You should make TGA first only if your sample is very unstable. Usually the glass transition and the melting peaks appear much below the decomposition temperature. Another case where TGA can be suggested if you have a considerable amount of volatile or water in your sample. TGA can be used to determine the maximum temperature where you can go with heating. If you have semicrystalline sample, it is advisable to make first a heating run above the melting point, cool back (registering the crystallization as well) and apply a second heating. This erases the thermal history of your sample in the first run. If the sample is soft at room temperature (i.e. above the glass transition temperature), you should cool down first by dry ice or by liquid nitrogen (if available) and heat it up to see the glass transition. Normally no chemical shold be added to the polymer sample, unless you want to study a forced decomposition (but be careful not to damage the instrument). Good DSC tutorials are available on the net.

You should make TGA first only if your sample is very unstable. Usually the glass transition and the melting peaks appear much below the decomposition temperature. Another case where TGA can be suggested if you have a considerable amount of volatile or water in your sample. TGA can be used to determine the maximum temperature where you can go with heating. If you have semicrystalline sample, it is advisable to make first a heating run above the melting point, cool back (registering the crystallization as well) and apply a second heating. This erases the thermal history of your sample in the first run. If the sample is soft at room temperature (i.e. above the glass transition temperature), you should cool down first by dry ice or by liquid nitrogen (if available) and heat it up to see the glass transition. Normally no chemical shold be added to the polymer sample, unless you want to study a forced decomposition (but be careful not to damage the instrument). Good DSC tutorials are available on the net.

There is no sequence of TGA or DSC analysis. TGA is basically destructive analysis. Which ever you want to do first, you can do it.

There is no need to add any material for performing TGA or DSC. Just use your polymeric material to analyse by TGA or DSC

Hi Olusola

Your question is not very clear, but I try an answer.

You can do whatever you want on a single sample before DSC... only if it does not degrade your sample, and depending of what you need to observe!

Usually, we used to clear the thermal history of a polymer sample before analyzing it by heating it upper the Tg for a while. So if your max temperature of TGA is not much higher than Tg, it will not cause problem.

 Use polymer alone for TGA (Not need any special additives).Thermogravimetric analyses were carried out in nitrogen and air at a heating rate of 20 degree Celsius /minute using a Parkin Elmer TGA model 4000. Thermograms were recorded from 0  to 800 degree Celsius. The temperature of onset of degradation, the temperature at which at the rate of weight loss is maximum (T max) and the residual weight percentage were evaluated.   

If you intend to use the same sample, by all means do DSC first. If separate samples, most common case, it really does not matter but I would do TGA first under conditions similar to those recommended by others to determine onset of decomposition. Your DSC should not be run to maximum temperatures close to that onset value. Simply a practical matter. No need of additives in either case unless that is what you want to study.

TGA gives thermal stability (Temperature vs Weight Loss) i.e decomposition temperature, whereas DSC gives transition temperature especially glass transition temperature (Tg)

Dear Olusola Ayeleru,

All the answers given here are valid, but I would like to know which specific polymer you are intending to analyse? This will determine which route to follow and the specific properties you want to determine. I gather you want to evaluate the influence of your additive,not so?

As Alexandre Finke also pointed out, your question is a bit vague. Could you please elaborate?

Kind regards

Louis van Rooyen

If you want to find out the degradation tendency of your polymer then I suggest you do TGA first. Once you know the degradation behaviour of your polymer, you may then use DSC accordingly, say; either for knowing the thermal events such as Tg, Tm, Tc, enthalpies, etc. or even for isothermal and non-isothermal crystallisation kinetics studies.

Also, it is better to do TGA without any additives to the polymer and that too in an inert atmosphere, say; nitrogen or argon. As Louis Van Rooyen pointed out; you should at least know what are the properties of your specific polymer from previous literature. At least a vague idea about degradation temp., melting temp., crystallization temp. will help you to determine the heating range as well as heating rate for TGA and DSC.   

I hope this helps you. All the best for your work!!

You should not add any reagent for thermal analysis DSC or TGA.

If you do TGA first you will come to know some information like degradation temperature. Depending on that you can make your methods for DSC.