Drying and physical properties of rubber wood impregnated with silver nanoparticles

Rubber wood can be used after latex exploration however, the high contents of carbohydrates contribute to its low biological durability, making natural drying impossible. Wood treatment with silver nanoparticles can improve physical, mechanical and biological properties, catalyze the drying process, reduce hygroscopicity, and increase dimensional stability and biological resistance. The objective of this research was to evaluate the effects of impregnation of silver nanoparticles and vaporization on the drying rate, volumetric, radial and tangential contractions and the anisotropy coefficient of Hevea brasiliensis wood. Samples from two clones (PB311-MDF180 and TP875) were subjected to a vaporization process for 24 hours to increase permeability, also to an application of vacuum (750 mmHg) to remove vessels and pits obstructions, and subsequently to impregnation with silver nanoparticles (22 ppm). The variables were monitored (every 15 minutes until the samples reached 12 % moisture) of the mass loss and dimensions of the pieces submitted to drying in an oven (65 °C). In general, the treatments with previous application of 30 and 60 minutes of vacuum followed by impregnation of silver nanoparticles (I30 and I60, respectively) had the best performance. Thus, the impregnation with silver nanoparticles provides significant gains in drying time and dimensional stability of rubber wood.