User:Bruce L. Burton/sandbox
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The portion below the following line is intended to replace only the introductory paragraph and the first section entitled "Epoxy". Some minor edits have already been made to other portions of the article. -- Bruce Burton
Epoxy (/ə-POCK-see/), a shortened term for "epoxy resin", can refer to either the resinous starting component(s) of an epoxy resin "formulation", or to the polymerized product. The formulation is recipe of the mixture used to create the final material. It may contain not only the reactive components of epoxy resins and cross-linking agents (also called hardeners) but also non-reactive liquids and solids added for improvements in processing, performance, and/or cost reduction. The polymerized product is typically a thermosetting plastic (a network polymer) and results from reaction of starting mixture. This final material may still be referred to as an epoxy, even though the polymerized, plastic material typically retains very few of the epoxide (a.k.a. oxirane) functional groups of the starting resin. This article covers both the starting materials, consisting of a resin, a hardener (also called the crosslinker, crosslinking agent, co-reactant, or catalyst) and the polymerized materials that result from the reaction of the starting materials with one another. Note that the polymerized, plastic material typically retains very few of the epoxide (a.k.a. oxirane) functional groups of the starting resin but is still referred to as epoxy resin.
Epoxy resin systems are widely known for their useful combinations of strength, modulus, solvent resistance, corrosion resistance, and adhesion. As for many plastics, the choice to use an epoxy is often based on a combination of its processing behavior, cost-effectiveness, and the mechanical and thermal properties of the cured (cross-linked) polymer. Epoxy resins are most commonly used in coating formulations, for electrical and electronic applications (see further below), and as the matrix material for composite materials such as fiber-wound pipes, storage tanks, and air-foils.
The history of epoxy resin technology is summarized in a review article[1]. (As a note of caution when using the article by Pham and Marks, the numbering is wrong in most of the reference section.)"
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The history of epoxy resin technology is summarized in a review article[1]. (As a note of caution when using the article by Pham and Marks, the numbering is wrong in most of the reference section.)
Epoxy resins, also known as polyepoxides, are a class of reactive prepolymers and polymers which contain epoxide groups. Epoxy 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 (polyphenols and phenolic resins), thiols (usually called mercaptans), and polyols. These co-reactants are often referred to as hardeners or curatives, and the cross-linking reaction is commonly referred to as curing. Reaction of polyepoxides with themselves or with polyfunctional hardeners forms a thermosetting polymer, often with favorable combinations of mechanical properties and the desired level of thermal and chemical resistance. Epoxy formulations have a wide range of applications, including coatings (for both metal and wood), use in electronics/electrical components/LEDs, high voltage electrical insulators, transformer coil windings, semi-conductor encapsulants, paint brush manufacturing, fiber-reinforced plastic materials and structural adhesives.