The epoxide group is also sometimes referred to as a oxirane group.īisphenol-based Synthesis of bisphenol A diglycidyl ether The other production route for epoxy resins is the conversion of aliphatic or cycloaliphatic alkenes with peracids: In contrast to glycidyl-based epoxy resins, this production of such epoxy monomers does not require an acidic hydrogen atom but an aliphatic double bond. Synthesis of an epoxide by use of a peracid Instead of a hydroxy group, also the nitrogen atom of an amine or amide can be reacted with epichlorohydrin. Dicarboxylic acids such as hexahydrophthalic acid are used for diglycide ester resins. Polyols can be compounds such as 1,4-butanediol. Phenols can be compounds such as bisphenol A and novolak. The hydroxy group may be derived from aliphatic diols, polyols (polyether polyols), phenolic compounds or dicarboxylic acids. Epoxy resins produced from such epoxy monomers are called glycidyl-based epoxy resins. First a hydroxy group reacts in a coupling reaction with epichlorohydrin, followed by dehydrohalogenation. Most of the commercially used epoxy monomers are produced by the reaction of a compound with acidic hydroxy groups and epichlorohydrin. Chemistry Coupling reaction of a hydroxy group with epichlorohydrin, followed by dehydrohalogenation Devoe & Raynolds, which was active in the early days of the epoxy resin industry, was sold to Shell Chemical the division involved in this work was eventually sold, and via a series of other corporate transactions is now part of Hexion Inc. In 1946, Sylvan Greenlee, working for the Devoe & Raynolds Company, patented resin derived from bisphenol-A and epichlorohydrin. Ciba's epoxy business was spun off as Vantico in the late 1990s, which was subsequently sold in 2003 and became the Advanced Materials business unit of Huntsman Corporation of the United States. of Switzerland, which went on to become one of the three major epoxy resin producers worldwide. Claims of discovery of bisphenol-A-based epoxy resins include Pierre Castan in 1943. History Ĭondensation of epoxides and amines was first reported and patented by Paul Schlack of Germany in 1934. The health risks associated with exposure to epoxy resin compounds include contact dermatitis and allergic reactions, as well as respiratory problems from breathing vapor and sanding dust, especially when not fully cured. for chips on board ), LEDs, high-tension electrical insulators, paint brush manufacturing, fiber-reinforced plastic materials, and adhesives for structural and other purposes. Epoxy has a wide range of applications, including metal coatings, composites, use in electronics, electrical components (e.g. Reaction of polyepoxides with themselves or with polyfunctional hardeners forms a thermosetting polymer, often with favorable mechanical properties and high thermal and chemical resistance. These co-reactants are often referred to as hardeners or curatives, and the cross-linking reaction is commonly referred to as curing. The IUPAC name for an epoxide group is an oxirane.Įpoxy resins may be reacted ( cross-linked) either with themselves through catalytic homopolymerisation, or with a wide range of co-reactants including polyfunctional amines, acids (and acid anhydrides), phenols, alcohols and thiols (sometimes called mercaptans). The epoxide functional group is also collectively called epoxy. Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. A syringe of "5-minute" epoxy glue, containing separate compartments for the epoxy resin and the hardener Structure of the epoxide group, a reactive functional group present in all epoxy resinsĮpoxy is the family of basic components or cured end products of epoxy resins. This article is about the thermoset plastic materials.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |