Array ( [0] => {{short description|Family of polymers}} [1] => {{this|thermoplastic polymer materials|carbonate-chain functional-groups|polycarbonate (functional group)}} [2] => [3] => {{Infobox material [4] => | name = Polycarbonate [5] => | image = Lexan.svg [6] => | image_size = 300px [7] => | caption = Repeating chemical structure unit of
'''Polycarbonate''' made from [[bisphenol A]] [8] => ---- [9] => [10] => [[File:VisibleLightSpectrum2.svg|center|300px]] [11] => Transmission spectrum of polycarbonate [12] => | density = 1.20–1.22 g/cm3 [13] => | abbe_number = 34.0 [14] => | refractive_index = [[List of indices of refraction|1.584–1.586]] [15] => | flammability = HB-V2 [16] => | limiting_oxygen_index = 25–29% [17] => | water_absorption_eq = 0.16–0.35% [18] => | water_absorption_24h = 0.1% [19] => | radiation_resistance = {{bg|#ffc|Fair}} [20] => | uv_resistance = {{bg|#ffc|Fair}} [21] => | youngs_modulus = 2.0–2.4 [[Giga|G]][[Pascal (unit)|Pa]] [22] => | tensile_strength = 55–75 [[Mega-|M]]Pa [23] => | compressive_strength = >80 MPa [24] => | elongation = 80–150% [25] => | poissons_ratio = 0.37 [26] => | hardness_rockwell = M70 [27] => | izod_impact_strength = 600–850 [[Joule|J]]/m [28] => | notch_test = 20–35 [[Kilo-|k]]J/m2 [29] => | abrasive_resistance_note =[[ASTM International|ASTM]] D1044 [30] => | abrasive_resistance = 10–15 [[Milli|m]][[Gram|g]]/1000 [[rotation|cycles]] [31] => | coeff_friction = 0.31 [32] => | speed_of_sound = 2270 m/s [33] => | glass_transition = {{convert|147|C|F}} [34] => | vicat_note = at 50 [[Newton (unit)|N]] [35] => | vicat = {{convert|145|-|150|C|F}}{{cite web|url=https://sfs.sabic.eu/wp-content/uploads/resource_pdf/1345453948-48623687-Technical-Manual-Coated-Uncoated-Sheet.pdf|title=Lexan sheet technical manual|publisher=[[SABIC]]|date=2009|access-date=2015-07-18|archive-url=https://web.archive.org/web/20150316235516/http://sfs.sabic.eu/wp-content/uploads/resource_pdf/1345453948-48623687-Technical-Manual-Coated-Uncoated-Sheet.pdf|archive-date=2015-03-16}} [36] => | heat_deflection_temp = {{unbulleted list [37] => |0.45 MPa: {{convert|140|C|F}} [38] => |1.8 MPa: {{convert|128|-|138|C|F}} [39] => }} [40] => | upper_working_temp = {{convert|115|-|130|C|F}} [41] => | lower_working_temp = {{convert|-40|C|F}}{{cite journal|author1=Parvin, M. |author2=Williams, J. G. |name-list-style=amp |title= The effect of temperature on the fracture of polycarbonate|journal=Journal of Materials Science|volume=10|issue=11|year=1975|page=1883|doi=10.1007/BF00754478|bibcode=1975JMatS..10.1883P|s2cid=135645940 }} [42] => | linear_expansion = 65–70 × 10−6/[[Kelvin|K]] [43] => | specific_heat = 1.2–1.3 kJ/([[Kilogram|kg]]·K) [44] => | thermal_conductivity_note = at 23 °C [45] => | thermal_conductivity = 0.19–0.22 [[Watt|W]]/(m·K) [46] => | thermal_diffusivity_note = at 25 °C [47] => | thermal_diffusivity = 0.144 mm²/s{{cite journal |author1= Blumm, J. |author2=Lindemann, A. |title= Characterization of the thermophysical properties of molten polymers and liquids using the flash technique|url=http://www.eyoungindustry.com/uploadfile/file/20151027/20151027211034_96662.pdf|year=2003 |journal=High Temperatures – High Pressures |volume= 35/36 |issue=6 |page= 627 | doi= 10.1068/htjr144 }} [48] => | dielectric_constant_note = at 1 M[[Hertz|Hz]] [49] => | dielectric_constant = 2.9 [50] => | permittivity_note = at 1 MHz [51] => | permittivity = 2.568 × 10−11 [[Farad|F]]/m [52] => | relative_permeability_note = at 1 MHz [53] => | relative_permeability = 0.866(2) [54] => | permeability_note = at 1 MHz [55] => | permeability = 1.089(2) [[Micro-|μ]]N/[[Ampere|A]]2 [56] => | dielectric_strength = 15–67 [[Kilovolt|kV]]/mm [57] => | dissipation_factor_note = at 1 [[Megahertz|MHz]] [58] => | dissipation_factor = 0.01 [59] => | surface_resistivity = 1015 [[Ohm|Ω]]/sq [60] => | volume_resistivity = 1012–1014 [[Ohm|Ω]]·m [61] => | chem_res_acid_c = {{bg|#fcc|Poor}} [62] => | chem_res_acid_d = {{bg|#cfc|Good}} [63] => | chem_res_alcohol = {{bg|#cfc|Good}} [64] => | chem_res_alkali = {{bg|#ffc|Good-Poor}} [65] => | chem_res_aromatic = {{bg|#fcc|Poor}} [66] => | chem_res_grease_oil = {{bg|#e5ffcc|Good-fair}} [67] => | chem_res_haloalkane = {{bg|#ffc|Good-poor}} [68] => | chem_res_halogen = {{bg|#fcc|Poor}} [69] => | chem_res_ketone = {{bg|#fcc|Poor}} [70] => | gas_perm_temp = 20 °C [71] => | gas_perm_N = 10–25 cm3·mm/(m2·day·[[Bar (unit)|Bar]]) [72] => | gas_perm_O = 70–130 cm3·mm/(m2·day·Bar) [73] => | gas_perm_CO2 = 400–800 cm3·mm/(m2·day·Bar) [74] => | gas_perm_H2O =1–2 g·mm/(m2·day) @ 85%–0% [[Relative humidity|RH]] [[gradient]] [75] => | price = 2.6–2.8 €/kgCES Edupack 2010, Polycarbonate (PC) specs sheet [76] => | footnotes = [77] => }} [78] => [79] => '''Polycarbonates''' ('''PC''') are a group of [[thermoplastic]] polymers containing [[carbonate ester|carbonate group]]s in their chemical structures. Polycarbonates used in engineering are strong, [[toughness|tough]] materials, and some grades are optically transparent. They are easily worked, [[injection molding|molded]], and [[thermoforming|thermoformed]]. Because of these properties, polycarbonates find many applications. Polycarbonates do not have a unique [[resin identification code|resin identification code (RIC)]] and are identified as "Other", 7 on the RIC list. Products made from polycarbonate can contain the precursor monomer [[bisphenol A]] (BPA). [80] => [81] => ==Structure== [82] => [[File:DINWOM10.png|thumb|left|Structure of dicarbonate (PhOC(O)OC6H4 )2CMe2 derived from bis(phenol-A) and two equivalents of phenol.