P {margin-top:2px;margin-bottom:2px;} Polycarbonate From Wikipedia, the free encyclopedia Jump to: navigation, search Polycarbonate Repeating chemical structure unit of Polycarbonate made from Bisphenol A Physical Properties Density (ρ) 1200-1220 kg/m³ Abbe number (V) 34.0 Refractive index (n) 1.584-6 Flammability V0-V2 Limiting oxygen index 25-27% Water absorption - Equilibrium(ASTM) 0.16-0.35% Water absorption - over 24 hours 0.1% Radiation resistance Fair Ultraviolet (1-380nm) resistance Fair Mechanical Properties Young’s modulus (E) 2-2.4 GPa Tensile strength (σt) 55-75 MPa Compressive strength (σc) >80 MPa Elongation (ε) @ break 80-150% Poisson’s ratio (ν) 0.37 Hardness - Rockwell M70 Izod impact strength 600-850 J/m Notch test 20-35 kJ/m² Abrasive resistance - ASTM D1044 10-15 mg/1000 cycles Coefficient of friction (μ) 0.31 Thermal Properties Melting temperature (Tm) 267 °C* Glass transition temperature(Tg) 150 °C Heat deflection temperature - 10 kN (Vicat B)[citation needed] 145 °C Heat deflection temperature - 0.45 MPa 140 °C Heat deflection temperature - 1.8 MPa 128-138 °C Upper working temperature 115-130 °C Lower working temperature -135 °C Linear thermal expansion coefficient (α) 65-70 × 10-6/K Specific heat capacity (c) 1.2-1.3 kJ/kg·K Thermal conductivity (k) @ 23 °C 0.19-0.22 W/(m·K) Heat transfer coefficient (h) 0.21 W/(m²·K) Electrical Properties Dielectric constant (εr) @ 1 MHz 2.9 Permittivity (ε) @ 1 MHz 2.568 x10-11F/m Relative permeability (μr) @ 1 MHz 0.866(2) Permeability (μ) @ 1 MHz 1.089(2) μN/A² Dielectric strength 15-67 kV/mm Dissipation factor @ 1 MHz 0.01 Surface resistivity 1015Ω/sq Volume resistivity (ρ) 1012-1014Ω·m Near to Short-wave Infrared Transmittance Spectrum Polycarbonate transmittance in 5/6 of the NIR & 1/5 of the SWIR regions. Also, polycarbonate is almost completely transparent throughout the entire visible region of the spectrum and very sharply cuts off to ~0% transmission at almost exactly 400 nm, blocking all UV light transmission. Chemical Resistance Acids - concentrated Poor Acids - dilute Good Alcohols Good Alkalis Good-Poor Aromatic hydrocarbons Poor Greases & Oils Good-Fair Halogenated Hydrocarbons Good-Poor Halogens Poor Ketones Poor Gas permeation @ 20 ºC Nitrogen 10 - 25 cm3.mm/(m2.day.Bar) Oxygen 70 - 130 cm3.mm/(m2.day.Bar) Carbon dioxide 400 - 800 cm3.mm/(m2.day.Bar) Water vapour 1 - 2 gram.mm/(m2.day) @ 85%-0% RH gradient) Economic Properties Price 5-9 €/kg Polycarbonates are a particular group of thermoplastic polymers. They are easily worked, moulded, and thermoformed; as such, these plastics are very widely used in the modern chemical industry. Their interesting features (temperature resistance, impact resistance and optical properties) position them between commodity plastics and engineering plastics. Their plastic identification code is 7. Contents [hide] 1 Chemistry 2 Synthesis 3 Processing 4 Applications 4.1 Trade names 5 Potential hazards in food contact applications 6 Chemical compatibility 7 See also 8 References [edit] Chemistry Polycarbonates received their name because they are polymers having functional groups linked together by carbonate groups (-O-(C=O)-O-) in a long molecular chain. Also carbon monoxide was used as a C1-synthon on an industrial scale to produce diphenyl carbonate, being later trans-esterified with a diphenolic derivative affording poly (aromatic carbonate)s. Taking into consideration the C1-synthon polycarbonates can be divided into poly(aromatic carbonate)s and poly(aliphatic carbonate)s. The second one, poly(aliphatic carbonate)s are a product of the reaction of carbon dioxide with epoxides, which owing to the thermodynamical stability of carbon dioxide requires the use of a catalyst. The working systems are based on porphyrins, alkoxides, carboxylates, salens and beta-diiminates as organic, chelating ligands and aluminium, zinc, cobalt and chromium as the metal centres. Poly(aliphatic carbonate)s display promising characteristics, have a better biodegradability than the aromatic ones and could be employed to develop other specialty polymers. One type of polycarbonate plastic is made from bisphenol A (BPA). This polycarbonate is a very durable material, and can be laminated to make bullet-proof “glass”, though “bullet-resistant” would be more accurate. Although polycarbonate has high impact-resistance, it has low scratch-resistance and so a hard coating is applied to polycarbonate eyewear lenses and polycarbonate exterior automotive components. The characteristics of polycarbonate are quite like those of polymethyl methacrylate (PMMA; acrylic), but polycarbonate is stronger, usable in a larger temperature range but also more expensive. This polymer is highly transparent to visible light and has better light transmission characteristics than many kinds of glass. CR-39 is a specific polycarbonate material — although it is usually referred to as CR-39 plastic — with good