Assignment of FTIR absorption   Relative absorbance wavenumber (cm-1) Untreated bagasse Pretreated bagasse Untreated straw Pretreated straw Pretreated bagasse-straw 1:1mixture O-H stretching (H-bonded) 3396 0.64 0.65 0.62 0.73 0.68 O-H vibration of phenolic group 1371 0.93 0.97 0.89 0.94 0.95 O-H stretching of secondary alcohol 1163 0.81 0.84 0.78 0.82 0.83 O-H stretching of primary alcohol 1051 0.70 0.77 0.61 0.72 0.74 Mean value   0.77 0.81 0.72 0.80 0.80               C-H vibration of methoxyl group 2850 0.89 0.92 0.84 0.91 0.89 C-H angular deformation of methoxyl group 1462 0.97 0.99 0.91 0.96 0.98 Mean value   0.93 0.95 0.87 0.93 0.93               C-Ph vibration 1604 0.93 0.98 0.91 0.98 0.97 C=C aromatic skeletal vibration 1633 0.93 1.02 0.90 0.98 0.97 C-C and C-O stretching of aromatic skeletal 1334 0.95 0.97 0.92 0.94 0.96 C-O stretching of phenols 1253 0.88 0.96 0.88 0.94 0.94 Mean value   0.91 0.96 0.90 0.94 0.95               C-H aliphatic axial deformation 2912 0.83 0.86 0.76 0.84 0.84 C-H aliphatic angular deformation 1425 0.96 0.98 0.90 0.95 0.97 C-O-C stretching 1113 0.76 0.78 0.68 0.76 0.77 β-glycisidic linkages 897 1.11 1.18 1.01 1.08 1.08 C=O stretching 1735 0.98 1.15 1.01 1.07 1.08

Table 3: Relative intensity of bands in the infrared spectrum of different groups in the untreated and pretreated sugarcane bagasse, straw and bagasse-straw 1:1 mixture.