无催化条件下乙酰化杨木的工艺与性能

Processing and Properties of Acetylated Poplar Treated without Catalysts

采用纯乙酸酐为处理液,在无催化剂条件下,分析反应温度和反应时间对乙酰化杨木增重率和反应速率的影响,并测试乙酰化杨木的性能。结果表明:随反应时间的延长和反应温度的升高,乙酰化杨木的增重率增大,密度略增,抗胀率增大,吸湿率减小;乙酰化对杨木弹性模量和抗弯强度的影响不显著。红外光谱分析表明,乙酰化木材中亲水性的羟基被乙酰基所取代,形成疏水性基团酯基,从而提高处理木材的尺寸稳定性。

In order to simplify the modification process and reduce the cost of wood acetylation, the authors developed a wood acetylation technology using pure acetic anhydride without any catalysts. Effects of reaction temperature and time on weight percentage gain （WPG） of the acetylated Populus ussuriensis wood were evaluated and physical and mechanical properties were tested. Testing results showed that the WPG of the acetylated wood improved with increased reaction temperature and time. Density and anti-swelling efficiency （ASE） of the acetylated wood improved with increased WPG. Effects of the acetylation on modulus of rupture （MOR） and modulus of elasticity （MOE） in static bending were insignificant. Fourier transform infrared （FTIR） analysis indicated that hydrophilic hydroxyls of chemical components of the acetylated wood were replaced by acetyls and hydrophobic esters formed after acetylation, which explained why dimensional stability of the treated wood was improved.