Bisphenol A, or BPA, is a chemical commonly used to create polycarbonate plastics and epoxy resins.
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Building the heat shield involved a so-called out of autoclave (OOA) cure process, a high temperature, high pressure method for manufacturing composite materials, such as carbon fiber and epoxy resins.
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Emerald comprises two units, with Kalama Chemical specializing in preservatives and aroma chemicals and CVC Thermoset Specialties supplying products such as liquid polymers, specialty epoxy resins, reactive diluents and curing agents.
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Emerald comprises two units, with Kalama Chemical specialising in preservatives and aroma chemicals and CVC Thermoset Specialties supplying products such as liquid polymers, specialty epoxy resins, reactive diluents and curing agents.
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Sometimes we writers get so excited about the methods that scientists use that we forget that we're probably going to lose the reader if we talk about things like grounding down epoxy resins.
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Solid epoxy resins are generally safer than liquid epoxy resins, and many are classified non-hazardous materials. One particular risk associated with epoxy resins is sensitization. The risk has been shown to be more pronounced in epoxy resins containing low molecular weight epoxy diluents. An assessment of skin sensitisation by the use of epoxy resin in the construction industry, 2003 Exposure to epoxy resins can, over time, induce an allergic reaction.
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The reaction is carried out in the presence of a base such as sodium hydroxide, analogous to the formation of bisphenol A-diglycidyl ether. Also aliphatic glycidyl epoxy resins usually have a low viscosity compared to aromatic epoxy resins. They are therefore added to other epoxy resins as reactive diluents or as adhesion promoters. Epoxy resins made of (long-chain) polyols are also added to improve tensile strength and impact strength.
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The diamine also serves as a cross-linking agent in epoxy resins.
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TMD is used as a component in certain curing agents for epoxy resins.
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Epoxy resins are thermosetting polymers, which are crosslinked using hardeners (curing agents). The most common curing agents for epoxy resins are polyamines, aminoamides, and phenolic compounds.Forrest, M.J.: Coatings and Inks for Food Contact Materials, in RAPRA review reports, vol. 16, no.
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In some cases, blends of dianhydrides and monoanhydrides can improve metering and mixing with liquid epoxy resins.
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However, the commercial use of fluorinated epoxy resins is limited by their high cost and low Tg.
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Hydrogenation of isophthalonitrile affords m-xylylenediamine, a curing agent in epoxy resins and a component of some urethanes.
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In the electronics industry epoxy resins are the primary resin used in overmolding integrated circuits, transistors and hybrid circuits, and making printed circuit boards. The largest volume type of circuit board—an "FR-4 board"—is a sandwich of layers of glass cloth bonded into a composite by an epoxy resin. Epoxy resins are used to bond copper foil to circuit board substrates, and are a component of the solder mask on many circuit boards. Flexible epoxy resins are used for potting transformers and inductors.
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66 (1985). (Article ) Epichlorohydrin, is prepared by the chlorohydrin method. It is a precursor in the production of epoxy resins.
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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 resins Epoxy refers to any of the basic components or 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 (and acid anhydrides), phenols, alcohols and thiols (usually called mercaptans). These co-reactants are often referred to as hardeners or curatives, and the cross-linking reaction is commonly referred to as curing.
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Various epoxy resins usually thinned with a solvent like acetone or methyl ethyl ketone (MEK) can be used to both preserve and seal wood.
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Formerly, it was used as a fuel in some explosives. It is used in the adhesive industry as a curing agent for epoxy resins.
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L. Hammerton, ed. by Rebecca Dolbey: Recent Developments in Epoxy Resins. RAPRA Review Reports, 1996, , S. 8. Cycloaliphatic epoxides are characterised by their aliphatic structure, high oxirane content and the absence of chlorine, which results in low viscosity and (once cured) good weather resistance, low dielectric constants and high Tg. However, aliphatic epoxy resins polymerize very slowly at room temperature, so higher temperatures and suitable accelerators are usually required.
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Halogenated epoxy resins are admixed for special properties, in particular brominated and fluorinated epoxy resins are used. Brominated bisphenol A is used when flame retardant properties are required, such as in some electrical applications (e.g. printed circuit boards). The tetrabrominated bisphenol A (TBBPA, 2,2-bis(3,5-dibromophenyl)propane) or its diglycidyl ether, 2,2-bis[3,5-dibromo-4-(2,3-epoxypropoxy)phenyl]propane, can be added to the epoxy formulation.
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However, unlike epoxy resins, rubber adhesives will stretch when pulled. Nitromors or Polystrippa solvent brands are used as a solvent but warm water can also loosen the bond.
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Zyvex Technologies (formerly Zyvex Performance Materials, ZPM) is a molecular engineering company headquartered in Columbus, Ohio. Zyvex Technologies focuses on developing advanced materials, including prepreg, epoxy resins, and adhesives.
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Metal beverage and food cans all have a thin coating on the inside to prevent corrosion of the metal and potential food contamination. Most can coatings are made from epoxy resins due to the following reasons: Tough, Adhesive, Formable, and Chemically Resistant. These coatings have made it possible for both beverages and food products to maintain both taste and quality, therefore extending their shelf life. Bisphenol A (BPA) is a main component in epoxy resins.
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Coupling reaction of a hydroxy group 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. First a hydroxy group reacts in a coupling reaction with epichlorohydrin, followed by dehydrohalogenation. Epoxy resins produced from such epoxy monomers are called glycidyl-based epoxy resins. The hydroxy group may be derived from aliphatic diols, polyols (polyether polyols), phenolic compounds or dicarboxylic acids.
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Instead of a hydroxy group, also the nitrogen atom of an amine or amide can be reacted with epichlorohydrin. Synthesis of an epoxide by use of a peracid The other production route for epoxy resins is the conversion of aliphatic or cycloaliphatic alkenes with peracids:Wolfgang Kaiser: Kunststoffchemie für Ingenieure. 3. Aufl. Hanser, München 2011, , S. 437 ff. 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.
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Epoxy resins diluents are typically formed by glycidylation of aliphatic alcohols or polyols. The resulting materials may be monofunctional (e.g. dodecanol glycidyl ether), difunctional (butanediol diglycidyl ether), or higher functionality (e.g. trimethylolpropane triglycidyl ether).
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Epoxy use is a main source of occupational asthma among users of plastics.MayoClinic --> Occupational asthma May 23, 2009 Bisphenol A, which is used to manufacture a common class of epoxy resins, is a known endocrine disruptor.
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This parameter is used to calculate the mass of co-reactant (hardener) to use when curing epoxy resins. Epoxies are typically cured with stoichiometric or near-stoichiometric quantities of hardener to achieve the best physical properties.
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3,4-Epoxycyclohexanecarboxylate methyl ester is a cycloaliphatic epoxide, which is added as monovalent monomer to other monomers for the production of crosslinked epoxy resins. 3,4-Epoxycyclohexanecarboxylate methyl ester itself would give a linear polymer when homopolymerized.
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Bisphenol A diglycidyl ether (commonly abbreviated BADGE or DGEBA) is an organic compound used as constituent of epoxy resins. The compound is a colorless solid (commercial samples can appear yellow) that melts slightly above room temperature.
