Effect of moisture and filler content on the structural, thermal and dielectric properties of polyamide‐6/boehmite alumina nanocomposites

• Published in: Polymer international 2019-05, Vol.68 (5), p.871-885
• Main Authors: Tomara, Georgia N, Karahaliou, Panagiota K, Anastassopoulos, Dimitris L, Georga, Stavroula N, Krontiras, Christoforos A, Karger‐Kocsis, Jozsef
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Boehmite; boehmite alumina; Broadband; Crystallization; Dielectric properties; Dielectric relaxation; dielectric spectroscopy; Direct melting; Drying; Gamma phase; Moisture; Nanocomposites; Organic chemistry; Polyamide resins; polyamide‐6; Spectroscopy; structural characterization; thermal analysis
• ISSN: 0959-8103; 1097-0126
• DOI: 10.1002/pi.5777

Polyamide‐6 (PA‐6)/boehmite alumina (BA) nanocomposites were prepared via direct melt compounding. Structural, thermal and dielectric properties of ‘as‐received’ (including moisture) and ‘dried’ (thermally treated) specimens were examined. The BA nanofiller was homogeneously dispersed in the PA‐6 matrix. XRD and FTIR revealed that crystallization of PA‐6 in the γ phase was favoured over α phase with increasing BA content. The crystallinity index (CI) and the percentage of α and γ phases were also evaluated. Dried specimens exhibited a lower CI than as‐received specimens while the CI decreased with the addition of filler. Broadband dielectric spectroscopy revealed the presence of γ, β and α relaxations, the Maxwell–Wagner–Sillars effect and the contribution of conductivity relaxation in the as‐received samples. The drying procedure unmasked a double feature of both β and α modes. The results of the complementary techniques were analysed and the effects of moisture and/or the incorporation of BA nanofiller on the microstructure of the PA‐6 matrix are disclosed. © 2019 Society of Chemical Industry Polyamide‐6/boehmite alumina nanocomposites were produced and investigated by SEM, XRD, DSC and broadband dielectric spectroscopy techniques. Dielectric relaxations were assigned and interpreted in connection with the results of the complementary techniques.