optical and mechanical properties, frequently used for eyeglass lenses. [edit] Synthesis Polycarbonate can be synthesized from bisphenol A and phosgene (carbonyl dichloride, COCl2). The first step in the synthesis of polycarbonate from bisphenol A is treatment of bisphenol A with sodium hydroxide. This deprotonates the hydroxyl groups of the bisphenol A molecule. The deprotonated oxygen reacts with phosgene through carbonyl addition to create a tetrahedral intermediate (not shown here), after which the negatively charged oxygen kicks off a chloride ion (Cl-) to form a chloroformate. The chloroformate is then attacked by another deprotonated bisphenol A, eliminating the remaining chloride ion and forming a dimer of bisphenol A with a carbonate linkage in between. Repetition of this process yields a polycarbonate with alternating carbonate groups and groups from bisphenol A. [edit] Processing Polycarbonate has a glass transition temperature of about 150 °C (302 °F), so it softens gradually above this point and flows above about 300 °C (572 °F). Injection moulding is more difficult than other common thermoplastics owing to its non-Newtonian fluid flow behaviour. Tools must be held at high temperatures, generally above 80 °C (176 °F) to make strain- and stress-free products. Low molecular mass grades are easier to mould than higher grades, but their strength is lower as a result. The toughest grades have the highest molecular mass, but are much more difficult to process. [edit] Applications Polycarbonate is becoming more common in housewares as well as laboratories and in industry, especially in applications where any of its main features—high impact resistance, temperature resistance, optical properties—are required. Main transformation techniques for polycarbonate resins: extrusion into tubes, rods and other profiles extrusion with cylinders into sheets (0.5–15 mm (0.020–0.59 in)) and films (below 1 mm (0.039 in)), which can be used directly or manufactured into other shapes using thermoforming or secondary fabrication techniques, such as bending, drilling, routing, laser cutting etc. injection molding into ready articles Typical injected applications: compact discs, DVDs, Blu-ray Discs drinking bottles drinking glasses lab equipment, research animal enclosures lighting lenses, sunglass/eyeglass lenses, safety glasses, automotive headlamp lenses MP3/Digital audio player cases Typical sheet/film application: Advertisement: signs, displays, poster protection Building: domelights, flat or curved glazing, and sound walls Computers: Apple’s MacBook, and Mac mini Industry: machined or formed, cases, machine glazing, riot shields, visors, instrument panels For use in applications exposed to weathering or UV-radiation, a special surface treatment is needed. This either can be a coating (e.g. for improved abrasion resistance), or a coextrusion for enhanced weathering resistance. Some polycarbonate grades are used in medical applications and comply with both ISO 10993-1 and USP Class VI standards (occasionally referred to as PC-ISO). Class VI is the most stringent of the six USP ratings. These grades can be sterilized using steam at 120 °C, gamma radiation or the ethylene oxide (EtO) method.[1] However, scientific research indicates possible problems with biocompatibility. Dow Chemical strictly limits all its plastics with regard to medical applications.[2][3] The cockpit canopy of the F-22 Raptor jet fighter is made from a piece of high optical quality polycarbonate, and is the largest piece of its type formed in the world.[4] In the automotive industry, injection moulded polycarbonate can produce very smooth surfaces that make it well suited for direct (without the need for a basecoat) metalised parts such as decorative bezels and optical reflectors. Its uniform mould shrinkage results in parts with greater accuracy than those made of polypropylene. However, due to its susceptibility to stress corrosion cracking, its use is limited to low stress applications. Being based on bisphenol A (a phenol based on benzene) pricing is largely dependent on phenol and benzene pricing. [edit] Trade names Other trade names for polycarbonate include: Calibre from Dow Chemicals Iupilon from Mitsubishi Engineering-Plastics Corp. Lexan from SABIC Innovative Plastics (formerly General Electric Plastics) Makrolife from Arlaplast Makrolon from Bayer Panlite from Teijin Chemical Limited Tarflon from Idemitsu Kosan Co.Ltd. [edit] Potential hazards in food contact applications Main article: Bisphenol A Polycarbonate may be appealing to manufacturers and purchasers of food storage containers due to its clarity and toughness, being described as lightweight and highly break resistant particularly when compared to silica glass. Polycarbonate may be seen in the form of single use and refillable plastic water bottles. More than 100 studies have explored the bioactivity of bisphenol A leachates from polycarbonates. Bisphenol A appeared to be released from polycarbonate animal cages into water at room temperature and that it may have been responsible for enlargement of the reproductive organs of female mice.