Time-dependent viscoelastic characteristics of montmorillonite dispersion examined by ultrasonic spinning rheometry

• Published in: Applied clay science 2022-02, Vol.217, p.106395, Article 106395
• Main Authors: Yoshida, Taiki, Tasaka, Yuji, Fischer, Peter, Murai, Yuichi
• Format: Article
• Language: English
• Subjects: Montmorillonite; Rheology; Thixotropy; Viscoelasticity
• ISSN: 0169-1317; 1872-9053
• DOI: 10.1016/j.clay.2021.106395

Time-dependent viscoelastic characteristics of montmorillonite (Mt) dispersion are examined by means of ultrasonic spinning rheometry (USR). In this study, multiple timescale rheology of Mt dispersion under oscillatory shear flows is elucidated by linear viscoelastic analysis of USR. As a result, Mt dispersion with dilute NaCl concentration shows different timescales with respect to applied oscillatory frequency and shear rate. By experimental approaches, the relation between NaCl concentration and thixotropic characteristic is examined. Through experimental approaches, the rheological properties of Mt dispersion are classified into parameters with three timescales: The relaxation time of anisotropy of the Mt particles O(10−1 s), the relaxation time depending on the applied oscillation frequency O(10−2 s) to O(100 s), and time for structure recovery O(104 s). As novel experimental methodology for evaluating viscoelasticity of Mt dispersion showing thixotropy, USR is informative for understanding its complex rheological characteristics under unsteady shear conditions. •Viscoelasticity of montmorillonite dispersion under unsteady shear flow is evaluated.•The viscoelasticity is different with respect to oscillation frequency.•Montmorillonite dispersion has rheological properties with multiple time scale.