The thermal analysis of carboxymethylated and unmodified lignin samples was conducted by using a thermogravimetric analyzer, TGA, i-1000 series, Instrument Specialist Inc. The samples were dried in an oven at 105 C overnight and 7.5 mg of unmodified and carboxymethylated lignin samples were used for this analysis. The analysis was carried out under nitrogen at a steady flow rate of 35 mL/min. Each sample was heated from room temperature to 800 C at the rate of 10 C/min.