[5] An analysis of the literature on bisphenol A leachate low-dose effects by vom Saal and Hughes published in August 2005 seems to have found a suggestive correlation between the source of funding and the conclusion drawn. Industry funded studies tend to find no significant effects while government funded studies tend to find significant effects.[6] Research by Ana M. Soto, professor of anatomy and cellular biology at Tufts University School of Medicine, Boston, published Dec. 6 in the online edition of Reproductive Toxicology (DOI: 10.1016/j.reprotox.2006.10.002) describes exposure of pregnant rats to bisphenol A at 2.5 to 1,000 µg per kilogram of body weight per day. At the equivalent of puberty for the pups (50 days old), about 25% of their mammary ducts had precancerous lesions, some three to four times higher than unexposed controls. The study is cited as evidence for the hypothesis that environmental exposure to bisphenol A as a fetus can cause breast cancer in adult women.[7] An expert panel of 12 scientists has found that there is “some concern that exposure to the chemical bisphenol A in utero causes neural and behavioral effects,” according to the draft report prepared by The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction. For the general adult population, the expert panel found a “negligible concern for adverse reproductive effects following exposures.”[8] A study of cross-sectional data from the 2003-2004 U.S. National Health and Nutritional Examination Survey published in the September 17, 2008 edition of the Journal of the American Medical Association (JAMA) demonstrated positive and statistically significant correlations between the concentration of bisphenol A in the urine and self-reported histories of cardiovascular disease and diabetes.[9] One point of agreement among those studying polycarbonate water and food storage containers may be that using sodium hypochlorite bleach and other alkali cleaners to clean polycarbonate is not recommended, as they catalyze the release of the bisphenol-A. The tendency of polycarbonate to release bisphenol A was discovered after a lab tech used strong cleaners on polycarbonate lab containers. Endocrine disruption later observed on lab rats was traced to exposure from the cleaned containers.[10][11] On April 18, 2008, Health Canada announced that bisphenol A is “toxic to human health”.[12] Canada is the first and only nation to make this designation. [edit] Chemical compatibility A chemical compatibility chart shows reactivity between chemicals such as polycarbonate and a cleaning agent.[13]Alcohol is one recommended organic solvent for cleaning grease and oils from polycarbonate. For treating mold, borax:H2O 1:96 to 1:8 may be effective.[citation needed] Compatibility with various chemicals[13] Will damage polycarbonate Require caution Considered safe Alkali bleaches such as sodium hypochlorite Acetone Acrylonitrile Ammonia Amyl acetate Benzene Bromine Butyl acetate Sodium hydroxide Chloroform Dimethylformamide Concentrated hydrochloric acid Concentrated hydrofluoric acid Iodine Methanol Methyl ethyl ketone Styrene Tetrachloroethylene Toluene Concentrated sulfuric acid Xylene Cyanoacrylate monomers Cyclohexanone Diesel oil Formic acid Gasoline Glycerine Heating oil Jet fuel Concentrated perchloric acid Sulfur dioxide Turpentine Acetic acid Ammonium chloride Antimony trichloride Borax in H2O Butane Calcium chloride Calcium hypochlorite Carbon dioxide Carbon monoxide Citric acid 10% Copper(II) sulfate Ethyl alcohol, i.e. ethanol 95% Ethylene glycol Formaldehyde 10% Hydrochloric acid 20% Hydrofluoric acid 5% Isopropyl alcohol Mercury Methane Oxygen Ozone Sulfur Urea Water† † At room temperature. Above 60 °C hydrolysis degradation can occur. Degradation also depends on time.[citation needed] Using sodium hypochlorite (bleach) and other alkali cleaners on polycarbonate is not recommended as they cause the release of bisphenol A, a known endocrine disruptor. [edit] See also Bioplastic CR-39 Organic electronics [edit] References Wikimedia Commons has media related to: Polycarbonate ^ Medical Applications of Polycarbonate ^ “Dow Plastics Medical Application Policy”. http://plastics.dow.com/plastics/medical/. ^ “Makrolon Polycarbonate Biocompatibility Grades”. http://www.omnexus.com/tc/polycarbonate/index.aspx?id=biocompatibility. ^ http://www.pacaf.af.mil/news/story.asp?id=123136810 ^ Howdeshell, KL; Peterman PH, Judy BM, Taylor JA, Orazio CE, Ruhlen RL, Vom Saal FS, Welshons WV (July 2003). “Bisphenol A is released from used polycarbonate animal cages into water at room temperature“. Environmental Health Perspectives 111 (9): 1180–7. doi:10.1289/ehp.5993. PMID 12842771. http://ehp.niehs.nih.gov/members/2003/5993/5993.html. Retrieved