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synthetic polymers

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Synthetic polymers

Synthetic polymersHuman made polymersPlastics are also called synthetic resins and are broadly classified into two categories: thermosetting resins and thermoplastic resins.

The thermosetting resins include phenolic resin and melamine resin, which are thermally hardened and never become soft again.Thermoplastic resins include PVC, polyethylene (PE), polystyrene (PS) and polypropylene (PP), which can be re-softened by heating.Usually, thermoplastics are supplied in the form of pelletised material (compounds) with additives (antioxidants, etc.) already blended in it.

Organic Polymers or (Common Polymers)Polyethylene terephthalate (PETE)Low Density Polyethylene(LDPE)High Density Polyethylene(HDPE)Polypropylene(PP)Polyvinyl Chloride(PVC)Polystyrene(PS)Nylon, nylon 6, nylon 6,6Polytetrafluoroethylene TeflonThermoplastic polyurethanes(TPU)Polycarbonate: LexanPolymethyl methacrylate: PlexiglassPolyethylene Terephthalate (PETE)PETE is one of the most widely used polymers in industry today, it is used to make most plastic bottles and containers.Low-density polyethylene(LDPE) LDPE is a thermoplastic made from the monomerethylene. It was the first grade of polyethylene,produce in 1933 by Imperial ChemicalIndustries(ICI) Low-density polyethylene(LDPE) LDPE is defined by a density range of 0.9100.940 g/cm3. It is not reactive atroom temperatures, except by strong oxidizing agents, and somesolventcause swelling. It can withstand temperatures of 80 C continuously and 95 C for a short time. Made in translucent or opaque variations, it is quite flexible, and tough but breakableHDPE is apolyethylene thermoplastic made frompetroleum. HDPE is known for its large strength to density ratio. The mass density of high-density polyethylene can range from 0.93 to 0.97 g/cm3.Although the density of HDPE is only marginally higher than that oflow-density polyethylene, HDPE has littlebranching, giving it strongerintermolecular forcesandtensile strengththan LDPE. The difference in strength exceeds the difference in density, giving HDPE a higherspecific strength.It is also harder and more opaque and can withstand somewhat highertemperatures(120 C/ 248 F for short periods, 110 C /230 F continuously).

High-density polyethylene(HDPE)

Polypropylene (PP) or PolypropenePP is athermoplastic polymerused in a wide variety of applications includingpackaging and labeling,textiles(e.g.,ropes, thermal underwear and carpets),stationery, plastic parts and reusable containers of various types, laboratory equipment,loudspeakers, automotive components.

Most commercial polypropylene has an intermediate level ofcrystallinitybetween that of low-densitypolyethylene(LDPE) and high-density polyethylene (HDPE). Polypropylene is normally tough and flexible, especially whencopolymerizedwith ethylene. This allows polypropylene to be used as anengineering plastic. Polypropylene is reasonably economical, and can be madetranslucent when uncolored but is not as readily made transparent aspolystyrene,acrylic, or certain other plastics. It is oftenopaqueor colored using pigments. Polypropylene has good resistance tofatigue.

Polypropylene (PP) or PolypropeneThe melting point of polypropylene occurs at a range, so a melting point is determined by finding the highest temperature of adifferential scanning calorimetrychart. Perfectly isotactic PP has a melting point of171 C(340F). Commercial isotactic PP has a melting point that ranges from 160 to 166 C (320to 331F).Polypropylene (PP) or PolypropeneMelt processing of polypropylene can be achieved viaextrusionandmolding. Common extrusion methods include production of melt-blown and spun-bond fibers to form long rolls for future conversion into a wide range of useful products, such as face masks, filters, diapers and wipes.The most common shaping technique isinjection molding.Polypropylene (PP) or PolypropenePolypropylene is used in the manufacturing piping systems; both ones concerned with high-purity and ones designed for strength and rigidity (e.g. those intended for use in potable plumbing, hydronic heating and cooling).This material is often chosen for its resistance to corrosion and chemical leaching, its resilience against most forms of physical damage, including impact and freezing, its environmental benefits, and its ability to be joined byheat fusionrather than gluing.Polypropylene (PP) or PolypropenePolypropylene (PP) or PolypropenePolypropylene lid of aTic-Tacbox, with aidentification codeunder its flap

Polyvinyl chloride (PVC)the third-most widely producedplastic, afterpolyethyleneandpolypropylene.PVC is used in constructionbecause it is more effective than traditional materials such as copper, iron or wood. It can be made softer and more flexible by the addition ofplasticizers. In this form, it is also used inclothingandupholstery, electrical cable insulation, inflatable products and many applications in which it replaces rubber.Pure polyvinyl chloride is a white, brittle solid. It is insoluble in alcohol, but slightly soluble intetrahydrofuran.

