- Study of Diels–Alder reactions between furan and maleimide model compounds and the preparation of a healable thermo-reversible polyurethane
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A study of the reactions between various furan and maleimide model compounds and the effects of reaction conditions was performed, allowing for a proper design and preparation of a thermo-reversible polyurethane (PU) material crosslinked via Diels–Alder (DA) bonds. Thus, a linear polyurethane containing furan groups along the main chain was synthesized and crosslinked with a bismaleimide by means of DA reaction. The obtained thermoset exhibited thermo-reversibility as evidenced by DSC and FTIR microscopy, providing the material recyclability and scratch healability. Optical microscopy, SEM and tensile analysis of a scratched PU film revealed that efficient scratch healing was enabled by heating at 110 °C for 30 min and subsequently keeping at room temperature for 24 h, resulting in an approximately 80% recovery of the pristine mechanical strength. This material is a promising candidate for the development of self-healing coatings.
- Truong, Thuy Thu,Nguyen, Ha Tran,Phan, Man Ngoc,Nguyen, Le-Thu T.
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Read Online
- Synthesis and analysis of thermally degradable polybutadiene containing Diels–Alder adduct
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The thermoreversible Diels–Alder reaction, a type of stimuli-responsive reversible organic reaction, is attractive because its direction can be easily controlled. In this study, the cross-linked Diels–Alder adduct-containing polybutadiene (DAPBD) was synthesized by the SN2 reaction of bromine-terminated polybutadiene with a furan-bismaleimide Diels–Alder adduct, and their thermodegradable behavior was analyzed by thermogravimetric analysis. DAPBD was dissociated by the retro-Diels–Alder reaction and dissolved in chlorobenzene at 132 °C to generate furan-terminated polybutadiene (FTPB) and bismaleimide that were identified by 1H NMR spectroscopy. This synthetic method using premade Diels–Alder adducts is expected to enhance the thermoreversibility of the materials by significantly increasing the concentration of the Diels–Alder adduct moieties in the final DAPBD. The polymerization performed at 35 °C will help widen the scope of the use of such materials.
- Chang, Sanghoon,Kim, Yongkyun,Park, Haneul,Park, Kwangyong
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p. 1602 - 1609
(2021/10/04)
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- A diphenylmethane bismaleimide synthetic method
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A diphenylmethane bismaleimide synthetic method, in order to maleic anhydride, 4, 4' - diamino diphenyl methane as the raw material, the catalyst is acetic anhydride, acetic acid as the solvent, a microwave reaction, recrystallized to obtain the diphenylmethane bismaleimide. The method of the invention the reaction is simple and easy to control, after treatment is convenient, the target product of the diphenylmethane bismaleimide purity is greater than 98%, overall yield can reach 90% or more, in accordance with the requirements of the green in the chemical industry.
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Paragraph 0024-0029
(2019/03/25)
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- Thermal and electrical behavior of hybrid thermosets based on epoxy and maleimide resins cured with p-aminobenzoic acid
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Two thermoset systems based on maleimides and diglycidyl ether of bisphenol A (DGEBA) cured with p-aminobenzoic acid were characterized in terms of thermal and electrical behavior. Thermal characterization has been undertaken by means of thermogravimetric analysis in nitrogen atmosphere up to 600°C using simultaneous thermogravimetric/Fourier transform infrared/mass spectrometry (TG/FT-IR/MS) analysis. In the first stage of thermal degradation, the global kinetic parameters [activation energy (Ea) and preexponential factor (log A1 (s?1))] were calculated using the isoconversional method of Friedman. The energies variation as well as the shape of the differential thermal analysis curves suggests that the thermal decomposition process occurred in multiple stages. The evolved gases analysis was conducted by simultaneous TG/FT-IR/MS coupled techniques. Dielectric relaxation spectroscopy characterization was also made.
