TGA of Silicone Elastomers
Purpose
To investigate the behavior of silicone elastomers during pyrolysis.
Sample
A cross-linked, SiO2–filled silicone elastomer (sample 1). For comparison, a pure uncross-linked polymer was measured (sample 2).
Conditions
Measuring cell: TGA/SDTA851e
Pan: Alumina 30 µl, with no lid
Sample preparation: Pieces of elastomer of approx. 7 mg
TGA measurement: Heating from 40 °C to 750 °C under nitrogen (80 ml/min), then from 750 °C to 900 °C under air (80 ml/min) Heating rate 30 K/min
Atmosphere: Nitrogen then air, automatically switched
Interpretation
Pyrolysis of the cross-linked elastomer occurred at relatively high temperatures. Decomposition begins above about 400 °C. The maximum of the DTG peak is at 600 °C. A smaller peak can be seen in the DTG curve at about 500 °C. Measurements performed on the pure uncross-linked polymer (sample 2) showed that this material exhibited a DTG peak just above 500 °C. We suspect that the small peak in the DTG curve in sample 1 is due to residual uncross-linked material. With silicone elastomers, no reaction occurs on switching from nitrogen to air because no carbon black is formed.
Conclusions
Silicone elastomers undergo pyrolysis at about 600 °C without the formation of carbon black
TGA of Silicone Elastomers | Thermal Analysis Application No.Hb461 | Application published in METTLER TOLEDO TA Application Handbook Elastomers, Volume 2.
