Results References [1].Mendoza, J. D. Lab 9: Dynamic Mechanical Analysis, Iowa State University Time-Temperature Superposition (TTS) Using DMA Acknowledgments This laboratory report utilized data from an actual laboratory performed by a previous Mat E 453 class at Iowa State University. Conclusions  By testing at different temperatures, a master curve for reference 270 ºC could be generated quickly.  The shifting was done to 270 ºC because that is where the glass transition of BECy is known to be.  The glass transition temperature can be observed by the differences of slopes of the high temperature and low temperature curves.  At higher temperatures, the storage modulus was lower, which agrees with expectations.  TTS shifting could also be used to generate a master curve for loss modulus and viscoelastic phase lag at 270 ºC  The TTS shifting was good, but not perfect.  To obtain better results, a smaller difference in temperatures could be used.  TTS shifting is not an exact method, as lines can overlap in multiple places and a choice of where to calculate shift factor must be made.  The shift factors could have been taken from the log(frequency) data, which would result in different shift factors even from the same data. Introduction Dynamic Mechanical Analysis (DMA) is a method that gives useful information on the viscoelastic properties of polymers. Most materials have a combination of elastic (Hookean) and viscous (Newtonian) behaviors and hence exhibit a phase lag between an applied sinusoidal stress and the strain. [1]This results in the material having a complex modulus which accounts for both behaviors. Rheological measurements are utilized to generate master curves that describe the viscoelastic behavior of a material. Temperature superposition (TTS) is a procedure in which a storage modulus versus frequency master curve is created by making measurements at varying temperatures and a range of frequencies and multiplying the frequencies by a shift factor to shift the curves left or right in the horizontal axis. [1] Mohammed Alzayer, Chris Clay, Xinhang Shen Mat E 453, Department of Materials Engineering, Iowa State University, Ames, IA Fig 2. Modulus versus frequency at varying temperatures. Testing Procedures The polymer investigated in this lab is bisphenol E cyanate ester (BECy) which has a glass transition temperature of 270 °C (reference temperature). Fig 3. Log-log graph of modulus versus frequency.  The shift factors were calculated from the raw frequency data, not from the log(frequency) data. The log of the shifted frequencies was then taken and plotted.  The shift factor listed for 290 ºC  270 ºC in Table 1 is actually the shift factor for 280 ºC  270 ºC multiplied by the shift factor for 290 ºC  280 ºC. Sample preparation: Width and thickness of BECy sample measured by caliper. Clamped the sample in DMA 800 to obtain a height of 10mm. Screen cover placed over the sample. Software programming: Thermal Advantage NT software was used. Tested Temperatures: 260, 270, 280, 290, and 300 ºC Frequency Range: Hz, 11 points per temperature. Amplitude: 5µm; Preload: 0.1N; Force Track: 125%. Fig 1. Sample in DMA 800 Sample Fig 4. Log-log graph of modulus versus frequency after TTS shifting Shift in TemperatureShift Factor 260 °C  270 °C °C  270 °C °C  270 °C °C  270 °C °C  270 °C Table 1. Shift Factors used to generate TTS plot