{{cite journal|doi=10.1021/ma00167a014|title=Crystalline features of 4,4'-isopropylidenediphenylbis(phenyl carbonate) and conformational analysis of the polycarbonate of 2,2-bis(4-hydroxyphenyl)propane|journal=Macromolecules|volume=20|issue=1|pages=68–77|year=1987|last1=Perez|first1=Serge|last2=Scaringe|first2=Raymond P.|bibcode=1987MaMol..20...68P}} This molecule reflects a subunit of a typical polycarbonate derived from bis(phenol-A).]] [83] => Carbonate esters have planar OC(OC)2 cores, which confer rigidity. The unique O=C bond is short (1.173 Å in the depicted example), while the C-O bonds are more ether-like (the bond distances of 1.326 Å for the example depicted). Polycarbonates received their name because they are [[polymers]] containing [[carbonate ester|carbonate group]]s (−O−(C=O)−O−). A balance of useful features, including temperature resistance, impact resistance and optical properties, positions polycarbonates between [[commodity plastics]] and [[engineering plastic]]s. [84] => [85] => ==Production== [86] => === Phosgene route === [87] => The main polycarbonate material is produced by the reaction of [[bisphenol A]] (BPA) and [[phosgene]] {{chem|COCl|2}}. The overall reaction can be written as follows: [88] => [89] => [[File:Polycarbonatsynthese.svg|450px]] [90] => [91] => The first step of the synthesis involves treatment of bisphenol A with [[sodium hydroxide]], which [[deprotonates]] the [[hydroxyl group]]s of the bisphenol A.Volker Serini "Polycarbonates" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2000. {{doi|10.1002/14356007.a21_207}} [92] => [93] => :(HOC6H4)2CMe2 + 2 NaOH → Na2(OC6H4)2CMe2 + 2 H2O [94] => [95] => The di[[phenoxide]] (Na2(OC6H4)2CMe2) reacts with phosgene to give a [[chloroformate]], which subsequently is attacked by another phenoxide. The net reaction from the diphenoxide is: [96] => [97] => :Na2(OC6H4)2CMe2 + COCl2 → 1/n [OC(OC6H4)2CMe2]n + 2 NaCl [98] => [99] => In this way, approximately one billion kilograms of polycarbonate is produced annually. Many other [[diol]]s have been tested in place of bisphenol A, e.g. 1,1-bis(4-hydroxyphenyl)cyclohexane and [[dihydroxybenzophenone]]. The cyclohexane is used as a comonomer to suppress crystallisation tendency of the BPA-derived product. [[Tetrabromobisphenol A]] is used to enhance fire resistance. [[Tetramethylcyclobutanediol]] has been developed as a replacement for BPA. [100] => [101] => === Transesterification route === [102] => An alternative route to polycarbonates entails [[transesterification]] from BPA and [[diphenyl carbonate]]: [103] => :(HOC6H4)2CMe2 + (C6H5O)2CO → 1/n [OC(OC6H4)2CMe2]n + 2 C6H5OH [104] => [105] => ==Properties and processing== [106] => Polycarbonate is a durable material. Although it has high impact-resistance, it has low scratch-resistance. Therefore, a hard coating is applied to polycarbonate [[eyewear]] [[corrective lens|lenses]] and polycarbonate exterior automotive components. The characteristics of polycarbonate compare to those of [[polymethyl methacrylate]] (PMMA, acrylic), but polycarbonate is stronger and will hold up longer to extreme temperature. Thermally processed material is usually totally amorphous,{{cite journal|last1=Djurner|first1=K.|last2=M??nson|first2=J-A.|last3=Rigdahl|first3=M.|title=Crystallization of polycarbonate during injection molding at high pressures|journal=Journal of Polymer Science: Polymer Letters Edition|volume=16|issue=8|year=1978|pages=419–424|issn=0360-6384|doi=10.1002/pol.1978.130160806|bibcode=1978JPoSL..16..419D}} and as a result is highly [[Transparency (optics)|transparent]] to [[visible light]], with better light transmission than many kinds of glass. [107] => [108] => Polycarbonate has a [[glass transition temperature]] of about {{convert|147|C|F|abbr=on}},[https://web.archive.org/web/20100210070124/http://www.bayermaterialsciencenafta.com/faq_pcs/index.html Answers to Common Questions about Bayer Polycarbonate Resins]. bayermaterialsciencenafta.com so it softens gradually above this point and flows above about {{convert|155|C|F|abbr=on}}.