Experimental Study on Bending Creep Behavior of Modified Fast-Grown Poplar Wood in Uncontrolled Condition

Three material properties (density, modulus of elasticity, bending creep deflection) of poplar wood modified with low molecular resin was examined and evaluated by an experimental approach. Poplar specimens were treated to achieve full penetration using a vacuum schedule with different low molecular resins. These resins were urea-formaldehyde (UF) and phenol-formaldehyde (PF) prepolymer solution. Creep tests were conducted under a varying climate with 16 °C ~ 31 °C and 40 % ~ 80 % relative humidity. The specimens were loaded in bending for approximately 140 days. Then the curves of the creep tests were analyzed to derive the development of bending creep performance. The results show modification leads to significant changes on material properties. Modification increases both the density and elastic modulus, and also tends to deflect creep deformation obviously less than untreated specimens.