Epoxy resin oligomers

Micro packed fused-silica columns showed high resolution by resolving a lot of components of complex mixtures. Solutes with wide poleurity were sepeirated on high-resolution micro packed fused-silica columns with the help of gradient elution. Chemically bonded open-tubular capillary columns with 31 ym i.d. could resolve epoxy resin oligomers although their performance was somewhat poorer than that of packed columns. 

Contact sensitizers from a patient s own materials, such as formaldehyde, isothiazolinones, nickel, chromium, cobalt, colophony (in the form of resin acids), epoxy resin oligomers, reactive diluents, acrylates, methacrylates, polyamines and di-isocyanates, can be analyzed. In fact, any product can be analyzed, but it is not a routine task for laboratories and may be very expensive. There are two main reasons for chemical analyses. First, on patch testing, the patient is found to be allergic to a specific chemical, and the causative product(s) are analyzed for the chemical. Second, the patient s own material has caused an allergic test reaction, but MSDS or other information from the manufacturer did not reveal the causative chemical. In this case, it may be reasonable to analyze the material... 

TetrabromobisphenolA. TBBPA is the largest volume reactive flame retardant. Its primary use is in epoxy resins (see Epoxyresins) where it is reacted with the bis-glycidyl ether of bisphenol A to produce an epoxy resin having 20—25% bromine. This brominated resin is typically sold as a 80% solution in a solvent. TBBPA is also used in the production of epoxy oligomers which are used as additive flame retardants. 

A second type of uv curing chemistry is used, employing cationic curing as opposed to free-radical polymerization. This technology uses vinyl ethers and epoxy resins for the oligomers, reactive resins, and monomers. The initiators form Lewis acids upon absorption of the uv energy and the acid causes cationic polymerization. Although this chemistry has improved adhesion and flexibility and offers lower viscosity compared to the typical acrylate system, the cationic chemistry is very sensitive to humidity conditions and amine contamination. Both chemistries are used commercially. 

In the narrow sense, bis-maleimide resin means the thermosetting resin eom-posed of the bis-maleimide of methylene dianiline (BMI, bis(4-maleimidophenyl)-methane) and methylene dianiline (MDA, bis(4-aminophenyl)methane) (Fig. 1). Beeause of the addition meehanism, the resin is eured without elimination, whieh is a eharacteristic of this resin. Bis-maleimide resin is used as a thermally stable matrix up to 204°C (400 F) whieh typical epoxy resins may not normally be used. However, in spite of having an imide structure, bis-maleimides are classified as being moderately thermally stable resins. The aliphatic structure of the resin is not stable for long periods above 232°C (450°F.) If a highly aromatic thermally stable thermosetting resin is necessary, acetylene end-capped aromatic imide-based oligomers should be used. 

Of the commercially available EB-curable adhesives [9-12], the resins fall within one of two categories based on their curing mechanisms. The majority of EB-curable resins are based on (meth)acrylate-functionalized oligomers involving a free-radical curing mechanism. The second category is the epoxy resins that cure by a cationic mechanism. 

Unsaturated acrylic oligomers are made from unsaturated acrylic monomers. For example, an epoxy acrylate may be made by reaction of acrylic acid with epoxy resin. 

After these preliminary studies, McGrath and co-workers have used ethylpiperazine terminated siloxane oligomers with varying molecular weights and backbone compositions throughout their studies 69 114,11S). Modifications of epoxy resins with siloxane oligomers were performed in two steps as depicted in Reaction Scheme XXIII. 

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. 

This rationale is evident also in other bromine-containing oligomers, for example those based on brominated epoxy resins (20) and on poly-pentabromobenzyl acrylates (21). 

Oligomers and Resins. Oligomers and resins used were Ebecryl 3700 epoxy acrylate, Radcure Specialties, Inc., Smyrna, GA 30080 Unicarb, which is 73% UVR 6128 (a cycloaliphatic epoxy), 26.5% polyol and 0.5% Silwet L-7602 (See under miscellaneous compounds), Union Carbide Chemicals and Plastics Co., Inc., Danbury, CT 06817-0001 and Heloxy 505 Modifier, Shell Chemical Co., Houston, TX 77210. 

The study relates to new classes of thermosetting oligomers based on N-cyanourea-terminated resins, which are useful as a monomer, a thermosetting resin, and a cross-linking agent for epoxy resins. 

Reactive oligomers such as epoxy resins, isocyanate-terminated compounds, and urethane-acrylates are extremely useful in the adhesive, coating, reaction injection molding (RIM), sealant and... 

Adhesive applications, thermosetting epoxy resin based on N-cyanourea-terminated oligomer, 107... 

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