Peculiarities of structure formation of epoxy-amine polymers upon curing of diglycidyl ester of diphenylolpropane with adamantane diamines

The peculiarities of structure formation of epoxy-amine polymers upon curing of diglycidyl ester of diphenylolpropane with adamantane diamines are discussed. It is shown that, at the initial stage of polycondensation, deceleration of the curing process takes place that is caused by glass transition of the polycondensation products. It is found that complete consumption of all functional groups is impossible without additional postcuring.     

Kinetics of curing of epoxy oligomers with adamantane diamines

The kinetics of curing of diglycidyl ester of diphenylolpropane (the first homolog of epoxy-diane oligomers) with diaminomethyladamantane is studied. It is shown that, at the initial stage, the autocatalytic polycondensation is developed which is characterized by an increase in viscosity, branching of a macromolecule, and increasing intermolecular interactions.     

Crosslinked polymers containing adamantane groups

Diglycidyl ethers of 1,3-bis-(p-hydroxyphenyl)adamantane (BHPA) and 3,3'-bis-(p-hydroxyphenyl)-1,1'-biadamantane (BHPBA) were prepared and condensed with m-phenylenediamine and methyl tetrahydrophthalic anhydride to give polymers with good high temperature mechanical properties and good oxidative stability. These bisphenols were also condensed with formaldehyde to give phenolic resins containing adamantane moieties.     

Epoxy polymers based on functional adamantane derivatives

The main routes for modification of epoxy polymers with functional adamantane derivatives consisting of four saturated cycles are considered. It is shown that the high thermodynamic stability and rigidity of adamantane structure define a complex of properties of epoxy polymers and materials, as compared to the known polymers based on acyclic epoxy resins.     

Synthesis of formamidine-containing polymers from aromatic diamines

Aromatic polymers containing formamidine groups in the polymer backbone were obtained from aromatic diamines in high yields with α,α-dichloromethyl ether and triethylorthoformate. The latter was the reagent of choice. Soluble, high-molecular-weight products were obtained with m-phenylene diamine and 4,4′ bis(aminophenyl)methane. These polymers were characterized by viscosity, microanalysis, and nuclear magnetic resonance and infrared spectroscopy. Generally, insoluble products were obtained from p-phenylene diamine and 2,6-diaminotoluene, although small amounts of dimethylsulfoxide (DMSO)-soluble fractions could be extracted and examined by NMR spectroscopy. IR analysis of the insoluble fractions confirmed formation of polymers with the formamidine-containing structures. The synthetic procedures developed here make readily available this new class of aromatic polymers.     

Arylation of adamantanamines: V. Palladium-catalyzed amination of isomeric chloroquinolines with diamines of the adamantane series

Palladium-catalyzed arylation of diamines of the adamantane series with isomeric 2-, 4-, and 6-chloroquinoline was studied, and optimal conditions for the synthesis of the corresponding N,N′-diaryl derivatives were found. N,N-Diarylation products of primary amino groups in the diamines bearing 2-aminoethyl and 4-aminophenyl substituents were readily formed.     

Investigation of kinetics of curing of triglycidyl-p-aminophenol with aromatic diamines by differential scanning calorimetry

The kinetics of curing of triglycidyl-p-aminophenol with four different diamines in stoichiometric amounts were investigated by means of differential scanning calorimetry. The results indicated that the curing reaction follows first-order Arrhenius kinetics with an activation energy in the range 40–70 kJ · mol^–1. The effect of the structure of the curing agent on the curing characteristics is discussed on the basis of the curing characteristics and the kinetic parameters. An epoxy fortifier was observed to lower the curing temperature of an epoxy-amine system when incorporated prior to curing.

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Zusammenfassung Mittels Differential-Scanning-Kalorimetrie wurde die Kinetik der Vernetzung von Triglycidyl-p-aminophenol mit stöchiometrischen Mengen vier verschiedener Amine untersucht. Laut den Ergebnissen verläuft die Vernetzungsreaktion mit einer Arrhenius-Kinetik erster Ordnung, wobei die Aktivierungsenergie im Bereich von 40–70 kJ/mol liegt. Auf Grundlage der Vernetzungscharakteristika und der kinetischen Parameter wird der Einfluss der Struktur des Vernetzungsreagenz auf die Vernetzungskenndaten beschrieben. Mit einem vor der Vernetzung eingebrachten Epoxyfortifyers konnte die Vernetzungstemperatur eines Epoxy-Amin-Systemes heruntergesetzt werden.

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One of the authors (R.D.P.) is grateful to the University Grants Commission, New Delhi, for the award of a Research Associateship under the Special Assistance Programme.     