- Mustata, Fanica,Tudorachi, Nita,Asandulesa, Mihai,Bicu, Ioan
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p. 799 - 814
(2019/08/07)
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- Cardanol based benzoxazine blends and bio-silica reinforced composites: Thermal and dielectric properties
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In the present work, a novel cardanol based benzoxazine was synthesised by reacting three different amines (aniline (CrAb), N,N-dimethylaminopropylamine (CrDb) and caprolactam modified N,N-dimethylaminopropylamine (CrCb)) with cardanol in the presence of formaldehyde under appropriate experimental conditions. The resulting benzoxazines were characterised for their molecular structure and thermal behaviour using different analytical methods. Among the different systems studied, the tertiary amine derivatives were found to reduce the curing temperature efficiently (CrAb-275 °C > CrDb-265 °C > CrCb-251 °C) and were confirmed by DSC analysis. These cardanol based CrAb benzoxazines were blended with conventional benzoxazines (Bzs) and bismaleimides (BMIs) as binary and ternary systems and their thermal properties were studied. Three different catalysts (4-hydroxy acetophenone, 4-aminophenol, and 4-hydroxyphenyl maleimide) were used to study the effect of lowering the curing temperature. Further, the prepared benzoxazines were reinforced with varying weight percentages (1, 3, 5 and 10 wt%) of bio-silica derived from rice husk to obtain hybrid composites. The dielectric studies of bio-silica reinforced cardanol benzoxazines infer that the values of dielectric constant decreased with increasing wt% of bio-silica. It was further observed that 10 wt% bio-silica reinforced cardanol benzoxazines show the lowest value of dielectric constant of 1.9 at 1 MHz. From the data obtained from the different studies, it is concluded that the blends of cardanol based benzoxazines can be used in the form of sealants, encapsulants, adhesives and matrices in the fields of microelectronics and automobile applications for better performance.
- Arumugam,Krishnan,Chavali,Muthukaruppan
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p. 4067 - 4080
(2018/03/21)
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- A facile and economical procedure for the synthesis of maleimide derivatives using an acidic ionic liquid as a catalyst
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Seven maleimide derivatives were synthesized in good yields and high purity from the corresponding maleamic acids using a Bronsted acidic room temperature ionic liquid (RTIL) as a catalyst. The products were obtained through merely a decanting and removal of the solvent, suggesting that this procedure is superior to the conventional routes, in which the strong organic/inorganic acids were used as the catalysts, as well as a complicated post-processing procedure for the separation and purification of the products was employed.
- Li, Kai,Yuan, Chao,Zheng, Shijun,Fang, Qiang
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experimental part
p. 4245 - 4247
(2012/08/28)
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- Synthesis, UV-Vis spectra, and Hammett correlation of some novel bis(dihydropyrrolo[3,4-c]pyrazoles)
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Twenty-nine novel bis(dihydropyrrolo[3,4-c]pyrazole) derivatives were obtained by reacting C, N-phenyl-substituted nitrilimines generated in situ from corresponding hydrazonyl chlorides with bismaleimides. The structures were elucidated by physical and spectroscopic methods [m.p., Rf, infrared (IR),1H nuclear magnetic resonance (NMR), 13C NMR, correlation spectroscopy (COSY), heteronuclear correlation (HETCOR), nuclear Overhauser effect (NOE), and high-resolution mass spectrometry (HRMS)]. Also, Hammett correlation graphs were obtained between Hammett constants σp and λmax values of bis(pyrrolopyrazoles) carrying p-substituted phenyl-ring-bearing electron-withdrawing and electrondonating groups and discussed in terms of substituent effects. Springer-Verlag 2010.
- Dueruest, Yasar,Yildirm, Muhammet
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scheme or table
p. 961 - 973
(2011/10/04)
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- New polymers with alkylidenesuccinimide structures based on bismaleimides and biscitraconimides
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New polymers containing alkylidenesuccinimide structures prepared from phosphorous ylides of bismaleimides or biscitraconimides and aromatic dialdehydes by the Witting reaction, are reported for the first time in the literature. Phosphorous ylides of bismaleimides or biscitraconimides were synthesized in situ by the reaction of bismaleimide or biscitraconimide or AB monomers containing both maleimide and aldehyde or citraconimide and aldehyde groups with triphenylphosphine in metha-cresol or acetic acid. The structures of monomers and polymers were confirmed by FTIR, 1H-NMR and UV-visible spectroscopy and elemental analysis. The thermal behaviour of polymers was studied by thermogravimetric analysis and differential calorimetric measurements.