{{cite web |title=Polycarbonate |publisher=city plastics |url=http://www.cityplastics.com.au/materials-polycarbonate/ |access-date=2013-12-18 |archive-url=https://web.archive.org/web/20181016161442/http://www.cityplastics.com.au/materials-polycarbonate |archive-date=2018-10-16 }} Tools must be held at high temperatures, generally above {{convert|80|C|F|abbr=on}} to make strain-free and stress-free products. Low [[molecular mass]] grades are easier to mold than higher grades, but their strength is lower as a result. The toughest grades have the highest molecular mass, but are more difficult to process. [109] => [110] => Unlike most thermoplastics, polycarbonate can undergo large plastic deformations without cracking or breaking. As a result, it can be processed and formed at room temperature using [[sheet metal]] techniques, such as bending on a [[Brake (sheet metal bending)|brake]]. Even for sharp angle bends with a tight radius, heating may not be necessary. This makes it valuable in prototyping applications where transparent or electrically non-conductive parts are needed, which cannot be made from sheet metal. [[Poly(methyl methacrylate)|PMMA/Acrylic]], which is similar in appearance to polycarbonate, is brittle and cannot be bent at room temperature. [111] => [112] => Main transformation techniques for polycarbonate resins: [113] => *[[extrusion]] into tubes, rods and other profiles including multiwall [114] => *extrusion with cylinders ([[calender]]s) into sheets ({{convert|0.5|-|20|mm|in|abbr=on}}) and films (below {{convert|1|mm|in|abbr=on}}), which can be used directly or manufactured into other shapes using [[thermoforming]] or secondary [[Manufacturing|fabrication]] techniques, such as bending, drilling, or routing. Due to its chemical properties it is not conducive to laser-cutting. [115] => *[[injection molding]] into ready articles [116] => [117] => Polycarbonate may become [[Brittleness|brittle]] when exposed to ionizing radiation above {{nowrap|25 [[Gray (unit)|kGy]] (kJ/kg).}}{{cite book |author1=David W. Plester |date=1973 |chapter=The Effects of Radiation Sterilization on Plastics |title=Sterilization Technology |chapter-url=http://infohouse.p2ric.org/ref/27/26567.pdf |archive-url=https://web.archive.org/web/20150512042131/http://infohouse.p2ric.org/ref/27/26567.pdf |archive-date=2015-05-12 |s2cid=18798850|quote=Polycarbonate can satisfactorily be given a single-dose sterilization exposure (22) but tends to become brittle much above 2.5 Mrad. |page=149}} [118] => [119] => [[File:Polycarbonate water bottle.JPG|thumb|A bottle made from polycarbonate]] [120] => [121] => ==Applications== [122] => [123] => ===Electronic components=== [124] => Polycarbonate is mainly used for electronic applications that capitalize on its collective safety features. A good electrical insulator with heat-resistant and flame-retardant properties, it is used in products associated with power systems and telecommunications hardware. It can serve as a [[dielectric]] in high-stability [[capacitor]]s. Commercial manufacture of polycarbonate capacitors mostly stopped after sole manufacturer [[Bayer AG]] stopped making capacitor-grade polycarbonate film at the end of 2000.{{cite web|url=http://my.execpc.com/~endlr/film.html|title=Film|work=execpc.com|access-date=2012-07-19|archive-date=2023-03-09|archive-url=https://web.archive.org/web/20230309161434/http://my.execpc.com/~endlr/film.html|url-status=dead}}{{cite web|title=WIMA|url=http://wima.cn/EN/polycarbonate.htm|url-status=live|archive-url=https://web.archive.org/web/20170612225417/http://www.wima.com/EN/polycarbonate.htm|archive-date=June 12, 2017|work=wima.com}} [125] => [126] => ===Construction materials=== [127] => [[File:Polycarbonate Greenhouse-00.jpg|thumb|Polycarbonate sheeting in a greenhouse]] [128] => The second largest consumer of polycarbonates is the construction industry, e.g. for domelights, flat or curved glazing, roofing sheets and [[sound wall]]s. [129] => Polycarbonates are used to create materials used in buildings that must be durable but light. [130] => [131] => ===3D Printing=== [132] => Polycarbonates are used extensively in 3D FDM printing, producing durable strong plastic products with a high melting point. Polycarbonate is relatively difficult for casual hobbyists to print compared to thermoplastics such as [[Polylactic acid]] (PLA) or [[Acrylonitrile butadiene styrene]] (ABS) because of the high melting point, difficulty with print bed adhesion, tendency to warp during printing, and tendency to absorb moisture in humid environments. Despite these issues, 3D printing using polycarbonates is common in the professional community. [133] => [134] => ===Data storage=== [135] => A major polycarbonate market is the production of [[compact disc]]s, [[DVD]]s, and [[Blu-ray]] discs.{{Cite news|url=https://www.bbc.com/news/entertainment-arts-46735093#:~:text=Sales%20of%20CDs%20plummeted%20by%2023%%20last%20year,,2008;%20and%20a%20drop%20of%209.6%20million%20year-on-year.|title = Is this the end of owning music?