14259 IUPAC Gold Book - transcrystalline layer 10.1351/goldbook.14259 14259 current 1 Polycrystalline layer nucleated and shaped by a pre-existing planar surface within or in contact with a polymer melt. In growth from unoriented melts, as in compression-molding, the transcrystalline layer consists of closely spaced, highly asymmetric spherulites, nucleated on the surface and elongated in the direction normal to the surface of the molded articles. In growth from oriented melts, as in injection-molding, two transcrystalline layers may result. The first is the skin layer and is formed by individual lamellae, while the second consists of spherulites. Both grow preferentially in the direction perpendicular to the flow direction and the external surface of the molded articles. Crystallization around macroscopic fibers in a polymer-fiber composite or at the surface of injection-molded articles (see also row structure). row structure https://goldbook.iupac.org/terms/view/14256 PAC, 2011, 83, 1831. 'Definitions of terms relating to crystalline polymers (IUPAC Recommendations 2011)' on page 1859 (https://doi.org/10.1351/PAC-REC-10-11-13) https://goldbook.iupac.org/terms/view/14259/html https://goldbook.iupac.org/terms/view/14259/json https://goldbook.iupac.org/terms/view/14259/plain Citation: 'transcrystalline layer' 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.14259 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. 2026-05-09T18:16:12+00:00