In this study, the effect of powder cellulose (PC) and 2 types of microcrystalline cellulose (MCC 101 and MCC 301) on pellet properties produced by an extrusion/spheronization process was investigated. The different investigated types of cellulose displayed different behavior during the extrusion/spheronization process. Pure PC was unsuitable for extrusion, because too much water was required and the added water was partly squeezed during the extrusion process. In contrast, MCC 101 and MCC 301 were extrudable at a wide range of water content, but the quality of the resulting products varied. In the extrusion/spheronization process, MCC 101 was the best substance, with easy handling and acceptable product properties. The properties of the extrudates and pellets were determined by Fourier transform (FT) Raman spectroscopy and environmental scanning electron microscopy (ESEM). FT-Raman spectroscopy was able to distinguish between the original substances and also between the wet and dried extrudates. The particle sizes of the raw material and of the extrudates were determined by ESEM without additional preparation. For MCC, the size of the resulting particles within the extrudate or pellet was smaller. However, in the extrudates of PC, changes in particle size could not be observed.
Keywords: powder cellulose, microcrystalline cellulose, pellet, Raman spectroscopy, environmental scanning electron microscopy, extrusion/spheronization