A SIMPLE APPROACH TOWARDS TUNING MORPHOLOGY OF MICROCRYSTALLINE CELLULOSE

Abstract

Microcrystalline cellulose (MCC) is a purified cellulose derivative. It is a white, highly oriented form of cellulose most commonly used in food, cosmetic, and pharmaceutical industries due to its advantageous properties of high crystallinity, large surface area, good compressibility etc. MCC is a high value added material that is widely used in pharmaceutical companies. For such applications, a large surface area of MCC is important. In this study, MCC was prepared from cellulosic fibres with a specific cross-section, i.e. trilobal, to produce trilobal microcrystalline cellulose (TMCC), which has a large surface area. This MCC is produced by a simple acid hydrolysis process. The process parameters in the production of MCC were optimised to maintain the cross-sectional shape of the fibres, even after conversion to MCC. The obtained MCC was characterized by various analytical techniques, such as Fourier transform-infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), B.E.T surface and X-ray diffraction (XRD) analyses. The cross and longitudinal morphology of the produced MCC was confirmed by scanning electron microscopy (SEM). The study shows that strong hydrolysis conditions, such as higher temperatures of 50 to 55 °C, lead to distortion of the cross-section, while lower reaction temperatures, i.e. 25 to 30 °C, help maintain a trilobal morphology. It was also found that the thermal stability of TMCC is higher, compared to that of regular MCC. The maximum decomposition temperature of TMCC was 304 °C, while it was 270 °C for regular MCC. The crystallinity index of all MCC was in a similar range. In addition, the water retention value (WRV) of TMCC was higher than that of circular MCC, indicating effectiveness of the increased surface area. The maximum WRV for MCC and TMCC was 66 and 85%, respectively.