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Major products made by Nippon Kayaku are: epoxy resins, UV-curing type resins, functional films, colors for inkjet printers, catalysts, dyes pharmaceuticals, pharmaceutical API and intermediates, diagnostics, airbag inflators, micro gas generators for seatbelt pretensioners, squibs, agrochemicals.
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Among the causative agents are flours, enzymes used in processing food, latex, isocyanates, welding fumes, epoxy resins, and formaldehyde. Accordingly, prognosis of occupational asthma is contingent on early diagnosis and the adoption of protective measures for rhinitis.
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In Europe, about 323,000 tonnes of epoxy resin were manufactured in 2017 generating some €1,055 million in sales. Germany is the largest market for epoxy resins in Europe, followed by Italy, France, the UK, Spain, the Netherlands and Austria. These commodity epoxy manufacturers mentioned above typically do not sell epoxy resins in a form usable to smaller end users, so there is another group of companies that purchase epoxy raw materials from the major producers and then compounds (blends, modifies, or otherwise customizes) epoxy systems from these raw materials. These companies are known as "formulators".
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Epoxy resins are typically cured by the use of additives, often called hardeners. Polyamines are often used. The amine groups ring-open the epoxide rings. In rubber, the curing is also induced by the addition of a crosslinker.
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Dow and the Bates laboratory have also developed a class of inexpensive block copolymers for toughening certain epoxy resins, which commonly used in microelectronics circuit boards, as well as new excipients for solubilizing otherwise intractable therapeutics for oral drug delivery.
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At a temperature greater than 90 °C, it forms methylene and dimethylene amino bridges. Novolacs have multiple uses as tire tackifier, high temperature resin, binder for carbon bonded refractories, carbon brakes, photoresists and as a curing agent for epoxy resins.
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Compared with LERs (liquid epoxy resins) they have very low viscosities. If, however, they are used in larger proportions as reactive diluents, this often leads to reduced chemical and thermal resistance and to poorer mechanical properties of the cured epoxides. Large scale epoxidized vegetable oils such as epoxidized soy and lens oils are used to a large extent as secondary plasticizers and cost stabilizers for PVC. Aliphatic glycidyl epoxy resins of low molar mass (mono-, bi- or polyfunctional) are formed by the reaction of epichlorohydrin with aliphatic alcohols or polyols (glycidyl ethers are formed) or with aliphatic carboxylic acids (glycidyl esters are formed).
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4-Vinylcyclohexene dioxide (VCD) is an organic compound that contains two epoxide functional groups. It is industrially used as a crosslinking agent for the production of epoxy resins. It is a colourless liquid. It is an intermediate for synthesis of organic compounds.
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MDI is a precursor to many polyurethane foams. Lower quantities are used as hardeners in epoxy resins and adhesives, as well as in the production of high-performance polymers. MDA is hydrogenated to give 4,4-diaminodicyclohexylmethane, which is also used in polymer chemistry.
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Diethylenetriamine is a common curing agent for epoxy resins in epoxy adhesives and other thermosets. It is N-alkylated upon reaction with epoxide groups forming crosslinks. Structure of a triamine-cured epoxy glue. The resin's epoxide groups have all reacted with the hardener.
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It is prepared by O-alkylation of bisphenol A with epichlorohydrin. This reaction mainly affords bisphenol A diglycidyl ether, as well as some oligomer. The degree of polymerization may be as low as 0.1. The epoxide content of such epoxy resins is of interest.
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ISRO has developed various structural and non-structural adhesives. silicon based, polyurethane elastomers and acrylic based adhesives are Non-structural. Epoxy resins, phenol based and rubber based adhesives using chloroprene and neoprene are Structural. These adhesives can be used in automobile and other engineering industries.
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Dimethylbenzylamine is the organic compound with the formula C6H5CH2N(CH3)2. The molecule consists of a benzyl group, C6H5CH2, attached to a dimethylamino functional group. It is a colorless liquid. It is used as a catalyst for the formation of polyurethane foams and epoxy resins.
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Epoxy resins are used as bonding matrix along with glass or carbon fiber fabrics to produce composites with very high strength to weight characteristics, allowing longer and more efficient rotor blades to be produced. In addition, for offshore and onshore wind energy installations, epoxy resins are used as protective coatings on steel towers, base struts and concrete foundations. Aliphatic polyurethane top coats are applied on top to ensure full UV protection, prolong operational lifetimes and lowering maintenance costs. Electric generators, connected via the drivetrain with the rotor blades, convert mechanical wind energy in usable electric energy, and rely on epoxies electrical insulation and high thermal resistance properties.
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The formulation may then be reacted in the same way as pure bisphenol A. Some (non-crosslinked) epoxy resins with very high molar mass are added to engineering thermoplastics, again to achieve flame retardant properties. Fluorinated epoxy resins have been investigated for some high performance applications, such as the fluorinated diglycidether 5-heptafluoropropyl-1,3-bis[2-(2,3-epoxypropoxy)hexafluoro-2-propyl]benzene. As it has a low surface tension, it is added as a wetting agent (surfactant) for contact with glass fibres. Its reactivity to hardeners is comparable to that of bisphenol A. When cured, the epoxy resin leads to a thermosetting plastic with high chemical resistance and low water absorption.
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Other materials may also be used and still be known as currency paper. Higher quality art papers are often made from cotton. It has found extensive use as a printed circuit board substrate when mixed with epoxy resins and classified into CEM 1, CEM 2 etc.
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Pierre Castan (born August 17, 1899 in Bern, † September 12, 1985 in Geneva) was a Swiss chemist, who was one of the pioneers of epoxy resins with Paul Schlack Dr. Piere Castan was promoted to the University of Geneva and was initially a chemist in the dye industry and at the Swiss Federal Institute of Viticulture in Lausanne. From 1936 he developed synthetic resins for dental prosthesis at the De Trey AG brothers in Zurich. At the same time, he developed epoxy resins (From reaction between epichlorohydrin with diphenols), which he applied for in Switzerland in 1938 (granted 1940) (without knowing of Schlack's simultaneous development in Germany). They were suitable as varnish and adhesive.
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The CIECH Group offers high-end chemical products such as: soda ash (the second largest European provider), baking soda, salt, polyester and epoxy resins, agricultural products and glass products, as well as other chemicals. They are used by glass, food and furniture industries, for detergent production, in agriculture and in construction.
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Epoxy resins may be thermally cured with anhydrides to create polymers with significant property retention at elevated temperatures for extended periods of time. Reaction and subsequent crosslinking occur only after opening of the anhydride ring, e.g. by secondary hydroxyl groups in the epoxy resin. Homopolymerization may also occur between epoxide and hydroxyl groups.
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Squeeze flow rheometry allows for evaluation of polymers under wide ranges of temperatures, shear rates, and flow indexes. Parallel plate plastometers provide analysis for high viscosity materials such as rubber and glass, cure times for epoxy resins, and fiber-filled suspension flows.Macosko, C. W., & Larson, R. G. (1994). Rheology: Principles, measurements, and applications.
