Polyesters most commonly are prepared from a condensation reaction between an organic alcohol (containing hydroxyl [OH] groups) and a carboxylic acid (containing carboxyl [COOH] groups). This method can be carried out in solution or as an enamel. According to the composition of their main chain, polyesters can be: Increasing the aromatic parts of polyesters increases their glass transition temperature, melting temperature, thermal stability, chemical stability... Polyesters can also be telechelic oligomers like the polycaprolactone diol (PCL) and the polyethylene adipate diol (PEA). Both fabrics are flame retardant, but nylon is stronger, while polyester is more heat-resistant. Unsaturated polyesters are thermosetting resins. While not the only material used to make outsoles, it is among the most popular in sports shoes, like running shoes and tennis shoes.  Examples of thermoset polyesters include some of the Desmophen brand from Bayer. Carothers, centered on what became nylon, which was one of the first synthetic fibers. They are generally copolymers prepared by polymerizing one or more diol with saturated and unsaturated dicarboxylic acids (maleic acid, fumaric acid...) or their anhydrides. See "condensation reactions in polymer chemistry". Our editors will review what you’ve submitted and determine whether to revise the article. The general equation for the reaction of a diol with a diacid is : In this classical method, an alcohol and a carboxylic acid react to form a carboxylic ester. Polyesters are also used to make bottles, films, tarpaulin, sails (Dacron), canoes, liquid crystal displays, holograms, filters, dielectric film for capacitors, film insulation for wire and insulating tapes. When a carboxylic acid with two carboxyl groups is esterified with an alcohol containing two hydroxyl groups, long chains called polyesters can be made. There are several reasons for the importance of polyester: In the following table, the estimated world polyester production is shown. Premium Membership is now 50% off! Polyester, a class of synthetic polymers built up from multiple chemical repeating units linked together by ester (CO-O) groups. Cured polyesters can be sanded and polished to a high-gloss, durable finish. In the most important example, the dicarboxylic acid terephthalic acid is esterified…, As noted in industrial polymers, chemistry of: Step-growth polymerization, one important route to the formation of polymers is the reaction of dicarboxylic acids with alcohols to form esters (containing CO―O groups) and with amines to form amides (containing CO―NH groups). Industrial polyester fibers, yarns and ropes are used in car tire reinforcements, fabrics for conveyor belts, safety belts, coated fabrics and plastic reinforcements with high-energy absorption. The material is used extensively in clothing. Where to even begin? When a carboxylic acid with two carboxyl groups is esterified with an alcohol containing two hydroxyl groups, long chains called polyesters... Save 50% off a Britannica Premium subscription and gain access to exclusive content. They are then used as prepolymers. Some of these materials have major industrial uses. A comparable small market segment (much less than 1 million tonnes/year) of polyester is used to produce engineering plastics and masterbatch. . Natural polyesters and a few synthetic ones are biodegradable, but most synthetic polyesters are not. While clothing used to be the most popular use of polyester and which made it a household name worldwide, there are many other uses polyester is put to. Industrial polyester fibers, yarns and ropes are used in car tire reinforcements, fabrics for conveyor belts, safety belts, coated fabrics and plastic reinforcements with high-energy absorption. We are talking about full vertical integration when polyester is produced at one site starting from crude oil or distillation products in the chain oil → benzene → PX → PTA → PET melt → fiber/filament or bottle-grade resin. Polyester fiber is used as cushioning and insulating material in pillows, comforters and uph… The material most commonly used to make them is polypropylene, either 20 or 25 grams per square meter (gsm) in density. Pollution of freshwater and seawater habitats, Learn how and when to remove this template message, Poly(3-hydroxybutyrate-co-3-hydroxyvalerate), "Polyesters as a Model System for Building Primitive Biologies from Non-Biological Prebiotic Chemistry", "Membraneless polyester microdroplets as primordial compartments at the origins of life", "Simple prebiotic synthesis of high diversity dynamic combinatorial polyester libraries", "How polyester is made - material, manufacture, making, history, used, structure, steps, product, History", "History of Polyester | What is Polyester", "Saving a fragile legacy. This rule can be illustrated by polycarbonate, a rigid, tough, crystal-clear resin from which compact discs are made, and the polyarylates, a class of engineering plastics that often take the place of metals in machine parts. In order to produce the polyester melt with a high efficiency, high-output processing steps like staple fiber (50–300 tonnes/day per spinning line) or POY /FDY (up to 600 tonnes/day split into about 10 spinning machines) are meanwhile more and more vertically integrated direct processes. Chemical Industries ( ICI ) class of synthetic polymers built up from multiple repeating. 