| It is an effective method to solve the problems of environmental pollution and single modification effect of wood modifiers and improve the properties of fast-growing wood by developing green and multi-functional modifiers using biomass resources as raw materials.In this paper,polyacid,reactive and bifunctional reactive rosin-based modifiers have been prepared from rosin secreted by natural tree as the starting materials.The physical properties,water resistance and mechanical properties of rosin derivatives modified wood were investgated,and the mechanisms of modification were further explored.The contents and results of the study are as follows:1)Using rosin polyacid as the modifier,the effect of rosin polyacid on the properties of fast-growing poplar were studied by the method of impregnation.The structure of the modified woods was characterized by Fourier transform infrared spectroscopy(FT-IR)and scanning electron microscope(SEM).The water resistance and mechanical properties of the modified woods were studied by contact angle measuring instrument and universal material testing machine.The results showed that the rosin polyacid infiltrated into the wood cells and did not change the wood fiber structure.The effect of rosin polyacid is higher than that of unmodified rosin on improving the performance of fast-growing poplar.And acrylic acid rosin(AAR)shows the prominent effect on the improvement the performance of fast-growing poplar.The water absorption of AAR modified wood is 79.7%,and the modulus of r upture(MOR)and modulus of elasticity(MOE)increases by 18.1% and 27.5%,respectively.Because of its rigid structure and high acid value,there are strong hydrogen-bond interections between AAR and wood components.Thus,the effects of AAR are the most excellent on the improvement of the performance for fast-growing poplar.2)Reactive rosin modifier(HRG)has been prepared by epoxy ring opening reaction using hydrogenated rosin(HR)and glycidyl methacrylate(GMA)as the starting materials.The structure of HRG was characterized by FT-IR and gel permeation chromatography(GPC).Isoborneol methacrylate(IBOMA)was used as a control compound.The fast-growing poplar wood was modified by different concentrations of HRG impregnation,and the physical properties and mechanical properties of the modified wood after curing were studied by using contact angle measuring instrument and universal material testing machine.The results show that HRG was filled in wood cell.And the water resistance and mechanical properties of the modified wood are obviously enhanced with the increase of HRG concentration impregnation.The WA of 30%HRG modified wood was 94.7%.Compared to the control I,the MOR and MOE increase by 33.0% and 36.3%,respectively.In the control group,the WA of 30% isobornyl methacrylate(IBOMA)modified wood was 111%,its MOR and MOE increase by 13.0% and13.8% respectively.Reactive rosin modifier(HRG)can obviously improve the physical properties and mechanical properties of fast-growing poplar.Due to the strong hydrophobic interections of tricyclic diterpene rigid structure and the hydrogen-bond interactions between modifier hydroxyl groups and wood components,the physical properties and mechanical properties of fast-growing poplar wood modifier HRG are extremely higher than that of IBOMA.3)Using HR and maleic anhydride as the starting materials,bifunctional reactive rosin modifier REMG was prepared though epoxy ring opening and esterification.The monofunctional modifier RESG prepared from HR and succinic anhydride(SA)was used as a control.The structure of modifier REMG and RESG was characterized by FT-IR and GPC.The modified fast-growing poplar wood was prepared by vacuum impregnation and heating curing,and the physical properties and mechanical properties of the modified wood were studied by using contact angle measuring instrument and universal material testing machine.The results showed that REMG was filled in wood cell.The WA of 30%REMG modified wood and30%RESG modified wood was 87.3% and 92.5%,respectively.Compared with the control wood,the MOR and MOE of 30%REMG modified wood increase by 34.3% and 37.9%,respectively.And the MOR and MOE of 30%RESG modified wood increase by 6.3% and 30.7%,separately.The polymer formed by double curing of REMG in wood can more effectively improve the physical properties and mechanical properties of fast-growing poplar than RESG. |