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Important epoxy resins are produced from combining epichlorohydrin and bisphenol A to give bisphenol A diglycidyl ethers. Structure of bisphenol-A diglycidyl ether epoxy resin: n denotes the number of polymerized subunits and is typically in the range from 0 to 25 Increasing the ratio of bisphenol A to epichlorohydrin during manufacture produces higher molecular weight linear polyethers with glycidyl end groups, which are semi-solid to hard crystalline materials at room temperature depending on the molecular weight achieved. This route of synthesis is known as the "taffy" process. More modern manufacturing methods of higher molecular weight epoxy resins is to start with liquid epoxy resin (LER) and add a calculated amount of bisphenol A and then a catalyst is added and the reaction heated to circa .
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Condensation of epoxides and amines was first reported and patented by Paul Schlack of Germany in 1934.P. Schlack, I. G. Farbenindustrie, German Patent 676 117 (1938), US Patent 2 136 928 (1938). Claims of discovery of bisphenol-A-based epoxy resins include Pierre Castan in 1943. Castan's work was licensed by Ciba, Ltd.
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These resins typically display low viscosity at room temperature (10-200 mPa.s) and are often referred to as reactive diluents. They are rarely used alone, but are rather employed to modify (reduce) the viscosity of other epoxy resins. This has led to the term ‘modified epoxy resin’ to denote those containing viscosity-lowering reactive diluents.
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Synthetic resins are of several classes. Some are manufactured by esterification of organic compounds. Some are thermosetting plastics in which the term "resin" is loosely applied to the reactant or product, or both. "Resin" may be applied to one of two monomers in a copolymer, the other being called a "hardener", as in epoxy resins.
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However, there are also products which are a combination of two types of resin, e.g. epoxy acrylate. For the adhesives and fillers there are also the corresponding accessories such as a wide range of colorants, cartridge (applicator) gun, mixing nozzles etc. Above all, fillers based on polyurethane and epoxy resins are manufactured for the automotive sector.
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Polyphenols, such as bisphenol A or novolacs can react with epoxy resins at elevated temperatures (), normally in the presence of a catalyst. The resulting material has ether linkages and displays higher chemical and oxidation resistance than typically obtained by curing with amines or anhydrides. Since many novolacs are solids, this class of hardeners is often employed for powder coatings.
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Polyester resins are typically low strength unless used with a reinforcing material like glass fibre, are relatively brittle unless reinforced, and have low adhesion. Epoxies, by contrast, are inherently strong, somewhat flexible and have excellent adhesion. However, polyester resins are much cheaper. Epoxy resins typically require a precise mix of two components which form a third chemical.
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3,4-Epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate (ECC) is a cycloaliphatic epoxy resin which is used in many industrial applications. It reacts by cationic polymerization using thermolatent photoinitiators to form crosslinked insoluble thermosets. Formulations based on cycloaliphatic epoxy resins such as ECC are known to form by curing thermosets with high heat and chemical resistance and good adhesion.
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Group 3: Not classifiable as to carcinogenicity to humans , International Agency for Research on Cancer From the 1990s onward, concern has been raised over this possible carcinogenicity because BADGE is also used in epoxy resins in the lining of some tin cans for foodstuffs, and unreacted BADGE may end up in the contents of those cans.
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Many resins are available waterborne but can be hybrids or blends. An example would be polyurethane dispersions blended or hybridized with acrylic resins. Waterborne epoxy resins may be modified with acrylate and then further modified with side chains having many fluorine atoms on them. Waterborne resins are also available that use both water and renewable raw materials.
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Epoxy resins have been in use in U.S. industry for over 40 years. Epoxy compounds are also referred to as glycidyl compounds. The epoxy molecule can also be expanded or cross-linked with other molecules to form a wide variety of resin products, each with distinct performance characteristics. These resins range from low- viscosity liquids to high-molecular weight solids.
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Activators increase the penetration rate; for dichloromethane water is suitable, other choices are amines, strong acids or strong alkalis. The activator's role is to disrupt the molecular and intermolecular bonds in the paint film and assist with weakening this. Its composition depends on the character of the paint to be removed. Mineral acids are used for epoxy resins to hydrolyze their ether bonds.
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This part is the most reactive group in the epoxy resins. Most commonly used FBE resins are derivatives of bisphenol A and epichlorohydrin. However, other types of resins (for example bisphenol F type) are also commonly used in FBE formulations to achieve various properties, combinations or additions. Resins are also available in various molecular lengths, to provide unique properties to the final coating.
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Polypropylene carbonate is used to increase the toughness of some epoxy resins. It is used as a sacrificial binder in the ceramic industry, which decomposes and evaporates during sintering. It has a low sodium content which makes it suitable for the preparation of electroceramics like dielectric materials and piezoelectric ceramics. Composites of polypropylene carbonate with starch (PPC/starch) are used as biodegradable plastics.
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4,4-Diaminodicyclohexylmethane is the name for organic compounds with the formula CH2(C6H10NH2)2. It is classified as a diamine. In the epoxy industry it is often referred to as PACM, short for _p_ ara-di _a_ minodi _c_ yclohexyl _m_ ethane. It is used as a curing agent for epoxy resins and to produce diisocyanates, which are precursors to polyurethane.
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From this reaction, the products are symmetrical primary amides, asymmetrical primary/ secondary diamides, and symmetrical secondary diamides. The remaining waste material products can be used for hardening of epoxy resins. Similarly, in solvolytic reaction, the polyester reacts with water, acid, amine or alcohol, and in aminoglycolysis reaction, the polyester reacts with TEA ( triethanolamine ). This is PET degradation with polyamines through aminolysis route.
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In halogen- free system, zinc borate can be used together with alumina trihydrate, magnesium hydroxide, red phosphorus, or ammonium polyphosphate. During burning the plastics, a porous borate ceramics is formed that protects the underlying layers. In presence of silica, borosilicate glass can be formed at plastic burning temperatures. Zinc borate is used in polyvinyl chloride, polyolefins, polyamides, epoxy resins, polyesters, thermoplastic elastomers, rubbers, etc.
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By using vacuum impregnation on uncured epoxy, winding-to-winding, winding-to-core, and winding-to-insulator air voids are eliminated. The cured epoxy is an electrical insulator and a much better conductor of heat than air. Transformer and inductor hot spots are greatly reduced, giving the component a stable and longer life than unpotted product. Epoxy resins are applied using the technology of resin dispensing.
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The global epoxy resin market was valued at approximately $8 billion in 2016. The epoxy resin market is dominated by the Asia-Pacific region, which contributes 55.2% of the total market share. China is the major producer and consumer globally, consuming almost 35% of the global resin production. The global market is made up of approximately 50–100 manufacturers of basic or commodity epoxy resins and hardeners.
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These resins do however contain hydroxyl groups throughout the backbone, which may also undergo other cross-linking reactions, e.g. with aminoplasts, phenoplasts and isocyanates. Epoxy resins are polymeric or semi-polymeric materials or an oligomer, and as such rarely exist as pure substances, since variable chain length results from the polymerisation reaction used to produce them. High purity grades can be produced for certain applications, e.g.
