Figure 1 . — Therma I 

 analysis apparatus 

 for obtaining DTAj 

 TGA, and DTG 

 thermograms . 



Pyrolysis was studied in a nitrogen atmosphere at a flow rate of 100 cubic centi- 

 meters per minute. A similar flow rate of air was used in investigations of combustion. 

 For samples pyrolyzed in nitrogen, the percent of weight remaining as a function of 

 sample temperature was monitored. For combustion analysis, an alternate method of 

 recording data was needed due to the highly exothermic character of the reaction. The 

 oven temperature and sample tepiperature were monitored for several blank runs using 

 a Moseley Autograf 7100B two-pen strip-chart recorder. After correlating the two 

 readings, the percent of weight remaining as a function of sample environment tempera- 

 ture could be calculated. In this way, decomposition in nitrogen and air could be 

 compared in terms of similar environmental temperatures instead of sample temperatures. 

 Endotherms and exotherms in N2 had a negligible effect making sample and sample environ- 

 ment temperature essentially equivalent.) 



Derivative thermogravimetric analyses (DTG) were obtained simultaneously with TGA 

 by differentiating the mass signal from the DuPont 950 using a Cahn 2030 Time Derivative 

 Computer.'* Calibration was accomplished using a constant weight loss rate, provided by 

 a Knudsen diffusion cell containing a 50 yl sample of 95 percent ethanol . The Knudsen 

 cell was placed in the furnace at 40° C. and TGA-DTG curves recorded. The Moseley two- 

 pen recorder was used to record both the DTG curves and sample or sample environment 

 temperature so a comparison of rate of weight loss and temperature could be made. 



The apparatus used for obtaining DTA, TGA, and DTG data is shown in figure 1. 



^This derivative computer provided a noisefree response that was not significantly 

 different in time to the weight loss response. 



3 



