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83-402: Polyethylene terephthalate (or poly(ethylene terephthalate) , PET , PETE , or the obsolete PETP or PET-P ), is the most common thermoplastic polymer resin of the polyester family and is used in fibres for clothing, containers for liquids and foods, and thermoforming for manufacturing, and in combination with glass fibre for engineering resins . In 2016, annual production of PET

166-440: A thin film of evaporated aluminium , gold , or other metal onto it. The result is much less permeable to gases (important in food packaging ) and reflects up to 99% of light , including much of the infrared spectrum. For some applications like food packaging, the aluminized boPET film can be laminated with a layer of polyethylene , which provides sealability and improves puncture resistance . The polyethylene side of such

249-399: A "sniffer test" on returned bottles to avoid cross-contamination of flavors. Different applications of PET require different degrees of polymerization, which can be obtained by modifying the process conditions. The molecular weight of PET is measured by solution viscosity. The preferred method to measure this viscosity is the intrinsic viscosity (IV) of the polymer. Intrinsic viscosity is

332-404: A 9-micrometre (0.00035 in) thick mylar film sandwiched between two layers of 4.5-micrometre (0.00018 in) thick aluminium foil bonded together. The manufacturing process begins with a film of molten polyethylene terephthalate (PET) being extruded onto a chill roll, which quenches it into the amorphous state. It is then biaxially oriented by drawing . The most common way of doing this

415-422: A byproduct. Polymerization is through a polycondensation reaction of the monomers (done immediately after esterification/transesterification) with water as the byproduct. Polyester fibres are widely used in the textile industry. The invention of the polyester fibre is attributed to J. R. Whinfield. It was first commercialized in the 1940s by ICI , under the brand 'Terylene'. Subsequently E. I. DuPont launched

498-481: A different form, without destroying the polymer; or recycled in a process that includes transesterification and the addition of other glycols, polyols, or glycerol to form a new polyol. The polyol from the third method can be used in polyurethane (PU foam) production, or epoxy-based products, including paints. In 2023 a process was announced for using PET as the basis for supercapacitor production. PET, being stoichiometrically carbon and H 2 O , can be turned into

581-475: A dimensionless measurement found by extrapolating the relative viscosity (measured in (dℓ/g)) to zero concentration. Shown below are the IV ranges for common applications: PET is often copolymerized with other diols or diacids to optimize the properties for particular applications. For example, cyclohexanedimethanol (CHDM) can be added to the polymer backbone in place of ethylene glycol . Since this building block

664-445: A few micrometers ) depending on its crystal structure and particle size. One process for making PET uses bis(2-hydroxyethyl) terephthalate , which can be synthesized by the esterification reaction between terephthalic acid and ethylene glycol with water as a byproduct (this is also known as a condensation reaction), or by transesterification reaction between ethylene glycol and dimethyl terephthalate (DMT) with methanol as

747-478: A form of carbon containing sheets and nanospheres, with a very high surface area. The process involves holding a mixture of PET, water, nitric acid , and ethanol at a high temperature and pressure for eight hours, followed by centrifugation and drying. Significant investments were announced in 2021 and 2022 for chemical recycling of PET by glycolysis, methanolysis, and enzymatic recycling to recover monomers. Initially these will also use bottles as feedstock but it

830-450: A multilayer structure is used. PET sandwiches an additional polyvinyl alcohol (PVOH) or polyamide (PA) layer to further reduce its oxygen permeability. Non-oriented PET sheet can be thermoformed to make packaging trays and blister packs . Crystallizable PET withstands freezing and oven baking temperatures. Both amorphous PET and BoPET are transparent to the naked eye. Color-conferring dyes can easily be formulated into PET sheet. PET

913-404: A product surface. PVDF is widely used in the chemical industry as piping for aggressive chemicals and high purity liquids. The PVDF material is used in construction, transportation, chemical processes, electricity, batteries, waste water and treatment. Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene is commonly recognized under the brand name Teflon . PTFE

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996-479: A significant amount of PET microparticles may be precipitated in sewage treatment plants. PET microfibers generated by apparel wear, washing or machine drying can become airborne, and be dispersed into fields, where they are ingested by livestock or plants and end up in the human food supply. SAPEA have declared that such particles 'do not pose a widespread risk'. PET is known to degrade when exposed to sunlight and oxygen. As of 2016, scarce information exists regarding