- Gaina, Viorica,Gaina, Constantin
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experimental part
p. 647 - 652
(2011/10/18)
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- A thermally remendable epoxy resin
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To provide epoxy resin with crack healing capability, an epoxy containing both furan and epoxide groups, N,N-diglycidyl-furfurylamine (DGFA), was synthesized through a two-step approach. When it reacted with N,N′-(4,4′-diphenylmethane) bismaleimide (DPMBM
- Tian, Qiao,Yuan, Yan Chao,Rong, Min Zhi,Zhang, Ming Qiu
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body text
p. 1289 - 1296
(2010/03/03)
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- Bismaleamic acid, bismaleimide and cured product thereof
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A bismaleamic acid obtained by reacting a bifunctional phenylene ether oligomer diamine, obtained by introducing aromatic amino groups into both terminals of a specific bifunctional phenylene ether oligomer, with maleic anhydride, a bismaleimide obtained from the bismaleamic acid as a raw material, which bismaleimide has high heat resistance, low dielectric characteristics and excellent solvent solubility and exhibits only a small change in dielectric characteristics even in high humidity, a curable resin composition containing the above bismaleimide and a cured product obtained by curing the curable resin composition.
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- METHOD OF PREPARATION OF MALEIMIDES BY THERMAL CYCLIZATION OF MALEAMIC ACIDS IN TH PRESENCE OF A CATALYST
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Method of preparation of maleimides by thermal cyclization of maleamic acids in the presence of a catalyst consists in that reaction of a substituted maleic anhydride with a primary amine is performed in an organic solvent in the presence of betaine at a temperature of 100 to 180 0C, at a ratio of the primary amine to the substituted maleic anhydride of 0.6 : 1.6. Maleimides, obtained in this way, are further purified by extraction, and finally, they are crystallized. As a catalyst, there may be also used betaine in a mixture with inorganic and organic acids, or betaine may be deposited on a solid carrier, or possibly, betaine may be deposited on a carrier in combination with inorganic acids.
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Page/Page column 5
(2008/06/13)
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- Thermosetting resin compositions containing maleimide and/or vinyl compounds
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In accordance with the present invention, there are provided novel thermosetting resin compositions which do not require solvent to provide a system having suitable viscosity for convenient handling. Invention compositions have the benefit of undergoing rapid cure. The resulting thermosets are stable to elevated temperatures, are highly flexible, have low moisture uptake and are consequently useful in a variety of applictions, e.g., in adhesive applications since they display good adhesion to both the substrate and the device attached thereto.
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- Adhesion promoters containing silane, carbamate or urea, and donor or acceptor functionality
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An adhesion promoter containing silane, and carbamate, thiocarbamate or urea functionality, and electron donor or electron acceptor functionality, displays low volatility.
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- Bismaleimide compounds
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The invention relates to a bismaleimide compound of the formula (I) substantially free of oligomeric, amidic and uncyclized impurities: STR1 wherein Ar is an optionally substituted aromatic residue; and Ar' is an optionally substituted aromatic residue which provides either good conjugation between the nitrogen-containing groups shown in formula (I) or steric or other restrictions capable of moderating the reactivity of an unreacted amine moiety attached to said residue, methods for their preparation and curable compositions containing them. The curable compositions may also be used in impregnated fibre reinforced materials and advanced composite materials.
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- Bisimide compound and process for the production thereof
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A bisimide compound of the following general formula (I). STR1 (wherein each of the R's is an alkyl group having 1 to 4 carbon atoms, a phenyl group or a phenyl group substituted with an alkyl or alkoxy group having 1 to 4 carbon atoms, a plurality of these R's may be the same or different, each of the Z's is STR2 a plurality of these Z's may be the same or different, Y is an arylene group or an aryleneoxy group whose terminal oxygen atom bonds to (CH2)n, n is an integer of 0 to 20, and m is an integer of 1 to 30.), and a process for the production of the above bisimide compound, which comprises reacting a bisamic acid corresponding to this bisimide compound in a cyclodehydration reaction.
