Static and Dynamic Large Strain Properties of Methyl Cellulose Hydrogels
2017
Rotbaum, Yonatan | Parvari, Galit | Eichen, Yoav | Rittel, Daniel
Methyl cellulose (MC) hydrogels display thermoreversible gelation upon heating. These hydrogels are abundantly employed in a variety of applications, rendering study of their mechanical properties relevant and important. Here we report on their basic elastic properties, based on ultrasonic measurements, and focusing on the heated solid gel, their mechanical properties in the quasi-static and dynamic (impact) large strain regimes are characterized. Unlike most other solids which soften upon heating, we find that methyl cellulose gels toughen increasingly on heating beyond the gelation point. Flow stress curves reveal polymer concentration dependent hardening. Contrary to most other soft materials, MC hydrogels do not present strain-rate sensitivity in the quasi-static range. Nevertheless, a dramatic change is observed in the dynamic regime, where at strain rates of ∼1500 s–¹ a 10–20-fold increase in flow strength is observed relative to the quasi-static regime. The results of this investigation complement the existing body of knowledge on the rheological properties of MC gels, extending the characterization to their large-strain, strain-rate dependent properties. Techniques presented in this work could be applied to examine other soft materials, and the characteristics found for methyl cellulose hydrogels could assist in advancing its employment in numerous applications.
显示更多 [+] 显示较少 [-]