1079-474: A skin for a geodesic dome , which he built with students at the University of Oregon . In 1955 Eastman Kodak used Mylar as a support for photographic film and called it "ESTAR Base". The very thin and tough film allowed 6,000-foot (1,800 m) reels to be exposed on long-range U-2 reconnaissance flights. In 1964, NASA launched Echo II , a 40-metre (131 ft) diameter balloon constructed from

1162-567: A stabilizer and a bluing agent such as cobalt salt is added to mask any yellowing. In the dimethyl terephthalate (DMT) process, DMT and excess ethylene glycol (MEG) are transesterified in the melt at 150–200 °C with a basic catalyst . Methanol (CH 3 OH) is removed by distillation to drive the reaction forward. Excess MEG is distilled off at higher temperature with the aid of vacuum. The second transesterification step proceeds at 270–280 °C, with continuous distillation of MEG as well. The reactions can be summarized as follows: In

1245-466: A substantial degree, for example about 75% in Switzerland. The term rPET is commonly used to describe the recycled material, though it is also referred to as R-PET or post-consumer PET (POSTC-PET). The prime uses for recycled PET are polyester fiber, strapping, and non-food containers. Because of the recyclability of PET and the relative abundance of post-consumer waste in the form of bottles, PET

1328-486: A typical Young's modulus of about 4 GPa (0.58 × 10 ^  psi). Another important consequence of the molecular orientation is that it induces the formation of many crystal nuclei. The crystallites that grow rapidly reach the boundary of the neighboring crystallite and remain smaller than the wavelength of visible light. As a result, biaxially oriented PET film has excellent clarity, despite its semicrystalline structure. If it were produced without any additives,

1411-598: A unique resin identification code. Items made from polycarbonate can contain the precursor monomer bisphenol A (BPA). Susceptible to UV light, exposure results in yellowing (degradation is especially visible in headlamps that lost or didn't have proper protective coating). Polyether sulfone (PES) or polysulfone is a class of specially engineered thermoplastics with high thermal, oxidative, and hydrolytic stability, and good resistance to aqueous mineral acids, alkalis, salt solutions, oils and greases. Polyoxymethylene (POM), also known as acetal, polyacetal and polyformaldehyde,

1494-464: Is hydrophobic : aqueous liquids do not wet the material, as fluorocarbons demonstrate mitigated London dispersion forces due to the high electronegativity of fluorine. This also supports its use in coatings of cooking ware. The polymer has one of the lowest coefficients of friction of any solid and is therefore commonly used for bearings and support of moving mechanical parts. BoPET BoPET ( biaxially oriented polyethylene terephthalate )

1577-427: Is isophthalic acid , replacing some of the 1,4-( para- ) linked terephthalate units. The 1,2-( ortho- ) or 1,3-( meta -) linkage produces an angle in the chain, which also disturbs crystallinity. Such copolymers are advantageous for certain molding applications, such as thermoforming , which is used for example to make tray or blister packaging from co-PET film, or amorphous PET sheet (A-PET/PETA) or PETG sheet. On

1660-409: Is a polyester film made from stretched polyethylene terephthalate (PET) and is used for its high tensile strength , chemical stability , dimensional stability , transparency reflectivity , and electrical insulation . . When metallized , it has gas and moisture barrier properties, The film is "biaxially oriented", which means that the polymer chains are oriented parallel to the plane of

1743-421: Is a family of similar materials categorized according to their density and molecular structure. It is also known as poly and is obtained by the addition polymerisation of ethylene. It may be of low density or high density depending upon the process used in its manufacturing. It is resistant to moisture and most of the chemicals. It is flexible at room temperature (and low temperature) and can be heat sealed. Since it

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1826-1009: Is a synthetic fiber with a very high melting point. It has exceptional thermal and chemical stability and does not readily ignite. It was first discovered by American polymer chemist Carl Shipp Marvel in the pursuit of new materials with superior stability, retention of stiffness, toughness at elevated temperature. Due to its high stability, polybenzimidazole is used to fabricate high-performance protective apparel such as firefighter's gear, astronaut space suits, high temperature protective gloves, welders' apparel and aircraft wall fabrics. In recent years, polybenzimidazole found its application as membrane in fuel cells. Polycarbonate (PC) thermoplastics are known under trademarks such as Lexan, Makrolon, Makroclear, and arcoPlus. They are easily worked, molded, and thermoformed for many applications, such as electronic components, construction materials, data storage devices, automotive and aircraft parts, check sockets in prosthetics, and security glazing. Polycarbonates do not have