Arylation of adamantanamines: VI. Palladium-catalyzed arylation of amines and diamines of the adamantane series with 3-bromopyridine

Palladium-catalyzed amination of 3-bromopyridine with amines of the adamantane series in the presence of Pd(dba)₂/L [L = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl or 2-dimethylamino-2′-dicyclohexylphosphinobiphenyl] gave the desired N-(pyridin-3-yl)-substituted amines in 74–97% yields. Diamines of the adamantane series reacted with 2 equiv of 3-bromopyridine in a complicated fashion to produce mono- and triaryl-substituted derivatives as by-products, while the yields of N,N′-diarylation products were 18–56%.     

Calorimetric study of supramolecular structure formation in the course of linear epoxide-amine polycondensation. Epoxy-amine catenate polymers

The formation of linear epoxy-amine polymers has been studied using the calorimetry method. Catenate polymer (olympic gel) is produced in the course of linear polycondensation of aniline with resorcinol diglycidyl ether. A relation was found to exist between the kinetics of the processes and the glassy state transition temperatures for the samples obtained in the reaction. A model of glassy state formation is proposed, In accordance with latter the polymeric glasses are considered to have the dissipative structure resulting from a kinetically controlled phase transition.Deceased April 8, 1991.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 5, pp. 889–895, May, 1993.The authors are grateful to Prof. Z. Rigbi (Izrael) for help and support and to V. A. Rosniatovskii for participation in the discussion of results     

Epoxy-amine composites with ultralow concentrations of single-layer carbon nanotubes

The physical and mechanical properties of composite materials based on epoxy-amine systems—diglycidyl ether of diphenylolpropane-eutectic mixture of aromatic amines (40 wt % m-phenylenediamine-60 wt % 4,4′-diaminodiphenylmethane) and epoxy-diane resin ED-20-eutectic mixture of aromatic diamines with ultralow contents (≤0.1 wt %) of single-layer carbon nanotubes—are studied. It is shown that, for the concentration dependence of the modulus of elasticity during tension, the additivity rule is obeyed only at the lowest concentrations of carbon nanotubes. In this case, the presence of near-surface layers of a matrix with an increased elastic modulus should be considered.     

Syntheses of optically active polymers by condensation polymerization of d-tartaric acid with some diamines

In order to synthesize optically active polymers which have asymmetric carbon atoms in the polymer main chain, polyamides were synthesized at high temperatures by the condensation of the salt prepared from d-tartaric acid with diamines, such as hexamethylenediamine, o-, m-, and p-phenylenediamine. Effects of the solvent, polymerization time, intrinsic viscosity, and pH on the degree of the specific rotation of polyhexamethylene-d-tartaramide, were investigated. From the results of hydrolyses of the polymers, it was found that d-tartaric acid is not racemized during condensation polymerization.     

Cross-reactive conjugated polymers: analyte-specific aggregative response for structurally similar diamines

A single cross-reactive conjugated polymer (poly(thiophene) 1) generates unique spectral patterns in response to structurally similar diamines. Multivariate statistics are used to deconvolute subtle variations in these spectral responses, allowing for identification and quantification of the analytes with >99% accuracy.     

Oligomeric epoxy binders with controllable molecular characteristics: Shrinkage upon curing

Experimental data and generalized dependences of the effect of molecular characteristics of epoxy diane oligomers (EDOs) and mixtures thereof of various compositions on the value of volume shrinkage are presented. It is established that EDOs and mixtures thereof with a low molecular weight (to 400) and the content of the first fraction over 90 vol % have the highest value of shrinkage by the moment of gel formation, which allows one to obtain polymeric composite materials and adhesive joints with a low level of residual stresses and high physicomechanical characteristics.     

Photoresponsive inorganic polymers obtained by metal alkoxides

The polymerization of metal alkoxides was carried out in organic solvents and light responsive polymers were obtained. As starting materials for polymerization, Ti(OBu)₄, Zr(OBu)₄, Nb(OEt)₅, and Ta(OEt)₅ were used. The polymerization yield roughly corresponds to the formation of TiO₂, ZrO₂, NbO₂(OEt), and TaO₂(OEt), respectively. The polymers obtained are paramagnetic and all give similar (dark) ESR spectra. When illuminated by visible light, a new ESR absorption is detected in the vicinity of g = 2.00, or 330–340 mT (for 9.450 GHz) region. The formation and decay rates of this ESR absorption was measured. The decay rate constants obtained from the formation curves were larger than those obtained from the decay curves, indicating relatively short lived species are formed during light illumination. The polymers thus prepared have photocatalytic activity and can photolyze 1 : 1 methanol/water system with visible light. Other possible uses of these polymers as paramagnetic or photochromic materials are discussed.     