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These are the most employed resins into the MEMS and microfluidic fields. They exploit cationic polymerization. One of the best known epoxy resin is SU-8, which allows thin film deposition (up to 500 µm) and polymerization of structures with a high aspect ratio. We can find many others epoxy resins such as: SCR-701, largely employed in micro moving objects, and the SCR-500.
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Epichlorohydrin is mainly converted to bisphenol A diglycidyl ether, a building block in the manufacture of epoxy resins. It is also a precursor to monomers for other resins and polymers. Another usage is the conversion to synthetic glycerol. However, the rapid increase in biodiesel production, where glycerol is a waste product, has led to a glut of glycerol on the market, rendering this process uneconomical.
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This produces a two-component system. An alternative is to use standard medium viscosity liquid epoxy resins and emulsify them in a water soluble polyamine or polyaminoamide hardener resin which also gives a two component system. Polyaminoamides are made by reacting ethylene amines with dimerized fatty acids to give a species with amide links but still having amine functionality. Water is liberated during the condensation reaction.
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Rubber cements are solutions of synthetic or natural rubber products in solvents, with or without resins and gums. Vulcanizers, accelerators, and stabilizers are considered problematic due to the nature of their compounds. One example is the additive of sulfur which is harmful to some types of material, including silver, because it can cause discoloration. Rubber adhesives can be confused with epoxy resins due to their similar appearance.
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Chloroform was one other chemical found in abundance on the site, with about 40,000 pounds found throughout the landfill. Chloroform is a type of cleaning solution, one of many that can be used for things such as; cleaning electronics, tools, engines, and automotive parts; dissolving oil, paint, and grease; to mix/thin paint, glue, pigments, epoxy resins, and pesticides; and to create other similar solvents or chemicals.
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Bisphenol A is primarily used to make plastics, such as this polycarbonate water bottle. In 2003, U.S. consumption was 856,000 tons, of which 75% was used to make polycarbonate plastic and 21% for epoxy resins. In the U.S., less than 5% of the BPA produced is used in food contact applications, but remains in the canned food industry and printing applications, such as sales receipts.
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Proceeding of The 39th IPA Conference and Exhibition, Jakarta, Indonesia, May 2015. The chemical reactions in both cases are exothermic. Large quantities of mix will generate their own heat and greatly speed the reaction, so it is usual to mix small amounts which can be used quickly. While it is common to associate polyester resins and epoxy resins, their properties are sufficiently different that they are properly treated as distinct materials.
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Typical epoxy resins have pendant hydroxyl (-OH) groups along their chain that can form bonds or strong polar attractions to oxide or hydroxyl surfaces. Most inorganic surfaces—i.e., metals, minerals, glasses, ceramics—have polarity so they have high surface energy. The important factor in determining good adhesive strength is whether the surface energy of the substrate is close to or higher than the surface energy of the cured adhesive.
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It is used as a hardening agent in epoxy resins used in manufacture of printed circuit boards. When reacted with nonhalogenated glycols, it forms halogenated polyols used as flame retardants in polyurethane foams. it is also used for production of dibutyl chlorendate and dimethyl chlorendate, which are used as reactive flame retardants in plastics. In limited amounts, it is used as an additive in acrylonitrile butadiene styrene copolymer.
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The first dye used commercially in this application was crystal violet lactone, which is widely used today. Other dyes and supporting chemicals used are PTSMH (p-toluene sulfinate of Michler's hydrol), TMA (trimellitic anhydride), phenol- formaldehyde resins, azo dyes, DIPN (diisopropyl naphthalenes), formaldehyde isocyanates, hydrocarbon-based solvents, polycyclic aromatic hydrocarbons, polyoxypropylene diamine, epoxy resins, aliphatic isocyanates, Bisphenol A, diethylene triamine, and others. The dyes in carbonless copy papers may cause contact dermatitis in sensitive persons.
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Epoxy paints tend to deteriorate, known as "chalking out", due to UV exposure. Change in color, known as yellowing, is a common phenomenon for epoxy materials and is often of concern in art and conservation applications. Epoxy resins yellow with time, even when not exposed to UV radiation. Significant advances in understanding yellowing of epoxies were achieved by Down first in 1984 (natural dark aging) and later in 1986 (high-intensity light aging) .
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Epoxy resins are a highly useful class of materials used in engineering applications. Some of these include use for adhesives, fiber-reinforced composites, and electronics coatings. Their rigidity and low crack propagation resistance makes epoxies a candidate of interest for rubber toughening research to fine- tune the toughening processes. Some of the factors affecting the toughness of epoxy nanocomposites include the chemical identity of the epoxy curing agent, entanglement density, and interfacial adhesion.
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Cracking and curling can be reduced by dividing the area to be covered into smaller sections and then pouring the material. Debonding of the granolithic material can also be significantly avoided by using bonding agents like epoxy resins or polymer latex. A high degree of skill in pouring and finishing the material is needed to prevent problems. Sealers and hardeners can be added to the granolithic material to improve its resistance to wear.
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These species are used as curing agents in epoxy resins. Another market for maleic anhydride is lubricating oil additives, which are used in gasoline and diesel engine crankcase oils as dispersants and corrosion inhibitors. Changes in lubricant specifications and more efficient engines have had a negative effect on the demand for lubricating oil additives, giving flat growth prospects for maleic anhydride in this application. A number of smaller applications for maleic anhydride.
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Axtell then carried out a reconstruction, completed by 2 February 1949, in which he was only successful in replacing three of the 37 loose fragments. He reportedly used "new adhesives" for this restoration, which some thought might be epoxy resins or shellac, but were later discovered to simply be the same type of animal glue that Doubleday used in 1845. He also filled some areas with wax. No documentation of his work was produced.
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The ratio of epoxy resins and curing agents in a formulation is determined by their relative equivalent weights. In addition to these two major components, FBE coatings include fillers, pigments, extenders and various additives, to provide desired properties. These components control characteristics such as permeability, hardness, colour, thickness, gouge resistance etc. All of these components are normally dry solids, even though small quantities of liquid additives may be used in some FBE formulations.
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Gillet, assign1: Arkema Inc., veröffentlicht am 27. Mai 2010 The latter are used as starting materials for di-isocyanates - for the preparation of polyurethanes - as diamines for the preparation of polyamides or as a hardener for epoxy resins. When monoethylene glycol as a diol is replaced with isosorbide in the polyester polyethylene terephthalate (PET), polyisosorbide terephthalate (PIT) is obtained, which is characterized by an extreme thermal stability (up to 360 °C under nitrogen).
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Aero Research Limited (ARL), founded in the UK in 1934, developed a new synthetic-resin adhesive for bonding metals, glass, porcelain, china and other materials. The name "Araldite" recalls the ARL brand: ARaLdite. De Trey Frères SA of Switzerland carried out the first production of epoxy resins. They licensed the process to Ciba AG in the early 1940s and Ciba first demonstrated a product under the tradename "Araldite" at the Swiss Industries Fair in 1945.
