Two-Dimensional FTIR as a Tool to Study the Chemical Interactions within Cellulose-Ionic Liquid Solutions

Abstract

In this study two-dimensional FTIR analysis was applied to understand the temperature effects on processing cellulose solutions in imidazolium-based ionic liquids. Analysis of the imidazolium ion ]C2-H peak revealed hydrogen bonding within cellulose solutions to be dynamic on heating and cooling. The extent of hydrogen bonding was stronger on heating, consistent with greater ion mobility at higher temperature when the ionic liquid network structure is broken. At ambient temperatures a blue shifted ]C2-H peak was indicative of greater cation-anion interactions, consistent with the ionic liquid network structure. Both cellulose and water further impact the extent of hydrogen bonding in these solutions. The FTIR spectral changes appeared gradual with temperature and contrast shear induced rheology changes which were observed on heating above 70 ∘ C and cooling below 40 ∘ C. The influence of cellulose on solution viscosity was not distinguished on initial heating as the ionic liquid network structure dominates rheology behaviour. On cooling, the quantity of cellulose has a greater influence on solution rheology. Outcomes suggest processing cellulose in ionic liquids above 40 ∘ C and to reduce the impacts of cation-anion effects and enhance solubilisation, processing should be done at 70 ∘ C.

Superiority of Cellulose Non-Solvent Chemical Modification over Solvent-Involving Treatment: Solution for Green Chemistry (Part I)

“…FT-IR spectra of UFC100 (Figure 3c-f) reveals some particular absorption bands characteristic of cellulose fibres, e.g., hydroxyl moieties at 3334 cm −1 [32] and 1030 cm −1 [33], C-H stretching vibration at 2896 cm −1 [34], -COO at 1200-900 cm −1 [35] which were also detected in different works [36,37]. Absorption bands assigned to the exact moieties are presented in Table 2.…”

Macromolecular Interactions Control Structural and Thermal Properties of Regenerated Tri-Component Blended Films

“…Lignin, on the other hand, shows the most unique IR expression in the fingerprint (700–1800 cm −1 ), with especially strong peaks at the methoxy (1450 cm −1 ) and aromatic (1630 cm −1 ) groups. In the spectrum for AMIMCl, there are pronounced peaks at 3050, 2965, 1570, and 1165 cm −1 , with these IR regions previously being characteristic of AMIMCl [42]. Since the ATR-FTIR spectra of AMIMCl and lignocellulose component samples used in this study corroborate past results [42,43], they can reliably be used as markers for analysis of the spectra for Experiments 1–4.…”

Generation of Spherical Cellulose Nanoparticles from Ionic Liquid Processing via Novel Nonsolvent Addition and Drying

“…When regenerated with the aprotic nonsolvent acetonitrile, this produces the observed particles as solvation is decreased. Conversely, when regenerated with water or with excess moisture, hydrogen bonding by the imidazolium ion is affected [18] which impacts cellulose solvation and may bring cellulose molecules together increasing chain entanglement, reforming of hydrogen bonds and inducing cellulose precipitation. e above results using acetonitrile nonsolvent addition demonstrate that preparation of spherical cellulose nanoparticles is possible from ionic liquid.…”