Cellulose Iβ investigated by IR-spectroscopy at low temperatures

Highly crystalline oriented Halocynthia roretzi cellulose Iβ films were investigated by IR-spectroscopy between −180 and +10 °C. Changes in the IR-spectra induced by temperature were compared to published changes induced by mechanical stretching. This made it possible to conclude that frequency shifts in the O–H stretching region of the IR-spectra due to temperature were not predominantly an indirect effect of thermal expansion leading to greater O–O distances, but were due directly to the effect of temperature on the O–H···O hydrogen bonds. Temperature induced frequency shifts of C–H stretching bands were consistent with the presence of weak inter-sheet C–H···O bonds. Furthermore, no phase transition in cellulose Iβ was found between −180 and +10 °C