Improvement of physical and mechanical properties of poplar wood via immobilization of rosin by grafting of vinyl chains

Rosin is renewable biomass with the potential to enhance wood properties. However, its high leaching rate restricts the durability of rosin impregnation. To immobilize rosin in wood structure, polymeric rosin (R-GMA) with vinyl chains was synthesized by the chemical reaction between rosin and glycidyl methacrylate (GMA) in the present work. Poplar wood was impregnated by different concentrations of the R-GMA. Due to the initiator and high temperature, R-GMA polymerized both in wood cell lumens and cell walls through radical polymerization. The polymer loading gradually increased with the concentration increased. As a result, the ASE can reach 50% with a WPG of 54%. Compared with the control sample, the 7-day water uptake of treated wood (WPG was 54%) was reduced by 55%. At 20% R-GMA concentration, the MOR, MOE, and CS of wood were increased by 23.5%, 46.6%, and 66%, respectively. The dynamic wettability of wood was remarkably reduced by the R-GMA impregnation. The lightness of the wood surface was reduced and the surface color became reddish and yellowish after modification. Additionally, the thermal stability of wood was marginally improved by the filling of R-GMA polymers.