Compression-induced morphological and molecular structural changes of cellulose tablets probed with near infrared imaging

An analytical technique based on band shift analysis to derive key information concerning molecular structural changes from near infrared (NIR) imaging data was demonstrated in the present study. Molecular structural changes induced by compression process of sets of cellulose tablets under varying pressure levels were monitored by NIR imaging. The detailed band position shift analysis of the spectral features has provided insight into the compression mechanism of cellulose tablets. It has been shown that fine features of the deformation of the crystalline structure can be readily captured by band shift analysis of specific peaks. Substantial band position shifts were observed when pressure was applied to cellulose samples, indicating the disintegration of crystalline structures and an increase in the amorphous component. Band shift analysis may be applicable to a wide range of NIR imaging data to derive an in-depth understanding of systems even if the NIR images exhibit unwanted baseline shifts due to morphological changes in the samples.