Theoretical study of isomerization and polymerization in polyethylene terephthalate

Hassan, Walid M.I.; Heikal, Lobna A.; Abou-Elyazed, Ahmed S.; Mohamed, Hamdy F. M.; Ibrahim, Medhat A.; Hamouda, Asmaa S.

doi:10.21608/ejchem.2021.104208.4813

Theoretical study of isomerization and polymerization in polyethylene terephthalate

Document Type : Original Article

Authors

¹ Chemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21589, Saudi Arabia. Chemistry Department, Faculty of Science, Cairo University, Egypt.

² Renewable Energy Science and Engineering Department, Faculty of Postgraduate Studies for Advanced Sciences, Beni-Suef University, Egypt.

³ Chemistry Department, Faculty of Science, Menoufia University, Egypt.

⁴ Physics Department, Faculty of Science, Minia University, P.O. Box 61519 Minia, Egypt.

⁵ Nanotechnology Research Centre (NTRC), The British University in Egypt (BUE), Suez Desert Road, El-Sherouk City, Cairo, 11837, Egypt Molecular Spectroscopy and Modeling Unit, Spectroscopy Department, National Research Centre, 33 El-Bohouth St., 12622, Dokki, Giza, Egypt

⁶ Environmental Sciences and Industrial Development Department, Faculty of Postgraduate studies for Advanced Sciences, Beni-Suef University, Egypt

10.21608/ejchem.2021.104208.4813

Abstract

Using ab initio DFT (Density Functional Theory) investigation, an attempt was made to gain insight into some physical properties of polyethylene terephthalate (PET) including polymerization (repeating monomer units) and cis-trans isomerization at 298 K. DFT calculations were performed at Becke's three parameter functional and Lee–Yang–Parr functional (B3LYP) level of calculation with 6-31+G(d,p) basis set. Geometry optimization of a series of conformations was employed to greatly increase the global energy minimum for each molecule. Molecular structure calculations yielded several thermochemical parameters, including the magnitude and direction of the dipole moment, electron densities, total electronic energy at 0 K, enthalpy, Gibbs free energy at 298 K of the investigated polymer, and its conformers. Both the highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) energy gaps were also represented.

Keywords