C-C, 347 kJ/mol from oxirane of epoxidized corn oil, Figure (f), and additional C=C, 614 kJ/mol, and C-H, 413 kJ/mol from epoxy resin, Figure (g), its further introductions to vinyl ester resin produce an exchange of Π-bonds from the double bonds and σ-bonds from the single bonds, creating a negative ∆H. Thus, the more exchanges of Π and σ-bonds, the higher the enthalpic changes . While the Gibbs Free energy showing a positive value means non-spontaneous reactions of the samples, which are attributed to the need for the presence of an external force like heat to incur reactions resulting in the final product.