Tuesday  |  Salon 11  |  10:00 AM–10:20 AM

#16015, Characterization of High Rate Behavior of Polycarbonate and Poly(Methyl Methacrylate) at Functions of Temperature

The viscoelastic nature of polymers has made them extremely useful in a wide range of applications in military, commercial, and industrial fields. Polymers offer unique properties that allows them to be used in a variety of conditions and polymer chemistries can be optimized for specific applications. However, unlike materials such as metals, polymers behavior can be significantly affected by small changes in the environment, most notably due to their dependence on temperature and the rate of deformation. The inter-relation between rate of deformation and the temperature of the polymer is widely predicted for most polymers through the Time-Temperature Superposition (TTS) method, however, this is only reliable in the small deformation regime and for thermos-rheologically simple polymers. In other conditions, the effect of rate and temperature of the polymers becomes more complex and thus more research is needed to determine the effect these loading parameters on the large deformation and failure of polymers.
In this work, the dynamic behavior of two widely used polymers will be studied well past the small deformation limits as functions of temperature and rate. Polycarbonate and poly(methyl methacrylate) (PMMA) are widely used in a multitude of applications, but present drastically different properties where polycarbonate is generally described as ductile and PMMA is generally described as brittle. By using a Split Hopkinson Pressure Bar (SHPB) equipped with an environmental chamber, high rate compressive testing is performed at a wide range of temperatures and strain rates. While in low rate tests, the temperature conditions may be kept isothermal, in SHPB tests, one can only assume a nearly adiabatic condition exists. Therefore, estimates of temperature rise through the test must be included in the analysis. The results of this study will be used in determining the flow and failure response of PMMA and PC under a wide range of conditions.

Alex Krueger   UMass Lowell
Alireza Amirkhizi   UMass Lowell