Ads
related to: how do epoxy bond different
Search results
Results From The WOW.Com Content Network
Epoxy is the family of basic components or cured end products of epoxy resins. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. The epoxide functional group is also collectively called epoxy. [1] The IUPAC name for an epoxide group is an oxirane.
It is a precursor in the production of epoxy resins. [19] Halohydrins react with base to give epoxides. [20] The reaction is spontaneous because the energetic cost of introducing the ring strain (13 kcal/mol) is offset by the larger bond enthalpy of the newly introduced C-O bond (when compared to that of the cleaved C-halogen bond).
Epoxy resins can be categorized into three distinct types based on the chemical structure of their resin backbone: aliphatic, cycloaliphatic, and aromatic epoxy resins. [4] An increase in the molecular length between reactive epoxy groups results in a reduction of crosslink density and resin modulus, while simultaneously enhancing the failure ...
The second most important part of FBE coatings is the curing agent or hardener. Curing agents react either with the epoxy ring or with the hydroxyl groups, along the epoxy molecular chain. Various types of curing agents, used in FBE manufacture, include dicyandiamide, aromatic amines, aliphatic diamines and organic acid anhydrides. [6]
An epoxy may be used for mounting, but can lead to failure in the epoxy/polymer interface instead of in the bonded joint. [2] The most common method for testing solvent bonds is the tensile shear test using a lap joint configuration. Specimens are tested in shear to failure at a given overlap cross section via tensile loading.
After evaporation of the solvent, a solid compound is formed. Chemical bonds are also important in certain adhesive / substrate combinations, for example when bonding glass using silicone adhesives, wood using polyurethane adhesives and aluminium using epoxy adhesives. Chemical bonding leads to significantly higher adhesion than physical bonding.