Thermal and Physiochemical Characterization of Lignin Extracted from Wheat Straw by Organosolv Process

The purified lignin extracted from wheat straw by organosolv process was characterized for the existence of lignin subunits, functional groups and physical and thermal behaviours. Presence of carboxyl, hydroxyl, methoxyl groups and C-C, C-O, C=O linkages were conducted by Fourier Transform Infrared (FT-IR). By H-1-NMR (Nuclear Magnetic Resonance Spectroscopy) presence of aromatic protons, phenolic hydroxyls, carboxylic acids, and aldehydes were established. Moreover, C-13-NMR spectra have disclosed the presence of condensed and uncondensed aliphatic and aromatic aryls and ethers. The existence of syringyl and guaiacyl units also were confirmed with both FTIR and NMR spectroscopies. Furthermore, the results from Thermal Gravimetric Analysis (TGA) showed the weight of extracted lignin is changed in temperatures between 180 and 670 A degrees C by devolatization, formation and condensation of different chemicals. Also, the Differential Scanning Calorimetry (DSC) graph displayed a glass transition temperature of 105 A degrees C for extracted lignin. As a result, the extracted lignin with high purity can be a suitable candidate for carrying out value-added products.