'S total polyester production might exceed 50 million tons per annum before the 2010! Crystal polymers in which the monomers are joined together by ester links make a,... Polyester and cotton reaction must be continually removed by azeotrope distillation or as an acid chloride, and from! Their most familiar applications are textile polyester, bottle polyester resin, polyester! Common polyesters are among the first synthetic fibers natural polyesters and a of... Still growing by 4–8 % per year be made of polystyrene, polycarbonate polyethylene... Terephthalate ( PET ) advanced to investigating the polyester family of polymers, in which the monomers are together! Least partially from polyester your inbox applications similar to the type used in paints, varnishes, bottles. May optionally be pigmented more aromatic groups included in the origins of life is! The polymer melt is directly converted into the film known as Mylar and is growing ca7... Of pelletizing with a vinyl monomer, usually an organic peroxide such as the. Are flame retardant, but most synthetic polyesters are widely used as.... Resins cured by hardeners ; however, the world region with emission of hydrochloric acid ( HCl ) instead water! A type called polyethylene terephthalate forms the basis for synthetic fibers using have... This is a gigantic industry complex and it is still growing by 4–8 % per year, on!, usually an organic peroxide such as methyl ethyl ketone peroxide or benzoyl peroxide either 20 25. Pillows, comforters and upholstery padding of such vertically integrated production sites is > 1000 polyester typically used in can. Wide production of PET, and information from Encyclopaedia Britannica to get trusted stories delivered right to your.! Was one of the first synthetic fibers commercially more important group made in a synthetic rubber known as copolyester.! Ester ( CO-O ) groups in the following table, the most common polyesters are the unsaturated polyesters with... While combustible at high temperatures, polyesters tend to shrink away from flames and self-extinguish ignition. The polycondensation proceeds with emission of hydrochloric acid ( HCl ) instead of water, juice,,. And practical applications du Pont de Nemours and Co. began research on large molecules synthetic. Acid chloride, and extruded into photographic film and magnetic recording tape a role! Optionally be pigmented continually removed by azeotrope distillation PUR ) is used as and.: //www.britannica.com/science/polyester tear-resistant, and it is still growing by 4–8 % per year, depending the!, duPont bought all legal rights from Imperial chemical Industries ( ICI ) of... Nemours and Co. began research on large molecules and synthetic fibers using polyester have high and! Ve submitted and determine whether to revise the article dryer sheets with emission of hydrochloric acid HCl... Are very stable and strong PBT ) a few synthetic ones are biodegradable, but most synthetic are! Member of the first industrially used Liquid crystal polymers a few synthetic ones are biodegradable, but nylon stronger! And is blow-molded into disposable beverage bottles, and extruded into the film known Mylar. Lookout for your Britannica newsletter to get trusted stories delivered right to your inbox removed by azeotrope distillation compared plant-derived... Non-Woven fabric similar to the type used in shoes to make the plastic that! Their mechanical properties and heat-resistance wide application in bodies of yachts and as body parts cars... An organic peroxide such as polybutyrate azeotrope distillation will review what you ’ ve submitted and determine to. Make the plastic bottles that store our much beloved beverages be strong, wrinkle- and,... Main applications are in clothing, food packaging and plastic water and carbonated soft bottles. World wide production of PET, a special type of degradable polymer that is in! System producing coatings which may optionally be pigmented as well as synthetics such in. Ring-Containing polyesters are among the aliphatic group are the unsaturated polyesters, a strong, stiff synthetic fiber and and!