Epoxy

From Wikipedia, the free encyclopedia

Epoxy or polyepoxide is a thermosetting polymer formed from reaction of an epoxide "resin" with polyamine "hardener". Epoxy has a wide range of applications, including fiber-reinforced plastic materials and general purpose adhesives.

History

The first commercial attempts to prepare resins from epichlorohydrin were made in 1927 in the United States. Credit for the first synthesis of bisphenol-A-based epoxy resins is shared by Dr. Pierre Castan of Switzerland and Dr. S.O. Greenlee of the United States in 1936. Dr. Castan's work was licensed by Ciba, Ltd. of Switzerland, which went on to become one of the three major epoxy resin producers worldwide. Ciba's epoxy business was spun off and later sold in the late 1990s and is now the advanced materials business unit of Huntsman Corporation of the United States. Dr. Greenlee's work was for the firm of Devoe-Reynolds of the United States. Devoe-Reynolds, which was active in the early days of the epoxy resin industry, was sold to Shell Chemical (now Hexion, formerly Resolution Polymers and others).

Applications

The applications for epoxy-based materials are extensive and include coatings, adhesives and composite materials such as those using carbon fiber and fiberglass reinforcements (although polyester, vinyl ester, and other thermosetting resins are also used for glass-reinforced plastic). The chemistry of epoxies and the range of commercially available variations allows cure polymers to be produced with a very broad range of properties. In general, epoxies are known for their excellent adhesion, chemical and heat resistance, good-to-excellent mechanical properties and very good electrical insulating properties. Many properties of epoxies can be modified (for example silver-filled epoxies with good electrical conductivity are available, although epoxies are typically electrically insulating). Variations offering high thermal insulation, or thermal conductivity combined with high electrical resistance for electronics applications, are available.

Did you know?

Vinegar is an effective and safe solvent to clean up tools, brushes, skin, and most surfaces contaminated with epoxy resin or hardener. Acetone can also be used, but it is very volatile and flammable, unlike vinegar. Vinegar is safer for cleaning epoxy resin from human skin than acetone: both liquids will dissolve the resin, but the resin/acetone solution can easily pass through the skin into the bloodstream, unlike vinegar. White vinegar can even clean up epoxy resin that is beginning to cure/harden. One should always avoid getting epoxy on skin. Citrus-based waterless hand cleaners will help to remove fresh resin from the skin. Vinegar and rubbing alcohol can also be effective in removing fresh uncured epoxy from skin. One should then follow with washing with soap and water. DME (Dimethoxyethane) is also a good solvent for epoxy resin and hardener that gives off very little vapor.