Molecular Modeling Simulation Study of Interactions in Starch/Poly(acrylic acid) Blend

Abstract

In this work we have studied the nature of interactions between starch and poly(acrylic acid) by using semi-empirical AM1 and PM3 methods. Theoretical computations involved the determination of optimal geometries, binding energies and vibrational frequencies of the blended polymers. Calculations are performed for four pairs of complexes of glucose (Glu) in starch and acrylic acid (mAA) in poly(acrylic acid) PAA. Based on results of calculation, the binding energies show negative values, which indicate that the interactions of glucose and acrylic acid are favorable at the lower energy. This means that the interactions of starch and PAA are stable. Vibrational frequency analysis of hydroxyl OH and carboxyl C=O groups of the 1Glu–1mAA, 1Glu–2mAA and 1Glu–3mAA complexes with single hydrogen bond showed that the stretching of these groups shifts to a lower wave number due to the formation of hydrogen bonds.

Keywords:Polymer blends, AM1, PM3.