1909-428: Is a tough, lightweight material that is durable, fairly rigid and versatile, and is resistant to acids and bases. Much of it is used by the construction industry, such as for vinyl siding, drainpipes, gutters and roofing sheets. It is also converted to flexible forms with the addition of plasticizers, thereby making it useful for items such as hoses, tubing, electrical insulation, coats, jackets and upholstery. Flexible PVC

1992-437: Is also rapidly gaining market share as a carpet fiber. PET, like many plastics, is also an excellent candidate for thermal disposal ( incineration ), as it is composed of carbon, hydrogen, and oxygen, with only trace amounts of catalyst elements (but no sulfur). In general, PET can either be chemically recycled into its original raw materials (PTA, DMT, and EG), destroying the polymer structure completely; mechanically recycled into

2075-441: Is also technically possible to make PTA from readily available bio-based furfural . There are two basic molding methods for PET bottles, one-step and two-step. In two-step molding, two separate machines are used. The first machine injection molds the preform, which resembles a test tube, with the bottle-cap threads already molded into place. The body of the tube is significantly thicker, as it will be inflated into its final shape in

2158-421: Is also used in inflatable products, such as water beds and pool toys. PVC is also a common material in vinyl action figures , especially in countries such as Japan , where the material is used extensively in so-called Sofubi figures (Soft vinyl toys ). As PVC bends easily and has a tendency to be bent during transit, a method to mitigate this deformation is to heat the plastic until it becomes mobile, then reform

2241-422: Is an engineering thermoplastic used in precision parts requiring high stiffness, low friction, and excellent dimensional stability. As with many other synthetic polymers, it is produced by different chemical firms with slightly different formulas and sold variously by such names as Delrin, Celcon, Ramtal, Duracon, Kepital and Hostaform. Polyether ether ketone (PEEK) is a colourless organic thermoplastic polymer in

2324-420: Is an inexpensive plastic it is made in large amounts to cater to the demand. For example: Polyphenylene oxide (PPO), which is obtained from the free-radical, step-growth oxidative coupling polymerization of 2,6-xylenol, has many attractive properties such as high heat distortion and impact strength, chemical stability to mineral and organic acids, and low water absorption. PPO is difficult to process, and hence

2407-440: Is commonly recycled , and has the digit 1 (♳) as its resin identification code (RIC). The National Association for PET Container Resources (NAPCOR) defines PET as: "Polyethylene terephthalate items referenced are derived from terephthalic acid (or dimethyl terephthalate ) and mono ethylene glycol , wherein the sum of terephthalic acid (or dimethyl terephthalate) and mono ethylene glycol reacted constitutes at least 90 percent of

2490-519: Is commonly used in water, chemical, hot and cold, delivery systems for residential, commercial, and industrial applications. Poly vinylidene fluoride , PVDF , belongs to the fluoropolymer class of thermoplastics and is known for its high chemical inertness and resistance. PVDF is obtained through the polymerization of the vinylidene fluoride monomer. PVDF thermoplastic is fabricated into sheets and pipes for engineering uses as well as powders and coatings that can be dissolved in solvents and applied across

2573-493: Is defined by the recyclable plastic number 5. Although relatively inert, it is vulnerable to ultraviolet radiation and can degrade considerably in direct sunlight. Polypropylene is not as impact-resistant as the polyethylenes (HDPE, LDPE). It is also somewhat permeable to highly volatile gases and liquids. Polystyrene is manufactured in various forms that have different applications and can have medium to very low density. Extruded polystyrene (PS or xPS, sometimes colored pink/blue)

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2656-681: Is expected that fibres will also be recycled this way in future. PET is also a desirable fuel for waste-to-energy plants , as it has a high calorific value which helps to reduce the use of primary resources for energy generation. At least one species of bacterium in the genus Nocardia can degrade PET with an esterase enzyme. Esterases are enzymes able to cleave the ester bond between two oxygens that links subunits of PET. The initial degradation of PET can also be achieved esterases expressed by Bacillus , as well as Nocardia . Japanese scientists have isolated another bacterium, Ideonella sakaiensis , that possesses two enzymes which can break down

