Merrill Goldenberg

Effect of mold material on the surface properties of an acrylic copolymer

Abstract We have demonstrated that the surface properties of a copolymer of glycidyl methacrylate and acrylic monomers depend on the material of the mold in which the polymerization reaction was carried out. On the basis of surface free energy measurements by contact angle goniometry, it is shown that the polarity (polar component of the surface free energy) of the polymer surface is directly related to the polarity of the mold surface; the more polar the mold material is, the more polar or hydrophilic the polymer surface becomes. The study of the effect of the mold material was also extended to the polymer samples that were further chemically treated with tris(hydroxymethyl)aminomethane. Upon treatment the polymer showed an increased polarity due to the creation of surface hydroxyl groups, but did not follow the same direct relationship between the polarity of the mold and that of the polymer, as observed with untreated polymer; instead, a surface saturation effect was observed. These observations are explained on the basis of the preferential adsorption of epoxy groups at the polymer surface induced by the polar mold surface during the polymerization reaction.