on 2006-06-07. ^ vom Saal, FS; Hughes C (August 2005). “An extensive new literature concerning low-dose effects of bisphenol A shows the need for a new risk assessment“. Environmental Health Perspectives 113 (8): 926–33. PMID 16079060. http://ehp.niehs.nih.gov/docs/2005/7713/abstract.html. Retrieved on 2006-06-07. ^ http://pubs.acs.org/cen/news/84/i50/8450bisphenol.html Retrieved on 2007-02-26 ^ Julie’s Health Club - Where alternative and mainstream health meet | Chicago Tribune | Blog | Julie’s Health Club ^ Lang, Iain A.; Tamara S. Galloway, Alan Scarlett, William E. Henley, Michael Depledge, Robert B. Wallace, and David Melzer (September 2008). “Association of Urinary Bisphenol A Concentration with Medical Disorders and Laboratory Abnormalities in Adults”. Journal of the American Medical Association 300 (1): 1303–1310. doi:10.1001/jama.300.11.1303. ^ Hunt, PA; Kara E. Koehler, Martha Susiarjo, Craig A. Hodges, Arlene Ilagan, Robert C. Voigt, Sally Thomas, Brian F. Thomas and Terry J. Hassold (April 2003). “Bisphenol A Exposure Causes Meiotic Aneuploidy in the Female Mouse” ([dead link]). Current Biology 13 (7): 546–553. doi:10.1016/S0960-9822(03)00189-1. http://www.mindfully.org/Plastic/Plasticizers/BPA-Mouse1apr03.htm. ^ Koehler, KE; Robert C. Voigt, Sally Thomas, Bruce Lamb, Cheryl Urban, Terry Hassold, and Patricia A. Hunt (April 2003). “When disaster strikes: rethinking caging materials” ([dead link]). Lab Animal 32 (4): 24–27. doi:10.1038/laban0403-24. http://www.mindfully.org/Plastic/Plasticizers/BPA-Lab-Animal-CagesApr03.htm. ^ “Questions and Answers for Action on Bisphenol A Under the Chemicals Management Plan”. http://www.chemicalsubstanceschimiques.gc.ca/faq/bisphenol_a_qa-qr_e.html. ^ a b Polycarbonate [show] v • d • e Plastics Cross-linked polyethylene (PEX or XLPE) · Polyethylene (PE) · Polyethylene terephthalate (PET or PETE) · Polyphenyl ether (PPE) · Polyvinyl chloride (PVC) · Polyvinylidene chloride (PVDC) · Polylactic acid (PLA) · Polypropylene (PP) · Polybutylene (PB) · Polybutylene terephthalate (PBT) · Polyamide (PA) · Polyimide (PI) · Polycarbonate (PC) · Polytetrafluoroethylene (PTFE) · Polystyrene (PS) · Polyurethane (PU) · Polyester (PEs) · Acrylonitrile butadiene styrene (ABS) · Polymethyl methacrylate (PMMA) · Polyoxymethylene (POM) · Polysulfone (PES) · Styrene-acrylonitrile (SAN) · Ethylene vinyl acetate (EVA)) · Styrene maleic anhydride (SMA) [show] v • d • e Health issues of plastics and Polyhalogenated compounds (PHC)’s Plasticizers: Phthalates DIBP · DBP · BBP aka BBzP · DEHP aka DOP · DIDP · DINP · DIDP Other plasticizers Organophosphates · Adipate-based (DEHA · DOA) Monomers Bisphenol A (in Polycarbonates) · Vinyl chloride (in PVC) Other additives incl. PHC’s PBDEs · PCBs · Organotins · PFCs Health issues Teratogen · Carcinogen · Endocrine disruptor · Diabetes · Obesity Miscellaneous PVC · Plastic recycling · Plastic bottle · Vinyl chloride · Dioxins · Polystyrene · Styrofoam · PTFE (Teflon) · California Proposition 65 (1986) · List of environmental health hazards · Persistent organic pollutant · European REACH regulation (2006) · Japan Toxic Substances Law · Toxic Substances Control Act Retrieved from “http://en.wikipedia.org/wiki/Polycarbonate“ Categories: Plastics | Polymers | Optical materials | Polycarbonates | Dielectrics | Thermoplastics | Transparent materials Hidden categories: All articles with dead external links | Articles with dead external links from May 2009 | All articles with unsourced statements | Articles with unsourced statements from February 2007 | Articles with unsourced statements from July 2007 | Articles with unsourced statements from March 2009 Views Article Discussion Edit this page History Personal tools Log in / create account Navigation Main page Contents Featured content Current events Random article Search Interaction About Wikipedia Community portal Recent changes Contact Wikipedia Donate to Wikipedia Help Toolbox What links here Related changes Upload file Special pages Printable version Permanent link Cite this page Languages Български Česky Dansk Deutsch Español Français 한국어 Italiano עברית Magyar Nederlands 日本語 ‪Norsk (bokmål)‬ Polski Português Русский Simple English Suomi Svenska Türkçe 中文 This page was last modified on 15 May 2009, at 23:34 (UTC). All text is available under the terms of the GNU Free Documentation License. (See Copyrights for details.) Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a U.S. registered 501(c)(3) tax-deductible nonprofit charity. Privacy policy About Wikipedia Disclaimers 대한 소방 공사 대표 김 성수 Zephyr Archangel (舊名 : 김 닷줄,筆才,學梵,東洙,成珠,따쭈리) Success Kim, Zephyr Archangel Korea Fire Fighting Corporation Mobile Phone : 82-10-9119-9362, Internet : 82-70-7510-9119 who are the discoverer of Nude Fire Extinguisher in Polycarbonate/Transparent Cylinder and Plastic Valves 大韓 消防 公社