2739-661: Is extensively used to make signs, including lettering and logos. In medicine, it is used in bone cement and to replace eye lenses. Acrylic paint consists of PMMA particles suspended in water. For many decades, PMMA has been the predominant methacrylic ester produced worldwide. Major players in the PMMA market are Mitsubishi Rayon (Japan), Arkema SA (France), LG MMA (South Korea), Chi Mei Corp. (Taiwan), Sumimoto Chemical Company Ltd (Japan), Evonik Industries (Germany), BASF (Germany), Dow Chemical Company (U.S.), AkzoNobel (The Netherlands), Quinn Plastics (UK) and Cytec Industries (U.S.). Regarding

2822-543: Is much larger (six additional carbon atoms) than the ethylene glycol unit it replaces, it does not fit in with the neighboring chains the way an ethylene glycol unit would. This interferes with crystallization and lowers the polymer's melting temperature. In general, such PET is known as PETG or PET-G (polyethylene terephthalate glycol-modified). It is a clear amorphous thermoplastic that can be injection-molded, sheet-extruded or extruded as filament for 3D printing . PETG can be colored during processing. Another common modifier

2905-439: Is necessary, as light is scattered strongly by crystallites larger than its wavelength. Amorphous and semi-amorphous plastics are less resistant to chemical attack and environmental stress cracking because they lack a crystalline structure. Brittleness can be decreased with the addition of plasticizers , which increases the mobility of amorphous chain segments to effectively lower the glass transition temperature. Modification of

2988-401: Is often referred to as unplasticized polyvinyl chloride (uPVC), which is the more commonly used type for installations such as water, waste, and sewer conveyance plumbing. Chemical modification often produces more drastic changes in properties. Chlorinated polyvinyl chloride (CPVC) is produced through exposing PVC to the continued free-radical chlorination reaction that originally formulates

3071-642: Is permeable to oxygen and carbon dioxide and this imposes shelf life limitations of contents packaged in PET. In the early 2000s, the global PET packaging market grew at a compound annual growth rate of 9% to €17 billion in 2006. Biaxially oriented PET (BOPET) film (including brands like "Mylar") can be aluminized by evaporating a thin film of metal onto it to reduce its permeability, and to make it reflective and opaque ( MPET ). These properties are useful in many applications, including flexible food packaging and thermal insulation (such as space blankets ). BOPET

3154-503: Is principally used in coating applications. This is done by spraying an aqueous slurry of PPS particles and heating to temperatures above 370 °C. Particular grades of PPS can be used in injection and compression molding at temperatures (300 to 370 °C) at which PPS particles soften and undergo apparent crosslinking. Principal applications of injection and compression molded PPS include cookware, bearings, and pump parts for service in various corrosive environments. Polypropylene (PP)

3237-403: Is produced largely from purified terephthalic acid (PTA), as well as to a lesser extent from (mono-)ethylene glycol (MEG) and dimethyl terephthalate (DMT). As of 2022, ethylene glycol is made from ethene found in natural gas , while terephthalic acid comes from p-xylene made from crude oil . Typically an antimony or titanium compound is used as a catalyst, a phosphite is added as

3320-1036: Is quite important, because if nothing masks the aroma, even extremely low concentrations (10–20 parts per billion in the water) of acetaldehyde can produce an off-taste. Commentary published in Environmental Health Perspectives in April 2010 suggested that PET might yield endocrine disruptors under conditions of common use and recommended research on this topic. Proposed mechanisms include leaching of phthalates as well as leaching of antimony . An article published in Journal of Environmental Monitoring in April 2012 concludes that antimony concentration in deionized water stored in PET bottles stays within EU's acceptable limit even if stored briefly at temperatures up to 60 °C (140 °F), while bottled contents (water or soft drinks) may occasionally exceed

3403-412: Is still of concern. The Swiss Federal Office of Public Health investigated the amount of antimony migration, comparing waters bottled in PET and glass: The antimony concentrations of the water in PET bottles were higher, but still well below the allowed maximum concentration. The Swiss Federal Office of Public Health concluded that small amounts of antimony migrate from the PET into bottled water, but that

