{ "id": "ep5hf0wap4", "slug": "polycondensation", "title": "Polycondensation", "updated": "2026-09-30", "topic_path": [ { "id": "physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/topics/physical" }, { "id": "physical.chemistry", "label": "Chemistry", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry" }, { "id": "physical.chemistry.methods", "label": "Chemical principles and methods", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods" }, { "id": "physical.chemistry.methods.chemical-synthesis", "label": "Chemical synthesis", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods.chemical-synthesis" }, { "id": "physical.chemistry.methods.chemical-synthesis.polymer-synthesis", "label": "Polymer synthesis", "api_url": "https://www.edgepedia.org/api/v1/topics/physical.chemistry.methods.chemical-synthesis.polymer-synthesis" } ], "geo": [ { "id": "geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis.polymer-synthesis", "label": "Non-geographic · 1800 to 1945: Polymer synthesis", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis.polymer-synthesis", "path": [ { "id": "geo.nongeo", "label": "Non-geographic", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo" }, { "id": "geo.nongeo.t1800", "label": "Non-geographic · 1800 to 1945", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800" }, { "id": "geo.nongeo.t1800.physical", "label": "Physical world and mathematics", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical" }, { "id": "geo.nongeo.t1800.physical.chemistry", "label": "Chemistry", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry" }, { "id": "geo.nongeo.t1800.physical.chemistry.methods", "label": "Chemical principles and methods", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods" }, { "id": "geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis", "label": "Chemical synthesis", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis" }, { "id": "geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis.polymer-synthesis", "label": "Polymer synthesis", "api_url": "https://www.edgepedia.org/api/v1/geo/geo.nongeo.t1800.physical.chemistry.methods.chemical-synthesis.polymer-synthesis" } ] } ], "excerpt": "Polycondensation is a polymerization in which polymer chains grow through condensation reactions that expel a small molecule such as water, producing polyesters, polyamides, and other industrial and natural polymers.", "snippet": "Polycondensation is a polymerization in which polymer chains grow through condensation reactions that expel a small molecule such as water, producing polyesters, polyamides, and other industrial and natural polymers.", "node": "physical.chemistry.methods.chemical-synthesis.polymer-synthesis", "markdown": "# Polycondensation\n\nPolycondensation is a polymerization in which polymer chains grow through condensation reactions, each step linking functional groups and expelling a small molecule such as water, alcohol, or hydrogen halide; it is the reaction type behind polyesters, polyamides, and many other industrial and natural polymers.\n\n| Key fact | Detail |\n|---|---|\n| IUPAC definition | A polymerization in which chain growth proceeds by condensation reactions between molecules of all degrees of polymerization [1](https://goldbook.iupac.org/terms/view/P04722) |\n| Growth-step equation | \\( P_{x} + P_{y} \\rightarrow P_{x+y} + L \\), where \\( P_{x} \\) and \\( P_{y} \\) are chains of degree of polymerization \\( x \\) and \\( y \\) and \\( L \\) is a low-molar-mass by-product [1](https://goldbook.iupac.org/terms/view/P04722) |\n| Current classification | Synonym of condensative step polymerization, a subclass of step polymerization (IUPAC Recommendations 2025) [2](https://iupac.org/wp-content/uploads/2025/08/PAC-REC-2025-0490.R1_PR20250813.pdf) |\n| Monomer requirement | Functionality of at least 2; bifunctional monomers give linear polymers, polyfunctional monomers give branched or crosslinked ones [3](https://faculty.ksu.edu.sa/sites/default/files/343CHEM%20-Chapter%202_Polymer%20Synthesis%20pdf.pdf) |\n| Typical by-products | Water, alcohol, ammonia, acetic acid, hydrogen sulfide, or hydrogen halide [2](https://iupac.org/wp-content/uploads/2025/08/PAC-REC-2025-0490.R1_PR20250813.pdf) • [3](https://faculty.ksu.edu.sa/sites/default/files/343CHEM%20-Chapter%202_Polymer%20Synthesis%20pdf.pdf) |\n| Everyday products | PET (recycling code 1), Dacron polyester fiber, and Nylon 66 [4](https://ecampusontario.pressbooks.pub/orgbiochemsupplement/chapter/condensation-polymers/) • [5](https://chem.libretexts.org/Courses/University_of_British_Columbia/UBC_CHEM_154%3A_Chemistry_for_Engineering/05%3A_Polymers/5.04%3A_Condensation_Polymers) |\n\n## How it works\n\nEach growth step is a condensation: two reactants join and a small molecule leaves. IUPAC defines condensation as a usually stepwise reaction that yields a product with accompanying formation of water or some other small molecule, for example ammonia, ethanol, acetic acid, or hydrogen sulfide.[2](https://iupac.org/wp-content/uploads/2025/08/PAC-REC-2025-0490.R1_PR20250813.pdf) Because every molecule carrying a functional group can react with any other, chains of all lengths couple with one another, which is what the growth-step equation \\( P_{x} + P_{y} \\rightarrow P_{x+y} + L \\) expresses.[1](https://goldbook.iupac.org/terms/view/P04722)\n\nMonomer functionality controls architecture. Monomers must carry at least two reactive groups.[6](https://doi.org/10.1515/pac-2021-0115) Bifunctional compounds, whether an AB monomer or a stoichiometric AA/BB pair, lead to linear condensation polymers, while polyfunctional compounds lead to branched, hyperbranched, or crosslinked products.[3](https://faculty.ksu.edu.sa/sites/default/files/343CHEM%20-Chapter%202_Polymer%20Synthesis%20pdf.pdf)\n\nThe canonical example is polyester synthesis from a diol and a dicarboxylic acid:\n\n\\[ n\\ \\mathrm{HO{-}R{-}OH} + n\\ \\mathrm{HOOC{-}R'{-}COOH} \\rightarrow \\mathrm{-[O{-}R{-}O{-}C(O){-}R'{-}C(O)]_{n}-} + 2n\\ \\mathrm{H_{2}O} \\]\n\nas given in the IUPAC terminology guide.[6](https://doi.org/10.1515/pac-2021-0115) When polyamides are prepared from diamines and dicarboxylic acids, the polymerization produces two molecules of water per repeat unit.[4](https://ecampusontario.pressbooks.pub/orgbiochemsupplement/chapter/condensation-polymers/)\n\n## How it is done\n\nIndustrial polycondensation processes comprise up to three distinct stages: prepolymerization, polymerization, and finishing.[7](https://aiche.onlinelibrary.wiley.com/doi/10.1002/aic.690380612) One or more of these stages often have serious reaction rate limitations due to chemical equilibrium and the need to remove a condensate product. Jacobsen and Ray, in an AIChE Journal analysis of melt and solution polycondensation, describe two process design tools, the mass-transfer potential and pressure-chain length plots, illustrated through design examples for nylon-6,6 and poly(ethylene terephthalate) production.[7](https://aiche.onlinelibrary.wiley.com/doi/10.1002/aic.690380612)\n\nA contrasting laboratory-scale route is interfacial polycondensation, in which a diamine reacts with a dicarboxylic acid chloride at the boundary between two liquid phases. It is carried out at low temperature (0–40 °C), is fast, the reaction usually being over in a few minutes, and yields high-molecular-weight polymer with simple equipment.[3](https://faculty.ksu.edu.sa/sites/default/files/343CHEM%20-Chapter%202_Polymer%20Synthesis%20pdf.pdf)\n\n## Origin\n\nThe modern definition of polycondensation, including the growth-step equation \\( P_{x} + P_{y} \\rightarrow P_{x+y} + L \\), was set out in the IUPAC Recommendations 1996 document *Glossary of basic terms in polymer science* by A. D. Jenkins and colleagues, published in Pure and Applied Chemistry.[8](https://doi.org/10.1351/pac199668122287) The online Gold Book entry carrying that definition cites the same 1996 source, in version 5.0.0 dated 2025.