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P {margin-top:2px;margin-bottom:2px;} Polycarbonate From Wikipedia, the free encyclopedia Jump to: navigation, search Polycarbonate Repeating chemical structure unit of Polycarbonate made from Bisphenol A Physical Properties Density (ρ) 1200-1220 kg/m³ Abbe number (V) 34.0 Refractive index (n) 1.584-6 Flammability V0-V2 Limiting oxygen index 25-27% Water absorption - Equilibrium(ASTM) 0.16-0.35% Water absorption - over 24 hours 0.1% Radiation resistance Fair Ultraviolet (1-380nm) resistance Fair Mechanical Properties Young’s modulus (E) 2-2.4 GPa Tensile strength (σt) 55-75 MPa Compressive strength (σc) >80 MPa Elongation (ε) @ break 80-150% Poisson’s ratio (ν) 0.37 Hardness - Rockwell M70 Izod impact strength 600-850 J/m Notch test 20-35 kJ/m² Abrasive resistance - ASTM D1044 10-15 mg/1000 cycles Coefficient of friction (μ) 0.31 Thermal Properties Melting temperature (Tm) 267 °C* Glass transition temperature(Tg) 150 °C Heat deflection temperature - 10 kN (Vicat B)[citation needed] 145 °C Heat deflection temperature - 0.45 MPa 140 °C Heat deflection temperature - 1.8 MPa 128-138 °C Upper working temperature 115-130 °C Lower working temperature -135 °C Linear thermal expansion coefficient (α) 65-70 × 10-6/K Specific heat capacity (c) 1.2-1.3 kJ/kg·K Thermal conductivity (k) @ 23 °C 0.19-0.22 W/(m·K) Heat transfer coefficient (h) 0.21 W/(m²·K) Electrical Properties Dielectric constant (εr) @ 1 MHz 2.9 Permittivity (ε) @ 1 MHz 2.568 x10-11F/m Relative permeability (μr) @ 1 MHz 0.866(2) Permeability (μ) @ 1 MHz 1.089(2) μN/A² Dielectric strength 15-67 kV/mm Dissipation factor @ 1 MHz 0.01 Surface resistivity 1015Ω/sq Volume resistivity (ρ) 1012-1014Ω·m Near to Short-wave Infrared Transmittance Spectrum Polycarbonate transmittance in 5/6 of the NIR & 1/5 of the SWIR regions. Also, polycarbonate is almost completely transparent throughout the entire visible region of the spectrum and very sharply cuts off to ~0% transmission at almost exactly 400 nm, blocking all UV light transmission. Chemical Resistance Acids - concentrated Poor Acids - dilute Good Alcohols Good Alkalis Good-Poor Aromatic hydrocarbons Poor Greases & Oils Good-Fair Halogenated Hydrocarbons Good-Poor Halogens Poor Ketones Poor Gas permeation @ 20 ºC Nitrogen 10 - 25 cm3.mm/(m2.day.Bar) Oxygen 70 - 130 cm3.mm/(m2.day.Bar) Carbon dioxide 400 - 800 cm3.mm/(m2.day.Bar) Water vapour 1 - 2 gram.mm/(m2.day) @ 85%-0% RH gradient) Economic Properties Price 5-9 €/kg Polycarbonates are a particular group of thermoplastic polymers. They are easily worked, moulded, and thermoformed; as such, these plastics are very widely used in the modern chemical industry. Their interesting features (temperature resistance, impact resistance and optical properties) position them between commodity plastics and engineering plastics. Their plastic identification code is 7. Contents [hide] 1 Chemistry 2 Synthesis 3 Processing 4 Applications 4.1 Trade names 5 Potential hazards in food contact applications 6 Chemical compatibility 7 See also 8 References [edit] Chemistry Polycarbonates received their name because they are polymers having functional groups linked together by carbonate groups (-O-(C=O)-O-) in a long molecular chain. Also carbon monoxide was used as a C1-synthon on an industrial scale to produce diphenyl carbonate, being later trans-esterified with a diphenolic derivative affording poly (aromatic carbonate)s. Taking into consideration the C1-synthon polycarbonates can be divided into poly(aromatic carbonate)s and poly(aliphatic carbonate)s. The second one, poly(aliphatic carbonate)s are a product of the reaction of carbon dioxide with epoxides, which owing to the thermodynamical stability of carbon dioxide requires the use of a catalyst. The working systems are based on porphyrins, alkoxides, carboxylates, salens and beta-diiminates as organic, chelating ligands and aluminium, zinc, cobalt and chromium as the metal centres. Poly(aliphatic carbonate)s display promising characteristics, have a better biodegradability than the aromatic ones and could be employed to develop other specialty polymers. One type of polycarbonate plastic is made from bisphenol A (BPA). This polycarbonate is a very durable material, and can be laminated to make bullet-proof “glass”, though “bullet-resistant” would be more accurate. Although polycarbonate has high impact-resistance, it has low scratch-resistance and so a hard coating is applied to polycarbonate eyewear lenses and polycarbonate exterior automotive components. The characteristics of polycarbonate are quite like those of polymethyl methacrylate (PMMA; acrylic), but polycarbonate is stronger, usable in a larger temperature range but also more expensive. This polymer is highly transparent to visible light and has better light transmission characteristics than many kinds of glass. CR-39 is a specific polycarbonate material — although it is usually referred to as CR-39 plastic — with good optical and mechanical