To measure the coefficient of thermal expansion of two silicone elastomers with different filler contents.
Carbon black filled silicone elastomers
Sample A: 61.6% inorganic filler
Sample B: 56.0% inorganic filler
Measuring cell: TMA/SDTA840
Sample preparation: Pieces of elastomer with flat, parallel faces, approx. 5 mm thick To distribute the force over the entire surface area, the sample was covered with a quartz glass disk.
TMA measurement: Heating from 30 °C to 310 °C at 5 K/min Load: 0.02 N
Atmosphere: Nitrogen, 50 ml/min
The blank curves were measured with quartz glass disks and subtracted from the actual measurement curves. The curves normalized to sample thickness are displayed in the upper coordinate system. The lower coordinate system shows the instantaneous coefficient of expansion as a function of temperature. This turns out to be more or less constant in the temperature range measured. The tables include several of the values that were determined. It can be seen that the coefficient of expansion of sample A (higher filler content) is about 203 ppm/K, whereas the coefficient of expansion of sample B, (lower filler content) is somewhat larger at 250 ppm/K. From 280 °C onward, the value measured for each coefficient of expansion decreases because the samples soften
The coefficient of expansion of the silicone elastomers is almost constant from room temperature to about 300 °C and is lower for higher filler contents.
Expansion Coefficient of Silicone Elastomers | Thermal Analysis Handbook No.HB416 | Application published in METTLER TOLEDO TA Application Handbook Elastomers, Volume 1.