|work = BBC News|date = 3 January 2019}} These discs are produced by injection-molding polycarbonate into a mold cavity that has on one side a metal stamper containing a negative image of the disc data, while the other mold side is a mirrored surface. Typical products of sheet/film production include applications in advertisement (signs, displays, poster protection). [136] => [137] => ===Automotive, aircraft, and security components=== [138] => In the automotive industry, injection-molded polycarbonate can produce very smooth surfaces that make it well-suited for [[sputter deposition]] or [[Evaporation (deposition)|evaporation deposition]] of aluminium without the need for a base-coat. Decorative bezels and optical reflectors are commonly made of polycarbonate. [139] => Its low weight and high impact resistance have made polycarbonate the dominant material for automotive headlamp lenses. However, automotive headlamps require outer surface coatings because of its low scratch resistance and susceptibility to ultraviolet degradation (yellowing). The use of polycarbonate in automotive applications is limited to low stress applications. Stress from fasteners, [[plastic welding]] and molding render polycarbonate susceptible to [[stress corrosion cracking]] when it comes in contact with certain accelerants such as salt water and [[plastisol]]. It can be laminated to make [[bullet-proof glass|bullet-proof "glass"]], although "bullet-resistant" is more accurate for the thinner windows, such as are used in bullet-resistant windows in automobiles. The thicker barriers of transparent plastic used in teller's windows and barriers in banks are also polycarbonate. [140] => [141] => So-called "theft-proof" large plastic packaging for smaller items, which cannot be opened by hand, is typically made from polycarbonate. [142] => [143] => [[File:F-22 Raptor and pilot at Marine Corps Air Station Miramar 25 Jun 2010.jpg|thumb|Lockheed Martin F-22 cockpit canopy]] [144] => The cockpit canopy of the [[Lockheed Martin F-22 Raptor]] jet fighter is fabricated from high optical quality polycarbonate. It is the largest item of its type.[http://www.pacaf.af.mil/news/story.asp?id=123136810 Egress technicians keep raptor pilots covered]. Pacaf.af.mil. Retrieved on 2011-02-26.{{cite book |last1=Emsley |first1=John |author1-link=John Emsley |title=A Healthy, Wealthy, Sustainable World |date=9 November 2015 |publisher=Royal Society of Chemistry |isbn=978-1-78262-589-6 |page=119 |url=https://books.google.com/books?id=qGsoDwAAQBAJ |access-date=1 October 2023 |language=en}} [145] => [146] => === Niche applications === [147] => Polycarbonate, being a versatile material with attractive processing and physical properties, has attracted myriad smaller applications. The use of injection molded drinking bottles, glasses and food containers is common, but the use of BPA in the manufacture of polycarbonate has stirred concerns (see [[#Potential hazards in food contact applications|Potential hazards in food contact applications]]), leading to development and use of "BPA-free" plastics in various formulations. [148] => [149] => [[File:Laboratory protection goggles-blue.jpg|thumb|Laboratory safety goggles]] [150] => Polycarbonate is commonly used in eye protection, as well as in other projectile-resistant viewing and lighting applications that would normally indicate the use of [[glass]], but require much higher impact-resistance. Polycarbonate lenses also protect the eye from [[Eyeglass#Polycarbonate|UV]] light. Many kinds of lenses are manufactured from polycarbonate, including automotive headlamp lenses, lighting lenses, [[sunglass]]/[[eyeglass]] [[Corrective lens|lenses]], swimming goggles and SCUBA masks, and safety glasses/goggles/visors including visors in sporting helmets/masks and police [[riot gear]] (helmet visors, riot shields, etc.). Windscreens in small motorized vehicles are commonly made of polycarbonate, such as for motorcycles, ATVs, golf carts, and small airplanes and helicopters. [151] => [152] => The light weight of polycarbonate as opposed to glass has led to development of electronic display screens that replace glass with polycarbonate, for use in mobile and portable devices. Such displays include newer [[e-ink]] and some LCD screens, though CRT, plasma screen and other LCD technologies generally still require glass for its higher melting temperature and its ability to be etched in finer detail. [153] => [154] => As more and more governments are restricting the use of glass in pubs and clubs due to the increased incidence of [[glassing]]s, polycarbonate glasses are becoming popular for serving alcohol because of their strength, durability, and glass-like feel.[https://web.archive.org/web/20130428193825/http://www.olgr.nsw.gov.au/alcohol_restrictions_for_violent_venues.asp Alcohol restrictions for violent venues]. State of New South Wales (Office of Liquor, Gaming & Racing)[https://web.archive.org/web/20130531123154/http://www.olgr.qld.gov.au/industry/liquor_compliance/glass_bans/index.shtml Ban on regular glass in licensed premises]. The State of Queensland (Department of Justice and Attorney-General) [155] => [156] => [[File:Lamy 2000 fountain pen, EF semi hooded nib.jpg|thumb|[[Lamy#2000|Lamy 2000]] piston filler made of polycarbonate and stainless steel, launched in 1966 and still in production]] [157] => [158] => [159] => Other miscellaneous items include durable, lightweight luggage, [[Digital audio player|MP3/digital audio player cases]], [[ocarina]]s, computer cases, [[riot shields]], instrument panels, tealight candle containers and food blender jars. Many toys and hobby items are made from polycarbonate parts, like fins, gyro mounts, and flybar locks in [[radio-controlled helicopter]]s,{{cite web|title=RDLohr's Clearly Superior Products|url=http://clearly.wavelandps.com/products.pdf|archive-url=https://web.archive.org/web/20100401062436/http://clearly.wavelandps.com/products.pdf|archive-date=1 April 2010|work=wavelandps.com}} and transparent [[LEGO]] ([[Acrylonitrile butadiene styrene#Applications|ABS]] is used for opaque pieces).