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- Non-crystalline ether-imide type high purity bismaleimide composition and process for producing the same
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A non-crystalline ether-imide type high purity bismaleimide composition represented by formula (I): STR1 wherein R1, R2, R3, and R4 each represent a hydrogen atom, a halogen atom, or an alkyl group having from 1 to 4 carbon atoms; R5 represents a hydrogen atom or a methyl group; and R6 represents a hydrogen atom, a methyl group or a phenyl group. The non-crystalline bismaleimide (I) has a purity of 95 wt % or higher, a melting point of not higher than 130° C., and exhibits excellent solubility in a solvent. It is prepared by a process comprising uniformly melting a crystalline bismaleimide (I) followed by rapid cooling to solidify or a process comprising subjecting a maleamic acid, which is obtained by addition reaction between a corresponding aromatic ether diamine and maleic anhydride in an aromatic hydrocarbon/aprotic polar solvent mixed solvent, to dehydrating cyclization in the presence of an acid catalyst while azeotropically removing by-produced water with the aromatic hydrocarbon solvent, removing the remaining aromatic hydrocarbon solvent by distillation, withdrawing the produced maleimide in a molten state, and rapidly cooling to solidify.
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- Bis(maleimido) phenoxy phenylphosphine oxide
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Bis(maleimido) phenoxy phenylphosphine oxide monomers are formed by reacting a bis(aminophenoxyphenyl) phosphine oxide, e.g., bis(3-aminophenoxy) triphenylphosphine oxide, with maleic anhydride forming the intermediate bismaleamic acid species which is cyclodehydrated to the desired bismaleimido compound. The improved properties include: (1) a low melting point (Tm =90° C.); (2) a wide processing temperature range (Tcure =210° C.); and (3) a high Tg value of 400° C.; and (4) a high char yield which suggests flame resistance.
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- Bismaleimides and their use in preparing polyimides
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Bismaleimides of the formula I STR1 wherein R denotes a radical of the formula II STR2 and polyimides which can be prepared from these bismaleimides, if appropriate with the addition of an aromatic diamine. The polyimides are optionally reinforced with fibers.
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- Aromatic bismaleimide derivatives and process for preparing same
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A novel aromatic bismaleimide of the formula (I): STR1 wherein X is STR2 where R1 R2, R3 and R4 are a hydrogen atom or a methyl group. The bismaleimide is prepared by reacting an aromatic diamine having the formula (II): STR3 wherein X is the same as in the formula (I), with maleic anhydride and then conducting the ring-closing reaction of the resultant aromatic bismaleamic acid.
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- Synthesis of bisimides
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The present invention relates to a process for producing bisimides of unsaturated cyclic dianhydrides by cyclodehydration of the corresponding bisamic acid using acetic anhydride and a base component characterised in that the base component is free of amino compounds and comprises a carbonate or bicarbonate of an alkali metal or an alkaline earth metal.
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- Novel bis-maleimide compounds containing sulfonate linkages
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Novel homo bis-maleimide compounds containing sulfonate linkages are made by reacting an aromatic disulfonyl halide with m- or p-hydroxy phenyl maleimide and have the following formula: STR1 Similarly, co-bis-maleimides are made by reaching an aromatic disulfonyl halide, aromatic dihydroxy compound and m or p hydroxy phenyl maleimide having the structural formula: STR2 Herein R and R' are the same or different and are divalent radicals selected from the group consisting of meta arylene, para arylene, naphthalene and radicals of the formula A--A and A--Z--A wherein A is selected from the group consisting of meta arylene, para arylene and naphthalene and Z is selected from the group consisting of meta arylene, para arylene, naphthalene, carbonyl, sulfone, sulfide, sulfonyl, sulfonate, sulfoxide, ether, methylene, isopropyl, oxygen, alkyl, --CH=CH-- and --C C-- and R1, R2, R3 and R4 are the same or different and are selected from the group consisting of hydrogen, an alkyl group having from 1 to about 4 carbon atoms and a halogen.
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- Process for the preparation of aromatic ether bismaleimides
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The present invention provides a process for producing aromatic ether bismaleimides of the Formula (II) STR1 wherein A is a divalent mononuclear or polynuclear aromatic linking group. The process provides good yields and can be scaled up readily to commerical size runs. The present invention also provides compositions containing at least about 80 weight % of the bismaleimide of Formula (II) above.
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- Polymers prepared from 4,4'-bis-[2-(3,4-(dicarboxyphenyl) hexafluoroisopropyl] diphenyl ether dianhydride
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The application relates to fluorine-containing polyimides, polyamide-acids/esters, polyamides, addition polyimides and imide oligomers which exhibit low melting points, better solubilities, low dielectric constants, superior thermal and thermal oxidative stability, and improved processing characteristics. The products of this application are characterized by the fact that they are derived from 4,4'-bis[2-(3,4-(dicarboxyphenyl)-hexafluoroisopropyl]diphenyl ether dianhydride.
