SURFACE REARRANGEMENT OF VINYL-ACETATE AND ACRYLATE TERPOLYMER ADHESIVES INVESTIGATED BY DYNAMIC CONTACT ANGLES

Terpolymer solution-based adhesives of vinyl acetate and acrylates wit h different long alkyl side chains were prepared by radical polymeriza tion. Dynamic contact angles of the adhesives-coated films measured by the Wilhelmy plate technique indicated that the reorientation of the adhesive surface varied with the length of the alkyl side chain. It wa s found that the changes of advancing contact angles (theta(a)) and re ceding contact angles (theta(r)) were relatively great within the rang e of lower immersion speeds at various temperatures, but approaching a certain velocity the contact angles became stable. The lower activati on energies of the change in contact angles revealed that the rearrang ement of surface groups can be achieved by small-scale secondary trans itions. In addition, the activation energies required for rearrangemen t from apolar to polar medium and the reverse process were different.