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3486-488: Is strong and impact-resistant. PET is hygroscopic and absorbs water. About 60% crystallization is the upper limit for commercial products, with the exception of polyester fibers. Transparent products can be produced by rapidly cooling molten polymer below the glass transition temperature (T g ) to form a non-crystalline amorphous solid . Like glass, amorphous PET forms when its molecules are not given enough time to arrange themselves in an orderly, crystalline fashion as

3569-537: Is the reduction in space, product handling and energy, and far higher visual quality than can be achieved by the two-step system. PET is subject to degradation during processing. If the moisture level is too high, hydrolysis will reduce the molecular weight by chain scission , resulting in brittleness. If the residence time and/or melt temperature (temperature at melting) are too high, then thermal degradation or thermooxidative degradation will occur resulting in discoloration and reduced molecular weight, as well as

3652-431: Is the sequential process, in which the film is first drawn in the machine direction using heated rollers and subsequently drawn in the transverse direction, i.e., orthogonally to the direction of travel, in a heated oven. It is also possible to draw the film in both directions simultaneously, although the equipment required for this is somewhat more elaborate. Draw ratios are typically around 3 to 4 in each direction. Once

3735-481: Is used in many consumer products, such as toys, appliances, and telephones. Nylon belongs to a class of polymers called polyamides . It has served as a substitute mainly for hemp, cotton and silk, in products such as parachutes, cords, sails, flak vests and clothing. Nylon fibres are useful in making fabrics, rope, carpets and musical strings, whereas, in bulk form, nylon is used for mechanical parts including machine screws, gears and power tool casings. In addition, it

3818-444: Is used in the backsheet of photovoltaic modules . Most backsheets consist of a layer of BOPET laminated to a fluoropolymer or a layer of UV stabilized BOPET. PET is also used as a substrate in thin film solar cells. PET can be compounded with glass fibre and crystallization accelerators, to make thermoplastic resins. These can be injection moulded into parts such as housings, covers, electrical appliance components and elements of

3901-469: Is used in the manufacture of disposable cutlery, rigid ground contact rated insulating foam board, CD and DVD cases, plastic models of cars and boats, and smoke detector housings. Expanded polystyrene foam (EPS or "styrofoam", white) is used in making insulation and packaging materials, such as the "peanuts" and molded foam used to cushion fragile products. Polystyrene copolymers are used in the manufacture of toys and product casings. Polyvinyl chloride (PVC)

3984-698: Is used in the manufacture of heat-resistant composite materials. Polylactic acid (polylactide) is a compostable thermoplastic aliphatic polyester derived from renewable resources , such as corn starch (in the United States), sugar beet pulp (in Europe), tapioca roots, chips or starch (mostly in Asia), or sugarcane . It is the most common material used for 3D printing with fused deposition modeling (FDM) techniques. Polybenzimidazole (PBI, short for Poly-[2,2’-(m-phenylen)-5,5’-bisbenzimidazole]) fiber

4067-508: Is useful for such diverse products as reusable plastic food containers, microwave- and dishwasher-safe plastic containers , diaper lining, sanitary pad lining and casing, ropes, carpets, plastic moldings, piping systems, car batteries , insulation for electrical cables and filters for gases and liquids. In medicine, it is used in hernia treatment and to make heat-resistant medical equipment. Polypropylene sheets are used for stationery folders and packaging and clear storage bins. Polypropylene

4150-434: Is why BOPET film and bottles are both crystalline, to a degree, and transparent. PET has an affinity for hydrophobic flavors, and drinks sometimes need to be formulated with a higher flavor dosage, compared to those going into glass, to offset the flavor taken up by the container. While heavy gauge PET bottles returned for re-use, as in some EU countries, the propensity of PET to absorb flavors makes it necessary to conduct

4233-685: The University of Texas at Austin . The PET-ase was found to able to degrade various products and could break them down as fast as 24 hours. Thermoplastic Most thermoplastics have a high molecular weight . The polymer chains associate by intermolecular forces , which weaken rapidly with increased temperature, yielding a viscous liquid. In this state, thermoplastics may be reshaped, and are typically used to produce parts by various polymer processing techniques such as injection molding , compression molding , calendering , and extrusion . Thermoplastics differ from thermosetting polymers (or "thermosets"), which form irreversible chemical bonds during