properties, frequently used for eyeglass lenses. [edit] Synthesis Polycarbonate can be synthesized from bisphenol A and phosgene (carbonyl dichloride, COCl2). The first step in the synthesis of polycarbonate from bisphenol A is treatment of bisphenol A with sodium hydroxide. This deprotonates the hydroxyl groups of the bisphenol A molecule. The deprotonated oxygen reacts with phosgene through carbonyl addition to create a tetrahedral intermediate (not shown here), after which the negatively charged oxygen kicks off a chloride ion (Cl-) to form a chloroformate. The chloroformate is then attacked by another deprotonated bisphenol A, eliminating the remaining chloride ion and forming a dimer of bisphenol A with a carbonate linkage in between. Repetition of this process yields a polycarbonate with alternating carbonate groups and groups from bisphenol A. [edit] Processing Polycarbonate has a glass transition temperature of about 150 °C (302 °F), so it softens gradually above this point and flows above about 300 °C (572 °F). Injection moulding is more difficult than other common thermoplastics owing to its non-Newtonian fluid flow behaviour. Tools must be held at high temperatures, generally above 80 °C (176 °F) to make strain- and stress-free products. Low molecular mass grades are easier to mould than higher grades, but their strength is lower as a result. The toughest grades have the highest molecular mass, but are much more difficult to process. [edit] Applications Polycarbonate is becoming more common in housewares as well as laboratories and in industry, especially in applications where any of its main features—high impact resistance, temperature resistance, optical properties—are required. Main transformation techniques for polycarbonate resins: extrusion into tubes, rods and other profiles extrusion with cylinders into sheets (0.5–15 mm (0.020–0.59 in)) and films (below 1 mm (0.039 in)), which can be used directly or manufactured into other shapes using thermoforming or secondary fabrication techniques, such as bending, drilling, routing, laser cutting etc. injection molding into ready articles Typical injected applications: compact discs, DVDs, Blu-ray Discs drinking bottles drinking glasses lab equipment, research animal enclosures lighting lenses, sunglass/eyeglass lenses, safety glasses, automotive headlamp lenses MP3/Digital audio player cases Typical sheet/film application: Advertisement: signs, displays, poster protection Building: domelights, flat or curved glazing, and sound walls Computers: Apple’s MacBook, and Mac mini Industry: machined or formed, cases, machine glazing, riot shields, visors, instrument panels For use in applications exposed to weathering or UV-radiation, a special surface treatment is needed. This either can be a coating (e.g. for improved abrasion resistance), or a coextrusion for enhanced weathering resistance. Some polycarbonate grades are used in medical applications and comply with both ISO 10993-1 and USP Class VI standards (occasionally referred to as PC-ISO). Class VI is the most stringent of the six USP ratings. These grades can be sterilized using steam at 120 °C, gamma radiation or the ethylene oxide (EtO) method.[1] However, scientific research indicates possible problems with biocompatibility. Dow Chemical strictly limits all its plastics with regard to medical applications.[2][3] The cockpit canopy of the F-22 Raptor jet fighter is made from a piece of high optical quality polycarbonate, and is the largest piece of its type formed in the world.[4] In the automotive industry, injection moulded polycarbonate can produce very smooth surfaces that make it well suited for direct (without the need for a basecoat) metalised parts such as decorative bezels and optical reflectors. Its uniform mould shrinkage results in parts with greater accuracy than those made of polypropylene. However, due to its susceptibility to stress corrosion cracking, its use is limited to low stress applications. Being based on bisphenol A (a phenol based on benzene) pricing is largely dependent on phenol and benzene pricing. [edit] Trade names Other trade names for polycarbonate include: Calibre from Dow Chemicals Iupilon from Mitsubishi Engineering-Plastics Corp. Lexan from SABIC Innovative Plastics (formerly General Electric Plastics) Makrolife from Arlaplast Makrolon from Bayer Panlite from Teijin Chemical Limited Tarflon from Idemitsu Kosan Co.Ltd. [edit] Potential hazards in food contact applications Main article: Bisphenol A Polycarbonate may be appealing to manufacturers and purchasers of food storage containers due to its clarity and toughness, being described as lightweight and highly break resistant particularly when compared to silica glass. Polycarbonate may be seen in the form of single use and refillable plastic water bottles. More than 100 studies have explored the bioactivity of bisphenol A leachates from polycarbonates. Bisphenol A appeared to be released from polycarbonate animal cages into water at room temperature and that it may have been responsible for enlargement of the reproductive organs of female mice.