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Article
Molecular Dynamics Simulation of Poly(ethylene terephthalate) Oligomers
Journal of Physical Chemistry B (2010)
  • David Keffer, University of Tennessee - Knoxville
  • Qifei Wang, University of Tennessee - Knoxville
  • Simioan Petrovan, University of Tennessee - Knoxville
  • J. Brock Thomas
Abstract

Molecular dynamics simulations of poly(ethylene terephthalate) (PET) oligomers are performed in the isobaric−isothermal (NpT) ensemble at a state point typical of a finishing reactor. The oligomer size ranges from 1 to 10 repeat units. We report thermodynamic properties (density, potential energy, enthalpy, heat capacity, isothermal compressibility, and thermal expansivity), transport properties (self-diffusivity, zero-shear-rate viscosity, thermal conductivity), and structural properties (pair correlation functions, hydrogen bonding network, chain radius of gyration, chain end-to-end distance) as a function of oligomer size. We compare the results with existing molecular-level theories and experimental data. Scaling exponents as a function of degree of polymerization are extracted. The distribution of the end-to-end distance is bimodal for the dimer and gradually shifts to a single peak as the degree of polymerization increases. The scaling exponents for the average chain radius of gyration and end-to-end distance are 0.594 and 0.571, respectively. The values of the heat capacity, isothermal compressibility, and thermal expansivity agree well with the available experimental data, which are of much longer PET chains. The scaling exponents for the self-diffusivity and zero-shear-rate viscosity are, respectively, −2.01 and 0.96, with the latter one being close to the theoretical prediction 1.0 for short-chain polymers.

Publication Date
2010
Citation Information
David Keffer, Qifei Wang, Simioan Petrovan and J. Brock Thomas. "Molecular Dynamics Simulation of Poly(ethylene terephthalate) Oligomers" Journal of Physical Chemistry B Vol. 114 Iss. 2 (2010)
Available at: http://works.bepress.com/david_keffer/3/