Addition polyimides. III. Thermal behavior of bismaleimides

This article describes the synthesis of N,N′-bis(3,3′-maleimidophenyl) sulfone (S) and its Michael addition products with (4,4′-diaminodiphenyl) methane (S-M), 4,4′-diaminodiphenyl ether (S-E), (3,3′-diaminodiphenyl) sulfone (S-DDS_m), (4,4′-diaminodiphenyl) sulfone (S-DDS_p), (3,3′,3″-tris aminophenyl) phosphine oxide (S-TAP), and 9,9-bis(p-aminophenyl) fluorene (S-B). Curing behavior of these bisimides was investigated by differential scanning calorimetry. Activation energy of curing reaction was determined by using isothermal and multiple heating rate method. Thermal stability of bisimides was evaluated by thermogravimetric analysis. Better char yields were obtained in S-TAP resins.     

Polyimides from 4,4′-(alkylene-α,ω-dioxy) bis(phenylsuccinic anhydride)s and bis(phenylglutaric anhydride)s

4,4′-(Alkylene-α,ω-dioxy)bis(phenylsuccinic anhydride)s and bis(glutaric anhydride)s were obtained by the condensation of 4,4′-diformyl-α,ω-diphenoxyalkanes with ethyl cyanoacetate followed by the addition of potassium cyanide or meldrum acid (2,2-dimenthyl-1,3-dioxane-4,6-dione), hydrolysis with concentrated hydrochloric acid, and dehydration with acetic anhydride. Alkylene groups were ethylene, trimethylene, and tetramethylene. Polyimides were prepared from these anhydrides with 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenyl sulfide, and 4,4′-diaminodiphenylmethane through thermal ring closure of polyamic acids obtained by solution polymerization in dimethylacetamide, and thermal stability of these polyimide film was examined by thermogravimetric analysis.     

Preparation of silicon containing polymers. II.. Effect of structure on the thermal stability of organosilicon aramids

Two silicon-containing acid dichlorides, bis(4-chlorocarbonylphenyl)dimethylsilane and bis(4-chlorocarbonylphenyl)diphenylsilane, were synthesized and reacted with 1,3-phenylene diamine, 1,4-phenylene diamine, 4,4′-diaminodiphenyl, 4,4′-diaminodiphenyl methane 4,4′-diaminodiphenyl ether, and 4,4′-diaminodiphenyl sulfone in the preparation of 12 structurally different high molecular weight aromatic polyamides. A low-temperature interfacial polycondensation technique was used. Most of the polyamides formed tough, transparent, flexible films and were characterized by solubility, solution viscosity, infrared spectroscopy (IR), and glass transition temperature (T_g). The thermal behavior of these aramids was studied by dynamic thermogravimetry. The effect of diamine and acid dichloride structure on the aramids properties is also discussed.     

Synthesis of polyamidines based on 1,4-dicyanobenzene and 4,4′-diaminodiphenyl oxide in ionic liquids

1,4-Dicyanobenzene and 4,4′-diaminodiphenyl oxide at 190–200°C in ionic liquids form polyamidines of different molecular weights, whose T _10% in air is in the range 250–270 °C.     

Synthesis and studies of homopolyamides based on 2,4-bis(6-chlorocarbonyl-2-naphthyloxy)-6-(4-methyl-1-piperazinyl)-s-triazine

Abstract  

Ten homopolyamides have been synthesized by polycondensation of the monomer 2,4-bis(6-chlorocarbonyl-2-naphthyloxy)-6-(4-methyl-1-piperazinyl)-s-triazine and different diamines such as 4,4′-biphenyldiamine, 4,4′-diaminobenzanilide, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfonamide, 2,4-diaminotoluene, o-phenylenediamine, m-phenylenediamine, p-phenylenediamine, and ethylenediamine. All polyamides were characterized by solubility, density, viscosity measurements, IR, NMR spectroscopy, and thermogravimetric analysis. The products were found to possess high thermal stability.     

Diglycidylphenylphosphate based fire retardant liquid crystalline thermosets

Organophosphorus liquid crystalline thermosets (LCTs) were developed using diglycidylphenylphosphate (DGPP) and various aromatic diamines. DGPP was prepared by the esterification of phenylphosphorodichloridate with glycidol. 2,5-Bis(p-aminophenyl)-1,3,4-oxadiazole (BPOD) was synthesized and three different commercial diamines, 4,4′-diaminodiphenyl sulphone (DDS), 4,4′-diaminodiphenyl methane (DDM) and biphenyl diamine (BPD) were used as curing agents. The mesomorphic behaviour of DGPP/diamine mixtures and their curing kinetics were monitored by differential scanning calorimetry and hot stage optical polarized microscopy. The thermogravimetric analysis data showed that the LCTs are stable in the range 261-292 °C and afford 36-48% char yield. The limiting oxygen index values are between 35 and 47 proving fire retardance. The mechanical properties of the cured LCTs were characterized by dynamic mechanical analysis.     

