DFT and quantum mechanical investigation of polyethylene and polypropylene monomers

The hydration reaction of polyethylene (PE) and polypropylene (PP) monomers was investigated by density functional theory method (DFT) and quantum mechanical calculations (QM), using various types of approximations with and without van der Waals (vdW) corrections. The transition state optimization required for computing the activation energy was validated by infrared (IR) spectra of the products and showed agreement with Markovinkov's rule. Among all approximations tested, second order Møller-Plesset perturbation theory (MP2) provided a more accurate description of the energy profile because this theory takes into account the electron correlation which result as an energy correction. These findings demonstrate a consistent computational method that enable reliable prediction of hydrocarbon hydration and polymeric reactivity under different theoretical levels.