Estudo das propriedades de fratura de tintas em pó à base de epóxi e poliéster

Abstract

The use and development of paints are not new, as its diversity of compositions and applications, since the use of water colors as a tool to assist in childhood education, the painting used in a building and even as a coating of large vessels and offshore structures that require high corrosion resistance. In any case, the knowledge of coating materials’ properties is crucial to ensure the structural integrity of the film and provide adequate protection and finish to the substrate. Among these properties, an important one is the mechanical resistance, in particular resistance to fracture. This study was focused on the evaluation of the applicability of the Essential Work of Fracture method in free films obtained from powder coating based on epoxy and polyester, and even more the methodology proposed by Nichols and colleagues to obtain the critical value of crack extension force (Gc) applied to the film and substrate system. Although the method of the Essential Work of Fracture could not be applied, conventional tensile tests were carried out, obtaining Gc values of 196,0 J/m2 for epoxy resins and 136,1 J/m2 for the polyester resins obtained by the method proposed by Nichols et al. have presented great coherence when compared with values presented by other authors.