Quinone-amine polymers. XII. Synthesis and characterization of novel polymers from 2-phenylbenzoquinone and aliphatic diamines

In order to study the effect of the presence of phenyl groups in poly (amino-quinone) (PAQ) polymers, several novel poly(amino-2-phenylbenzoquinone) (PhPAQ) polymers have been prepared from 2-phenylbenzoquinone and aliphatic diamines, such as 1,6-diaminohexane, 1,8-diaminooctane, 1,12-diaminodod+++++, and 1,4-diaminocyclohexane. Prior to the polymerization, 2-phenylbenzoquinone was generated in situ from 2-phenylhydroquinone in the presence of calcium hypochlorite as the oxidizing agent in dichloromethane. All of the polymers synthesized have been characterized with respect to their corresponding model compounds. It was also found that unlike their analogous PAQ polymers, PhPAQ polymers were highly soluble in many common organic solvents because of the presence of phenyl groups in their polymer backbone. © 1994 John Wiley & Sons, Inc.     

Chemical reactions and reactivity of primary,secondary, and tertiary diamines with acid functionalized polymers

Reactive melt processing of different types of diamines with polyethylene containing carboxylic acid groups and polystyrene containing anhydride groups was carried out. The reactivity of primary, secondary, and tertiary diamines with these acid polymers was determined using various techniques. Molecular weight increases due to crosslinking were observed through (1) changes in the torque during the reactive processing, (2) decrease in melt flow indices, and (3) decrease in solubility of the reaction products. The chemical compositions of the reaction products were examined by Fourier transform infrared (FTIR) spectroscopy. Thermal analysis using differential scanning calorimetry (DSC) was carried out to determine the crystallization behavior, glass transition temperatures, and thermal stabilities of the reaction products. Results show that the primary amine is the most reactive towards carboxylic acid or anhydride groups followed by the secondary and then the tertiary amine. Anhydride groups on polymers are of higher activity towards secondary or primary amino groups than carboxylic acid groups in the nucleophilic acyl substitution reactions. Reaction products crosslinked with the primary diamine are less stable than their parent acidic polymers. On the other hand, crosslinking with the secondary or tertiary diamine gives products with higher thermal stability than the parent acidic polymers. The formation of reversible and irreversible crosslinks with different types of diamines is also reported. © 1992 John Wiley & Sons, Inc.     

A flexible simulation code for microwave curing of polymers

We describe a modular simulation code for microwave curing of polymers. The exposed item geometry can be either 3D or 2D (extruded draw pieces), the item can be multi-component and contain metal insertions as well. The applied microwave field can be either resonant or traveling wave, with or without mode-stirring. The output of the code is in the form of cross-linking degree and temperature maps. Utilities are included to input the problem's geometry and to display the outputs.     

Kinetic analysis of curing of tetraepoxides and diamines in the presence of etherification side reactions

The theory of branching processes is used to describe the polymer network formation resulting from the reaction of tetraepoxides with diamines using various initial compositions. Differences in reactivities of primary and secondary amine groups and the reaction between the epoxide groups and reaction-generated hydroxyl groups are taken into account; however, intramolecular reactions in the pregel stage are neglected. Expressions are derived for the critical epoxide conversion at the gel point, molecular weight in the pregel stage, changes in sol and gel fraction in the post-gel stage, and the concentration of elastically active network chains as a function of reaction conditions. The analysis of the simulation results shows that etherification reactions significantly raise the concentration of elastically active network chains of the mixture under stoichiometric excess of epoxide groups.     

Macroporous polymers obtained in highly concentrated emulsions stabilized solely with magnetic nanoparticles

Magnetic macroporous polymers have been successfully prepared using Pickering high internal phase ratio emulsions (HIPEs) as templates. To stabilize the HIPEs, two types of oleic acid-modified iron oxide nanoparticles (NPs) were used as emulsifiers. The results revealed that partially hydrophobic NPs could stabilize W/O HIPEs with an internal phase above 90%. Depending upon the oleic acid content, the nanoparticles showed either an arrangement at the oil-water interface or a partial dispersion into the oil phase. Such different abilities to migrate to the interface had significant effects on the maximum internal phase fraction achievable and the droplet size distribution of the emulsions. Highly macroporous composite polymers were obtained by polymerization in the external phase of these emulsions. The density, porosity, pore morphology and magnetic properties were characterized as a function of the oleic acid content, concentration of NPs, and internal phase volume of the initial HIPEs. SEM imaging indicated that a close-cell structure was obtained. Furthermore, the composite materials showed superparamagnetic behavior and a relatively high magnetic moment.