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Thus, organic peroxides are useful as initiators for some types of polymerisation, such as the epoxy resins used in glass-reinforced plastics. MEKP and benzoyl peroxide are commonly used for this purpose. However, the same property also means that organic peroxides can either intentionally or unintentionally initiate explosive polymerisation in materials with unsaturated chemical bonds, and this process has been used in explosives. Organic peroxides, like their inorganic counterparts, are powerful bleaching agents.
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Types of stonemasonry are: ;Fixer masons: This type of masons have specialized into fixing the stones onto the buildings. They might do this with grouts, mortars, and lifting tackle. They might also use things like single application specialized fixings, simple cramps, and dowels as well as stone cladding with things like epoxy resins, mastics, and modern cements. ;Memorial masons: These are the masons that make headstones and carve the inscriptions on them.
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BPF is used in the manufacturing of plastics and epoxy resins. It is used in the industry as a way of increasing the thickness and durability of materials. Its use in this way is important in the production of tank and pipe linings, industrial floors, road and bridge deck toppings, structural adhesives, grouts, coatings and electrical varnishes. BPF is also utilized in liners, lacquers, adhesives, plastics, and the coating of drinks and food cans.
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IPDA is used as a precursor in the manufacture of isophorone diisocyanate by phosgenation. Like other diamines, it is a curing agent for epoxy resins. When used in coatings applications the higher cost compared to other amines is justified by the enhanced UV stability and thus lower yellowing tendency. In the production of Advanced composite materials (engineering) its higher cost compared to other amines is less critical as performance is the key criteria.
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Over the past few decades concern about the possible adverse health effects of many aromatic amines has led to increased use of aliphatic or cycloaliphatic amine alternatives. Amines are also blended, adducted and reacted to alter properties and these amine resins are more often used to cure epoxy resins than a pure amine such as TETA. increasingly, WATER BASED polyamines are also used to help reduce the toxicity profile among other reasons. TETA, a typical hardener.
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CAPB Amidoamines are a class of chemical compounds that are formed from fatty acids and diamines. They are used as intermediates in the synthesis of surfactants, such as cocamidopropyl betaine (CAPB), some of which are used in personal care products including soaps, shampoos, and cosmetics. Amidoamines can also serve as curing agents for epoxy resins. Patch test studies have concluded that most apparent allergic reactions to products containing CAPB are more likely due to amidoamine than to CAPB itself.
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In 1930 he founded Gustavus J. Esselen, Inc., which following a merger, became Esselen Research Division of United States Testing Co., Inc. Among the successful projects for industrial clients he was involved with was the development of anhydride curing agents for epoxy resins and polyvinyl butyral as an improved material for the subsequent commercialization of laminated glass for use in vehicles etc. More than 40 U.S. patents were issued as a result of his research efforts.
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Thermoset polymer matrix properties can be fine tuned by the choice of substituents in the bisphenolic compound. Bisphenol A and novolac based cyanate esters are the major products; bisphenol F and bisphenol E are also used. The aromatic ring of the bisphenol can be substituted with an allylic group for improved toughness of the material. Cyanate esters can also be mixed with bismaleimides to form BT-resins or with epoxy resins to optimize the end use properties.
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In addition to SAP, aspartic acid has applications in the $19Bn fertilizer industry, where polyaspartate improves water retention and nitrogen uptake; the $1.1Bn (2020) concrete floor coatings market, where polyaspartic is a low VOC, low energy alternative to traditional epoxy resins;Global concrete floor coatings market will be worth US$1.1Bn by 2020. Transparency Market Research (2015). and lastly the >$5Bn scale and corrosion inhibitors market.Corrosion inhibitors market analysis by product, by application, by end-use industry, and segment forecasts to 2020.
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Structural formula of 3,4-Epoxycyclohexylmethyl-3’,4’-epoxycyclohexane carboxylate There are two common types of aliphatic epoxy resins: those obtained by epoxidation of double bonds (cycloaliphatic epoxides and epoxidized vegetable oils) and those formed by reaction with epichlorohydrin (glycidyl ethers and esters). Cycloaliphatic epoxides contain one or more aliphatic rings in the molecule on which the oxirane ring is contained (e.g. 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate). They are produced by the reaction of a cyclic alkene with a peracid (see above).
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Because aliphatic epoxies have a lower electron density than aromatics, cycloaliphatic epoxies react less readily with nucleophiles than bisphenol A-based epoxy resins (which have aromatic ether groups). This means that conventional nucleophilic hardeners such as amines are hardly suitable for crosslinking. Cycloaliphatic epoxides are therefore usually homopolymerized thermally or UV-initiated in an electrophilic or cationic reaction. Due to the low dielectric constants and the absence of chlorine, cycloaliphatic epoxides are often used to encapsulate electronic systems, such as microchips or LEDs.
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Image shows a fractured surface with voiding.Cavitation is common in epoxy resins and other craze resistant toughened polymers, and is prerequisite to shearing in Izod impact strength testing. During the deformation and fracture of a toughened polymer, cavitation of the strained rubber particles occurs in crazing-prone and non-crazing-prone plastics, including, ABS, PVC, nylon, high impact polystyrene, and CTBN toughened epoxies. Engineers use an energy- balance approach to model how particle size and rubber modulus factors influence material toughness.
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A number bioplastic classes have been synthesized from plant and animal derived fats and oils. Polyurethanes, polyesters, epoxy resins and a number of other types of polymers have been developed with comparable properties to crude oil based materials. The recent development of olefin metathesis has opened a wide variety of feedstocks to economical conversion into biomonomers and polymers. With the growing production of traditional vegetable oils as well as low cost microalgae derived oils, there is huge potential for growth in this area.
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After ten years, she moved with Shell to England where she worked as a business development manager. Later Coleman-Kammula transferred to both Belgium and Houston, Texas, as the head of the epoxy resins unit creating plastics. In 2000, she left Shell and became a senior vice president at Basell Polyolefins, where she focused on asset management, innovation and strategic marketing. She also served on the Board of Directors of Indelpro, a joint venture between Basell and Alfa in Mexico.
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Formed by the condensation reaction of a diamine with maleic anhydride, and processed basically like epoxy resins ( cure). After an elevated post-cure (), they will exhibit superior properties. These properties are influenced by a 400-450 °F (204-232 °C) continuous use temperature and a glass transition of . Bismaleimide resin synthetic pathway and structure This thermoset polymer type is merged into composites as a prepreg matrix used in electrical printed circuit boards, and for large scale structural aircraft – aerospace composite structures, etc.
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Chemence (Inc., Ltd., Medical, Graphics) is a multinational conglomerate which manufactures products including cyanoacrylate adhesives, anaerobic adhesives, impregnation sealants, adhesive activators, epoxy resins, UV adhesives, photopolymer resins, custom printer ink cartridges, Gas pipe sealants, and soak off nail polishes. Chemence is a supplier of photopolymer and commercial printers to the flexographic industry in the US and Europe, as well as the primary sealant supplier to British Gas, and a primary supplier of private- label adhesives to companies including Tesco, 3M, Bostik, and Bondo.
