Efeito da modificação térmica com parafina nas propriedades higroscópicas e es - tabilidade dimensional da madeira de Louro-preto (Nectandra dioica)

Abstract

The dissemination of techniques such as thermal treatment with eventual impregnation of waxes and oils would make it possible to improve undesirable characteristics in woods of low commercial value. The aim of this study was to evaluate the effect of thermal modification with the presence of paraffin on the hygroscopicity and dimensional stability of Nectandra dioica wood, using modification temperatures of 190ºC and 210ºC with a treatment time of 2.5 hours. The material was subjected to a thermal modification process and impregnated with paraffin solution in a laboratory oven. After treatment, the samples were subjected to three immersion-drying cycles to evaluate the water absorption rate and the anti-swelling efficiency of the wood. With regard to dimensional stability, there is an increase proportional to the intensity of the treatment, which is enhanced with the addition of paraffin solution. The same behavior was observed for water absorption by wood, registering rates of up to 0.77% in the most severe treatment. When comparing the immersion and drying cycles (1st and 3rd cycle), the efficiency of the treatments regarding water absorption is observed. The 210ºC treatment with paraffin impregnation showed the best results when compared. Therefore, the combined treatment of wood with heat and paraffin emulsion results in some advantages with regard to dimensional stability and water repellency, making it an option for wood in external applications.