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Thermosetting plastic
 
 
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Thermosetting plastics (thermosets) are polymer
Polymer

A polymer is a large molecule composed of repeating structural units typically connected by covalent chemical bonds. While polymer in popular usage suggests plastic, the term actually refers to a large class of natural and synthetic materials with a variety of properties....
 materials that irreversibly cure
Curing (chemistry)

Curing is a term in polymer chemistry and process engineering that refers to the toughening or hardening of a polymer material by cross-linking of polymer chains, brought about by chemical additives, ultraviolet radiation, electron beam or heat....
 form. The cure may be done through heat (generally above 200 degrees Celsius
Celsius

Celsius is a temperature scale that is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death....
), through a chemical reaction (two-part epoxy
Epoxy

In chemistry, epoxy or polyepoxide is a thermosetting epoxide polymer that cures when mixed with a catalyst agent or hardener. Most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A....
, for example), or irradiation
Irradiation

Irradiation is the process by which an item is exposed to radiation. The exposure can be intentional, sometimes to serve a specific purpose, or it can be accidental....
 such as electron beam processing
Electron beam processing

Electron beam processing involves irradiation of products using a high-energy electron beam accelerator. Electron beam accelerators utilize an on-off technology, with a common design being similar to that of a cathode ray television....
.

Thermoset materials are usually liquid or malleable prior to curing and designed to be molded
Molding (process)

Molding or moulding is the process of manufacturing by shaping pliable raw material using a rigid frame or model called a pattern....
 into their final form, or used as adhesive
Adhesive

Adhesive or glue is a compound in a liquid or semi-liquid state that adhesion or bonds items together. Adhesives may come from either natural or Chemical synthesis sources....
s. Others are solids like that of the molding compound used in semiconductors and integrated circuits (IC's).

curing process transforms the resin into a plastic
Plastic

Plastic is the general common term for a wide range of synthetic or semisynthetic organic chemistry solid materials suitable for the manufacture of industrial products....
 or rubber
Rubber

Natural rubber is an elastomer?an Elasticity_ hydrocarbon polymer?that was originally derived from a milky colloidal suspension, or latex , found in the sap of some plants....
 by a cross-link
Cross-link

Cross-links are bonds that link one polymer chain to another. They can be covalent bonds or ionic bonds. "Polymer chains" can refer to synthetic polymers or natural polymers ....
ing process.






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Encyclopedia


Thermosetting plastics (thermosets) are polymer
Polymer

A polymer is a large molecule composed of repeating structural units typically connected by covalent chemical bonds. While polymer in popular usage suggests plastic, the term actually refers to a large class of natural and synthetic materials with a variety of properties....
 materials that irreversibly cure
Curing (chemistry)

Curing is a term in polymer chemistry and process engineering that refers to the toughening or hardening of a polymer material by cross-linking of polymer chains, brought about by chemical additives, ultraviolet radiation, electron beam or heat....
 form. The cure may be done through heat (generally above 200 degrees Celsius
Celsius

Celsius is a temperature scale that is named after the Swedish astronomer Anders Celsius , who developed a similar temperature scale two years before his death....
), through a chemical reaction (two-part epoxy
Epoxy

In chemistry, epoxy or polyepoxide is a thermosetting epoxide polymer that cures when mixed with a catalyst agent or hardener. Most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A....
, for example), or irradiation
Irradiation

Irradiation is the process by which an item is exposed to radiation. The exposure can be intentional, sometimes to serve a specific purpose, or it can be accidental....
 such as electron beam processing
Electron beam processing

Electron beam processing involves irradiation of products using a high-energy electron beam accelerator. Electron beam accelerators utilize an on-off technology, with a common design being similar to that of a cathode ray television....
.

Thermoset materials are usually liquid or malleable prior to curing and designed to be molded
Molding (process)

Molding or moulding is the process of manufacturing by shaping pliable raw material using a rigid frame or model called a pattern....
 into their final form, or used as adhesive
Adhesive

Adhesive or glue is a compound in a liquid or semi-liquid state that adhesion or bonds items together. Adhesives may come from either natural or Chemical synthesis sources....
s. Others are solids like that of the molding compound used in semiconductors and integrated circuits (IC's).

Process

The curing process transforms the resin into a plastic
Plastic

Plastic is the general common term for a wide range of synthetic or semisynthetic organic chemistry solid materials suitable for the manufacture of industrial products....
 or rubber
Rubber

Natural rubber is an elastomer?an Elasticity_ hydrocarbon polymer?that was originally derived from a milky colloidal suspension, or latex , found in the sap of some plants....
 by a cross-link
Cross-link

Cross-links are bonds that link one polymer chain to another. They can be covalent bonds or ionic bonds. "Polymer chains" can refer to synthetic polymers or natural polymers ....
ing process. Energy and/or catalysts are added that cause the molecular chains to react at chemically active sites (unsaturated or epoxy sites, for example), linking into a rigid, 3-D
Dimension

In mathematics, the dimension of a space is roughly defined as the minimum number of coordinates needed to specify every point within it. For example: a point on the unit circle in the plane can be specified by two Cartesian coordinates but one can make do with a single coordinate , so the circle is 1-dimensional even though it exists in...
 structure. The cross-link
Cross-link

Cross-links are bonds that link one polymer chain to another. They can be covalent bonds or ionic bonds. "Polymer chains" can refer to synthetic polymers or natural polymers ....
ing process forms a molecule with a larger molecular weight, resulting in a material with a higher melt
Melt

Melt can refer to:*Melting, in physics, the process of heating a solid substance to a liquid*Melt , a term referring to the working material during steelmaking or thermoplastic forming...
ing point. During the reaction, the molecular weight has increased to a point so that the melting point is higher than the surrounding ambient temperature, the material forms into a solid material.

