水溶性乙烯基单体/戊二醛协同改性杨木的物理力学性能

Physical and mechanical properties of poplar wood synergistically modified with water-soluble acrylic-based monomer and glutaraldehyde

速生人工林木具有生长周期短、环境适应性强等显著优势,但其材质较差、尺寸稳定性低等不足限制了其使用范围。以速生大青杨(Populus ussuriensis)木材为研究对象,采用20%质量分数水溶性单体甲基丙烯酸-2-羟乙酯(HEMA)和N-羟甲基丙烯酰胺(NMA)分别与不同质量分数的戊二醛(GA)复合制备改性剂HEMA-GA(HG)、NMA-GA(NG)处理杨木,分析了改性剂在木材中的分布,研究了改性处理对杨木物理力学性能的影响。结果表明,改性材密度、质量增加率、增容率、抗胀缩系数(ASE)随着GA质量分数的提高而增加,药剂流失率则与之呈负相关。当GA质量分数为6%时,HG组试样质量增加率为23.6%时,ASE最高可达49.9%,NG组试样质量增加率为38.6%时,ASE最高可达54.2%。尤其是6%质量分数的GA和HEMA单体复合改性处理的杨木,ASE相较于未加GA时提高了3倍。与素材相比,HG和NG组木材的抗弯强度、抗弯弹性模量都有所提高;HG组木材的冲击韧性有所降低,NG组木材冲击韧性基本不变。研究结果显示,水溶性乙烯基单体与戊二醛协同改性处理能显著改善木材尺寸稳定性,为拓宽速生杨木的应用范围提供了新方案。

Fast-growing wood possesses the distinct advantages of rapid growth and environmental adaptability.However,they face challenges such as imperfect quality and poor dimensional stability.In this study,poplar(Populus ussuriensis)wood was treated with 20%water-soluble 2-hydroxyethyl methacrylate(HEMA)or N-hydroxymethacrylamide(NMA)by adding a certain mass ratio(2%,4%,or 6%)of glutaraldehyde(GA)as cross-link agent.The obtained solutions were named as HG and NG,respectively.The permeability and distribution of incorporated chemicals in poplar wood was assessed according to the density,mass percentage gain(WPG),and bulking coefficient(BC).The dimensional stability and leachability were measured by cycling of water-soaking and drying.The results indicated that the increase in GA mass ratio resulted in treated wood with higher density,WPG,BC,and anti-shrink efficiency(ASE),as well as reduced leachability of chemicals.The effects of the treatment on physical and mechanical properties of the wood were investigated by the bending and impact tests.The results showed that ASE of the treated wood can reach up to 49.6%for HG group at 23.6%WPG and 54.2%for NG group at 38.6%WPG when the cross-link agent of GA mass ratio was 6%.In particular,GA had an excellent cross-linking function,so that the poplar treated with HEMA monomers with 6%GA showed a threefold WPG and a fourfold ASE compared to that without GA.The bending test results showed that the modulus of rupture(MOR)and modulus of elasticity(MOE)of the wood in all HG and NG groups were improved compared to the untreated wood.Both the HG and NG groups with 6%GA had the highest increase in each group,MOR of HG6 group samples increased from(81.3±7.2)MPa(untreated)to(133.4±9.3)MPa,and MOR of NG6 group samples increased to(140.0±10.0)MPa.Meanwhile,MOE of HG6 and NG6 increased by 160.3%and 170.6%,respectively.When comparing HG6 with NG6,it can be seen that both MOR and MOE of NG6 were enhanced,which can be attributed to the fact that NG6 had a higher WPG.Significantly,both HG and NG treatments had an ignorable effect on the toughness,in which,the toughness of the HG groups were reduced slightly and the NG groups maintained the toughness values.The above results demonstrated that treatments with HG and NG can significantly improve the quality of fast-growing poplar wood,so that it may be used in a broader area.