Polyamide - wikipedia Polyamide A polyamide is a macromolecule with repeating units linked by amide bonds. Polyamides occur both naturally and artificially. Examples of naturally occurring polyamides are proteins, such as wool and silk. Artificially made polyamides can be made through step - growth polymerization or solid - phase synthesis yielding materials such as nylons, aramids, and sodium poly ( aspartate ). Synthetic polyamides are commonly used in textiles, automotive applications, carpets and sportswear due to their high durability and strength. The transportation manufacturing industry is the major consumer, accounting for 35 % of polyamide ( PA ) consumption. Contents 1 Classification 2 Polymerization chemistry 3 See also 4 References 5 Further reading Classification Polymers of amino acids are known as polypeptides or proteins. According to the composition of their main chain, synthetic polyamides are classified as follows : Polyamide family Main chain Examples of polyamides Examples of commercial products Aliphatic polyamides Aliphatic Nylon PA 6 and PA 66 Zytel from DuPont, Technyl from Solvay, Rilsan and Rilsamid from Arkema, Radipol from Radici Group Polyphthalamides Semi-aromatic PA 6T = hexamethylenediamine + terephthalic acid Trogamid T from Evonik Industries, Amodel from Solvay Aramids = aromatic polyamides Aromatic Paraphenylenediamine + terephthalic acid Kevlar and Nomex from DuPont, Teijinconex, Twaron and Technora from Teijin, Kermel from Kermel. All polyamides are made by the formation of an amide function to link two molecules of monomer together. The monomers can be amides themselves ( usually in the form of a cyclic lactam such as caprolactam ), α, ω - amino acids or a stoichiometric mixture of a diamine and a diacid. Both these kinds of precursors give a homopolymer. Polyamides are easily copolymerized, and thus many mixtures of monomers are possible which can in turn lead to many copolymers. Additionally many nylon polymers are miscible with one another allowing the creation of blends. Polymerization Chemistry Production of polymers requires the repeated joining of two groups to form an amide linkage. In this case this specifically involves amide bonds, and the two groups involved are an amine group, and a terminal carbonyl component of a functional group. These react to produce a carbon - nitrogen bond, creating a singular amide linkage. This process involves the elimination of other atoms previously part of the functional groups. The carbonyl - component may be part of either a carboxylic acid group or the more reactive acyl halide derivative. The amine group and the carboxylic acid group can be on the same monomer, or the polymer can be constituted of two different bifunctional monomers, one with two amine groups, the other with two carboxylic acid or acid chloride groups. The condensation reaction is used to synthetically produce nylon polymers in industry. Nylons must specifically include an straight chain ( aliphatic ) monomer. The amide link is produced from an amine group ( alternatively known as an amino group ), and a carboxylic acid group. The hydroxyl from the carboxylic acid combines with a hydrogen from the amine, and gives rise to water, the elimination byproduct that is the namesake of the reaction. As an example of condensation reactions, consider that in living organisms, Amino acids are condensed with one another by an enzyme to form amide linkages ( known as peptides ). The resulting polyamides are known as proteins or polypeptides. In the diagram below, consider the amino - acids as single aliphatic monomers reacting with identical molecules to form a polyamide, focusing on solely the amine and acid groups. Ignore the substituent R groups -- under the assumption the difference between the R groups are negligible : The reaction of two amino acids. Many of these reactions produce long chain proteins For fully aromatic polyamides or ' aramids ' e.g. Kevlar, the more reactive acyl chloride is used as a monomer. The polymerization reaction with the amine group eliminates hydrogen chloride. The acid chloride route can be used as a laboratory synthesis to avoid heating and obtain an almost instantaneous reaction. The aromatic moiety itself does not participate in elimination reaction, but it does increase the rigidity and strength of the resulting material which leads to Kevlar 's renowned strength. In the diagram below, Aramid is made from two different monomers which continuously alternate to form the polymer. Aramid is an aromatic polyamide : The reaction of 1, 4 - phenyl - diamine ( para-phenylenediamine ) and terephthaloyl chloride to produce Aramid Polyamides can also be synthesized from dinitriles using acid catalysis via an application of the Ritter