INVOLVEMENT OF THE IMPREGNATION IN THE DEGREE OF POLYMERIZATION OF CELLULOSE DURING SODA PULPING OF SUGAR-CANE BAGASSE

A comparative study had been carried out on the behaviour of the degree of polymerization (DP) of sugar cane bagasse during different times of digestion (soda pulping) with and without previous impregnation. Determination of the average DP (DPBAR-eta) and its distribution show that the impregnated materials undergo degradation during the digestion, what in contrary is not to observe when digestion is carried out without previous impregnation. It is supposed that the impregnation alters the chemical structure of the cellulose, facilitating thus the degradation during digestion. From the distribution curves arises furthermore, independent from impregnation or not and independent from the digestion time, a very pronounced maximum (about 25 wt.-% of total mass) at DP < 150 belonging to a non-cellulosic polysaccharide present in the sugar cane bagasse, which is removed neiher by digestion nor by nitration.