Resistance to artificial weathering of five tropical woods and of two finish products

This work aimed at evaluating the photodecomposition process of five tropical wood species and the protection effect of two wood finishing products under artificial weathering. Woods of Tabebuia impeginosa, Mezilaurus itauba, Manilkara huberi, Bagassa guianensis and Couratari sp. were employed. Samples were submitted to cycles of 2,000 hours of ultraviolet radiation (UV) and 400 hours of water leaching. Changes in the natural color of wood, indicative of the photodegradation process, and the protection degree of a transparent poliuretanic varnish and a semitransparent stain were monitored by spectrocolorimetry. The most resistant wood species were Tabebuia impetiginosa and Couratari sp. followed by Manilkara huberi, Mezilaurus itauba and Bagassa guianensis, respectively. The varnish protected Tabebuia impetiginosa and Manilkara huberi for a long period, while the stain seemed to be more efficient for Mezilaurus itauba and Bagassa guianensis. Both products presented similar performance for Couratari sp.