TGA of Acrylonitrile-Butadiene Rubber (NBR)

Purpose

To measure a typical TGA curve of NBR.

Sample

Unvulcanized NBR

Conditions

Measuring cell: TGA/SDTA851^e 

Pan: Alumina 30 µl  

Sample preparation: Piece of rubber of approx. 4.77 mg 

TGA measurement: Heating from 50 °C to 600 °C under nitrogen (80 ml/min), and then from 600 °C to 800 °C under air (80 ml/min) Heating rate 30 K/min  

Atmosphere: Nitrogen then air, automatically switched

The DTG curve shows that the pyrolysis of NBR takes place in two steps. The curve exhibits a shoulder around 400 °C followed by the main peak with a maximum at about 476 °C. After switching from nitrogen to air, the TGA curve shows a loss of mass of about 2% due to the combustion of carbon. This was formed as carbon black during pyrolysis. About 3% volatile compounds vaporize before the actual pyrolysis occurs.  

Evaluation

The evaluation of the individual steps is summarized in the following table:

Conclusions

NBR pyrolyzes at about 475 °C. Some 2.2% carbon black was formed during pyrolysis. The proportion of volatile compounds was about 3.4%, and the ash content about 0.6%.

_{TGA of Acrylonitrile-Butadiene Rubber (NBR) | Thermal Analysis Handbook No.HB427 | Application published in METTLER TOLEDO TA Application Handbook Elastomers, Volume 2}