Influence of the structure of the diol on the properties of aromatic polyesterimides

A series of aromatic polyesterimides with ester bonds in the side-chains has been obtained by the partial esterification of a polyamic acid prepared from pyromellitic dianhydride and 4,4′-diaminodiphenyl ether with the following aromatic diols: 4,4′-di(2-hydroxyethoxy)-1,1′-binaphthyl, 2,2′-di(2-hydroxyethoxy)-1,1′-binaphthyl.di(2-hydroxyethoxy-1 -naphthyl)methane,2,2-di[4-(2-hydroxyethoxy)phenyl] propane.Influence of the structure of the diol on the thermal, mechanical and dielectric properties of resultant polymer foils has been studied. Properties of these foils have been compared with those obtained for the polypyromellitimide film of the 4,4′-diaminodiphenyl ether.     

Polycondensation of pyridine-2,6-dicarboxylic acid with some di- and tetraamino compounds

Pyridine-2,6-dicarboxylic acid phenyl ester was condensed with 3,3′-diaminobenzidine and 3,3′,4,4′-tetraaminodiphenyl ether. Polyamides were also synthesized by condensation of the above ester with p-phenylenediamine, benzidine, 4,4′-diaminodiphenyl sulfide and 4,4′-diaminodiphenyl sulfone. These amides had higher inherent viscosities and greater thermal stability than was reported before. Model compounds of imidazoles were prepared by condensation of the same ester with o-phenylenediamine and 2,3-diaminopyridine and of polyamides by condensation with aniline and 2-aminopyridine. In the case of the polyimidazole, the completely closed ring of imidazole did not form. The ultraviolet spectra of model compounds were compared with those of the polymers. The thermogravimetric curves show that the polymers are stable up to more than 400°C under argon atmosphere. All polymers were insoluble in most organic and inorganic solvents. They dissolved only partially in DMSO and DMF. Inherent viscosity was measured for the soluble polymer fraction.     

Synthesis of polyimide and poly(imide-benzoxazole) in polyphosphoric acid

A polyimide made from 4,4′-diaminodiphenyl ether (ODA) and 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA) was synthesized in polyphosphoric acid. Although the polymerization proceeded heterogeneously, a polyimide with an inherent viscosity of 0.90 was obtained, and a tough and flexible film was made from this polyimide. This polymerization was a one-step reaction including polycondensation and imidization; this was also confirmed by a model reaction between aniline and phthalic anhydride. Utilizing this polymerization method, 3,3′-dihydroxy-4,4′-diaminobiphenyl and 2 mol of 4-aminobenzoic acid were reacted in PPA, then BPDA was reacted to obtain an alternate copolymer containing imide and oxazole rings. This reaction gave a homogeneous solution of the poly(imide-benzoxazole). © 1993 John Wiley & Sons, Inc.     

New fluorinated aromatic poly(ether-amide)s derived from 2,2′-bis(3,4,5-trifluorophenyl)-4,4′-diaminodiphenyl ether and various dicarboxylic acids

A new class of highly fluorinated aromatic poly(ether-amide)s was prepared through triphenyl phosphite-activated polycondensation of 2,2′-bis(3,4,5-trifluorophenyl)-4,4′-diaminodiphenyl ether (FPAPE) and four dicarboxylic acid comonomers. All the resulting polymers were thoroughly characterized by FT-IR, UV, and NMR spectroscopic methods. The effects of the fluorine atoms directly linked to the lateral phenyl rings as well as fluoro-containing phenyl groups attached to the macromolecular chains on some properties of the polymers were investigated by comparing with poly(ether-amide)s prepared from 4,4′-oxydianiline (4,4′-ODA) and 2,2′-diphenyl-4,4′-diaminodiphenyl ether (PAPE). The FPAPE-derived polymers exhibited excellent solubility in a variety of organic solvents. Results obtained from X-ray studies showed that the presence of the bulky fluoro-containing phenyl groups attached to the chains disrupts their structural order in a great amount, and leads to a decrease in crystallinity extent of the macromolecules. Furthermore, the highly fluorinated polymeric chains showed a significant enhancement in organo-solubility, heat-stability and T_g values when compared to their non-fluorinated counterparts.     

