Examining the Cold Temperature Properties of elastomeric systems in the Linear and Non- Linear Viscoelastic Ranges
Event:186th Technical Meeting Location: Nashville, TN Date: October 14, 2014 Author: D. M. Tucker*, R. A. Webb, Y. Fayman and W. Gaspar Paper Number: 89
An understanding of the low temperature behavior of polymers and elastomeric compounds is critical to material design and engineering decisions. There is heavy reliance on glass transition measurements. The latter attempts to identify the temperature range over which the material changes from being rubbery to brittle. Glass transitions are studied via many techniques. This includes the Differential Scanning Calorimetry (DSC), The Dynamic mechanical analyzer (DMA) and the Thermomechanical Analyzer (TMA). The glass transition measurement vary according to the technique used and according to the testing conditions (e.g. heating rate) This paper discusses the glass transition determinations using conventional and modulated DSC. Significant attention was then given to measurements via the DMA. Using the ASTM procedure as a benchmark attention was given to the effects of increasing frequencies and increasing strain. The study was limited to the capabilities of the DMA instrument used, i. e. it was not possible to study all combinations of high strains and high frequencies over the normal time period of the Tg run. It was possible to conduct experiments for Lissajous Curves. Fourier evaluations of these plots and Chevychev polynomials (of the first kind) provided insight into the elastic and viscoelastic behavior at the medium to high strain conditions.