Uncontrolled reheating of the material results in reaching the decomposition temperature before the melting point is obtained. Therefore, a thermoset material cannot be melt
Melt

Melt can refer to:*Melting, in physics, the process of heating a solid substance to a liquid*Melt , a term referring to the working material during steelmaking or thermoplastic forming...
ed and re-shaped after it is cured. This implies that thermosets cannot be recycled, except as filler material.

Statistics

Thermoset materials are generally stronger than thermoplastic
Thermoplastic

A thermoplastic is a polymer that turns to a liquid when heated and freezes to a very glassy state when cooled sufficiently. Most thermoplastics are high-molecular mass polymers whose Chain s associate through weak Van der Waals forces ; stronger dipole interactions and hydrogen bonding ; or even stacking of aromatic rings ....
 materials due to this 3-D network of bonds, and are also better suited to high-temperature
Temperature

In physics, temperature is a physical property of a Physical system that underlies the common notions of hot and cold; something that feels hotter generally has the greater temperature....
 applications up to the decomposition temperature of the material.

Examples

Some examples of thermosets are:

  • Polyester fiberglass systems: (SMC Sheet molding compounds and BMC Bulk molding compounds)
  • Vulcanized rubber
    Vulcanization

    Vulcanization refers to a specific curing process of rubber involving high heat and the addition of sulfur or other equivalent curatives. It is a chemical process in which polymer molecules are linked to other polymer molecules by atomic bridges composed of sulfur atoms or carbon to carbon bonds....
  • Bakelite
    Bakelite

    Bakelite is a material based on the thermosetting plastic phenol formaldehyde resin polyoxybenzylmethylenglycolanhydride, developed in 1907?1909 by Demographics of Belgium Dr....
    , a phenol-formaldehyde resin (used in electrical insulators and plasticware)
  • Duroplast
    Duroplast

    Duroplast is a composite thermosetting plastic, a close relative of Formica and bakelite. It is a resin plastic reinforced with fibers making it a fiber-reinforced plastic similar to glass-reinforced plastic....
    , similar to Bakelite
  • Urea-formaldehyde
    Urea-formaldehyde

    Urea-formaldehyde, also known as urea-methanal, named so for its common synthesis pathway and overall structure, is a transparency thermosetting resin or plastic, made from urea and formaldehyde heated in the presence of a mild base such as ammonia or pyridine....
     foam (used in plywood
    Plywood

    Sorry, no overview for this topic
    , particleboard and medium-density fibreboard)
  • Melamine resin
    Melamine resin

    Melamine resin or melamine formaldehyde is a hard, thermosetting plastic material made from melamine and formaldehyde by polymerization....
     (used on worktop surfaces)
  • Epoxy resin
    Epoxy

    In chemistry, epoxy or polyepoxide is a thermosetting epoxide polymer that cures when mixed with a catalyst agent or hardener. Most common epoxy resins are produced from a reaction between epichlorohydrin and bisphenol-A....
     (used as an adhesive and in fibre reinforced plastics such as glass reinforced plastic and graphite-reinforced plastic)
  • Polyimides (used in printed circuit boards and in body parts of modern airplanes)
  • Mold or Mold Runners (the black plastic part in Integrated Circuits (IC) or semiconductors)


Some methods of molding thermosets are:

  • Reactive injection molding (used for objects like milk bottle crates)
  • Extrusion molding (used for making pipes, threads of fabric and insulation for electrical cables)
  • Compression molding
    Compression molding

    Compression molding is a method of molding in which the molding material, generally preheated, is first placed in an open, heated mold cavity. The mold is closed with a top force or plug member, pressure is applied to force the material into contact with all mold areas, while heat and pressure are maintained until the molding material has cur...
     (used to shape most thermosetting plastics)
  • Spin casting
    Spin casting

    Spin casting, also known as centrifugal rubber mold casting , is a method of utilizing centrifugal force to produce castings from a rubber mold....
     (used for producing fishing lures
    Fishing lure

    In terms of recreational fishing, a lure is an object attached to the end of the fishing line and designed to resemble and move like an item of fish prey....
     and jigs
    Jig (fishing)

    Jigging, not to be confused with gigging, is the practice of fishing with a jig.A jig is a type of fishing lure consisting of a lead sinker with a hook molded into it and usually covered by a soft body to attract fish....
    , gaming miniatures, figurines
    Figurines

    Figurines is an indie rock band from Denmark, formed in the mid-1990s. The band released their first EP, The Detour, in 2001 and their first full-length album, Shake a Mountain, in 2003....
    , emblems as well as production and replacement parts)


See also

  • Vulcanization
    Vulcanization

    Vulcanization refers to a specific curing process of rubber involving high heat and the addition of sulfur or other equivalent curatives. It is a chemical process in which polymer molecules are linked to other polymer molecules by atomic bridges composed of sulfur atoms or carbon to carbon bonds....
  • Fusion bonded epoxy coating
    Fusion bonded epoxy coating

    Fusion bonded epoxy coating, also known as fusion-bond epoxy powder coating and commonly referred to as FBE coating, is an epoxy based powder coating that is widely used to protect steel pipe used in pipeline construction, concrete reinforcing bars and on a wide variety of piping connections, valves etc....