PVC's relatively low cost, biological and chemical resistance and workability have resulted in it being used for a wide variety of applications. It is used forsewerage pipesand other pipe applications where cost or vulnerability tocorrosionlimit the use ofmetal. With the addition of impact modifiers and stabilizers, it has become a popular material forwindowanddoorframes. By adding plasticizers, it can become flexible enough to be used in cabling applications as awireinsulator. It has been used inmany other applications. Polyvinyl chloride (PVC)

PVC pellets

PS is a syntheticaromaticpolymermade from themonomerstyrene, a liquidpetrochemical. Polystyrene can be rigid or foamed. General purpose polystyrene is clear, hard and brittle. It is a very inexpensive resin per unit weight. It is a rather poor barrier to oxygen and water vapor and has a relatively low melting point.Polystyrene is one of the most widely usedplastics, the scale of its production being several billion kilograms per year.Polystyrene can be naturallytransparent, but can be colored with colorants. Polysterene (PS)As athermoplasticpolymer, polystyrene is in a solid (glassy) state at room temperature but flows if heated above about 100 C on itsglass transition temperature then becomes rigid again when cooled. This temperature behavior is exploited forextrusion, and also formoldingandvacuum forming, since it can be cast into molds with fine detail.Polysterene (PS)It is very slow tobiodegradeand therefore a focus of controversy, since it is often abundant as a form oflitterin the outdoorenvironment, particularly along shores and waterways especially in its foam form.Polysterene (PS)Polysterene

Polysterene

Polysterene

PolysterenePolysterene

CD case made from general purpose polystyrene (GPPS) and high impact polystyrene (HIPS)Disposable polystyrene razorPolysterene

Expanded polystyrene packaging

Theresin identification code symbol for polystyrenePolysterene

Polystyrene foam is a major component of plastic debris in the ocean, where it becomes hazardous to marine life and "could lead to the transfer [of] toxic chemicals to the food chain . Animals do not recognize this artificial material and may even mistake it for food. Polystyrene foam blows in the wind and floats on water, and is abundant in the outdoor environment. It can be lethal to any bird or sea creature that swallows significant quantities.Restricting the use of foamed polystyrene takeout food packaging is a priority of many solid wasteenvironmental organizations. Efforts have been made to find alternatives to polystyrene, especially foam in restaurant settings. The original impetus was to eliminate chlorofluorocarbons(CFC), which was former component of foam.

PolystereneNylonNylonis a generic designation for a family ofsynthetic polymersknown generically as aliphaticpolyamides, first produced on February 28, 1935, byWallace CarothersatDuPont's research facility at theDuPont Experimental Station. Nylon is one of the most commonly used polymers.Key representatives arenylon-6,6,nylon-6,nylon-6,9,nylon-6,12,nylon-11,nylon-12andnylon-4,6.

Nylon is athermoplastic,silky material, made ofrepeating units linked byamidebondsand is frequently referred to aspolyamide(PA).

Nylon was the firstcommerciallysuccessful synthetic thermoplastic polymer. There are two common ways of making nylon for fiber applications. In one approach, molecules with an acid (-COOH) group on each end are reacted with molecules containing amine (-NH2) groups on each end. The resulting nylon is named on the basis of the number of carbon atoms separating the two acid groups and the two amines. These are formed intomonomersof intermediatemolecular weight, which are then reacted to form longpolymerchains.

NylonNylon was intended to be a synthetic replacement forsilkand substituted for it in many different products after silk became scarce duringWorld War II. It replaced silk in military applications such asparachutesandflak vests, and was used in many types of vehicle tires.

NylonEngineering-grade nylon is processed byextrusion,casting, andinjection molding. Type Nylon 6,6 is the most common commercial grade of nylon, and Nylon 6 is the most common commercial grade of molded nylon. Nylon

Nylon

Nylon

Nylon

Nylon

Nylon

NylonPolytetrafluoroethylene(PTFE)Is a syntheticfluoropolymer of tetrafluoroethylene that has numerous applications. The best known brand name of PTFE isTeflonbyDuPontCo.

PTFE is afluorocarbonsolid, as it is a high-molecular-weightcompound consisting ofcarbonandfluorine. PTFE ishydrophobic: neither water nor water-containing substances wet PTFE and possesses fairly high heat resistance, as fluorocarbons demonstrate mitigatedLo

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