Temperature-Dependent Changes in Hydrogen Bonds in Cellulose la Studied by Infrared Spectroscopy in Combination with Perturbation-Correlation Moving-Window Two-Dimensional Correlation Spectroscopy:Comparison with Cellulose l beta

摘要

Our recent IR study demonstrated that hydrogen-bond structure in cellulose I beta drastically changes around 220 °C (Watanabe et al.Biomacromolecules 2006,7,3164).In the present study,temperature-dependent IR spectra of cellulose I alpha from 30 to 260 °C were analyzed by use of perturbation-correlation moving-window two-dimensional correlation spectroscopy.It was observed that as in the case of cellulose I beta abrupt changes in the hydrogen-bond structure occur around 220 °C in cellulose la.It was also revealed that although weakly hydrogen-bonded OH groups in I beta are stable below 230 °C thermal oxidation of those in I alpha is accelerated around 220 °C.In this way,the present study has clarified a difference between the thermal behavior of I alpha and that of I beta at the functional group level.Our result suggests that the drastic change in the hydrogen-bond structure around 220 °C makes cellulose I alpha much more unstable than I beta.