[5] An analysis of the literature on bisphenol A leachate low-dose effects by vom Saal and Hughes published in August 2005 seems to have found a suggestive correlation between the source of funding and the conclusion drawn. Industry funded studies tend to find no significant effects while government funded studies tend to find significant effects.[6] Research by Ana M. Soto, professor of anatomy and cellular biology at Tufts University School of Medicine, Boston, published Dec. 6 in the online edition of Reproductive Toxicology (DOI: 10.1016/j.reprotox.2006.10.002) describes exposure of pregnant rats to bisphenol A at 2.5 to 1,000 µg per kilogram of body weight per day. At the equivalent of puberty for the pups (50 days old), about 25% of their mammary ducts had precancerous lesions, some three to four times higher than unexposed controls. The study is cited as evidence for the hypothesis that environmental exposure to bisphenol A as a fetus can cause breast cancer in adult women.[7] An expert panel of 12 scientists has found that there is “some concern that exposure to the chemical bisphenol A in utero causes neural and behavioral effects,” according to the draft report prepared by The National Toxicology Program (NTP) Center for the Evaluation of Risks to Human Reproduction. For the general adult population, the expert panel found a “negligible concern for adverse reproductive effects following exposures.”[8] A study of cross-sectional data from the 2003-2004 U.S. National Health and Nutritional Examination Survey published in the September 17, 2008 edition of the Journal of the American Medical Association (JAMA) demonstrated positive and statistically significant correlations between the concentration of bisphenol A in the urine and self-reported histories of cardiovascular disease and diabetes.[9] One point of agreement among those studying polycarbonate water and food storage containers may be that using sodium hypochlorite bleach and other alkali cleaners to clean polycarbonate is not recommended, as they catalyze the release of the bisphenol-A. The tendency of polycarbonate to release bisphenol A was discovered after a lab tech used strong cleaners on polycarbonate lab containers. Endocrine disruption later observed on lab rats was traced to exposure from the cleaned containers.[10][11] On April 18, 2008, Health Canada announced that bisphenol A is “toxic to human health”.[12] Canada is the first and only nation to make this designation. [edit] Chemical compatibility A chemical compatibility chart shows reactivity between chemicals such as polycarbonate and a cleaning agent.[13]Alcohol is one recommended organic solvent for cleaning grease and oils from polycarbonate. For treating mold, borax:H2O 1:96 to 1:8 may be effective.[citation needed] Compatibility with various chemicals[13] Will damage polycarbonate Require caution Considered safe Alkali bleaches such as sodium hypochlorite Acetone Acrylonitrile Ammonia Amyl acetate Benzene Bromine Butyl acetate Sodium hydroxide Chloroform Dimethylformamide Concentrated hydrochloric acid Concentrated hydrofluoric acid Iodine Methanol Methyl ethyl ketone Styrene Tetrachloroethylene Toluene Concentrated sulfuric acid Xylene Cyanoacrylate monomers Cyclohexanone Diesel oil Formic acid Gasoline Glycerine Heating oil Jet fuel Concentrated perchloric acid Sulfur dioxide Turpentine Acetic acid Ammonium chloride Antimony trichloride Borax in H2O Butane Calcium chloride Calcium hypochlorite Carbon dioxide Carbon monoxide Citric acid 10% Copper(II) sulfate Ethyl alcohol, i.e. ethanol 95% Ethylene glycol Formaldehyde 10% Hydrochloric acid 20% Hydrofluoric acid 5% Isopropyl alcohol Mercury Methane Oxygen Ozone Sulfur Urea Water† † At room temperature. Above 60 °C hydrolysis degradation can occur. Degradation also depends on time.[citation needed] Using sodium hypochlorite (bleach) and other alkali cleaners on polycarbonate is not recommended as they cause the release of bisphenol A, a known endocrine disruptor. [edit] See also Bioplastic CR-39 Organic electronics [edit] References Wikimedia Commons has media related to: Polycarbonate ^ Medical Applications of Polycarbonate ^ “Dow Plastics Medical Application Policy”. http://plastics.dow.com/plastics/medical/. ^ “Makrolon Polycarbonate Biocompatibility Grades”. http://www.omnexus.com/tc/polycarbonate/index.aspx?id=biocompatibility. ^ http://www.pacaf.af.mil/news/story.asp?id=123136810 ^ Howdeshell, KL; Peterman PH, Judy BM, Taylor JA, Orazio CE, Ruhlen RL, Vom Saal FS, Welshons WV (July 2003). “Bisphenol A is released from used polycarbonate animal cages into water at room temperature“. Environmental Health Perspectives 111 (9): 1180–7. doi:10.1289/ehp.5993. PMID 