Epoxy resin systems

Eor more demanding uses at higher temperatures, for example, in aircraft and aerospace and certain electrical and electronic appHcations, multifunctional epoxy resin systems based on epoxy novolac resins and the tetraglycidyl amine of methylenedianiline are used. The tetraglycidyl amine of methylenedianiline is currently the epoxy resin most often used in advance composites. Tetraglycidyl methylenedianiline [28768-32-3] (TGALDA) cured with diamino diphenyl sulfone [80-08-0] (DDS) was the first system to meet the performance requirements of the aerospace industry and is still used extensively. 

Monofunctional aliphatic glycidyl ethers, eg, based on / -butanol or mixed Cg—alcohols, are used exclusively as reactive diluents to reduce viscosities of epoxy resin systems. Some loss of desirable cured properties results from the lowered functionality of the systems. 

Table 5.56 Typical exposure effects associated with epoxy resin systems ...

Crivello, J.V., Electron beam curable epoxy compositions, US Patent 5,260,349, 1993. Janke, C.J., Dorsey, G.F., Havens, S.J. and Lopata, V.J., A toughened epoxy resin system and a method thereof, US Patent 5,726,216, 1998. 

Amine-epoxy resin systems, 10 443 Amine equivalent weight (AEW), 10 399 Amine ethoxylates, 24 150-151 Amine extractants, 10 791 Amine functional curing agents,... 

ASTM standard procedures, for measuring epoxy resin system properties,... 

Two-component epoxy resin systems, 10 453 2D foam studies, 12 16, 17 2-Dimensional gas chromatography, 4 617-618... 

In recent years acetylene terminated resins (AT-resins) have shown promise in the area of high temperature applications and are possible replacements for state-of-the-art epoxy resin systems where humidity exposure is expected. Acetylene terminated resins have two important advantages over previously developed systems ... 

C 882 Test Method for Bond Strength of Epoxy-Resin Systems Used With Concrete C 884 Test Method for Thermal Compatability Between Concrete and an Epoxy-Resin Overlay... 

Uses. Reactive diluent in epoxy resin systems stabilizer of chlorinated compounds manufacture of rubber... 

Toxicology. The toxicity of epoxy resin systems results from the toxicity of the various components, each of which must be considered. 

Fawcett IW, Taylor AJN, Pepys J Asthma due to inhaled chemical agents—Epoxy resin systems containing phthalic acid anhydride, trimellitic acid anhydride and triethylene tetramine. Clin Allergy 7 1-14, 1977... 

Glycidol is an epoxide used as a chemical intermediate in the production of functional epoxides, glycidyl urethanes, pharmaceuticals and other products. It is also used as a reactive diluent in epoxy resin systems and as a sterilant. Occupational exposure may occur during its production and use. No data were available on environmental exposure to glycidol. 

Figure 6.5 Equilibrium void stability map for a typical epoxy resin system. Curves indicate stable void equilibrium states for liquid-resin pressures indicated. Growth takes place above the lines and dissolution occurs below the lines for any given resin pressure...

Reactivity of Amine Accelerators with Anhydride-Epoxy Resin Systems ... 

An alternative is a cationically initiated epoxy resin system cured by electron beam. The experiments with this process showed the following advantages ... 

Determination Of MBOCA in Human Urine. MBOCA is commercially important as a curing agent for polyurethanes and epoxy resin systems. Since MBOCA was found to be carcinogenic in animals and is a suspected human carcinogen, it is important to have a reliable method available for the determination of MBOCA in the urine of those workers who are potentially exposed to this compound. In a NIOSH publication a GC method was described for the determination of MBOCA in urine. However, since HPLC does not require derivatization and a lower detection limit was expected, the GC method was modified to be performed by HPLC/ . In order to be able to compare both methods, we used the same extraction procedure. The extraction and sample preparation procedures are as follows ... 

A modified BMI-epoxy resin system has been introduced by Shell Chemical Company. The system is a highly reactive blend of a bismaleimide, COM-PIMIDE 1206 (55-60% by weight solution of BMI in DMF), and EPON Resin 1151, a polyfunctional epoxy resin (60). In contrast to many polyimide resins on the market, no free MDA is present in the product. This is an important feature, since MDA has been identified as an animal carcinogen and possibly a human carcinogen. This resin system has been fully evaluated for use in multilayer PCB boards (61). 2-Methylimidazole is recommended as a catalyst. However, if required, the processing window can be widened by using 2-phenylimidazole... 

It is clear that other components quite different chemically from the main constituents of the epoxy resin system may be present in the starting material. The structure of the cured epoxy may or may not incorporate these components. To the extent that these other species are not part of the crosslinked epoxy network, they can be concentrated at the interphase or they may be able to migrate to the interphase during the curing process. 

A very wide range of curing times and temperatures exists for epoxy resin systems. Therefore, they offer a great deal of design flexibility for use both as structural bonding adhesives and protective surface coatings. 

Although FT-IR allows one to obtain quality spectra of epoxy resin systems, the interpretation aspect of the spectra has not changed. It is still necessary to have some insight into the structural origin of the numerous infrared bands in order to use them... 

Oxidation studies have been made for cured epoxy resins and the relative stability of the functional groups was established by following the changes in the absorbance ratios of bands associated with the particular functional group 231>. Hence the most unstable groups can be determined easily and their reactions separated from the more stable units. The irreversible 232) and reversible 2331 effects of moisture on epoxy resin systems have also been studied by FT-IR using the difference spectrum method 234). (Fig. 20) shows the interaction spectra obtained after three cycles of water sorption and redrying. The reversible nature of the interactions are clearly demonstrated. 

Figure 12.9 Compressive yield stress versus Tg for various epoxy resin systems. (Reprinted from Burton and Bertram, 1996 by courtesy of Marcel Dekker Inc.)... 

R. Kotsilkova, D. Fragiadakis, and P. Pissis, Reinforcement effect of carbon nanofillers in an epoxy resin system rheology, molecular dynamics, and mechanical studies, J. Polym. Sci. B 43, 522-533 (2005). 

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