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BPA (Bisphenol A) is the monomer used to manufacture polycarbonate plastic and epoxy resins used as a lining in most food and beverage cans. BPA global capacity is in excess of per year and thus is one of the highest-volume chemicals produced worldwide. The ester bonds in the BPA-based polycarbonates could be subject to hydrolysis and leaching of BPA. But in the case of epoxypolymers formed from bisphenol A, it is not possible to release bisphenol A by such a reaction.
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Epoxy resins derived from BPA are used to line water pipes, as coatings on the inside of many food and beverage cans, and in making thermal paper such as that used in sales receipts. In 2015, an estimated 4 million tonnes of BPA-derived chemical were produced, making it one of the highest volume of chemicals produced worldwide. BPA is a xenoestrogen, exhibiting estrogen-mimicking, hormone-like properties. Although the effect is very weak, the pervasiveness of BPA-containing materials raises concerns.
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Thermosetting plastics are divided into two types: formaldehyde cross-linking type and other cross-linking type. Thermosets includes phenolic resins, polyesters and epoxy resins, all of which are used widely in composite materials when reinforced with stiff fibers such as fiberglass and aramids. Since crosslinking stabilises the thermoset polymer matrix of these materials, they have physical properties more similar to traditional engineering materials like steel. However, their very much lower densities compared with metals makes them ideal for lightweight structures.
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Glycidylamine epoxy resins are higher functionality epoxies which are formed when aromatic amines are reacted with epichlorohydrin. Important industrial grades are triglycidyl-p-aminophenol (functionality 3) and N,N,N′,N′-tetraglycidyl-bis-(4-aminophenyl)-methane (functionality 4). The resins are low to medium viscosity at room temperature, which makes them easier to process than EPN or ECN resins. This coupled with high reactivity, plus high temperature resistance and mechanical properties of the resulting cured network makes them important materials for aerospace composite applications.
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Defects known as voids and dry resin (in the case of resin transfer molding) are possible in transfer molding and often are exacerbated by high viscosity materials. This is because a high viscosity plastic flowing through a thin mold may miss entire vacated areas, leaving air pockets. When air pockets are left in the presence of fiber, this creates a “dry” area, which prevents load from being transferred through the fibers in the dry area. Materials used for the plastic are often polyurethanes or epoxy resins.
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Epoxy resins derived from bisphenol A are used as coatings on the inside of almost all food and beverage cans; however, due to BPA health concerns, in Japan epoxy coating was mostly replaced by PET film. Bisphenol A is a preferred color developer in carbonless copy paper and thermal point of sale receipt paper. When used in thermal paper, BPA is present as "free" (i.e., discrete, non-polymerized) BPA, which is likely to be more available for exposure than BPA polymerized into a resin or plastic.
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Specific highly brominated molecules can also be added that participate in the polymerisation process For example, tetrabromobisphenol A can be added to polyesters or epoxy resins, where it becomes part of the polymer. Epoxies used in printed circuit boards are normally made from such flame retardant resins, indicated by the FR in the abbreviation of the products (FR-4 and FR-2). In some cases the bromine containing compound may be added after polymerisation. For example, decabromodiphenyl ether can be added to the final polymers.
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The primary risk associated with epoxy use is often related to the hardener component and not to the epoxy resin itself. Amine hardeners in particular are generally corrosive, but may also be classed as toxic or carcinogenic/mutagenic. Aromatic amines present a particular health hazard (most are known or suspected carcinogens), but their use is now restricted to specific industrial applications, and safer aliphatic or cycloaliphatic amines are commonly employed. Liquid epoxy resins in their uncured state are mostly classed as irritant to the eyes and skin, as well as toxic to aquatic organisms.
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Paraffin wax does not always provide a sufficiently hard matrix for cutting very thin sections (which are especially important for electron microscopy). Paraffin wax may also be too soft in relation to the tissue, the heat of the melted wax may alter the tissue in undesirable ways, or the dehydrating or clearing chemicals may harm the tissue. Alternatives to paraffin wax include, epoxy, acrylic, agar, gelatin, celloidin, and other types of waxes. In electron microscopy epoxy resins are the most commonly employed embedding media, but acrylic resins are also used, particularly where immunohistochemistry is required.
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The Nimbus-4DM is typical of the Nimbus-4 design, except for variations in cockpit and powerplant configuration and associated operating limitations. It is a 2-seat, high- performance motorized glider, constructed from fiber reinforced plastic (FRP) composites, featuring full span flight controls and a T-tail (with fixed horizontal stabilizer and two-piece elevator). The manufacturing process uses a hand lay-up of composite material plies and epoxy resins. The wing's 26.5-meter (87-foot) span consists of three sections per side, consisting of a wing tip, outboard section, and inboard section.
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November 2009 (a bis-epoxide) is formed, which can be used as a replacement for the analog bisphenol A bis- epoxide. Isosorbide bis-glycidyl ether can be crosslinked to a thermosetting epoxy resins with suitable curing agents, such as polyamines or cyclic acid anhydrides. These resins are used as adhesives, paints or coatings for food cans.Press Release NEWARK, Feb 24 2010: NJIT Patent May Be Able To Replace BPA; Make Consumer Products Safer Furthermore, polyoxazolidones are described which can be obtained by reaction of isosorbide diglycidyl ethers with diisocyanates.
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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.
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Formerly, ignition coils were made with varnish and paper insulated high-voltage windings, inserted into a drawn-steel can and filled with oil or asphalt for insulation and moisture protection. Coils on modern automobiles are cast in filled epoxy resins which penetrate any voids within the winding. A modern single-spark system has one coil per spark plug. To prevent premature sparking at the start of the primary pulse, a diode or secondary spark gap is installed in the coil to block the reverse pulse that would otherwise form.
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Expanding monomers are interesting for application as in matrix resins in radically polymerized dental fillings, high-strength composites (e. g. in epoxy resins), adhesives, coatings, precision castings, and sealant materials to counteract shrinking during polymerization. This can be necessary in case of dental fillings since polymerization shrinkage and subsequent contraction stress in the resin composite and at the bonding interface may lead to debonding, microleakage, post-operative sensitivity, a compromise in the material's physical properties and even cracks in healthy tooth structure. They are used in the other called applications to remedy similar problems.
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After gaining his doctorate, Renfrew worked for DuPont in New Jersey, where he produced a number of patents on polymethyl methacrylate, including one on photopolymerization,M. M. Renfrew (1948) US Patent 2448828 Photopolymerization material for tooth repair,M. M. Renfrew (1943) US Patent 2335133 Tooth Reconstruction as well as epoxy resinsM. M. Renfrew & H. Wittcoff (1955) US Patent 2705223 Thermosetting resinous compositions from epoxy resins and polyamides derived from polymeric fat acids and the first method of synthesis of poly(tetrafluoroethylene) in a form which was suitable for the commercial production of Teflon.
