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44-448: In 2008, the global HDPE market reached a volume of more than 30 million tons. HDPE is known for its high strength-to-density ratio. The density of HDPE ranges from 930 to 970 kg/m. Although the density of HDPE is only marginally higher than that of low-density polyethylene , HDPE has little branching , giving it stronger intermolecular forces and tensile strength (38 MPa versus 21 MPa) than LDPE. The difference in strength exceeds

88-581: A certain elevated temperature and solidifies upon cooling. 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

132-438: A major type of thermoplastic. LDPE is widely used for manufacturing various containers, dispensing bottles, wash bottles, tubing, plastic parts for computer components, and various molded laboratory equipment. Its most common use is in plastic bags . Other products made from it include: Thermoplastic A thermoplastic , or thermosoftening plastic , is any plastic polymer material that becomes pliable or moldable at

176-433: A malfunction instead of shattering and becoming shrapnel like the other materials. Milk bottles, jugs, and other hollow goods manufactured through blow molding are the most important application area for HDPE, accounting for one-third of worldwide production, or more than 8 million tonnes. Above all, China, where beverage bottles made from HDPE were first imported in 2005, is a growing market for rigid HDPE packaging, as

220-404: 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

264-517: A result of its improving standard of living . In India and other highly populated, emerging nations, infrastructure expansion includes the deployment of pipes and cable insulation made from HDPE. The material has benefited from discussions about possible health and environmental problems caused by PVC and polycarbonate associated bisphenol A (BPA), as well as its advantages over glass, metal, and cardboard. Industrial production of HDPE from ethylene happens through either Ziegler-Natta polymerization or

308-598: 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,

352-421: 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

396-1009: 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

440-428: 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

484-421: 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

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528-422: 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

572-420: 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

616-519: 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

660-538: Is defined by a density range of 917–930 kg/m . At room temperature it is not reactive, except to strong oxidizers; some solvents cause it to swell. It can withstand temperatures of 65 °C (149 °F) continuously and 90 °C (194 °F) for a short time. Made in translucent and opaque variations, it is quite flexible and tough. LDPE has more branching (on about 2% of the carbon atoms) than HDPE , so its intermolecular forces ( instantaneous-dipole induced-dipole attraction ) are weaker, its tensile strength

704-493: 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)

748-657: 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

792-412: Is lower, and its resilience is higher. The side branches mean that its molecules are less tightly packed and less crystalline, and therefore its density is lower. When exposed to consistent sunlight, the plastic produces significant amounts of two greenhouse gases : methane and ethylene . Because of its lower density (high branching), it breaks down more easily than other plastics; as this happens,

836-439: 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

880-401: 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

924-503: 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)

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968-442: Is resistant to many different solvents , and is exceptionally challenging to glue; joints are typically made by welding. The physical properties of HDPE can vary depending on the molding process that is used to manufacture a specific sample; to some degree, a determining factor is the international standardized testing methods employed to identify these properties for a specific process. For example, in rotational molding, to identify

1012-481: 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

1056-469: 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)

1100-683: 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

1144-508: 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

1188-561: Is usually economic: HDPE is also used for cell liners in United States subtitle D sanitary landfills , wherein large sheets of HDPE are either extrusion welded or wedge welded to form a homogeneous chemical-resistant barrier, with the intention of preventing the pollution of soil and groundwater by the liquid constituents of solid waste . HDPE is preferred by the pyrotechnics trade for mortars over steel or PVC tubes, being more durable and safer: HDPE tends to rip or tear in

1232-414: 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

1276-530: The HDPE has been synthesized, it is ready to be used in commercial products. Industrial production methods for HDPE products include injection molding for complex shapes such as toys. Extrusion molding is used for constant-profile products such as pipes and films. Blow molding is intended for hollow products, specifically bottles and plastic bags. Rotational molding is used for large, seamless parts such as chemical drums and kayaks. The method used during processing depends on

1320-478: 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

1364-573: 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

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1408-456: The Phillips slurry process. The Ziegler-Natta method uses a combination of catalysts, including titanium tetrachloride, in contact with gaseous ethylene to precipitate high-density polyethylene. In a similar way, the Phillips slurry process uses silica-based catalysts in contact with a fast-moving hydrocarbon and polyethylene slurry to precipitate high density polyethylene. Processing will determine

1452-428: 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

1496-504: 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

1540-448: The difference in density, giving HDPE a higher specific strength . It is also harder and more opaque and can withstand somewhat higher temperatures (120 °C/248 °F for short periods). High-density polyethylene, unlike polypropylene , cannot withstand normally required autoclaving conditions. The lack of branching is ensured by an appropriate choice of catalyst (e.g., Ziegler–Natta catalysts ) and reaction conditions. HDPE

1584-400: The environmental stress crack resistance of a sample, the notched constant tensile load test (NCTL) is put to use. Owing to these desirable properties, pipes constructed out of HDPE are ideally applicable for drinking water and waste water (storm and sewage). HDPE has a wide variety of applications; for applications that fall within the properties of other polymers, the choice to use HDPE

1628-428: 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

1672-696: 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)

1716-450: The polyethylene chains, and helps determine properties such as flexibility, yield strength, and melt temperature. After the precipitate is formed, the temperature, pressure, and cooling time during processing will dictate the degree of crystallinity, with a higher degree of crystallinity resulting in greater rigidity and chemical resistance. Depending on the application, the method and processing steps can be adjusted for an ideal result. Once

1760-494: 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

1804-450: The product requirements, with each having benefits for a given application. Low-density polyethylene Low-density polyethylene ( LDPE ) is a thermoplastic made from the monomer ethylene . It was the first grade of polyethylene , produced in 1933 by Dr John C. Swallow and M.W Perrin who were working for Imperial Chemical Industries (ICI) using a high pressure process via free radical polymerization . Its manufacture employs

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1848-451: The properties of the HDPE. The method used to synthesize the HDPE is crucial because the micro structure of the HDPE will vary. The Phillips Slurry process results in HDPE with less branching and more precise molecular weights than the Ziegler process, but the Ziegler process provides greater flexibility in the type of polyethylene produced. The molecular weight of HDPE refers to the length of

1892-476: The same method today. The EPA estimates 5.7% of LDPE ( resin identification code 4 ) is recycled in the United States. Despite competition from more modern polymers, LDPE continues to be an important plastic grade. In 2013 the worldwide LDPE market reached a volume of about US$ 33 billion. Despite its designation with the recycling symbol, it cannot be as commonly recycled as No. 1 (polyethylene terephthalate) or 2 plastics (high-density polyethylene) . LDPE

1936-562: The surface area increases. Production of these trace gases from virgin plastics increases with surface area and with time, so that LDPE emits greenhouse gases at a more unsustainable rate than other plastics. In a test at the end of 212 days' incubation, emissions recorded were 5.8 nmol g d of methane, 14.5 nmol g d of ethylene, 3.9 nmol g d of ethane, and 9.7 nmol g d of propylene. When incubated in air, LDPE emits methane and ethylene at rates about 2 times and about 76 times, respectively, more than in water. Polyolefins (LDPE, HDPE, PP) are

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