Akademik Veri Yönetim Sistemi
Materials Chemistry and Physics, cilt.346, 2025 (SCI-Expanded)
This study investigates the structural and dielectric properties of sepiolite/PMMA composites fabricated by depositing polymethyl methacrylate (PMMA) onto sepiolite, a fibrous magnesium silicate clay. A series of composites were prepared with varying PMMA loadings (25–300 mg per 1 g sepiolite) to explore the effects of polymer content on interfacial interaction, dielectric behavior, and relaxation dynamics. FTIR and XRD analyses revealed that PMMA primarily interacts with the surface hydroxyl groups of sepiolite without penetrating its internal channels, as evidenced by the unchanged internal Si–O–Si vibrations and basal spacing. SEM imaging demonstrated a gradual transition from fiber-coated structures to polymer-rich agglomerates with increasing PMMA content, confirming saturation of surface interactions beyond 100 mg. Dielectric spectroscopy indicated a significant reduction in permittivity (ε′) and dielectric loss (ε″) at low frequencies due to suppressed dipolar polarization and electrode effects. The Maxwell–Wagner–Sillars (MWS) model adequately described interfacial polarization at low PMMA loadings, while the Havriliak–Negami (HN) model provided a superior fit across all frequency ranges, capturing the broad and asymmetric relaxation processes at higher polymer loadings. The evolution of α and β parameters further confirmed distributed relaxation dynamics caused by structural heterogeneity. These results demonstrate that optimized PMMA loading can enhance dielectric stability while preserving the fibrous architecture of sepiolite, making these composites promising candidates for advanced low-loss dielectric applications.