[1](https://goldbook.iupac.org/terms/view/P04722)\n\n## Variants\n\nThe term has narrowed over time. Earlier, polycondensation was synonymous with condensation polymerization and embraced both what is now called polycondensation and condensative chain polymerization.[1](https://goldbook.iupac.org/terms/view/P04722) Additive step polymerization (synonym [polyaddition](https://www.edgepedia.org/polyaddition)) and condensative step polymerization (synonym polycondensation) are the two subclasses of step polymerization.[2](https://iupac.org/wp-content/uploads/2025/08/PAC-REC-2025-0490.R1_PR20250813.pdf) Condensative step polymerization is defined as step polymerization that proceeds with the generation of low-molar-mass by-product(s), exemplified by a diol reacting with a diester or diacid to form polyesters with elimination of alcohol or water.[2](https://iupac.org/wp-content/uploads/2025/08/PAC-REC-2025-0490.R1_PR20250813.pdf)\n\nCondensative chain polymerization appears in the literature under names including chain-growth condensation polymerization, catalyst transfer polymerization, and catalyst-transfer polycondensation; IUPAC rules that terms calling it a form of polycondensation are not acceptable.[2](https://iupac.org/wp-content/uploads/2025/08/PAC-REC-2025-0490.R1_PR20250813.pdf) Historically, polyaddition and polycondensation were collectively known as step-growth polymerization, a term whose use is now discouraged.[6](https://doi.org/10.1515/pac-2021-0115)\n\n## Applications\n\nIn broad textbook groupings of condensation or step-growth polymers, four main classes are usually distinguished: polyamides, polyesters, phenolics, and polyurethanes, though conventional polyurethane synthesis from diisocyanates and diols is step-growth polyaddition that generates no low-molar-mass by-product.[4](https://ecampusontario.pressbooks.pub/orgbiochemsupplement/chapter/condensation-polymers/) Polyesters can be formed from a diol plus a dicarboxylic acid, a diol plus a dioyl chloride, or a hydroxycarboxylic acid; polyamides from a diamine plus a dicarboxylic acid or dioyl chloride, or an aminocarboxylic acid.[9](https://www.chemistrystudent.com/cie-a-level/35-polymerisation/condensation-polymerisation.html)\n\nThe most familiar products are PET (polyethylene terephthalate), the most common thermoplastic polymer resin of the polyester family, used in fibers for clothing, containers for liquids and foods, and glass-fiber engineering resins, carrying recycling code 1 [4](https://ecampusontario.pressbooks.pub/orgbiochemsupplement/chapter/condensation-polymers/); Dacron, a polyester; and [Nylon 66](https://www.edgepedia.org/nylon-66), a polyamide.[5](https://chem.libretexts.org/Courses/University_of_British_Columbia/UBC_CHEM_154%3A_Chemistry_for_Engineering/05%3A_Polymers/5.04%3A_Condensation_Polymers) These step-growth polymers generally grow by carbon-heteroatom bond formation, C–O in Dacron and C–N in Nylon, unlike chain-growth polymers, which grow by C–C bond formation.[5](https://chem.libretexts.org/Courses/University_of_British_Columbia/UBC_CHEM_154%3A_Chemistry_for_Engineering/05%3A_Polymers/5.04%3A_Condensation_Polymers)\n\nNature uses the same chemistry: examples of naturally occurring condensation polymers are cellulose, the polypeptide chains of proteins, and poly(β-hydroxybutyric acid), a polyester synthesized by certain soil and water bacteria.[5](https://chem.libretexts.org/Courses/University_of_British_Columbia/UBC_CHEM_154%3A_Chemistry_for_Engineering/05%3A_Polymers/5.04%3A_Condensation_Polymers)\n\n## Limitations and alternatives\n\nCondensation polymers form more slowly than addition polymers, often require heat, and are generally lower in molecular weight. Because the terminal functional groups on a chain remain active, groups of shorter chains combine into longer chains only in the late stages of polymerization.