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4316-414: The polyacrylic acids (PAA) and its ester derivatives (PAc) market, on the other hand, the poly(methyl methacrylate) (PMMA) market. PMMA is also known by trade names such as Lucite, Perspex and Plexiglas. It serves as a sturdy substitute for glass for items such as aquariums, buttons, motorcycle helmet visors, aircraft windows, viewing ports of submersibles, and lenses of exterior lights of automobiles. It

4399-564: The terephthalic acid process, MEG and PTA are esterified directly at moderate pressure (2.7–5.5 bar) and high temperature (220–260 °C). Water is eliminated in the reaction, and it is also continuously removed by distillation : Bio-PET is the bio-based counterpart of PET. Essentially in Bio-PET, the MEG is manufactured from ethylene derived from sugar cane ethanol . A better process based on oxidation of ethanol has been proposed, and it

4482-421: The EU limit after less than a year of storage at room temperature. Antimony (Sb) is a metalloid element that is used as a catalyst in the form of compounds such as antimony trioxide (Sb 2 O 3 ) or antimony triacetate in the production of PET. After manufacturing, a detectable amount of antimony can be found on the surface of the product. This residue can be removed with washing. Antimony also remains in

4565-481: The PAA and PAc market, key manufacturers are Nippon Shokubai Company Ltd. (Japan), Arkema SA (France) and Dow Chemical Company (U.S.) Acrylonitrile butadiene styrene (ABS) is a terpolymer synthesized from styrene and acrylonitrile in the presence of polybutadiene . ABS is a light-weight material that exhibits high impact resistance and mechanical toughness. It poses few risks to human health under normal handling. It

4648-478: The PET into smaller pieces digestible by the bacteria. A colony of I. sakaiensis can disintegrate a plastic film in about six weeks. French researchers report developing an improved PET hydrolase that can depolymerize (break apart) at least 90 percent of PET in 10 hours, breaking it down into individual monomers . Also, an enzyme based on a natural PET-ase was designed with the help of a machine learning algorithm to be able to tolerate pH and temperature changes by

4731-576: The PVC polymer. The chlorination reaction continues to add chlorine atoms to the polymer hydrocarbon backbone until most commercial applications reach a percent range between 56 and 74% total chlorine. This increase in elemental chlorine content contributes to CPVC's increased expression of chlorine-based characteristics, such as chemical durability, resistance to acids, bases, and salts; susceptibility to ammonia-based compounds, aromatics, esters, ketones; chemical stability; heat energy transfer resistance. CPVC

4814-461: The UK were found to contain up to 44.7 μg/L of antimony, well above the EU limits for tap water of 5 μg/L. Clothing sheds microfibres in use, during washing and machine drying. Plastic litter slowly forms small particles. Microplastics which are present on the bottom of the river or seabed can be ingested by small marine life, thus entering the food chain. As PET has a higher density than water,

4897-405: The brand 'Dacron'. As of 2022, there are many brands around the world, mostly Asian. Polyester fibres are used in fashion apparel often blended with cotton, as heat insulation layers in thermal wear, sportswear and workwear and automotive upholstery. Plastic bottles made from PET are widely used for soft drinks , both still and sparkling . For beverages that are degraded by oxygen, such as beer,

4980-428: The commercial resin (Noryl) is made by blending PPO with high-impact polystyrene (HIPS), which serves to reduce the processing temperature. Polyphenylene sulfide (PPS) obtained by the condensation polymerization of p-dichlorobenzene and sodium sulfide, has outstanding chemical resistance, good electrical properties, excellent flame retardance, low coefficient of friction and high transparency to microwave radiation. PPS

5063-504: The curing process. Thermosets do not melt when heated, but typically decompose and do not reform upon cooling. Above its glass transition temperature and below its melting point , the physical properties of a thermoplastic change drastically without an associated phase change . Some thermoplastics do not fully crystallize below the glass transition temperature, retaining some or all of their amorphous characteristics. Amorphous and semi-amorphous plastics are used when high optical clarity

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5146-439: The drawing is completed, the film is " heat set " and crystallized under tension in the oven at temperatures typically above 200 °C (392 °F). The heat setting step prevents the film from shrinking back to its original unstretched shape and locks in the molecular orientation in the film plane. The orientation of the polymer chains is responsible for the high strength and stiffness of biaxially oriented PET film, which has