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Another early form of insulation was paper, however, paper is hygroscopic and absorbs moisture which is detrimental and is disadvantaged by the inflexible linear designs. Cast resin technology, has dominated insulated products since the 1960s, due to its flexibility of shape and its higher dielectrical strength. Typically, paper insulation is later impregnated either with oil (historically), or more commonly today with resin. In the case of resin, the paper is film coated with a Phenolic resin to become Synthetic Resin Bonded Paper, (SRBP) or impregnated after dry winding with epoxy resins, to become Resin Impregnated Paper or Epoxy Resin Impregnated Paper (RIP, ERIP).
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The names of the adhesives and stone fillers usually indicate their chemical components, for instance epoxy resin adhesive, and their field of application, for example marble filler. The adhesives can be used to attain load-carrying bonds between workpieces made of natural stone and engineered quartz composite as well as other materials. The fillers are used to fill pores or imperfections in natural stone products. In the natural stone sector the most frequently implemented adhesive systems are based on epoxy resins (EP resins) and unsaturated polyester resins (UP resins) as well as acrylic resins, methacrylate resins and polyurethane systems (PUR resins).
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Fusion Bonded Epoxy Powder Coatings (FBE) are extensively used for corrosion protection of steel pipes and fittings used in the oil and gas industry, potable water transmission pipelines (steel), and concrete reinforcing rebar. Epoxy coatings are also widely used as primers to improve the adhesion of automotive and marine paints especially on metal surfaces where corrosion (rusting) resistance is important. Metal cans and containers are often coated with epoxy to prevent rusting, especially for foods like tomatoes that are acidic. Epoxy resins are also used for decorative flooring applications such as terrazzo flooring, chip flooring, and colored aggregate flooring.
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Several wood glues have poor "gap-filling" ability, meaning they either soak into the wood and leave the gap empty, or remain to fill the gap but have little structural integrity. Therefore, woodworkers commonly use tight-fitting joints that need surprisingly little glue to hold large pieces of wood. Most wood glues need to be clamped while the glue sets. Epoxy resins and some other glues can be thickened with structural fillers (or with thicker formulations of the resin) to help fill gaps, however it is preferable to try to minimize gaps in the first place so the problem is not faced.
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Triethylamine is commonly employed in organic synthesis as a base. For example, it is commonly used as a base during the preparation of esters and amides from acyl chlorides. Such reactions lead to the production of hydrogen chloride which combines with triethylamine to form the salt triethylamine hydrochloride, commonly called triethylammonium chloride. This reaction removes the hydrogen chloride from the reaction mixture, which can be required for these reactions to proceed to completion (R, R' = alkyl, aryl): :R2NH + R'C(O)Cl + Et3N -> R'C(O)NR2 \+ Et3NH+Cl− Like other tertiary amines, it catalyzes the formation of urethane foams and epoxy resins.
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There are three main categories of powder coatings: thermosets, thermoplastics, and UV curable powder coatings. Thermoset powder coatings incorporates a cross-linker into the formulation. Most common cross-linkers are solid epoxy resins in so-called hybrid powders in mixing ratios of 50/50, 60/40 and 70/30 (polyester resin/ epoxy resin) for indoor applications and triglycidyl isocyanurate (TGIC) in a ratio of 93/7 and β-hydroxy alkylamide (HAA) hardener in 95/5 ratio for outdoor applications. When the powder is baked, it reacts with other chemical groups in the powder to polymerize, improving the performance properties.
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Georgina Sinclair is a freelance journalist, who makes a living contributing to trade magazines. Her main work is with the journal "Adhesives in the Modern World", which features articles about Epoxy resins and other aspects of gluing. After her lawyer husband Euripides "Rip" Sinclair walks out of the marriage, Georgina finds herself involved with elderly neighbor Mrs Shapiro, a 92-year-old Jewish emigre, who lives in a smelly and decrepit North London mansion. The house is a desirable property, and secondary characters including social workers and real estate agents seek to gain its sale for their own profit.
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Isosorbide has a high thermal stability and is by now well available from renewable raw materials. This makes isosorbide of interest as a monomer for thermoplastic (bio)polymers such as polyesters and polycarbonates, as well as for thermosets such as polyurethanes or epoxy resins. The hydroxy groups can be converted into the primary amino groups via the tosylates and azides or by addition of acrylonitrile followed by hydrogenation into the corresponding aminopropyl derivatives.US-Patentanmeldung US 2010/0130759A1 Novel functional compounds with an isosorbide or isosorbide isomer core, production process and uses of these compounds, invent1: J.-P.
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A small transformer potted in epoxy. The surface visible on the right is formed by the potting compound that has been poured into the plastic box In electronics, potting is a process of filling a complete electronic assembly with a solid or gelatinous compound for high voltage assemblies by excluding gaseous phenomena such as corona discharge, for resistance to shock and vibration, and for the exclusion of water, moisture, or corrosive agents. Thermosetting plastics or silicone rubber gels are often used, though epoxy resins are also very common. Many sites recommend using a potting product to protect sensitive electronic components from impact, vibration, and loose wires.
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Nama Chemicals was established as a local chemicals company in Jubail, Saudi Arabia in 1992. The city lays along the Persian Gulf on the eastern coast of Saudi Arabia and since the establishment of the company, has grown to become a major industrial city. NAMA was part of a consortium of private companies to bid for a development contract for which was to become Saudi Arabia's first privately owned refinery in 2011, but lost the bid to the state oil company Saudi Aramco. In 2014, NAMA finished the expansion of its largest epoxy resins plant, raising the production capacity from 60,000 to 120,000 tons of epoxy per year.
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Bisphenol A (BPA) is an organic synthetic compound with the chemical formula (CH3)2C(C6H4OH)2 belonging to the group of diphenylmethane derivatives and bisphenols, with two hydroxyphenyl groups. It is a colorless solid that is soluble in organic solvents, but poorly soluble in water (0.344 wt % at 83 °C). BPA is a precursor to important plastics, primarily certain polycarbonates and epoxy resins, as well as some polysulfones and certain niche materials. BPA-based plastic is clear and tough, and is made into a variety of common consumer goods, such as plastic bottles including water bottles, food storage containers (commonly called "Tupperware"), baby bottles, sports equipment, CDs, and DVDs.
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The tracks, wheels and suspension of a tank are outside the armoured hull and are some of the most vulnerable spots. The easiest way to disable a tank (other than a direct hit in a vulnerable area with a full-power anti-tank weapon) is to target the tracks for a "mobility kill" (m-kill), or target all external visual aids with rubbery cohesive substances such as melted rubber or blackened high viscosity epoxy resins. Once a tank is disabled it is easier to destroy. This is why side-skirts are an important feature; they can deflect heavy machine-gun bullets and trigger the detonation of HEAT rounds before they strike the running gear.
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Since all resins shrink (epoxy resins shrink far less than poly and vinyl ester versions) and it is impossible to bond to a sewer that has fats, oils, and grease an annular space exists between the new CIPP liner and the host pipe. The annular space exists in all installations just some are larger than others and depending on the severity may need additional rehabilitation. There are multiple ways to prevent water from tracking in the annular space and entering back into the waste stream including: water swelling material (hydrophilic), lining of the entire connection and host pipe with a continuous repair (YT repair) gaskets, and point repairs placed at the ends of the host pipe.
