SURFACE FREE-ENERGIES OF STYRENE-ACRYLIC ACID COPOLYMER PLATES PREPARED IN VARIOUS FRAMES

Styrene (St)-acrylic acid (AA) copolymer plates were synthesized in the frames made of glass, aluminum (Al) and poly(difluoroethylene) (PDFE). Surface properties of the prepared copolymer plates were characterized with regard to critical surface tension (gamma(C)), chemical component by IR analysis and surface energies (total energy, gamma(S); dispersion force components, gamma(S)d; polar component, gamma(S)p; hydrogen bonding component, gamma(S)h) and the following results were obtained. The gamma(C) values of the copolymer plates increased with AA content and also depended on the sort of the used frame. The increasing order of the gamma(C) values of the copolymer plates corresponded to those of the used frames, namely, PDFE frame < Al frame < Glass frame. The prepared copolymer plates with low AA contents (ca. 10 mol%) were enriched in the AA moiety in the surface layer regardless of the kind of the used frame. The total and the individual components of the surface free energies of the copolymer plates were largely affected by the property of the used frame. The glass frame gave the plate with higher gamma(S)h, values suggesting preferential orientation of the polar site of AA component.