reaction. This method is applicable for preparation of nylon 1, 6 from adiponitrile, formaldehyde and water. Additionally, polyamides can be synthesized from glycols and dinitriles using this method as well. Synthesis of Nylon 1, 6 from adiponitrile, formaldehyde, and water using sulfuric acid as a catalyst See also Polyamide - imide References Jump up ^ Palmer, R.J. 2001. Polyamides, Plastics. Encyclopedia Of Polymer Science and Technology. doi : 10.1002 / 0471440264. pst251 Jump up ^ Market Study Engineering Plastics, Ceresana, Sep 2013 Jump up ^ `` Making nylon : The `` nylon rope trick '' ``. Royal Society of Chemistry. Retrieved 19 April 2015. Jump up ^ Magat, Eugene E. ; Faris, Burt F. ; Reith, John E. ; Salisbury, L. Frank ( 1951 - 03 - 01 ). `` Acid - catalyzed Reactions of Nitriles. I. The Reaction of Nitriles with Formaldehyde1 ''. Journal of the American Chemical Society. 73 ( 3 ) : 1028 -- 1031. doi : 10.1021 / ja01147a042. ISSN 0002 - 7863. Jump up ^ Lakouraj, Moslem Mansour ; Mokhtary, Masoud ( 2009 - 02 - 20 ). `` Synthesis of polyamides from p - Xylylene glycol and dinitriles ''. Journal of Polymer Research. 16 ( 6 ) : 681. doi : 10.1007 / s10965 - 009 - 9273 - z. ISSN 1022 - 9760. Further reading Kohan, Melvin I. ( 1995 ). Nylon Plastics Handbook. Hanser / Gardner Publications. ISBN 9781569901892 Plastics Chemical types Acrylonitrile butadiene styrene ( ABS ) Cross-linked polyethylene ( PEX, XLPE ) Ethylene vinyl acetate ( EVA ) Poly ( methyl methacrylate ) ( PMMA ) Polyacrylic acid ( PAA ) Polyamide ( PA ) Polybutylene ( PB ) Polybutylene terephthalate ( PBT ) Polycarbonate ( PC ) Polyetheretherketone ( PEEK ) Polyester ( PEs ) Polyethylene ( PE ) Polyethylene terephthalate ( PET, PETE ) Polyimide ( PI ) Polylactic acid ( PLA ) Polyoxymethylene ( POM ) Polyphenyl ether ( PPE ) Polypropylene ( PP ) Polystyrene ( PS ) Polysulfone ( PES ) Polytetrafluoroethylene ( PTFE ) Polyurethane ( PU ) Polyvinyl chloride ( PVC ) Polyvinylidene chloride ( PVDC ) Styrene maleic anhydride ( SMA ) Styrene - acrylonitrile ( SAN ) Mechanical types Thermoplastic Duroplast Corrugated plastic Polymeric foam High performance plastics Additives Polymer additive Colorants Plasticizer Stabilizer for polymers Biodegradable additives Products Plastic industry Commodity plastics Engineering plastics Plastic film Plastic bottle Plastic bag Plastic shopping bag Plastic cutlery Blister pack Foam food container Construction Geosynthetics Category : Plastics applications Environment and health Health issues of plastics and polyhalogenated compounds ( PHCs ) Plasticizers : Phthalates DIBP DBP BBP ( BBzP ) DIHP DEHP ( DOP ) DIDP DINP Miscellaneous plasticizers Organophosphates Adipates ( DEHA DOA ) Monomers Bisphenol A ( BPA, in Polycarbonates ) Vinyl chloride ( in PVC ) Miscellaneous additives incl. PHCs PBDEs PCBs Organotins PFCs Perfluorooctanoic acid Health issues Teratogen Carcinogen Endocrine disruptor Diabetes Obesity Obesogen Polymer fume fever Pollution Plastic pollution Great Pacific garbage patch Persistent organic pollutant Dioxins List of environmental health hazards Regulations California Proposition 65 European REACH regulation Japan Toxic Substances Law Toxic Substances Control Act Waste Plastic pollution Great Pacific garbage patch Persistent organic pollutant Dioxins List of environmental health hazards Plastic recycling Biodegradable plastic Identification codes Fibers Natural Plant Abacá Bagasse Bamboo Coir Cotton Fique Flax Linen Hemp Jute Kapok Kenaf Piña Pine Raffia Ramie Rattan Sisal Wood Animal Alpaca Angora Byssus Camel hair Cashmere Catgut Chiengora Guanaco Hair Llama Mohair Pashmina Qiviut Rabbit Silk Tendon Spider silk Wool Vicuña Yak Mineral Asbestos Man - made Regenerated Art silk Semi-synthetic Acetate Diacetate Lyocell Modal Rayon Triacetate Synthetic Mineral Glass Carbon Tenax Basalt Metallic Polymer Acrylic Aramid Twaron Kevlar Technora Nomex Microfiber Modacrylic Nylon Olefin Polyester Polyethylene Dyneema Spectra Spandex Vinylon Vinyon Zylon Commons GND : 4175096 - 2 NDL : 00569143 Retrieved from `` https://en.wikipedia.org/w/index.php?title=Polyamide&oldid=813816465 '' Categories : Polyamides Dielectrics Thermoplastics Hidden categories : Wikipedia articles with GND identifiers Talk Contents About Wikipedia Català Čeština Deutsch Eesti Ελληνικά Español Euskara فارسی Français 한국어 Հայերեն हिन्दी Bahasa Indonesia Italiano Magyar മലയാളം Nederlands 日本 語 Norsk Oʻzbekcha / ўзбекча Polski Português Română Русский Simple English Basa Sunda Suomi Svenska Türkçe Українська 中文 23 more Edit links This page was last edited on 5 December 2017, at 11 : 14. 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Question: what type of reaction leads to the production of polymers
Answer: condensation reaction