Thermal Gravimetric Analyses Of Cellulose In Lignocellulosic Biomass

Cellulose, the most abundant organic polymer on earth, constitute more than 50% of plant biomass and is critical to the establishment of bio-refinery processes. Most cellulose coexistent with other polysaccharides and lignin, and this heterogeneous polymer is known as lignocellulose. Thermal gravimetric analysis (TGA) is believed to be a useful technique for the characterization of the heterogeneous materials such as lignocellulosic biomass. To evaluate the thermal degradation of cellulose in lignocellulosic biomass, TGA of various pretreated lignocellulosebased materials was carried out such as raw cotton dust, cotton, Japanese cypress sawdust, ball milled Japanese cypress, organosolv-treated Japanese cypress, and alkaline-hydrogen-peroxide treated Japanese cypress. The cellulose content in all samples was approximately 5 mg, and the samples were cast in the tablet form prior to TGA. The derivative thermogravimetric (DTG) curves of each sample varied although the amount of cellulose in the samples was the same. The DTG curves of cotton and organosolv-treated Japanese cypress were similar with that of microcrystalline cellulose powder, and were sharp than those of the raw and ball-milled samples. The temperatures at the maximum DTG values of cotton and other refined sample were approximately 335-360 degrees C, and were greater than that of the ball-milled sample, which has a low crystallinity and non-cellulosic susstances. These results suggested that the sharpness of the DTG curves and the temperature at the maximum DTG values probably depended on the degree of cellulose refinement and crystallinity. Thermal degradation behaviors represented by DTG curves may serve as an indication of cellulose purity and other physical properties of lignocellulosic biomass.