Effect of successive processing on properties of ligno-cellulosic micro-fines from pinus densiflora with microwave irradiation

This study compares the chemical characteristics of lingo-cellulosic micro-fines (LCMFs) obtained from successive microwave-assisted organosolv-processed wood powders. Both the yields and the Klason lignin (KL) contents of the LCMFs were found to decrease dramatically following the first microwave-assisted organosolv process. However, the KL content of successive microwave-assisted organosolved-LCMFs decreased only slightly compared with the LCMFs from first process. Moreover, after the first microwave-assisted organosolv process, the particle size of the LCMFs decreased dramatically, but resulted in little change after successive microwave-assisted organosolv processes. The chemical composition of the LCMFs was characterized by the elution of most of the hemi-cellulose and lignin during the first microwave-assisted organosolv process. In addition, the process significantly reduced the monosaccharide content of hemicellulose, whereas the crystallinity index of the first LCMFs increased. However, in subsequent repetitions of the microwave-assisted organosolv process, the similarities between the crystallinity index, vanillin content, and monosaccharide content of the LCMFs were maintained.