Various factors such as moisture content, molecular structure of the polymer affect the degradation process. Following articles might be helpful for you.
http://www.ewp.rpi.edu/hartford/~ernesto/F2012/EP/MaterialsforStudents/Patel/Beyler_Hirschler_SFPE_Handbook_3.pdf
http://depts.washington.edu/mseuser/Equipment/RefNotes/TGA_Notes.pdf
Dear all;
the reason is the existance of a multiple energy barriers for chain scission arising from the different bonds that may exist. Regards
This type of analysis usually is employed for studyng decomposition mechanism and kinetic parameters, which are very important to evaluate the thermal reactivity, sensitivity and storage properties.
http://pubs.rsc.org/en/content/articlehtml/2014/cp/c4cp03479a
As in the previous reponses there are some reasons for mass lossing in TG analysis: below 100 oC the sample loss the absorbed water between 100-200 oC, the bound water and absorbed solvents (light volatiles), above 200 oC the polymer loss the groups covalently bound to polymer backbone (ex: -SO3H, -NH2). The degradation of polymer chain was finished up to 700 oC. These are the reasons for mass loss that I know.
I think that Irina Petreanu gives the more clear explanation, in spite of all the other are right from different point of view.
In addition to the above comments, if you want to get an accurate and thorough answer to your question one would need to know whether you are working in an inert atmosphere, in air, or under oxygen.
Because depending on the structure of your polymer part of the chain may oxydize and volatilize faster than other. ie COOH, COH, CO, amides, ..., branches....
The answers are already given. The volatiles go first followed by groups which are less thermally stable. Then the thermally stable aromatics will go. Sometimes, carboxyl, esters form anhydride during decomposition. As it is stable it goes at later stage. Beyond 600 degreeC residual carbon is removed. Inorganic materials remain at the end. If heavily crosslinked or aromatics the char yield will be more.
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