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- Polymers prepared from 4,4'-bis-(2-(amino (halo) phenoxyphenyl) hexafluoroisopropyl) diphenyl ether
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The application relates to fluorine-containing polyimides, polyamide-acids/esters, polyamides, addition polyimides and imide oligomers which exhibit low melting points, better solubilities, low dielectric constants, superior thermal and thermal oxidative stability, and improved processing characteristics. The products of this application are characterized by the fact that they are derived from 4,4'-bis[2-(amino(halo)phenoxyphenyl)hexafluoroisopropyl]diphenyl ether.
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- Process for the preparation of aromatic ether bismaleimides
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The present invention provides a process for producing aromatic ether bismaleimides of the Formula (II) STR1 wherein A is a divalent mononuclear or polynuclear aromatic linking group. The process provides good yields and can be scaled up readily to commercial size runs. The present invention also provides compositions containing at least about 80 weight % of the bismaleimide of Formula (II) above.
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- Flexible bismaleimides
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Bismaleimides having the general formula STR1 in which n is a whole number between 5 and 70 and --X-- is --O-- or --NH-- are prepared through the reaction of the corresponding amino-terminated polyoxybutylenes with 2 moles of maleic anhydride. They are suited as toughening agents in high grade reactive resins.
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- Fire and heat resistant laminating resins based on maleimido and citraconimido substituted 1-[(diorganooxyphosphonyl)methyl]-2,4- and -2,6-diaminobenzenes
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The subject invention pertains to a novel class of fire- and heat-resistant bisimide resins prepared by thermal polymerization of maleimido or citraconimido substituted 1-[(dialkoxyphosphonyl)methyl]-2-4 and -2,6-diaminobenzenes. Typical polymer precursors have the chemical structure: STR1 wherein R is alkyl, substituted alkyl or aryl, and R1 is hydrogen or lower alkyl. The polymer precursors are prepared by reacting 1-[(diorganooxyphosphonyl)methyl]-2-4- and -2,6-diaminobenzenes with maleic anhydride or citraconic anhydride in a mole ratio 1:2. Chain extension of the monomers is achieved by reacting the mono-N-maleimido derivatives of 1-[(diorganooxyphosphonyl)methyl]-2,4 and -2,6-diaminobenzenes with aryl tetracarboxylic dianhydrides, such as benzophenone tetracarboxylic dianhydride, or aryl diisocyanates, such as methylenebis(4-phenylisocyanate), in a mole ratio 2:1. The polymerization of the monomers is studied by differential scanning calorimetry (DSC) and the thermal stability of the polymers is ascertained by thermogravimetric analysis (TGA).
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- Bismaleimide compounds
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Bismaleimides of the formula STR1 wherein R1 and R2 each independently is H, C1-4 -alkyl, C1-4 -alkoxy, C1 or Br, or R1 and R2 together form a fused 6-membered hydrocarbon aromatic ring, with the proviso that R1 and R2 are not t-butyl or t-butoxy; X is O, S or Se; n is 1-3; and the alkylene bridging group, optionally, is substituted by 1-3 methyl groups or by fluorine, form polybismaleimide resins which have valuable physical properties. Uniquely, these compounds permit extended cure times, i.e., they remain fluid for a time sufficient to permit the formation of a homogeneous melt prior to curing.
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- Process for the production of maleimides
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There is described a process for the production of maleimides, particularly N-substituted maleimides or N,N'-bis-maleimides, by isomerization of the corresponding isoimides in the presence of specific catalysts, such as mixtures of phenol and triethylamine. Maleimides of high purity and in good to very good yields under mild conditions and with the use of small amounts of catalyst are obtained by the process according to the invention.
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- Process for the manufacture of maleimides
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The invention relates to the improvement of the conventional processes for manufacturing monomaleimides and polymaleimides, in which it is known to cyclodehydrate corresponding monomaleamic or polymaleamic acids in the presence of acetic anhydride and tertiary amines. According to the invention, the tertiary amines are used only in very small amounts (0.1 to 0.5 mole per mole of maleamic acid group) and the dehydration is carried out at temperatures between 10° and 50° C. The end products are obtained in purer form and greater yield than in conventional processes.
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