软化处理对杨木刨切单板性能的影响

Effect of softening treatment on the performance of sliced poplar veneer

采用化学方法对杨木刨切单板进行软化处理试验,为杨木铅笔板的制备提供技术参数。分别采用25%乙二胺、25%氨水、10%NaOH溶液、25%乙酸溶液对杨木单板进行软化处理,测定处理后试件的密度、硬度、抗弯弹性模量等物理力学性能,并与未处理材进行对比。研究结果表明:软化剂的种类、软化时间、软化温度和加压压力对单板力学性能都有一定的影响;最佳软化工艺为:软化剂为25%氨水,软化温度为60℃,软化时间为50 min,加压压力为0.6 MPa。微观构造进一步证明软化后杨木的细胞壁膨润变形,导管破损,软化减弱了细胞壁的骨架作用。

Sliced poplar veneer was softened with chemical agents to prepare pencil slat. 25% ethylenediamine, 25% ammonia, 10% NaOH solution and 25% acetic acid solution were chosen as the agents. Properties of the treated veneer, including density, hardness and modulus of elasticity （ MOE）, were tested and compared with the untreated. The results indicated that the agent type, softening time, softening temperature and the pressure had certain impact on mechanical properties of the veneer. The optimum softening parameters were： softening agent 25% ammonia, temperature 60℃, time 50min, pressure 0.6 MPa. Microstructure study showed that poplar cell wall was wetted and deformed after the treatment, causing vessel damage and weakening the cell wall＇ s frame function.