Studies on pour point depression of EVA polymers in solvent mixtures containing wax

Measurements of the change of the pour point depression (DeltaT(PP)) were p erformed for the wax solutions made of four solvent mixtures: ethyl acetate /hexane (EA/HEX), 1,2-dichloroethane/cyclohexane (DCE/CYH), butanone/heptan e (MEK/HEP), and acetone/chloroform (AC/CF) doped with EVA polymers. The va lues of DeltaT(PP) increase significantly with increasing of the selective solvent EA, DCE, MEK, and AC components, for the vinyl acetate (VA) segment in EVA copolymers, in the solvent mixtures. The solvent effect of DeltaT(P P) occurring in wax solutions can also come from the solutions of EVA polym er, which were prepared by solvent mixtures with various compositions and u sed as parent solutions of EVA pour point depressant. From the experimental results such as the NMR of EVA macromolecules; viscosities of EVA, waxes, and their blends; and solubilities of wax with and without EVA macromolecul es in the solvent mixtures, the complexation between wax molecules and orde red ethylene segment, and wax solubilization within ordered ethylene segmen ts in EVA macromolecules are suggested for qualitative description of the o bserved significant variation of DeltaT(PP). (C) 2002 John Wiley & Sons, In c. J Appl Polym Sci 83: 815-821, 2002.