Predicting plasticization efficiency from three-dimensional molecular structure of a polymer plasticizer

In polymeric coatings, plasticizers are used to improve the film-forming characteristic of the polymers. In this study, a computerized method (VolSurf with GRID) was used as a novel tool for the prediction plasticization efficiency (beta) of test compounds, and for determining the critical molecular properties needed for polymer plasticization.

The film-former, starch acetate DS 2.8 (SA), was plasticized with each of 24 tested compounds. A decrease in glass transition temperature of the plasticized free films (determined by differential scanning calorimeter (DSC)) was used as an indicator for beta. Partial least squares discriminant analysis was used to correlate the experimental data with the theoretical molecular properties of the plasticizers.

A good correlation (r2 = 0.77, q2 = 0.58) between the molecular modeling results and the experimental data demonstrated that beta can be predicted from the three-dimensional molecular structure of a compound. Favorable structural properties identified for the potent SA plasticizer were strong hydrogen bonding capacity and a definitive hydrophobic region on the molecule.

The VolSurf method is a valuable tool for predicting the plasticization efficiency of a compound. The correlation between experimental and calculated glass transition temperature values verifies that physicochemical properties are primary factors influencing plasticization efficiency of a compound.