Temperature dependence of polymer crystalline morphology in nylon 6/montmorillonite nanocomposites

• Published in: Polymer (Guilford) Vol. 42; no. 25; pp. 09975 - 09985
• Main Authors: Lincoln, Derek M, Vaia, Richard A, Wang, Zhi-Gang, Hsiao, Benjamin S, Krishnamoorti, Ramanan
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.12.2001; Elsevier
• Subjects: Applied sciences; COMPOSITE MATERIALS; Composites; CRYSTAL STRUCTURE; Exact sciences and technology; Forms of application and semi-finished materials; MATERIALS SCIENCE; MONTMORILLONITE; Nanocomposites; NATIONAL SYNCHROTRON LIGHT SOURCE; NYLON; Nylon 6; Polymer industry, paints, wood; POLYMERS; Technology of polymers; TEMPERATURE DEPENDENCE; Wide-angle X-ray scattering; Nylon 6; Nanocomposites; Wide-angle X-ray scattering; Amide 6 polymer; Lamellar structure; Crystal form; Montmorillonite; Supramolecular structure; Temperature effect; Dispersion reinforced material; Crystallinity; Experimental study; Composite material
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/S0032-3861(01)00542-0

The influence of nanodispersed montmorillonite layers and process history on the crystal structure of nylon 6 between room temperature and melting is examined with simultaneous small- and wide-angle X-ray scattering and modulated differential scanning calorimetry. For the examined process history, nylon 6 exhibits predominantly α-phase behavior from room temperature to melting, with a gradual shift in chain–chain and sheet–sheet spacings from ∼100°C to melting. In contrast, the presence of aluminosilicate layers stabilizes a dominant γ-crystal phase, which persists, essentially unmodified, until melting. The temperature dependence of the total crystallinity and the relative fractions of α- and γ-phases is strongly dependent on the layered silicate content and the interaction between the nylon 6 and the aluminosilicate layers. Additionally, the temperature dependence of the α- and γ-phases imply that the γ-phase is preferentially in the proximity of the silicate layers, whereas the α-phase exists away from the polymer–silicate interphase region: In general, process history and use-temperature will determine the relative fraction of the crystalline polymer phases in semi-crystalline polymer nanocomposites, and thus have significant influence on the stability of the crystalline region at elevated temperatures.