5229-506: The film, and therefore oriented in two axes. A variety of companies manufacture boPET and other polyester films under different brand names . In the UK and US, the best-known trade names are Mylar , Melinex , Lumirror and Hostaphan . It was the first biaxially oriented polymer to be manufactured on a mass commercial scale. BoPET film was developed in the mid-1950s, originally by DuPont , Imperial Chemical Industries (ICI), and Hoechst . In 1953 Buckminster Fuller used Mylar as

5312-429: The formation of acetaldehyde , and the formation "gel" or "fish-eye" formations through cross-linking . Mitigation measures include copolymerisation with other monomers like CHDM or isophthalic acid , which lower the melting point and thus the melt temperature of the resin, as well as the addition of polymer stabilisers such as phosphites . Acetaldehyde , which can form by degradation of PET after mishandling of

5395-503: The gradual formation acetaldehyde over the object's lifespan. This proceeds via a Type II Norrish reaction . When acetaldehyde is produced, some of it remains dissolved in the walls of a container and then diffuses into the product stored inside, altering the taste and aroma. This is not such a problem for non-consumables (such as shampoo), for fruit juices (which already contain acetaldehyde), or for strong-tasting drinks like soft drinks. For bottled water, however, low acetaldehyde content

5478-476: The health risk of the resulting low concentrations is negligible (1% of the " tolerable daily intake " determined by the WHO ). A later (2006) but more widely publicized study found similar amounts of antimony in water in PET bottles. The WHO has published a risk assessment for antimony in drinking water. Fruit juice concentrates (for which no guidelines are established), however, that were produced and bottled in PET in

5561-671: The ignition system. PET is stoichiometrically a mixture of carbon and H 2 O , and therefore has been used in an experiment involving laser-driven shock compression which created nanodiamonds and superionic water . This could be a possible way of producing nanodiamonds commercially. PET was patented in 1941 by John Rex Whinfield , James Tennant Dickson and their employer the Calico Printers' Association of Manchester , England. E. I. DuPont de Nemours in Delaware, United States, first produced Dacron (PET fiber) in 1950 and used

5644-436: The life-time of the synthetic polymers in the environment. While most thermoplastics can, in principle, be recycled, PET bottle recycling is more practical than many other plastic applications because of the high value of the resin and the almost exclusive use of PET for widely used water and carbonated soft drink bottling. PET bottles lend themselves well to recycling (see below). In many countries PET bottles are recycled to

5727-603: The mass of monomer reacted to form the polymer, and must exhibit a melting peak temperature between 225 °C and 255 °C, as identified during the second thermal scan in procedure 10.1 in ASTM D3418, when heating the sample at a rate of 10 °C/minute." Depending on its processing and thermal history, polyethylene terephthalate may exist both as an amorphous (transparent) and as a semi-crystalline polymer . The semicrystalline material might appear transparent (particle size less than 500  nm ) or opaque and white (particle size up to

5810-428: The material into the desired shape. PVC is produced in many specific modifications to affect its chemical and physical properties. In plasticized polyvinyl chloride (pPVC), plasticizers are added to the raw material before molding to make it more flexible or pliable. Early on, the health and environmental aspects of this were poorly understood and replacements and product bans resulted after studies. The original form

5893-503: The material itself and can, thus, migrate out into food and drinks. Exposing PET to boiling or microwaving can increase the levels of antimony significantly, possibly above US EPA maximum contamination levels. The drinking water limit assessed by WHO is 20 parts per billion (WHO, 2003), and the drinking water limit in the United States is 6 parts per billion. Although antimony trioxide is of low toxicity when taken orally, its presence

5976-441: The material, is a colorless, volatile substance with a fruity smell. Although it forms naturally in some fruit, it can cause an off-taste in bottled water. As well as high temperatures (PET decomposes above 300 °C or 570 °F) and long barrel residence times, high pressures and high extruder speeds (which cause shear raising the temperature), can also contribute to the production of acetaldehyde. Photo-oxidation can also cause

6059-471: The melt is cooled. While at room temperature the molecules are frozen in place, if enough heat energy is put back into them afterward by heating the material above T g , they can begin to move again, allowing crystals to nucleate and grow. This procedure is known as solid-state crystallization. Amorphous PET also crystallizes and becomes opaque when exposed to solvents , such as chloroform or toluene . A more crystalline product can be produced by allowing

