Compression and Compaction Behaviour of Microcrystalline Cellulose from Sorghum and Andropogon Stalks

Sources and processing techniques could affect performance of Microcrystalline Cellulose (MCC). This study therefore evaluated the suitability of some agricultural wastes as novel sources of MCC; Sorghum Bicolour and Andropogon gayanus. The physics of compaction of the new grades of cellulose; Sorghum MCC (SOMCC) or Andropogon MCC (AMCC) was compared with Avicel PH101. The SOMCC and AMCC were isolated from mineral acid hydrolysed de-lignified α-cellulose of the plant stalks. Particle size distribution was analysed. The carver hydraulic press was used for compaction study. Heckle plots, tensile strength, reworking potentials (RWP), disintegration and friability profiles were used as basis for assessment. The median particle size was 52.5 or 80 µm for AMCC and SOMCC with interquartile coefficient of skewness (IQCS) of 19.2 and 21.5%.respectively. Particle size fractions of 125-250 µm produced compacts with similar strength profiles. The polymer grades, AMCC, SOMCC and Avicel PH101 at fixed compression pressure of 62.4 N/mm2 exhibited similar tensile strength in the range of 2.7- 2.8 N/mm2. Heckel plot analysis showed similarity in yield pressure of 152.3 N/mm2 or 151.5 N/mm2 for Avicel PH101 and SOMCC with notable higher value in AMCC at 192.1 N/mm2. The degree of packing achieved by the particles at low compression pressure was 1.23, 1.39 and 1.12 for SOMCC, Avicel PH101 or AMCC while the extent of particle rearrangement at initial compression vide the relative densities (DB) was in the order 0.519, 0.539 and 0.454 respectively. The results are heavily suggestive of deformation by plastic flow mechanism for the new polymers. In ranking, the degree of compaction and consolidation of SOMCC ≈ Avicel PH101 > AMCC. The reworking potential was in the order AMCC < SOMCC ≈ Avicel PH101.