Populus × euramericana ‘I-214’ (poplar) is a fast-growing species widely distributed throughout the world, and in the Castile-Leon region of Spain it accounts for more than 50% of all plantations. Its wood is becoming increasingly appreciated, yet its low durability against xylophagous agents —termites being one of the most aggressive and destructive in warm climates— continues to be a limitation. Thus, nanotechnology could offer an alternative to improve this wood’s natural durability, in line with the current trend towards environmentally-friendly wood protectives. This work was conducted to evaluate the resistance to subterranean termites' degradation of I-214 poplar clone wood that had been pressure vacuum-treated with a binary composite consisting of silver nanoparticles (AgNPs) and chitosan oligomers (COS). Twenty-year-old Spanish poplar wood was used, and the sampling and selection of timber specimens were carried out following EN 350:2016 for commercial sawn timber. Five preservative treatments were applied: AgNPs 4 ppm + COS 20 g/L, AgNPs 2 ppm + COS 10 g/L, AgNPs 1 ppm + COS 5 g/L + AgNPs 0.5 ppm + COS 5 g/L, and AgNPs 0.25 ppm + COS 2.5 g/L. Additionally, control test specimens and solvent control (water) specimens in poplar wood, as well as pine wood reference samples for validation tests, were used. The resistance of poplar wood to subterranean termites (Reticulitermes grassei) was determined in accordance with EN 117:2012. The durability class was assessed according to EN 350:2016 and the use class was estimated according to EN 335:2013. The AgNPs 4 ppm + COS 20 g/L formulation was the only one that improved the resistance of poplar to termites, in such a way that the treated wood may be classified as ‘moderately durable’ according to attack ratings (EN 350:2016) and used as class 1 to 3 in indoor use with dry conditions, or outdoors with occasional wetting, but without contact with the ground (EN 335:2013). To further evaluate the efficacy of the silver nanoparticles and chitosan binary composite, these studies should be extended.

Download document (317 kb)
free for the members of IRG. Available if purchased.

Purchase this document