Effect of ultraviolet radiation on the color of freij\uf3 wood ( Cordia goeldiana Huber) after application of finishing products

A radia\ue7\ue3o ultravioleta \ue9 considerada a mais prejudicial ao uso da madeira afetando suas propriedades, sobretudo a sua cor superficial. A aplica\ue7\ue3o de produtos de acabamentos, como os vernizes, os stains, as tintas, podem minimizar a atua\ue7\ue3o dessa radia\ue7\ue3o. Este trabalho teve como objetivo avaliar o efeito da radia\ue7\ue3o ultravioleta, relativo ao envelhecimento artificial acelerado, na colora\ue7\ue3o da madeira de freij\uf3 ( Cordia goeldiana Huber) tratadas com polisten e seladora (nitrocelulose), com monitoramento por meio de um espectrocolorimetrico. As amostras da madeira foram submetidas a ciclos de radia\ue7\ue3o ultravioleta em um reator fotoqu\uedmico, em tempos de 84 e 168 horas. Os par\ue2metros colorim\ue9tricos (L*, a*, b* C e h*) foram medidos antes a ap\uf3s os tratamentos. O tratamento com polisten foi o que ofereceu maior prote\ue7\ue3o \ue0s radia\ue7\uf5es ultravioletas, dando uma maior estabilidade aos par\ue2metros. O tratamento com seladora foi o que apresentou uma maior altera\ue7\ue3o da cor ap\uf3s a simula\ue7\ue3o de envelhecimento no reator fotoqu\uedmico.Ultraviolet radiation is considered the most damaging radiation to wood, affecting its properties and especially its color. The application of finishing products such as varnishes, stains and inks can minimize the action of this radiation. This study aimed to evaluate the effect of ultraviolet radiation, through artificially accelerated aging, on the color of freij\uf3 wood ( Cordia goeldiana Huber) treated with \u201cpolisten\u201d and sealer (nitrocellulose), by means of spectrocolorimetric tracking. The samples of wood were subjected to cycles of ultraviolet radiation in a photochemical reactor for 84 and 168 hours. The colorimetric parameters (L*, a*, b*, C, h*) were measured before and after the treatments. The treatment with \u201cpolisten\u201d offered greater protection against ultraviolet radiation, yielding greater stability to the parameters. The treatment with sealer led to a greater change in color after the simulation of aging in the photochemical reactor