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Acetone is used to synthesize methyl methacrylate. It begins with the initial conversion of acetone to acetone cyanohydrin: :(CH3)2CO + HCN → (CH3)2C(OH)CN In a subsequent step, the nitrile is hydrolyzed to the unsaturated amide, which is esterified: :(CH3)2C(OH)CN + CH3OH → CH2=(CH3)CCO2CH3 \+ NH3 The third major use of acetone (about 20%) is synthesizing bisphenol A. Bisphenol A is a component of many polymers such as polycarbonates, polyurethanes, and epoxy resins. The synthesis involves the condensation of acetone with phenol: :(CH3)2CO + 2 C6H5OH → (CH3)2C(C6H4OH)2 \+ H2O Many millions of kilograms of acetone are consumed in the production of the solvents methyl isobutyl alcohol and methyl isobutyl ketone. These products arise via an initial aldol condensation to give diacetone alcohol.
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Many environmentalists are enthusiastic about the use of paulownia alaia boards because of their minimal impact on the environment, while fiberglass and epoxy surfboards are known for their many pollutants and long decomposition time. Beyond avoiding fiberglass and epoxy resins, Wegener argues that modern Alaia boards have less impact on the environment based on the way the Paulownia wood is harvested, used and recycled. “Paulownia is plantation grown… The trees grow like weeds, about in three years and they are never from an old growth forest. Just sustainable tree farms…the leaves and flowers, is either fed to cattle or the dust and shavings are mulched… Paulownia dust (and shavings) is very good in the garden and breaks down quickly.
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4,4’-Oxydianiline is used in the production of a wide variety of polymer resins. The primary use lies in the production of polyimide and poly(ester)imide resins. These resins are used for their temperature-resistant properties and are utilized in products including wire enamels, coatings, film, adhesives, insulating varnishes, coated fabrics, flame-retardant fibers, oil sealants and retainers, insulation for cables and printed circuits, and laminates and composite for aerospace vehicles. Other applications of 4,4’-oxydianiline include the production of poly(amide)imide resins (which are used in the manufacture of heat-resistant wire enamels and coatings), as an intermediate in the manufacture of epoxy resins and adhesives, and in the production of aromatic polyether imides. A specific reaction involving industrial use of 4,4’-oxydianiline is in the production of thermostable poly(amideurea) acids, which can be prepared from 4,4’-oxydianiline, pyromellitic dianhydride, and diisocyanates.
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Certain epoxy resins and their processes can create a hermetic bond to copper, brass, or epoxy itself with similar coefficients of thermal expansion, and are used in the manufacture of hermetic electrical and fiber optic hermetic seals. Epoxy hermetic seal designs can be used in hermetic seal applications for low or high vacuum or pressures, effectively sealing gases or fluids including helium gas to very low helium gas leak rates similar to glass or ceramic. Hermetic epoxy seals also offer the design flexibility of sealing either copper alloy wires or pins, instead of the much less electrically conductive Kovar pin materials required in glass or ceramic hermetic seals. With a typical operating temperature range of -70°C to +125°C or 150°C, epoxy hermetic seals are more limited in comparison to glass or ceramic seals, although some hermetic epoxy designs are capable of withstanding 200°C.
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This technique was made possible by the evolution of glues and the massification of polyester and epoxy resins combined with fiberglass tape. The new technique basically did away with the chine logs and mechanical fasteners and all the problems associated with their use (mainly the limitation of shape in the design phase, the carpentry challenge in the construction phase and damp/rot in the medium to long term). Instead of using a chine to join the precut panels, in stitch and glue, the preshaped panels are wrapped around bulkheads and/or frames in the same way as before. However, the panels are only temporarily held in place using nails, duct tape, cable ties, masking tape, wire or other mechanical means, while the seams are filled (both inside and outside the hull) with a resin and filler paste covered in one or more layers of fiberglass cloth or tape which in turn is saturated in resin.
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The 2008 European Union Risk Assessment Report on , published by the European Commission and European Food Safety Authority (EFSA), concluded that -based products, such as polycarbonate plastic and epoxy resins, are safe for consumers and the environment when used as intended.Rapporteur: United Kingdom. (2008). JRC.it Updated European Risk Assessment Report: 4,4'-ISOPROPYLIDENEDIPHENOL (BISPHENOL-A) FINAL APPROVED VERSION AWAITING FOR PUBLICATION. EFSA, Press release By October 2008, after the Lang Study was published, the EFSA issued a statement concluding that the study provided no grounds to revise the current Tolerable Daily Intake (TDI) level for BPA of bodyweight. On 22 December 2009, the EU Environment ministers released a statement expressing concerns over recent studies showing adverse effects of exposure to endocrine disruptors. In September 2010, the European Food Safety Authority (EFSA) concluded after a "comprehensive evaluation of recent toxicity data […] that no new study could be identified, which would call for a revision of the current TDI".
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Phenol-formaldehyde resins, as a group, are formed by a step-growth polymerization reaction that can be either acid- or base- catalysed. Since formaldehyde exists predominantly in solution as a dynamic equilibrium of methylene glycol oligomers, the concentration of the reactive form of formaldehyde depends on temperature and pH. Phenol reacts with formaldehyde at the ortho and para sites (sites 2, 4 and 6) allowing up to 3 units of formaldehyde to attach to the ring. The initial reaction in all cases involves the formation of a hydroxymethyl phenol: : HOC6H5 \+ CH2O → HOC6H4CH2OH The hydroxymethyl group is capable of reacting with either another free ortho or para site, or with another hydroxymethyl group. The first reaction gives a methylene bridge, and the second forms an ether bridge: : HOC6H4CH2OH + HOC6H5 → (HOC6H4)2CH2 \+ H2O : 2 HOC6H4CH2OH → (HOC6H4CH2)2O + H2O The diphenol (HOC6H4)2CH2 (sometimes called a "dimer") is called bisphenol F, which is an important monomer in the production of epoxy resins.
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Synthesis of bisphenol A diglycidyl ether The most common epoxy resins are based on reacting epichlorohydrin (ECH) with bisphenol A, resulting in a different chemical substance known as bisphenol A diglycidyl ether (commonly known as BADGE or DGEBA). Bisphenol A-based resins are the most widely commercialised resins but also other bisphenols are analogously reacted with epichlorohydrin, for example Bisphenol F. In this two-stage reaction, epichlorohydrin is first added to bisphenol A (bis(3-chloro-2-hydroxy-propoxy)bisphenol A is formed), then a bisepoxide is formed in a condensation reaction with a stoichiometric amount of sodium hydroxide. The chlorine atom is released as sodium chloride (NaCl), the hydrogen atom as of water. Higher molecular weight diglycidyl ethers (n ≥ 1) are formed by the reaction of the bisphenol A diglycidyl ether formed with further bisphenol A, this is called prepolymerization: Synthesis of bisphenol- A-diglycidyl ether with a high molar mass A product comprising a few repeat units (n = 1 to 2) is a viscous, clear liquid; this is called a liquid epoxy resin.
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