{{cite web|url=http://info.craftechind.com/blog/which-plastic-material-is-used-in-lego-sets |archive-url=https://web.archive.org/web/20170305114209/http://info.craftechind.com/blog/which-plastic-material-is-used-in-lego-sets |archive-date=2017-03-05 |url-status=usurped |title=Which Plastic Material is Used in Lego Sets? |author=Linda Jablanski |date=2015-03-31 }} [160] => [161] => Standard polycarbonate resins are not suitable for long term exposure to UV radiation. To overcome this, the primary resin can have UV stabilisers added. These grades are sold as UV stabilized polycarbonate to injection moulding and extrusion companies. Other applications, including polycarbonate sheets, may have the anti-UV layer added as a special coating or a [[Plastics extrusion#Coextrusion|coextrusion]] for [[enhanced weathering]] resistance. [162] => [163] => Polycarbonate is also used as a printing substrate for [[nameplate]] and other forms of industrial grade under printed products. The polycarbonate provides a barrier to wear, the elements, and fading. [164] => [165] => ==== Medical applications ==== [166] => Many 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 by the [[ethylene oxide]] (EtO) method.{{cite web|url=http://devicelink.com/mpb/archive/98/09/003.html|archive-url=https://web.archive.org/web/19990223191619/http://www.devicelink.com/mpb/archive/98/09/003.html|archive-date=23 February 1999|title=Medical Applications of Polycarbonate|last=Powell|first=Douglas G.|work=Medical Plastics and Biomaterials Magazine|date=September 1998}} Trinseo strictly limits all its plastics with regard to medical applications.{{cite web|title=Dow Plastics Medical Application Policy|url=http://plastics.dow.com/plastics/medical/|archive-url=https://web.archive.org/web/20100209013827/http://plastics.dow.com/plastics/medical/|archive-date=February 9, 2010|website=Plastics.dow.com}}{{cite web|url=http://www.omnexus.com/tc/polycarbonate/index.aspx?id=biocompatibility|title=Makrolon Polycarbonate Biocompatibility Grades|access-date=2007-04-14|archive-url=https://web.archive.org/web/20130410054745/http://www.omnexus.com/tc/polycarbonate/index.aspx?id=biocompatibility|archive-date=2013-04-10}} Aliphatic polycarbonates have been developed with improved biocompatibility and degradability for nanomedicine applications.{{cite journal|last1=Chan|first1=Julian M. W.|last2=Ke|first2=Xiyu|last3=Sardon|first3=Haritz|last4=Engler|first4=Amanda C.|last5=Yang|first5=Yi Yan|last6=Hedrick|first6=James L.|title=Chemically Modifiable N-Heterocycle-Functionalized Polycarbonates as a Platform for Diverse Smart Biomimetic Nanomaterials|journal=Chemical Science|date=2014|volume=5|issue=8|pages=3294–3300|doi=10.1039/C4SC00789A}} [167] => [168] => === Mobile phones === [169] => {{anchor|Phones}} [170] => Some smartphone manufacturers use polycarbonate. Nokia used polycarbonate in their phones starting with the [[Nokia N9|N9]]'s unibody case in 2011. This practice continued with various phones in the [[Lumia series]]. Samsung started using polycarbonate with [[Samsung Galaxy S III|Galaxy S III]]'s ''hyperglaze''-branded removable battery cover in 2012. This practice continues with various phones in the [[Samsung Galaxy|Galaxy]] series. Apple started using polycarbonate with the [[iPhone 5C]]'s [[unibody]] case in 2013. [171] => [172] => Benefits over glass and metal back covers include durability against shattering (advantage over glass), bending and scratching (advantage over metal), shock absorption, low manufacturing costs, and no interference with radio signals and [[wireless charging]] (advantage over metal). [173] => {{cite web |title=Build materials: metal vs glass vs plastic |url=https://www.androidauthority.com/build-materials-metal-vs-glass-vs-plastic-617553/ |website=Android Authority |date=19 July 2018 [174] => }} [175] => [176] => Polycarbonate back covers are available in glossy or matte [[surface texture]]s. [177] => [178] => ==History== [179] => Polycarbonates were first discovered in 1898 by [[Alfred Einhorn]], a German scientist working at the [[University of Munich]].{{cite web|title=Polycarbonate (PC)|url=http://www.ides.com/pm/9_Polycarbonate.asp|publisher=[[UL (safety organization)|UL]] Prospector|access-date=5 May 2014}} However, after 30 years' laboratory research, this class of materials was abandoned without commercialization. Research resumed in 1953, when [[Hermann Josef Schnell|Hermann Schnell]] at [[Bayer]] in Uerdingen, Germany patented the first linear polycarbonate. The brand name "Makrolon" was registered in 1955.