with a DuPont Model 900-950 thermal analyzer, programed at the rate of 15°/minute. 

 The experiments were conducted in a nitrogen atmosphere, using silica beads as the 

 reference for DTA and 5 or 10 mg. of the groundwood or its components as the sample 

 For TGA the gas flow was regulated at the rate of 100 ml. /minute. Because Klason 

 lignin is condensed and altered under the drastic acid treatment, it was augmented 

 with milled wood lignin which is much closer to the native material (Browning 1963) 

 The results obtained are shown in figures 2 and 3. 



Figure 2 , — Differentia I 

 thermal analysis of 

 aottonwood j cellulose 

 xylan, and lignin. 



Temperature (°C ) 



