Lignin as the largest reservoir of aromatic polymer is being discarded as waste or burnt to recover heat and electricity even though it has a great potential as a feedstock of new bio-based wood adhesives. The structural complexity and heterogeneity o...
Lignin as the largest reservoir of aromatic polymer is being discarded as waste or burnt to recover heat and electricity even though it has a great potential as a feedstock of new bio-based wood adhesives. The structural complexity and heterogeneity of lignin is known as a limitation to convert it into value-added products. Hence, in this study, we prepared the homogeneous or reduced polydispersity Kraft lignin by one-step fractionation with acetone. The objective of this study is to investigate chemical characteristics of acetone-soluble and acetone-insoluble Kraft lignin from hardwood and softwood, using Fourier transform infrared (FTIR) spectroscopy. The results showed that 65% portion of hardwood Kraft lignin is dissolved in acetone while 35% remained insoluble. By contrast, 55% of softwood Kraft lignin is dissolved in acetone, whereas 45% is insoluble in acetone. Furthermore, FTIR results revealed the presence of aromatic skeletal vibrations of both hardwood and softwood Kraft lignin. As expected, syringil and guaiacyl bands were detected in hardwood Kraft lignin, whereas guaiacyl band was present only in softwood Kraft lignin. However, acetone-soluble and acetone-insoluble of Kraft lignin showed considerable different peaks.