The Dow Chemical Company | Thermosetting polymers from aromatic aldehydes, azines and isopropenyl phenols |
-
1984
- 1984-05-11 US US06/609,156 patent/US4500690A/en not_active Expired - Fee Related
-
1985
- 1985-05-09 AU AU44029/85A patent/AU566620B2/en not_active Ceased
- 1985-05-09 BR BR8506739A patent/BR8506739A/en unknown
- 1985-05-09 JP JP60502380A patent/JPS61500619A/en active Granted
- 1985-05-09 WO PCT/US1985/000848 patent/WO1985005366A1/en not_active Application Discontinuation
- 1985-05-09 EP EP19850902771 patent/EP0182865A4/en not_active Ceased
- 1985-05-10 IL IL75163A patent/IL75163A/en unknown
- 1985-05-10 CA CA000481327A patent/CA1231793A/en not_active Expired
- 1985-05-10 ZA ZA853558A patent/ZA853558B/en unknown
- 1985-05-10 ES ES543048A patent/ES8702933A1/en not_active Expired
-
1986
- 1986-01-10 DK DK12886A patent/DK12886D0/en unknown
- 1986-01-10 NO NO860078A patent/NO860078L/en unknown
-
1987
- 1987-08-24 JP JP62210021A patent/JPS63191819A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| US4500690A (en) | 1985-02-19 |
| ES543048A0 (en) | 1987-01-16 |
| ES8702933A1 (en) | 1987-01-16 |
| WO1985005366A1 (en) | 1985-12-05 |
| IL75163A0 (en) | 1985-09-29 |
| AU4402985A (en) | 1985-12-13 |
| AU566620B2 (en) | 1987-10-22 |
| JPS63191819A (en) | 1988-08-09 |
| ZA853558B (en) | 1987-01-28 |
| EP0182865A1 (en) | 1986-06-04 |
| IL75163A (en) | 1988-10-31 |
| NO860078L (en) | 1986-01-10 |
| JPH0366330B2 (en) | 1991-10-17 |
| EP0182865A4 (en) | 1986-09-23 |
| BR8506739A (en) | 1986-09-23 |
| DK12886A (en) | 1986-01-10 |
| DK12886D0 (en) | 1986-01-10 |
| JPS61500619A (en) | 1986-04-03 |
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