{{cite book [180] => |author1=Philip Kotler [181] => |author2=Waldemar Pfoertsch [182] => |title=Ingredient Branding: Making the Invisible Visible [183] => |url=https://books.google.com/books?id=UYNBbCvK69UC&pg=PA200 [184] => |date=17 May 2010 [185] => |publisher=Springer Science & Business Media [186] => |isbn=978-3-642-04214-0 [187] => |pages=205–}} [188] => [189] => Also in 1953, and one week after the invention at Bayer, [[Daniel Fox (chemist)|Daniel Fox]] at [[General Electric]] (GE) in Pittsfield, Massachusetts, independently synthesized a [[Branching (polymer chemistry)|branched]] polycarbonate. Both companies filed for U.S. patents in 1955, and agreed that the company lacking priority would be granted a license to the technology.{{cite web|url=http://www.chemicallyspeaking.com/archive/2010/11/16/polycarbonate-is-polyfunctional.aspx|title=Polycarbonate is Polyfunctional|publisher=Chemical Institute of Canada|access-date=5 May 2014|archive-url=https://web.archive.org/web/20140505145205/http://www.chemicallyspeaking.com/archive/2010/11/16/polycarbonate-is-polyfunctional.aspx|archive-date=5 May 2014}}{{cite book|author=Jerome T. Coe|title=Unlikely Victory: How General Electric Succeeded in the Chemical Industry|chapter-url=https://books.google.com/books?id=bgdvYy80AHUC&pg=PA71|date=27 August 2010|publisher=John Wiley & Sons|isbn=978-0-470-93547-7|pages=71–77|chapter=Lexan Polycarbonate: 1953–1968}} [190] => [191] => Patent priority was resolved in Bayer's favor, and Bayer began commercial production under the trade name Makrolon in 1958. GE began production under the name Lexan in 1960, creating the [[SABIC|GE Plastics]] division in 1973.{{cite web|url=https://www.nytimes.com/2007/05/22/business/22plastics.html|title=General Electric to Sell Plastics Division|publisher=NY Times|access-date=2020-07-21|date=2007-05-22}} [192] => [193] => After 1970, the original brownish polycarbonate tint was improved to "glass-clear". [194] => [195] => ==Potential hazards in food contact applications== [196] => {{Main article|Bisphenol A|Endocrine disruptor}} [197] => The use of polycarbonate containers for the purpose of food storage is controversial. The basis of this controversy is their hydrolysis (degradation by water, often referred to as leaching) occurring at high temperature, releases [[bisphenol A]]: [198] => :1/n [OC(OC6H4)2CMe2]n + H2O → (HOC6H4)2CMe2 + CO2 [199] => [200] => More than 100 studies have explored the bioactivity of bisphenol A derived from polycarbonates. Bisphenol A appeared to be released from polycarbonate animal cages into water at room temperature and it may have been responsible for enlargement of the reproductive organs of female mice.{{cite journal|first = KL|last = Howdeshell|author2=Peterman PH |author3=Judy BM |author4=Taylor JA |author5=Orazio CE |author6=Ruhlen RL |author7=Vom Saal FS |author8=Welshons WV |year = 2003|title = Bisphenol A is released from used polycarbonate animal cages into water at room temperature|journal = Environmental Health Perspectives|volume = 111|issue = 9|pages = 1180–7|pmid = 12842771|doi = 10.1289/ehp.5993|pmc = 1241572}} However, the animal cages used in the research were fabricated from industrial grade polycarbonate, rather than FDA food grade polycarbonate. [201] => [202] => 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 whereas government-funded studies tend to find significant effects.{{cite journal |vauthors=vom Saal FS, Hughes C |title=An extensive new literature concerning low-dose effects of bisphenol A shows the need for a new risk assessment |journal=Environ. Health Perspect. |volume=113 |issue=8 |pages=926–33 |year=2005 |pmid=16079060 |pmc=1280330 |doi=10.1289/ehp.7713}} [203] => [204] => [[Sodium hypochlorite]] bleach and other alkali cleaners catalyze the release of the bisphenol A from polycarbonate containers.{{cite journal|first = PA|last = Hunt |author2=Kara E. Koehler |author3=Martha Susiarjo |author4=Craig A. Hodges |author5=Arlene Ilagan |author6=Robert C. Voigt |author7=Sally Thomas |author8=Brian F. Thomas |author9=Terry J. Hassold|year = 2003|title = Bisphenol A Exposure Causes Meiotic Aneuploidy in the Female Mouse|journal = Current Biology|volume = 13|issue = 7|pages = 546–553|doi = 10.1016/S0960-9822(03)00189-1|pmid = 12676084|s2cid = 10168552 |doi-access = free}}{{cite journal|first = KE|last = Koehler|author2 = Robert C. Voigt|author3 = Sally Thomas|author4 = Bruce Lamb|author5 = Cheryl Urban|author6 = Terry Hassold|author7 = Patricia A. Hunt|year = 2003|title = When disaster strikes: rethinking caging materials|url = http://www.mindfully.org/Plastic/Plasticizers/BPA-Lab-Animal-CagesApr03.htm|journal = Lab Animal|volume = 32|issue = 4|pages = 24–27|doi = 10.1038/laban0403-24|pmid = 19753748|s2cid = 37343342|access-date = 2008-05-06|archive-url = http://arquivo.pt/wayback/20090706101746/http://www.mindfully.org/Plastic/Plasticizers/BPA-Lab-Animal-CagesApr03.htm|archive-date = 2009-07-06}} Polycarbonate is incompatible with ammonia and acetone. [[Alcohol (chemistry)|Alcohol]] is a recommended [[organic solvent]] for cleaning grease and oils from polycarbonate. [205] => [206] => ==Environmental impact== [207] => [208] => ===Disposal=== [209] => Studies have shown that at temperatures above 70 °C, and high humidity, polycarbonate will hydrolyze to [[bisphenol A]] (BPA). After about 30 days at 85 °C/96% RH, surface crystals are formed which for 70% consisted of BPA.