12842771. http://ehp.niehs.nih.gov/members/2003/5993/5993.html. Retrieved on 2006-06-07. ^ vom Saal, FS; Hughes C (August 2005). “An extensive new literature concerning low-dose effects of bisphenol A shows the need for a new risk assessment“. Environmental Health Perspectives 113 (8): 926–33. PMID 16079060. http://ehp.niehs.nih.gov/docs/2005/7713/abstract.html. Retrieved on 2006-06-07. ^ http://pubs.acs.org/cen/news/84/i50/8450bisphenol.html Retrieved on 2007-02-26 ^ Julie’s Health Club - Where alternative and mainstream health meet | Chicago Tribune | Blog | Julie’s Health Club ^ Lang, Iain A.; Tamara S. Galloway, Alan Scarlett, William E. Henley, Michael Depledge, Robert B. Wallace, and David Melzer (September 2008). “Association of Urinary Bisphenol A Concentration with Medical Disorders and Laboratory Abnormalities in Adults”. Journal of the American Medical Association 300 (1): 1303–1310. doi:10.1001/jama.300.11.1303. ^ Hunt, PA; Kara E. Koehler, Martha Susiarjo, Craig A. Hodges, Arlene Ilagan, Robert C. Voigt, Sally Thomas, Brian F. Thomas and Terry J. Hassold (April 2003). “Bisphenol A Exposure Causes Meiotic Aneuploidy in the Female Mouse” ([dead link]). Current Biology 13 (7): 546–553. doi:10.1016/S0960-9822(03)00189-1. http://www.mindfully.org/Plastic/Plasticizers/BPA-Mouse1apr03.htm. ^ Koehler, KE; Robert C. Voigt, Sally Thomas, Bruce Lamb, Cheryl Urban, Terry Hassold, and Patricia A. Hunt (April 2003). “When disaster strikes: rethinking caging materials” ([dead link]). Lab Animal 32 (4): 24–27. doi:10.1038/laban0403-24. http://www.mindfully.org/Plastic/Plasticizers/BPA-Lab-Animal-CagesApr03.htm. ^ “Questions and Answers for Action on Bisphenol A Under the Chemicals Management Plan”. http://www.chemicalsubstanceschimiques.gc.ca/faq/bisphenol_a_qa-qr_e.html. ^ a b Polycarbonate [show] v • d • e Plastics Cross-linked polyethylene (PEX or XLPE) · Polyethylene (PE) · Polyethylene terephthalate (PET or PETE) · Polyphenyl ether (PPE) · Polyvinyl chloride (PVC) · Polyvinylidene chloride (PVDC) · Polylactic acid (PLA) · Polypropylene (PP) · Polybutylene (PB) · Polybutylene terephthalate (PBT) · Polyamide (PA) · Polyimide (PI) · Polycarbonate (PC) · Polytetrafluoroethylene (PTFE) · Polystyrene (PS) · Polyurethane (PU) · Polyester (PEs) · Acrylonitrile butadiene styrene (ABS) · Polymethyl methacrylate (PMMA) · Polyoxymethylene (POM) · Polysulfone (PES) · Styrene-acrylonitrile (SAN) · Ethylene vinyl acetate (EVA)) · Styrene maleic anhydride (SMA) [show] v • d • e Health issues of plastics and Polyhalogenated compounds (PHC)’s Plasticizers: Phthalates DIBP · DBP · BBP aka BBzP · DEHP aka DOP · DIDP · DINP · DIDP Other plasticizers Organophosphates · Adipate-based (DEHA · DOA) Monomers Bisphenol A (in Polycarbonates) · Vinyl chloride (in PVC) Other additives incl. PHC’s PBDEs · PCBs · Organotins · PFCs Health issues Teratogen · Carcinogen · Endocrine disruptor · Diabetes · Obesity Miscellaneous PVC · Plastic recycling · Plastic bottle · Vinyl chloride · Dioxins · Polystyrene · Styrofoam · PTFE (Teflon) · California Proposition 65 (1986) · List of environmental health hazards · Persistent organic pollutant · European REACH regulation (2006) · Japan Toxic Substances Law · Toxic Substances Control Act Retrieved from “http://en.wikipedia.org/wiki/Polycarbonate“ Categories: Plastics | Polymers | Optical materials | Polycarbonates | Dielectrics | Thermoplastics | Transparent materials Hidden categories: All articles with dead external links | Articles with dead external links from May 2009 | All articles with unsourced statements | Articles with unsourced statements from February 2007 | Articles with unsourced statements from July 2007 | Articles with unsourced statements from March 2009 Views Article Discussion Edit this page History Personal tools Log in / create account Navigation Main page Contents Featured content Current events Random article Search Interaction About Wikipedia Community portal Recent changes Contact Wikipedia Donate to Wikipedia Help Toolbox What links here Related changes Upload file Special pages Printable version Permanent link Cite this page Languages Български Česky Dansk Deutsch Español Français 한국어 Italiano עברית Magyar Nederlands 日本語 ‪Norsk (bokmål)‬ Polski Português Русский Simple English Suomi Svenska Türkçe 中文 This page was last modified on 15 May 2009, at 23:34 (UTC). All text is available under the terms of the GNU Free Documentation License. (See Copyrights for details.) Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a U.S. registered 501(c)(3) tax-deductible nonprofit charity. Privacy policy About Wikipedia Disclaimers 대한 소방 공사 대표 김 성수 Zephyr Archangel (舊名 : 김 닷줄,筆才,學梵,東洙,成珠,따쭈리) Success Kim, Zephyr Archangel Korea Fire Fighting Corporation Mobile Phone : 82-10-9119-9362, Internet : 82-70-7510-9119 who are the discoverer of Nude Fire Extinguisher in Polycarbonate/Transparent Cylinder and Plastic Valves 大韓 消防 公社

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