14253 IUPAC Gold Book - polymer fibre 10.1351/goldbook.14253 14253 current 1 Uniaxially oriented polymer filament with macroscopic cylindrical symmetry, in which the average direction of the polymer chain axis coincides with the cylindrical symmetry axis. A crystalline polymer fiber generally consists of lamellar crystals or fringed micelle-type crystals (see fringed micelle model) with an interconnecting amorphous phase, or, rarely, of extended-chain crystals. The cylindrical symmetry shown by crystalline polymer fibers is not at the molecular scale but results from the random orientation of crystallites around the axis of the fiber. PAC, 2011, 83, 1831. 'Definitions of terms relating to crystalline polymers (IUPAC Recommendations 2011)' on page 1856 (https://doi.org/10.1351/PAC-REC-10-11-13) https://goldbook.iupac.org/terms/view/14253/html https://goldbook.iupac.org/terms/view/14253/json https://goldbook.iupac.org/terms/view/14253/plain Citation: 'polymer fibre' 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.14253 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. 2026-06-07T03:20:26+00:00