Synthesis of N-(1,5,3-dithiazepan-3-yl)- and N-(1,5,3-dithiazocan-3-yl)amides in the presence of lanthanide catalysts

A new method was developed for preparation of N-(1,5,3-dithiazepan-5-yl)- and N-(1,5,3-dithiazocan-5-yl)amides by transamination of N-tert-butyl-1,5,3-dithiazepane and N-tert-butyl-1,5,3-dithiazocane, and also by recyclization of 1-oxa-3,6-dithiacycloheptane and 1-oxa-3,7-dithiacyclooctane with carboxylic acids hydrazides in the presence of catalysts based on rare earth elements.     

Films of polyamides with phenylpyridine units in the backbone

New polyamides derived from 2-(4-aminophenyl)-5-aminopyridine, 4,4-diaminodiphenyl ether, and 4,4′-terephthaloyloxybis(3-methoxybenzoic) acid dichloride were prepared. These polyamides are of interest as macromolecular ligands. The deformation-strength, thermomechanical, and thermal properties of films of polyamides with various content of phenylpyridine fragments were studied.     

Curing kinetics and thermal stability of diglycidyl ether of bisphenol

Curing kinetics of diglycidyl ether of bisphenol-A (DGEBA) in the presence of varying molar ratios of aromatic imide-amines and 4,4′-diaminodiphenylsulfone (DDS) were investigated by the dynamic differential scanning calorimetry. The imide-amines were prepared by reacting 1 mole of benzophenone 3,3′,4,4′-tetracarboxylic acid dianhydride (B) with 2.5 moles of 4,4′-diaminodiphenyl ether (E)/ or 4,4′-diaminodiphenyl methane (M)/ or 4,4′-diaminodiphenylsulfone (S) and designated as BE/ or BM/ or BS. The mixture of imide-amines and DDS at ratio of 0:1, 0.25:0.75, 0.5:0.5, 0.75:0.25 and 1:0 were used to investigate the curing behaviour of DGEBA. The multiple heating rate method (5, 10, 15 and 20°C min⁻¹) was used to study the curing kinetics of epoxy resins. The peak exotherm temperature was found to be dependent on the heating rate, structure of imide-amines as well as on the ratio of imide-amine: DDS used. A broad exotherm was observed in the temperature range of 180–230°C on curing with mixture of imide-amines and DDS. Curing of DGEBA with mixture of imide-amines and/or DDS resulted in a decrease in characteristic curing temperatures. Activation energy of curing reaction as determined in accordance to the Ozawa’s method was found to be dependent on the structure of amine. The thermal stability of the isothermally cured resins was also evaluated using dynamic thermogravimetry in a nitrogen atmosphere. The char yield was highest in case of resins cured using mixture of DDS: BS (0.25:0.75; EBS-3), DDS: BM (0.5: 0.5; EBM-2) and DDS: BE (0.5: 0.5; EBE-2).     

Macroheterocyclic Compounds with p-Diamines of the Diaryl Series

The reactions of indane-1,3-dione with 4,4′-diaminodiphenyl sulfone, 4,4′-diaminodiphenyl sulfide, and 4,4′-diaminodiphenyl ether were used to synthesize symmetrical macroheterocyclic compounds.__________Translated from Zhurnal Obshchei Khimii, Vol. 75, No. 6, 2005, pp. 1017–1021.Original Russian Text Copyright © 2005 by Berezina, Vorob’ev, Vorob’eva, Sadova.     

Adsorption of thorium(IV) from aqueous solutions by poly(cyclotriphosphazene-co-4,4′-diaminodiphenyl ether) microspheres

Journal of Radioanalytical and Nuclear Chemistry - Poly(cyclotriphosphazene-co-4,4′-diaminodiphenyl ether) microspheres (PZA) was based on hexachlorocyclotriphosphazene (HCCP) and...     

Sorption and transport properties of MY720/DDS epoxy reacted with blocking reagents

Thin films of the epoxy formed by the reaction of tetraglycidyl 4,4'-diamino-diphenylmethane and 4,4'-diaminodiphenyl sulfone (73:27 w/w) were reacted with acrylonitrile (ACN) and isocyanates as blocking reagents for hydroxyl, amine, and epoxy groups. The water uptake at 30, 45, 55, and 70°C of the epoxy resin was monitored gravimetrically. At each temperature the epoxy exhibited case I or Fickian behavior. The diffusion coefficient D increased from 30 to 55°C, but decreased at 70°C because of the reaction of water with residual oxirane groups. Diffusion of ACN is accompanied by both reaction and polymerization, so equilibrium could not be reached. Sorption of the isocyanates essentially follows case I or Fickian behavior. Equilibrium moisture absorptions showed a correspondence between the reduction of moisture absorption and the number of blocked functional groups, irrespective of the nature of the blocking groups. Moisture absorption reductions as high as 68% were obtained. Moisture diffusion of the films after blocking with the various reactants exhibits case I or Fickian behavior. At 30°C, D values are significantly higher for reacted films. At 70°C, the value of D is unchanged as compared with the 30°C value for films reacted with ACN, but D values are significantly lower for films reacted with isocyanate blocking reagents as compared with the epoxy resin.     