[5](https://chem.libretexts.org/Courses/University_of_British_Columbia/UBC_CHEM_154%3A_Chemistry_for_Engineering/05%3A_Polymers/5.04%3A_Condensation_Polymers) Efficient removal of the condensate is required, which is why equilibrium limitation and condensate removal dominate the design of melt and solution processes.[7](https://aiche.onlinelibrary.wiley.com/doi/10.1002/aic.690380612)\n\nThe nearest alternative is polyaddition, the other subclass of step polymerization, which forms polymers without generating a low-molar-mass by-product.[2](https://iupac.org/wp-content/uploads/2025/08/PAC-REC-2025-0490.R1_PR20250813.pdf) Where very high molecular weight is needed quickly and at low temperature, interfacial polycondensation with acid chlorides offers a fast, low-temperature route, at the cost of using acid chloride monomers.[3](https://faculty.ksu.edu.sa/sites/default/files/343CHEM%20-Chapter%202_Polymer%20Synthesis%20pdf.pdf)\n\n## References\n\n1. [IUPAC Gold Book – polycondensation (P04722)](https://goldbook.iupac.org/terms/view/P04722)\n2. [Basic Classification and Definitions of Polymerization Reactions (IUPAC Recommendations 2025)](https://iupac.org/wp-content/uploads/2025/08/PAC-REC-2025-0490.R1_PR20250813.pdf)\n3. [Polymers and Petrochemicals – Step-growth (condensation) polymerization chapter (KSU course notes)](https://faculty.ksu.edu.sa/sites/default/files/343CHEM%20-Chapter%202_Polymer%20Synthesis%20pdf.pdf)\n4. [27.6 Condensation Polymers – Organic and Biochemistry Supplement (eCampusOntario)](https://ecampusontario.pressbooks.pub/orgbiochemsupplement/chapter/condensation-polymers/)\n5. [5.4: Condensation Polymers – Chemistry LibreTexts](https://chem.libretexts.org/Courses/University_of_British_Columbia/UBC_CHEM_154%3A_Chemistry_for_Engineering/05%3A_Polymers/5.04%3A_Condensation_Polymers)\n6. [A brief guide to polymerization terminology (IUPAC Technical Report)](https://doi.org/10.1515/pac-2021-0115)\n7. [Analysis and design of melt and solution polycondensation processes (Jacobsen & Ray, AIChE Journal, 1992)](https://aiche.onlinelibrary.wiley.com/doi/10.1002/aic.690380612)\n8. [A. D. Jenkins and colleagues (1996). Glossary of basic terms in polymer science (IUPAC Recommendations 1996). Pure and Applied Chemistry.](https://doi.org/10.1351/pac199668122287)\n9. [35.1 Condensation polymerisation | CIE A-Level Chemistry](https://www.chemistrystudent.com/cie-a-level/35-polymerisation/condensation-polymerisation.html)\n\n---\n*Topic: Encyclopedia › Physical world and mathematics › Chemistry › Chemical principles and methods › Chemical synthesis › Polymer synthesis*\n\n*Initially written Sep 29, 2026 · Reviewed: Sep 30, 2026 · Edited: Sep 30, 2026 · Last review: Sep 30, 2026*\n\n*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*\n\nLicense: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license\n", "same_as": [], "url": "https://www.edgepedia.org/polycondensation", "markdown_url": "https://www.edgepedia.org/polycondensation.md", "license": { "name": "Edgepedia Community License 1.0", "url": "https://www.edgepedia.org/edgepedia/license", "summary": "Free with credit, commercial use included. AI training is open to everyone. For other uses, organizations over USD 100M in revenue or 100M monthly users license separately.", "spdx": "LicenseRef-Edgepedia-Community-1.0" }, "credit": "\"Polycondensation\", Edgepedia (EdgeChat), https://www.edgepedia.org/polycondensation. Edgepedia Community License 1.0.", "credit_md": "\"[Polycondensation](https://www.edgepedia.org/polycondensation)\", Edgepedia (EdgeChat), [https://www.edgepedia.org/polycondensation](https://www.edgepedia.org/polycondensation). [Edgepedia Community License 1.0](https://www.edgepedia.org/edgepedia/license).", "credit_html": "\"Polycondensation\", Edgepedia (EdgeChat), https://www.edgepedia.org/polycondensation. Edgepedia Community License 1.0.", "speakable": "Polycondensation is a polymerization in which polymer chains grow through condensation reactions that expel a small molecule such as water, producing polyesters, polyamides, and other industrial and natural polymers." }