樟子松密实化前后吸能特性的对比

A comparison of energy absorption characteristics of Mongolian pine wood before and after densification

针对速生材材质疏松、力学强度较低的特性,以樟子松为研究对象,采用低分子量酚醛树脂对其浸渍强化后进行横纹压缩密实化试验,研究樟子松密实化前后各项物理力学性能及能量吸收特性的变化。结果表明:最佳横纹压缩密实化工艺条件即热压温度为140℃,热压压力为4.0 MPa,热压时间为30 min。经过浸渍压缩密实化后,樟子松试样的密度提高了139%,抗弯强度提高了189%;当应变为0.068时,樟子松试样的能量吸收值提高了180%,吸能效率提高了85%。本研究的实施是高效利用低质速生材的有益探索,可为速生材在包装行业的推广应用提供一定的理论依据。

As the lack of the global forest resources and the increasing consumption of wood,the enormous demand for wood has become a great challenge which needs to be addressed urgently. One strategy is to increase the use of fastgrowing wood as it has the advantages of short rotation period. However,the fast-growing wood has some undesirable characteristics,such as loose texture,low mechanical strength,low density,etc. To solve these problems,the phenolic resin with low molecular weight was impregnated in Mongolian pine wood in this study. The phenolic resin with molecular weight of below 500 and mass ratio of 15% were prepared in the laboratory. The process of impregnation was carried in a well closed container and the soaking time for impregnation was 12 h. In order to explore the change of physical and mechanical properties and energy absorption characteristics of the wood,the compression strength perpendicular to the grain was tested for the treated and untreated samples by a universal mechanical testing machine. The results showed that the temperature,pressure and hot-pressing time of the optimal process were 140 ℃,4 MPa and 30 min,respectively.After the resin impregnation and compression,the density and bending strength of the wood were increased by 139% and189%,respectively. When the strain of the Mongolian pine wood was 0. 068,the energy absorption value increased by180%,and the energy absorption efficiency increased by 85%. This study showed a promising solution to cost-effectively utilize low grade wood and provided a theoretical foundation for the application of fast-growing wood in the packaging industry.