{{Cite journal|date=1981-06-01|title=Hydrolysis of polycarbonate to yield BPA|journal=Journal of Applied Polymer Science|language=en|volume=26|issue=6|page=1777|doi=10.1002/app.1981.070260603|last1=Bair|first1=H. E.|last2=Falcone|first2=D. R.|last3=Hellman|first3=M. Y.|last4=Johnson|first4=G. E.|last5=Kelleher|first5=P. G.}} BPA is a compound that is currently on the list of potential environmental hazardous chemicals. It is on the watch list of many countries, such as United States and Germany.{{Cite journal|last1=Morin|first1=Nicolas|last2=Arp|first2=Hans Peter H.|last3=Hale|first3=Sarah E.|title=Bisphenol A in Solid Waste Materials, Leachate Water, and Air Particles from Norwegian Waste-Handling Facilities: Presence and Partitioning Behavior |journal=Environmental Science & Technology |volume=49 |issue=13 |pages=7675–7683 |doi=10.1021/acs.est.5b01307 |date=July 2015 |pmid=26055751 |bibcode=2015EnST...49.7675M}} [210] => [211] => :-(-OC6H4)2C(CH3)2CO-)-n + H2O → (CH3)2C(C6H4OH)2 + CO2 [212] => [213] => The leaching of BPA from polycarbonate can also occur at environmental temperature and normal pH (in landfills).The amount of leaching increases as the polycarbonate parts get older. A study found that the decomposition of BPA in landfills (under anaerobic conditions) will not occur. It will therefore be persistent in landfills. Eventually, it will find its way into water bodies and contribute to aquatic pollution.{{Cite journal|last1=Chin|first1=Yu-Ping|last2=Miller|first2=Penney L.|last3=Zeng|first3=Lingke|last4=Cawley|first4=Kaelin|last5=Weavers|first5=Linda K.|title=Photosensitized Degradation of Bisphenol A by Dissolved Organic Matter †|journal=Environmental Science & Technology|volume=38|issue=22|pages=5888–5894|doi=10.1021/es0496569 |date=November 2004 |pmid=15573586 |bibcode=2004EnST...38.5888C}} [214] => [215] => === Photo-oxidation of polycarbonate === [216] => [217] => In the presence of UV light, oxidation of this polymer yields compounds such as ketones, phenols, o-phenoxybenzoic acid, benzyl alcohol and other unsaturated compounds. This has been suggested through kinetic and spectral studies. The yellow color formed after long exposure to sun can also be related to further oxidation of phenolic end group{{Cite thesis |degree=Master |last=Chow |first=Jimmy T. |date=2007-08-06|title=Environmental assessment for bisphenol-a and polycarbonate |publisher=Kansas State University |hdl=2097/368 |hdl-access=free |language=en-US}} [218] => [219] => :(OC6H4)2C(CH3)2CO )n + O2 , R* → (OC6H4)2C(CH3CH2)CO)n [220] => [221] => This product can be further oxidized to form smaller unsaturated compounds. This can proceed via two different pathways, the products formed depends on which mechanism takes place.{{Cite journal|last1=Carroccio|first1=Sabrina|last2=Puglisi|first2=Concetto|last3=Montaudo|first3=Giorgio|title=Mechanisms of Thermal Oxidation of Poly(bisphenol A carbonate)|journal=Macromolecules|volume=35|issue=11|pages=4297–4305|doi=10.1021/ma012077t|year=2002|bibcode=2002MaMol..35.4297C}} [222] => [223] => '''Pathway A''' [224] => [225] => :(OC6H4)2C(CH3CH2)CO + O2, H* \longrightarrow HO(OC6H4)OCO + CH3COCH2(OC6H4)OCO [226] => [227] => '''Pathway B''' [228] => [229] => :(OC6H4)2C(CH3CH2)CO)n + O2, H* \longrightarrow OCO(OC6H4)CH2OH + OCO(OC6H4)COCH3 [230] => [231] => === Photo-aging reaction === [232] => [233] => Photo-aging is another degradation route for polycarbonates. Polycarbonate molecules (such as the aromatic ring) absorb UV radiation. This absorbed energy causes cleavage of covalent bonds which initiates the photo-aging process. The reaction can be propagated via side chain oxidation, ring oxidation or [[Fries rearrangement#Photo-Fries rearrangement|photo-Fries rearrangement]]. Products formed include [[phenyl salicylate]], dihydroxybenzophenone groups, and hydroxydiphenyl ether groups.{{Cite journal|last1=Collin|first1=S.|last2=Bussière|first2=P. -O.|last3=Thérias|first3=S.|last4=Lambert|first4=J. -M.|last5=Perdereau|first5=J.|last6=Gardette|first6=J. -L.|date=2012-11-01|title=Physicochemical and mechanical impacts of photo-ageing on bisphenol a polycarbonate|journal=Polymer Degradation and Stability|volume=97|issue=11|pages=2284–2293|doi=10.1016/j.polymdegradstab.2012.07.036}}{{Cite web|title=The effects of ultraviolet radiation on polycarbonate glazing|year=1999|author1=Tjandraatmadja, G. F. |author2=Burn, L. S. |author3=Jollands, M. J. |url=https://www.irbnet.de/daten/iconda/CIB1832.pdf}} [234] => [235] => :(C16H14O3)n \longrightarrow C16H17O3 + C13H10O3 [236] => [237] => === Thermal degradation === [238] => [239] => Waste polycarbonate will degrade at high temperatures to form solid, liquid and gaseous pollutants. A study showed that the products were about 40–50 wt.% liquid, 14–16 wt.% gases, while 34–43 wt.% remained as solid residue. Liquid products contained mainly phenol derivatives (~75wt.%) and bisphenol (~10wt.%) also present. Polycarbonate, however, can be safely used as a carbon source in the steel-making industry.