BT-Epoxy belongs to the group of thermoset resins used in printed circuit boards (PCBs). It is a mixture of epoxy resin, a common raw material for PCBs and BT resins. BT stands for Bismaleimide-Triazine resin. This is in turn a mixture of bismaleimide, which is also used as a raw material for PCBs and cyanate ester. Three cyano groups of the cyanate ester are trimerized to a triazine ring structure, hence the T in the name. In presence of a bismaleimide, the double bond of the maleimide group can copolymerize with the cyano groups to heterocyclic 6-membered aromatic ring structures with two nitrogen atoms (pyrimidines). The cure reaction occurs at temperatures up to 250 degrees C, and is catalyzed by strongly basic molecules like Dabco (diazabicyclooctane) and 4-DMAP (4-dimethylaminopyridin). Products with very high glass transition temperatures (Tg)- up to 300 degrees C - and very low dielectric constant can be obtained. These properties make these materials very attractive for use in PCBs, which are often subjected to such conditions.
In polymer chemistry and materials science, resin is a solid or highly viscous substance of plant or synthetic origin that is typically convertible into polymers. Resins are usually mixtures of organic compounds. This article focuses on naturally-occurring resins.
A printed circuit board (PCB) mechanically supports and electrically connects electronic components or electrical components using conductive tracks, pads and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Components are generally soldered onto the PCB to both electrically connect and mechanically fasten them to it.
Cyanate esters are chemical substances in which the hydrogen atom of the phenolic OH group is substituted by a cyanide group. The resulting product with an -OCN group is named a cyanate ester. Cyanate esters based on a bisphenol or novolac derivative are used in the production of resins.
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A composite material is a material made from two or more constituent materials with significantly different physical or chemical properties that, when combined, produce a material with characteristics different from the individual components. The individual components remain separate and distinct within the finished structure, differentiating composites from mixtures and solid solutions.
Epoxy is either any of the basic components or the cured end products of epoxy resins, as well as a colloquial name for the epoxide functional group. 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, phenols, alcohols and thiols. 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 mechanical properties and high thermal and chemical resistance. Epoxy has a wide range of applications, including metal coatings, use in electronics/electrical components/LEDs, high tension electrical insulators, paint brush manufacturing, fiber-reinforced plastic materials and structural adhesives. Epoxy is sometimes used as a glue.
A thermosetting polymer, resin, or plastic, often called a thermoset, is a polymer that is irreversibly hardened by curing from a soft solid or viscous liquid prepolymer or resin. Curing is induced by heat or suitable radiation and may be promoted by high pressure, or mixing with a catalyst. It results in chemical reactions that create extensive cross-linking between polymer chains to produce an infusible and insoluble polymer network.
Phenol formaldehyde resins (PF) or phenolic resins are synthetic polymers obtained by the reaction of phenol or substituted phenol with formaldehyde. Used as the basis for Bakelite, PFs were the first commercial synthetic resins (plastics). They have been widely used for the production of molded products including billiard balls, laboratory countertops, and as coatings and adhesives. They were at one time the primary material used for the production of circuit boards but have been largely replaced with epoxy resins and fiberglass cloth, as with fire-resistant FR-4 circuit board materials.
Polymer degradation is a change in the properties—tensile strength, color, shape, etc.—of a polymer or polymer-based product under the influence of one or more environmental factors such as heat, light or chemicals such as acids, alkalis and some salts. These changes are usually undesirable, such as cracking and chemical disintegration of products or, more rarely, desirable, as in biodegradation, or deliberately lowering the molecular weight of a polymer for recycling. The changes in properties are often termed "aging".
A hermetic seal is any type of sealing that makes a given object airtight. The term originally applied to airtight glass containers, but as technology advanced it applied to a larger category of materials, including rubber and plastics. Hermetic seals are essential to the correct and safe functionality of many electronic and healthcare products. Used technically, it is stated in conjunction with a specific test method and conditions of use.
Vinyl ester resin, or often just vinyl ester, is a resin produced by the esterification of an epoxy resin with acrylic or methacrylic acids. The "vinyl" groups refer to these ester substituents, which are prone to polymerize. The diester product is then dissolved in a reactive solvent, such as styrene, to approximately 35–45 percent content by weight. Polymerization is initiated by free radicals, which are generated by UV-irradiation or peroxides.
Polyester is a category of polymers that contain the ester functional group in their main chain. As a specific material, it most commonly refers to a type called polyethylene terephthalate (PET). Polyesters include naturally occurring chemicals, such as in the cutin of plant cuticles, as well as synthetics such as polybutyrate. Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. The material is used extensively in clothing.
Curing is a chemical process employed in polymer chemistry and process engineering that produces the toughening or hardening of a polymer material by cross-linking of polymer chains. It is strongly associated with the production of thermosetting polymers. Curing can be effected by heat, radiation, electron beams, or chemical additives. Characteristically curing entails an increase in viscosity or hardness.
Epoxy granite, also known as synthetic granite, is a mixture of epoxy and granite commonly used as an alternative material for machine tool bases. Epoxy granite is used instead of cast iron and steel for better vibration damping, longer tool life, and lower assembly cost.
Fiberglass sheet laminating is the process of taking a thin fiberglass sheet and laminating it to another material in order to provide strength and support to that material.
A thermoset polymer matrix is a synthetic polymer reinforcement first developed for structural applications, such as glass-reinforced plastic radar domes on aircraft and graphite-epoxy payload bay doors on the space shuttle. In polymer matrix composites, polymers act as binder or matrix to secure in place incorporated particulates, fibres or other reinforcements.
Bisphenol A diglycidyl ether is an organic compound used as constituent of epoxy resins. The compound is a colorless solid that melts slightly above room temperature.
Hydrocyanation of unsaturated carbonyl compounds is a special case of the Michael reaction which can lead to β-cyanoketones, β-cyano-cyanohydrins, or vinyl cyanohydrins. Fine-tuning reaction conditions allows access to any of these products.
Advanced composite materials (ACMs) are also known as advanced polymer matrix composites. These are generally characterized or determined by unusually high strength fibres with unusually high stiffness, or modulus of elasticity characteristics, compared to other materials, while bound together by weaker matrices. These are termed advanced composite materials (ACM) in comparison to the composite materials commonly in use such as reinforced concrete, or even concrete itself. The high strength fibers are also low density while occupying a large fraction of the volume
Conductive anodic filament, also called CAF, is a metallic filament that forms from an electrochemical migration process and is known to cause printed circuit board (PCB) failures.