Thixotropy of cellulose nanocrystal suspensions
نویسندگان
چکیده
The thixotropy of cellulose nanocrystal (CNC) water suspensions is intrinsically dependent on the hierarchical structure suspension. diverse hierarchies that comprise individual CNC nanoparticles and mesophase liquid crystalline domains, chiral nematic structures, contribute selectively to rheological material response. Here, we combine rheology with polarized light imaging (PLI) elucidate thixotropic behavior CNCs suspended in water. simultaneous monitoring PLI tests enables observation mesogens their orientation dynamics. Creep, dynamic time sweep, ramped hysteresis loop, recovery combined aim differentiate contribution different levels thixotropy. range concentrations investigated comprised biphasic (4 5 wt. %) phase (6, 7, 8 %). exhibited complex behavior, such as viscosity bifurcations creep overshoot loop tests. restructuring destructuring appeared correspond structure, depending mainly phase, agreement previous studies. Restructuring was attributed re-organizations an CNC, e.g., isotropic fraction at mesogen interfaces suspensions. However, by increasing concentrations, could also involve mesogens, indicated For flow conditions above yield stress, evidenced tests, dominated direction, a process readily observable form “Maltese-cross” patterns. Finally, show simple model, while unable capture finer details suspension’s be employed predict general features thereof.
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ژورنال
عنوان ژورنال: Journal of Rheology
سال: 2021
ISSN: ['1520-8516', '0148-6055']
DOI: https://doi.org/10.1122/8.0000281