A systematic study of the microwave and thermal cure kinetics of the DGEBA/DDS and DGEBA/DDM epoxy‐amine resin systems

The microwave and thermal cure processes for the epoxy-amine systems (epoxy resin diglycidyl ether of bisphenol A, DGEBA) with 4,4′-diaminodiphenyl sulphone (DDS) and 4,4′-diaminodiphenyl methane (DDM) have been investigated for 1 : 1 stoichiometries by using fiber-optic FT-NIR spectroscopy. The DGEBA used was in the form of Ciba-Geigy GY260 resin. The DDM system was studied at a single cure temperature of 373 K and a single stoichiometry of 20.94 wt% and the DDS system was studied at a stoichiometry of 24.9 wt% and a range of temperatures between 393 and 443 K. The best values of the kinetic rate parameters for the consumption of amines have been determined by a least squares curve fit to a model for epoxy/amine cure. The activation energies for the polymerization of the DGEBA/DDS system were determined for both cure processes and found to be 66 and 69 kJ mol⁻¹ for the microwave and thermal cure processes, respectively. No evidence was found for any specific effect of the microwave radiation on the rate parameters, and the systems were both found to be characterized by a negative substitution effect. Copyright © 2002 John Wiley & Sons, Ltd.     

引入不对称结构对聚酰亚胺模塑料加工性能的改善

采用联苯四酸二酐（BPDA）与4,4′-二胺基二苯醚(4,4′-ODA)和3,4′-二胺基二苯醚(3,4′-ODA)聚合后,经亚胺化,制备了一系列二胺不同配比的高强度易加工的聚酰亚胺模塑料。 并对其流变性能、力学性能及热学性能进行测试。 结果表明,随着3,4′-ODA含量的增加模塑料的冲击强度没有大的改变,而流变性能随3,4′-ODA含量的增加而提高,w(3,4′-ODA)在50%时,玻璃化转变温度为275 ℃,材料的冲击强度为141 kJ/m2。 模压压力为20 MPa时加工性能优异。     

Curing and thermal behaviour of epoxy resin in the presence of a mixture of imide-amines

The curing behaviour of diglycidyl ether of bisphenol-A (DGEBA) was investigated by the dynamic differential scanning calorimetry using varying molar ratios of aromatic imide-amines and 4,4′-diaminodiphenylsulfone (DDS). The imide-amines were prepared by reacting 1 mole of naphthalene 1,4,5,8-tetracarboxylic dianhydride (N) and 4,4′-oxodiphthalic anhydride (O) with 2.5 moles of 4,4′-diaminodiphenyl ether (E) or 4,4′-diaminodiphenyl methane (M) or 4,4′-diaminodiphenylsulfone (S) and designated as NE/OE or NM/OM or NS/OS. The mixture of the imide-amines and DDS at ratio of 0:1, 0.25:0.75, 0.5:0.5, 0.75:0.25 and 1:0 were used to investigate the curing behaviour of DGEBA. A single exotherm was observed on curing with mixture of imide-amines and DDS. This clearly shows that the two amines act as co-curing agents. Curing temperatures were higher with imide-amines having sulfone linkage irrespective of anhydride. Curing of DGEBA with mixture of imide-amines and or DDS resulted in a decrease in characteristic curing temperatures. The thermal stability of the isothermally cured resins was also evaluated using dynamic thermogravimetry in a nitrogen atmosphere. The char yield was higher in case of resins cured imide-amines based on N and E. The activation energy of decomposition and integral procedural decomposition temperature were also calculated from the TG data.     

4,4'-二氨基二苯醚分子印迹聚合物/聚4,4'-二氨基二苯醚的电化学合成及其吸波性能研究

本文采用二次电聚合法,在石墨烯修饰铅笔芯电极(G-PEC)表面制备出4,4'-二氨基二苯醚分子印迹聚合物复合聚4,4'-二氨基二苯醚(4,4'-ODL-MIP/P-4,4'-ODL)新型电磁材料,考察了电极有效导电长度、石墨烯浓度、缓冲液pH、4,4'-二氨基二苯醚与功能单体丙烯酰胺的浓度及其浓度比、扫描电位范围、扫描圈数、扫描速率、洗脱时间等各种条件对复合材料荷电量的影响。矢量网络分析仪测试结果显示,所合成的复合材料在12.56GHz处出现-10.57dB的反射损耗,有效电磁波吸收率达到90%;而单一的4,4'-ODL-MIP和石墨烯反射损耗均高于-10dB,有效电磁波吸收率分别仅约为68%和60%,因而复合材料具备良好的吸波性。