Epoxy resins structure

Superior toughness and mechanical properties The strength of properly formulated epoxy resins usually surpasses other types of casting resins. The cured epoxy resins [Structure (4.35)] are seven times tougher than the cured phenolic resins [Structure (4.36)] as is evident from Figure 4.15. The relative toughness is attributed to the distance between the crosslinking sites and presence of internal aliphatic chains. 

Epoxy Resins The term epoxy refers to an epoxide group which is a three-membered oxide ring. An epoxy resin is defined as a molecule containing more than one epoxy group capable of being converted into a thermoset (cured) form. The simple structure of epoxy resin [Structure (4.37)] is ... 

Since, in general, factors which influence the adhesion of metal/epoxy resin structural joints also influence adhesion in metal/epoxy resin protective coating systems, these two separate cases will often be combined and referred to simply as metal/epoxy adhesion systems. 

FIGURE 2.8 Several common cycloapliphatic epoxy resin structures.10... 

The type of epoxy group and its location within the molecule influence reactivity. Some epoxy resin structures prefer to react with acid curing agents, and others with basic curing agents. Certain epoxy structures are extremely reactive with specific catalysts, and others are virtually inactive. Several types of epoxy resins are reactive with almost all classes of curing agents. 

From the limited fracture data available for similarly cured networks generated from these various resin types, little can be concluded as to the role of the resin in fracture. Certainly, the resin backbone contributes to the Tg of the network, and comparisons should take this into account because, as previously discussed, the initiation of crack growth is very sensitive to temperature. If the epoxy resin structure results in complicated network forming reactions, as is possible for TGDM/DDS networks, the structure of the final network will be affected and may likely influence fracture. 

C HOCH,. Appears as the terminal group of epoxy resin structures resulting from reaction of epichlo-... 

Cycioaliphatic epoxy resin Figure 3.1 Main epoxy resin structures. 

Newer adhesives of the acrylic, anaerobic or radiation-curable types must, if they are structural, have a relatively high degree of toughness and durability if they are to compete with or challenge epoxy adhesive systems. Likewise, newer radiation-curable, pressure-sensitive adhesive systems must exhibit the properties of permanence largely associated with cross-linked adhesive masses deposited from an acrylic solution polymer base. Epoxy resin structural adhesives largely define the existing area on the one hand the cross-linked acrylics deposited on plastic or metallic films the other. 

Epoxy resins Structural components, boat hulls, chemical engineering plant, pressure vessels, aerospace structural components, helicopter blades and racing cars [74]... 

Relationship Between Cured Epoxy Resin Structure and Properties. 

Common operations in which exposure to MDA is likely to occur include the following Manufacture of MDA Manufacture of Methylene diisocyanate Curing agent for epoxy resin structures Wire coating operations and filament winding. 

Materials that can be used as main components of thermosetting adhesives are urea resin, melamine resin, phenolic resin, resorcinol resin, epoxy resin, structural acrylic resin, polyester, polyurethane, polyimide, polybenzimidazole, etc. 

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