Equation of State for Polymethylmethacrylate (PMMA)

Author: Montgomery, Wren Bowlan

Year: 2000

Degree: Senior thesis (Major)

Advisor: Goddard, William A., III

Committee Member: None, None

Option: Physics; Geophysics

DOI: 10.7907/ADK8-TW81

Abstract

With ever-increasing computing power, simulations of larger, more complex systems are becoming more and more feasible. The ability to model systems, especially those not easily studied in the laboratory, is desired. But with these strictly computational problem there comes a question of accuracy. In this paper, a well-studied polymer, polymethylmethacrylate (PMMA), will verify the computational results obtained for polymers which are less easily (if at all) studied experimentally. Assuming that a small sample accurately represents the system as a whole, energy calculations with the simulation engine Cerius2 will be used to determine a cold compression curve, followed by a series of molecular dynamics calculations to determine the Griineisen parameter. These calculations may be compared with the ample experimental evidence available for PMMA, providing a calibration for those substances (such as Kel-F) which cannot be studied experimentally. Further basis for comparision can be obtained using various viscoelastic and thermodynamic properties. Additionally, the Griineisen parameter may be used to revese the traditional experimental approach to calculate the Hugoniot data, providing further basis for comparision and an opportunity for improving the accuracy of the model.

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