TGA of Ethylene-Propylene-Diene Rubber (EPDM)

Purpose

To perform thermogravimetric measurements on different types of EPDM.

Sample

Three types of unvulcanized EPDM: x Buna EPG 3440 x Buna EPG 6170 x Buna EPG 8450

Conditions

Measuring cell: TGA/SDTA851e

Pan: Alumina 30 Pl Sample preparation: Pieces of rubber of approx. 15 mg

TGA measurement: Heating from 50 °C to 625 °C under nitrogen (50 ml/min), and then from 625 °C to 860 °C under air (50 ml/min) Heating rate 30 K/min

Atmosphere: Nitrogen then air, automatically switched.

Interpretation

The TGA curves of EPDM rubber show only one clear weight loss step. The volatile compounds together with the carbon black formed during pyrolysis and the residual ash account for less than 1% of the initial mass. The pyrolysis of the polymer gives rise to a peak in the DTG curve with a maximum at about 480 °C. This temperature depends slightly on the type of EPDM measured.

Evaluation

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

Conclusions

The volatile components, the carbon black formed during pyrolysis and the residual ash can be neglected for the EPDM samples. Pyrolysis occurs typically at about 480 °C. The pyrolysis temperature of Buna EPG6170 is about 10 K higher compared with the other types of EPDM and the residue after pyrolysis (carbon black and ash) is about 0.5% higher. 

^{TGA of Ethylene-Propylene-Diene rubber (EPDM) | Thermal Analysis Handbook No.HB429 | Application published in METTLER TOLEDO TA Application Handbook Elastomers, Volume  2}