{{cite journal [240] => | last1 = Assadi [241] => | first1 = M. Hussein N. [242] => | last2 = Sahajwalla [243] => | first2 = V. [244] => | date = 2014 [245] => | title = Recycling End-of-Life Polycarbonate in Steelmaking: Ab Initio Study of Carbon Dissolution in Molten Iron [246] => | journal = Ind. Eng. Chem. Res. [247] => | volume = 53 [248] => | issue = 10 [249] => | pages = 3861–3864 [250] => | doi = 10.1021/ie4031105 [251] => | arxiv = 2204.08706 [252] => | s2cid = 101308914 [253] => }} [254] => [255] => Phenol derivatives are environmental pollutants, classified as volatile organic compounds (VOC). Studies show they are likely to facilitate ground level ozone formation and increase photo-chemical smog.{{Cite web|url=http://pollution.unibuc.ro/?substance=47|title=Pollution Database|website=pollution.unibuc.ro|access-date=2016-11-14|archive-url=https://web.archive.org/web/20171229231820/http://pollution.unibuc.ro/?substance=47|archive-date=2017-12-29}} In aquatic bodies, they can potentially accumulate in organisms. They are persistent in landfills, do not readily evaporate and would remain in the atmosphere.{{Cite web|url=http://apps.sepa.org.uk/spripa/Pages/SubstanceInformation.aspx?pid=81|title=Pollutant Fact Sheet|website=apps.sepa.org.uk|access-date=2016-11-14|archive-url=https://web.archive.org/web/20170109183955/http://apps.sepa.org.uk/spripa/Pages/SubstanceInformation.aspx?pid=81|archive-date=2017-01-09}} [256] => [257] => ===Effect of fungi=== [258] => In 2001 a species of fungus in [[Belize]], ''[[Geotrichum candidum]]'', was found to consume the polycarbonate found in [[compact disc]]s (CD).{{Cite journal|url=http://www.nature.com/news/1998/010628/full/news010628-11.html|title= Fungus eats CD|date=2001-06-27|author=Bosch, Xavier|doi=10.1038/news010628-11 |journal=Nature News}} This has prospects for [[bioremediation]]. However, this effect has not been reproduced. [259] => [260] => ==See also== [261] => * [[CR-39]], allyl diglycol carbonate (ADC) used for eyeglasses [262] => * [[Mobile phone accessories]] [263] => * [[Organic electronics]] [264] => * [[Thermoplastic polyurethane]] [265] => * [[Vapor polishing]] [266] => [267] => ==References== [268] => {{Reflist|30em}} [269] => [270] => == External links == [271] => {{Commons category|Polycarbonate}} [272] => [273] => {{Plastics}} [274] => {{HealthIssuesOfPlastics}} [275] => {{Authority control}} [276] => [277] => [[Category:Polycarbonates| ]] [278] => [[Category:Commodity chemicals]] [279] => [[Category:Dielectrics]] [280] => [[Category:Optical materials]] [281] => [[Category:Plastics]] [282] => [[Category:Thermoplastics]] [283] => [[Category:Transparent materials]] [284] => [[Category:German inventions]] [] => )
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Polycarbonate

Polycarbonate is a type of high-performance plastic that is widely used in various industries for its exceptional durability, transparency, and heat resistance. It is a versatile material that can be molded into different shapes, making it suitable for a wide range of applications.

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It is a versatile material that can be molded into different shapes, making it suitable for a wide range of applications. The Wikipedia page on polycarbonate provides detailed information about this material, including its properties, production process, and uses. It explains that polycarbonate is a thermoplastic polymer made from bisphenol A (BPA) and phosgene, and highlights its unique features such as impact resistance, optical clarity, and ability to withstand high temperatures. The page also describes the history and development of polycarbonate, starting from its discovery in the mid-20th century to its commercialization and widespread adoption in various industries such as automotive, electrical, and construction. It discusses the advancements in polycarbonate production techniques, including the development of copolymers and blends to enhance its properties. Moreover, the Wikipedia page delves into the applications of polycarbonate in different fields. It highlights its use in consumer products, such as eyeglasses, CDs, and water bottles, as well as its presence in automotive parts, aerospace components, and electronic devices. It further explores the use of polycarbonate as a substitute for glass due to its impact resistance and lighter weight. Furthermore, the page covers the environmental and health concerns associated with polycarbonate, particularly due to the presence of BPA, which has been linked to potential health risks. It discusses the efforts made by manufacturers to develop BPA-free alternatives and the regulations in place to ensure the safe use of polycarbonate. In conclusion, the Wikipedia page on polycarbonate offers a comprehensive overview of this versatile plastic material. It provides a detailed understanding of its properties, production, applications, and associated concerns. Whether for research purposes or general interest, this page serves as a valuable resource for anyone seeking information on polycarbonate.

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