Revisiting the thermal recrystallization of mechanically amorphized lignocellulose

Abstract

The products of mechanical activation of lignocellulose are subject to the process of recrystallization of amorphized cellulose sections in some cases, this process reduces the efficiency of subsequent chemical and enzymatic treatment of plant raw materials. The process of recrystallization was studied on lignin-containing raw material - wheat straw. The crystal structure, particle and crystallite size of wheat straw ware studied by X-ray diffraction and granulometric analysis. It was found that the degree of crystallinity of cellulose in the composition of wheat straw decreases from 70 to 19 % in the process of mechanical activation in an AGO-2 planetary ball mill, the destruction of cellulose chains is observed predominantly along the [010] direction. The grinding limit was reached after 10 minutes of activation. Thermocycling at the boiling point of liquid nitrogen (-196 °C ) and at 180 °C of lignocellulose revealed that under these conditions the degree of recrystallization of amorphous regions of cellulose is negligible, which can be explained by the presence of lignin and a low water content in a material with a material moisture content (about 5.0 wt. %).