15278 IUPAC Gold Book - polyester 10.1351/goldbook.15278 15278 current 1 Polymer composed of macromolecules containing carboxylic ester linkages in the backbone: \[\ce{-O-CO\bond{-}}\] A polyester comprising unsaturated constitutional units such as a polyester prepared from maleic anhydride or from but-2-yne-1,4-diol is referred to as an unsaturated polyester. A polyester prepared from a polyol (typically a triol or tetrol), and a mixture of dicarboxylic anhydrides and fatty acids (e.g., linseed oil or tall oil) is referred to as an alkyd polymer or alkyd. Structure motifs of an alkyd polymer prepared from phthalic anhydride, glycerol, pentaerythritol [2,2-bis(hydroxymethyl)propane-1,3-diol], and fatty acids are shown below (MU stands for monomeric unit): Polycarbonates, polythioesters, and unsaturated polyesters are subclasses of polyesters. A polymer containing only pendent ester groups is excluded, for example, an acrylic polymer. Polycarbonates https://goldbook.iupac.org/terms/view/15275 acrylic polymer https://goldbook.iupac.org/terms/view/15244 polythioesters https://goldbook.iupac.org/terms/view/15306 PAC, 2009, 81, 1131. 'Glossary of class names of polymers based on chemical structure and molecular architecture (IUPAC Recommendations 2009)' on page 1154 (https://doi.org/10.1351/PAC-REC-08-01-30) https://goldbook.iupac.org/terms/view/15278/html https://goldbook.iupac.org/terms/view/15278/json https://goldbook.iupac.org/terms/view/15278/plain Citation: 'polyester' in IUPAC Compendium of Chemical Terminology, 5th ed. International Union of Pure and Applied Chemistry; 2025. Online version 5.0.0, 2025. 10.1351/goldbook.15278 The IUPAC Gold Book is licensed under Creative Commons Attribution-ShareAlike CC BY-SA 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) for individual terms. If you are interested in licensing the Gold Book for commercial use, please contact the IUPAC Executive Director at executivedirector@iupac.org . The International Union of Pure and Applied Chemistry (IUPAC) is continuously reviewing and, where needed, updating terms in the Compendium of Chemical Terminology (the IUPAC Gold Book). Users of these terms are encouraged to include the version of a term with its use and to check regularly for updates to term definitions that you are using. 2026-06-10T08:17:39+00:00