6142-414: The molten polymer to cool slowly. Rather than forming one large single crystal, this material has a number of spherulites (crystallized areas) each containing many small crystallites (grains). Light tends to scatter as it crosses the boundaries between crystallites and the amorphous regions between them, causing the resulting solid to be translucent. Orientation also renders polymers more transparent. This

6225-619: The other hand, crystallization is important in other applications where mechanical and dimensional stability are important, such as seat belts. For PET bottles, the use of small amounts of isophthalic acid, CHDM, diethylene glycol (DEG) or other comonomers can be useful: if only small amounts of comonomers are used, crystallization is slowed but not prevented entirely. As a result, bottles are obtainable via stretch blow molding ("SBM"), which are both clear and crystalline enough to be an adequate barrier to aromas and even gases, such as carbon dioxide in carbonated beverages. Polyethylene terephthalate

6308-696: The polyaryletherketone (PAEK) family, used in engineering applications. It was originally introduced by Victrex PLC, then ICI (Imperial Chemical Industries) in the early 1980s. It has attractive properties like good abrasion resistance, low flammability and emission of smoke and toxic gases. Polyetherimide (PEI), produced by a novel nitro displacement reaction involving bisphenol A, 4, 4’-methylenedianiline and 3-nitrophthalic anhydride, has high heat distortion temperature, tensile strength and modulus. They are generally used in high performance electrical and electronic parts, microwave appliances, and under-the-hood automotive parts. Polyethylene (polyethene, polythene, PE)

6391-494: The polymer through copolymerization or through the addition of non-reactive side chains to monomers before polymerization can also lower it. Before these techniques were employed, plastic automobile parts would often crack when exposed to cold temperatures. These are linear or slightly branched long chain molecules capable of repeatedly softening on heating and hardening on cooling. Today's acrylics industry can be divided into two distinct multibillion-dollar markets: on one hand

6474-572: The second step using stretch blow molding . In the second step, the preforms are heated rapidly and then inflated against a two-part mold to form them into the final shape of the bottle. Preforms (uninflated bottles) are now also used as robust and unique containers themselves; besides novelty candy, some Red Cross chapters distribute them as part of the Vial of Life program to homeowners to store medical history for emergency responders. The two-step process lends itself to third party production remote from

6557-415: The surface of the film would be so smooth that layers would adhere strongly to one another when the film is wound up, similar to the sticking of clean glass plates when stacked. To make handling possible, microscopic inert inorganic particles, such as silicon dioxide , are usually embedded in the PET to roughen the surface of the film. Biaxially oriented PET film can be metallized by vapor deposition of

6640-788: The trademark Mylar (boPET film) in June 1951 and received registration of it in 1952. It is still the best-known name used for polyester film. The current owner of the trademark is DuPont Teijin Films. In the Soviet Union, PET was first manufactured in the laboratories of the Institute of High-Molecular Compounds of the USSR Academy of Sciences in 1949, and its name "Lavsan" is an acronym thereof ( ла боратории Института в ысокомолекулярных с оединений А кадемии н аук СССР). The PET bottle

6723-472: The user site. The preforms can be transported and stored by the thousand in a much smaller space than would finished containers, for the second stage to be carried out on the user site on a 'just in time' basis. In one-step machines, the entire process from raw material to finished container is conducted within one machine, making it especially suitable for molding non-standard shapes (custom molding), including jars, flat oval, flask shapes, etc. Its greatest merit

6806-543: Was 56 million tons. The biggest application is in fibres (in excess of 60%), with bottle production accounting for about 30% of global demand. In the context of textile applications, PET is referred to by its common name, polyester , whereas the acronym PET is generally used in relation to packaging. Polyester makes up about 18% of world polymer production and is the fourth-most-produced polymer after polyethylene (PE), polypropylene (PP) and polyvinyl chloride (PVC). PET consists of repeating (C 10 H 8 O 4 ) units. PET

6889-548: Was invented in 1973 by Nathaniel Wyeth and patented by DuPont. PET in its most stable state is a colorless, semi-crystalline resin . However it is intrinsically slow to crystallize compared to other semicrystalline polymers . Depending on processing conditions it can be formed into either non-crystalline ( amorphous ) or crystalline articles. Its amenability to drawing in manufacturing makes PET useful in fibre and film applications. Like most aromatic polymers , it has better barrier properties than aliphatic polymers . It

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