Oligomer epoxy resin

GPC is used for polymer profiling, i.e., when MWD is not required - examples are production quality control, checking lot-to-lot variations, and analysis of competitors products. The technique has been applied to numerous polymers and resins, and to oligomers, e.g., tetrahydrofuran (THF) solutions of a mixture of PS oligomers, epoxy resins, or mixed dimethyl formamide tetrahydrofuran solutions of styrene butadiene latex. 

As a rule, silanes are introduced 10 parts by weight of epoxy resin. At room temperature, polysulfide oligomer-epoxy resin mixtures solidify slowly this fact demands addition of activating agents. In this case, activating agents of the aminic type (ethylenediamine, dimethylurea, urotropine, polyalkylenepolyamine, amino-phenols, and phenols) are applied (871. 

Curing of polysulfide oligomer-epoxy resin mixtures with MnOj implies partial binding by chemical links of the resin. 

The nonbonded part can be chemically extracted with organic solvents. The viscosity of polysulfide oligomer-epoxy resin mixtures are modified during preservation. This phenomenon results from the interaction of —OH groups with the epoxy resins. 

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... 

Step-growth polymerization. Epoxy resins were prepared from nadlc methyl anhydride and Epon 828. This blfunctlonal oxirane also supplies reactive hydrogen sites. The major component is at 1=0, minor components include oligomers with 1=1,2,3. Their concentrations rapidly diminish as degree of polymerization Increases. 

Uncured resins are oligomers of relatively low molecular weight that may be a liquid or a solid. Before epoxy resins can become useful products, they must be cured, with the addition of a curing agent. Curing involves the cross-linkage by polymerization of the reactive epoxy groups into a three-dimensional matrix. 

Reactive prepolymers used as binders are produced by acrylation of oligomers, such as epoxy resins, urethanes, polyesters, silicones, oligo-buta-diene, melamine derivatives, cellulose, and starches. Prepolymers are the principal ingredients of coating formulations and largely determine the basic properties of the coating. Examples of industrially important acrylated prepolymers are in Table 5.9. 

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