Polypropylene Surface Modification by Entrapment Functionalization

A new approach to prepare surface-functionalized polypropylene using block cooligomers of propylene and acrylate esters is described. Using boron-promoted radical polymerization and a vinyl-terminated polypropylene oligomer, block cooligomers of propylene and tert -butyl acrylate were prepared. Codissolution of such cooligomers with excess isotactic polypropylene and film casting produced functionalized films. Acidolysis of the tert -butyl esters at the surface of these films produced a poly(acrylic acid)-grafted polypropylene film that could be further modified chemically. Incorporation of pH-sensitive dyes into this poly(acrylic acid) surface in turn produced films whose reactivity in proton-transfer chemistry in various solvent suspensions was studied as a function of solvent.