polycarbonates


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polycarbonates,

group of clear, thermoplastic polymerspolymer
, chemical compound with high molecular weight consisting of a number of structural units linked together by covalent bonds (see chemical bond). The simple molecules that may become structural units are themselves called monomers; two monomers combine to form a dimer,
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 used mainly as molding compounds (see plasticplastic,
any organic material with the ability to flow into a desired shape when heat and pressure are applied to it and to retain the shape when they are withdrawn. Composition and Types of Plastic
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). Polycarbonates are prepared by the reaction of an aromatic difunctional phenol with either phosgene or an aromatic or aliphatic carbonate. The commercially important polycarbonates use 2,2-bis (4-hydroxyphenol)-propane (bisphenol A) and diphenyl carbonate. This polymer is a clear plastic with a slight yellow discoloration. It has excellent electrical properties and a high impact strength.
References in periodicals archive ?
Bayer has a broad portfolio of polycarbonate resins, blends and films; thermoplastic polyurethane films; and polyurethane-based adhesives and foams - all formulated for the medical device and healthcare market.
Teijin has other Panlite polycarbonates achieving UL94 V-0 from 2 mm, and has developed the new grade as part of a strategy to expand its polycarbonate markets in the electrical and electronics fields, particularly for LEDs and other lighting applications.
First, MRC received UL 94V-0 classifications for four of its Naxell recycled polycarbonates, including unfilled and 10% glass-filled grades in medium and low viscosities.
As part of the worldwide consolidation of its business with sheets made of the high-performance plastic polycarbonate, Bayer MaterialScience has decided to close its site in Darmstadt, Germany.
Alkalube glyceryl, simple, and complete esters function as internal, external, or intermediate lubricants and flow modifiers for rigid PVC, polycarbonates, phenolics, acrylics, and nylons.
Aromatic polycarbonates are important engineering thermoplastics with transparency, heat resistance, and toughness, and are used in many applications.
Applications include engineering resins such as nylons, polycarbonates, acetals, TPEs, and most commodity resins.
Patent 7,232,854 (June 19, 2007), "Polycarbonate Compositions With Thin-Wall Flame Retardance," Shiping Ma, Thomas Ebeling, and Shrish Rane (General Electric Co., Schenectady, New York, USA).
Company has a new heavy-duty, CFC-free release agent designed specifically to prevent crazing or blemishes on polycarbonates. Called Polycarbonate 41412, it is odorless and can be used where parts are to be painted, hot-stamped or metallized.
Over the last few months, the company has developed and commercialized Paraloid EXL-5137, a gloss-reducing agent for engineering resins; Paraloid EXL-3657, an MBS-based toughener that dramatically improves the impact strength of polycarbonate systems; and Paraloid EXL-3361, an acrylic core-shell toughener that provides strong thermal and uv stability to polycarbonate and polycarbonate blends.
Alkanox 240 is a solid arylphosphite antioxidant for use in adhesives and a variety of plastics including nylon, polycarbonates, acrylics, and styrenics.
Michelle Jou, Global Head of Covestros Polycarbonates segment, said, There is a rapidly growing demand for polycarbonate resins and blends, in particular in China.