DGEBA A

Table IV. Electrical, Chemical and Physical Properties of Ethylenetriamine-Cured DGEBA (A) and DGEBA - Phthalic Anhydride (B) (DGEBA Epoxide Equivalent of 200)...

In order to obtain a phase diagram in conversion-composition coordinates, a particular system consisting of a diepoxide based on diglycidylether of bis-phenol A (DGEBA), a stoichiometric amount of a diamine (4,4 -diamino-3,3 -dimethyldicyclohexyl-methane, 3DCM), as a hardener, and a rubber based on a statistical copolymer of butadiene and acrylonitrile, will be considered [65]. The increase in the number-average molar mass for the polycondensation of a stoichiometric diepoxy-diamine mixture, is given by [65]... 

Fig. 34. Average paitide size as a function of cure temperature for different rubber (ETBN) modified epoxies fbased on DGEBA) a) and b) differ in the nature of the rubber while c) corresponds to a different diamine (Reprinted from Journal of Applied Polymer Science, 42, D. Verchte, J.P. Pascault, H. Sautereau, S.M. Moschiar, C.C. Ric-cardi, R.J.J. Williams, RubiKr-modified epoxies. II. Influence of the cure schedule and rubber concentration on the generated morophology, 701-716, Copyright (1991), with kind permission from John Wiley Sons, Inc., New York, USA)...

DGEBA. See Bisphenol A, diglycidyl ether. Bisphenol A, diglycidyl ether (DGEBA) [1675-54-3]... 

The pure diglycidyl ether of bisphenol A [1675-54-3] DGEBA is a crystalline soHd (mp 43°C) with a weight per epoxide (WPE) = 170. The typical commercial unmodified Hquid resins are viscous Hquids with viscosities of 11—16 Pa-s (110—160 P) at 25°C, and an epoxy equivalent weight of ca 188. 

The diglycidyl ether (DGEBA) and the polyglycidyl compound (PGCBA) were mixed and heated to about 120 °C. The stoichiometric amount of bisphenol A was dissolved in the resin and, after cooling to about 60 °C, 0,1% by weight of 2-ethyl-4-methyl-imidazol was added to the mixture. The well stirred composition was degassed in a vacuum oven in order to remove trapped air. Afterwards, the reactive mixture was poured into preheated moulds and cured for two hours at 140 °C followed by two hours at 180 °C. 

Fig. 4. Moisture uptakes as a function of water partial pressure for DGEBA-TETA net resin. Influence of previous exposure to 60 °C and 95% relative humidity on the apparent sorptivity. Open circles conditioned samples full circles reference samples. (22)...

The diffusional transport model for systems in which sorbed molecules can be divided in two populations, one formed by completely immobilized molecules and the other by molecules free to diffuse, has been developed by Vieth and Sladek 33) in a modified form of the Fick s second law. However, if linear isotherms are experimentally found, as in the case of the DGEBA-TETA system in Fig. 4, the diffusion of the penetrant may be described by the classical diffusion law with constant value of the effective diffusion coefficient,... 

Diglycidyl ether of bisphenol A (DGEBA, MW 340 Da) and 4,4 -dihydroxy-diphenylmethane (DHDPM, MW 200 Da) were analysed by SEC-MALS [784]. DGEBA and DHDPM are the basic oligomers of epoxy resins and phenol-formaldehyde condensates, respectively, which are widely used in the electronic and automotive industries. Excellent reproducibility ( 1 %) and good accuracy (better than 10%) were observed. SEC has also been used for the determination of mineral oil in extended elastomers [785] and in PS [178]. With heptane containing 0.05% isopropanol as the mobile phase, mineral oil is completely unretained and elutes before the solvent via SEC all other components in a PS extract are retained on silica and elute after the solvent peak. 

CBS, CZ (V-Cyclohexyl-2-benzothiazole DGEBA Diglycidyl ether of bisphenol A... 

Shell s Epon 828, a blend of oligomers of diglycidyl ether of bisphenol A (DGEBA, n=0), was used. 

The resin is more than 90% DGEBA with the remaining material predominately at n=1. The curing agent, nadic methyl anhydride (NMA), is manufactured by Allied Chemical. The catalyst was benzyl dimethylamine (BDMA). All materials were stored in a desiccator to minimize moisture pickup. 

Initially, oligomers of DGEBA are present in Epon 828 at a specific, but low ratio. It is also likely that some residual acid is contained within NMA (less than a few percent). Both contribute to... 

Dezincing, lead refining by, 14 754-755 DGEBA-aromatic polyamine adduct system, 10 416, 417. See also Diglycidyl ether of bisphenol A (DGEBA)... 

This paper describes the synthesis and characterization of a new zwitterionic water-soluble thiosulfate polymer (Poly[7-(amino -thiosulfate) etheij-PATE) via chemical reaction of a diglicydyl ether of bisphenol A (DGEBA) with aminoethane thiosulfuric acid (AETSA) as a reactive... 

Yamani and Young (5) applied the theory to explain the plastic deformation of a diglycidyl ether of bisphenol A (DGEBA) epoxy resin cured with various amount of triethylene tetramine (TETA). They found that the theory gave a reasonable description for the resins below the glass transition temperatures T. ... 

Materials Description. Three CIBA-GEIGY epoxy/hardener systems were studied Araldite 6010/906, Araldite 6010/HY 917 and Araldite 6010/972 with stoichiometries 100/80, 100/80 and 100/27, respectively. Araldite 6010 was a DGEBA epoxy resin. The hardeners 906, HY 917 and 972 were, respectively, methyl nadic anhydride (MNA), methyltetrahydro phthalic anhydride (MTPHA) and methylene dianiline (MDA). These systems were investigated previously for the matrix controlled fracture in composites (6-8). The curing cycles used can be found in (6). The ideal chemical structures of the systems are shown in Table I. Neat resins were thoroughly degassed and cast into 1.27 cm thick plates for preparation of test specimens. 

All the systems studied appear to have similar A values, which are however lower than A=0.169 ( 1 = 0.35) according to Equation 5. This difference can be attributed to the real molecular cross-sections different from the circular one assumed in the Argon theory (3). In general, all the systems have molecular parameters (a, z ) similar to the DGEBA/TETA systems studied by Yamani and Young (5) as shown in Table II. 

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