We have been extensively investigating molecular assembly states of β-1,4-glucan chains in noncrystalline regions of pure cellulose films using Fourier transform infrared (FTIR) spectroscopy. The difficulty in analyzing hydroxyl (OH) bands of cellulose noncrystalline regions stems from the overlapped IR bands due to various vibrational modes of OH groups. In this paper, noncrystalline films of regioselectively methylated cellulose derivative, 6-<i>O</i>-methylcellulose (6MC), which is supposed to have restricted formation of hydrogen bonding, were employed for analyses using FTIR spectroscopy, vapor-phase deuteration and a kinetic analysis of the reaction rates. The method could provide information on molecular assembly states in noncrystalline regions, prior to an interpretation of how hydrogen bonding are engaged using the generalized two-dimensional correlation analysis. As the result, films were found to be composed of no less than three kinds of domains. The detected hydrogen bonds at 3490 cm<sup>-1</sup> in the domains in the noncrystalline regions were likely derived from the intramolecular hydrogen bonds between the OH groups at C-3 of the anhydroglucose ring and the OH groups at C-5 of the adjacent ring. Eventually, our FTIR methodology with the two-dimensional correlation analysis was capable of providing detailed information on the noncrystalline regions for 6MC films.

Analyses on hydrogen bonding in noncrystalline regions of regioselectively methylated cellulose films by a combination of vapor-phase deuteration and generalized two-dimensional correlation IR spectroscopy

251st National Meeting (2016)

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