Static bending creep properties of furfurylated poplar wood

Abstract

Moisture content (MC) and its variation have a significant influence on creep in wood. Therefore, reducing moisture absorptive/desorptive effect is one of the best means to minimize creep deformation in wood. Moreover, furfuration treatment of wood is one of the most economical methods to achieve this purpose. In this project, samples of Poplar wood (Populuseuramevicana) were treated with 30% furfuryl alcohol solution (furfurylated wood) and then tested for normal creep (NC) and mechanical sorptive creep (MSC) at different stress levels in several relative humidity (RH) conditions. Results from the experiment and analysis indicated that the normal creep performance of furfurylated wood was similar to that of classical untreated wood material. Nevertheless, furfurylated wood at different stress levels (less than 35%) or in different relative humidity environments did not follow MSC performance (i.e. creep deflection increases during moisture desorption while decreases during moisture absorption) of untreated wood and only exhibited wood NC characteristics (i.e. creep deflection increases continuously with time). Moreover, the maximum MSC deflection of furfurylated wood was 72.3% and 72.2% lower than that of untreated wood at the same 10% stress level and the same range of 65–98% relative humidity variation, respectively. The stress level was positively related to the deformations of instantaneous elastic, viscoelastic, viscous and bending creep, but negatively related to deformation of furfurylated wood creep recovery. Furthermore, it was also found that variation in RH did not have a significant impact on MSC deflection of furfurylated wood compared with untreated wood. The 4-element Burgers model and the 2-parameter Weibull distribution could well simulate the normal creep and creep-recovery responses respectively for furfurylated wood.