Time-Temperature Superposition Testing: Optimization of Test Parameters, Effect of Heat History, and Accuracy of Fit for Various Filled Compounds and One Unfilled Compound
By Jonathan E. Martens and Kaylan Yaceczko
Akron Rubber Development Laboratory, Inc., 75 Robinson Ave., Barberton, OH, USA
The Time-Temperature Superposition (TTS) principle is helpful for determining high or low frequency properties beyond the capability of the dynamic mechanical test instrument. While there has been a handful of research conducted on this test method from its discovery to the present, there has not been any research into how many frequencies or what temperature step size should be included to obtain the best results while minimizing instrument time.
In this study, recommendations will be made for these test parameters. The effect of heat history on TTS results will also be discussed. One common observation about using the Williams-Landel-Ferry (WLF) fit equation is the need to be less than 100 degrees above the glass transition temperature (Tg) of the material. However, this observation is for an unfilled compound and not a filled compound. There has not been much research into fitting the TTS of a filled compound to the common fit equations like WLF.
This study will analyze the TTS results of six different filled compounds and one unfilled compound, all of which will be tested following the optimized test parameters discussed previously.
Additionally, a Metravib Very High Frequency DMA (VHF104) will be utilized to verify the accuracy of the TTS shifts as this instrument is capable of testing up to 10 000 Hz without the need to extrapolate results. By comparing the TTS master curves to these high frequency results, the best practice for shifting the TTS results for filled compounds will be determined.
C-Therm Technologies is proud to distribute the Metravib line of DMA instruments in North America. These instruments can operate at the highest frequency and force on the market to provide the user with high sensitivity and resolution, flexible test programming, and multiple test sequencing. The DMA+ series can also be outfitted with fatigue testing capabilities, crack growth testing capabilities, and heat build up testing. These instruments by Metravib are leading the rubber industry in materials characterization.
This webinar will air on October 29, 2024 @ 2:00PM GMT-3.
Register here