Improvement of wood properties by urea-formaldehyde resin and nano-SiO₂

In order to improve properties of triploid clones of Populus tomentosa,urea-formaldehyde(UF) resin was compounded with nano-SiO₂,coupling agents and flame retardants in different ways to prepare five kinds of modifiers.The poplar wood samples were impregnated with the modifiers and heated to prepare UF-SiO₂-wood composites.The antiswelling efficiency,oxygen index,and hardness of the composites were measured.Results showed that all of the modifiers reduced water absorption of poplar wood and enhanced its flame resistance and hardness.Nano-SiO₂ showed a marked effect in improving the hardness of wood.In addition,all of the modifiers except UF-C-SiO₂-polymer could improve the dimensional stability of poplar wood.The compound of UF resin and nano-SiO₂ could improve general properties of poplar wood.