bm7b00789_si_001.pdf (831.57 kB)
The Effect of Water on Rheology of Native Cellulose/Ionic Liquids Solutions
journal contribution
posted on 2017-08-09, 00:00 authored by Behzad Nazari, Nyalaliska W. Utomo, Ralph H. ColbyCellulose coagulates
upon adding water to its solutions in ionic
liquids. Although cellulose remains in solution with much higher water
contents, here we report the effect of 0–3 wt % water on solution
rheology of cellulose in 1-butyl-3-methylimidazolium chloride and
1-ethyl-3-methylimidazolium acetate. Fourier transform infrared spectroscopy,
thermal gravimetric analysis, and polarized light microscopy were
also used to study water absorbance to the solutions. Tiny amounts
of water (0.25 wt %) can significantly affect the rheological properties
of the solutions, imparting a yield stress, while dry solutions appear
to be ordinary viscoelastic liquids. The yield stress grows linearly
with water content and saturates at a level that increases with the
square of cellulose content. Annealing the solutions containing small
amounts of water at 80 °C for 20 min transforms the samples to
the fully dissolved “dry” state.