结构用桉木重组木的适宜性制备工艺

Study on suitability manufacture process of structure Eucalyptus scrimber

为实现桉木资源的大规模高附加值应用,采用重组技术制备不同密度与施胶量的结构用桉木重组木,对其适宜性制备工艺进行研究,探究密度与施胶量对结构用重组木抗弯性能与耐水性能的影响规律。参照GB/T 17657—2013《人造板及饰面人造板理化性能试验方法》对重组木抗弯性能与耐水性能进行测试,并对重组木的抗弯性能进行数值拟合;同时利用材料表面三维轮廓放大观察系统观察材料耐水测试后的端面开裂形貌与表面翘曲现象。结果表明:密度对重组木抗弯性能与耐水性能有显著影响,密度越大,重组木抗弯性能与耐水性能越好。随着密度的增加,重组木静曲强度与弹性模量逐渐增大,吸水率、宽度膨胀率与厚度膨胀率逐渐降低,同时耐水测试后端面开裂现象越发明显。本试验条件下不同密度(0.9~1.3 g/cm^(3))重组木抗弯性能均达到GB/T 20241—2006《单板层积材》中结构用单板层积材的160E级别;施胶量对重组木抗弯性能无显著影响,对重组木耐水性能有显著影响。施胶量越大,重组木抗弯性能无明显变化趋势,静曲强度与弹性模量在小范围内波动,吸水率、宽度膨胀率与厚度膨胀率逐渐降低,同时表面翘曲现象越发不明显。结构用桉木重组木可通过调整密度与施胶量对其性能进行调控,以适应不同性能要求的应用场合,为桉木的大规模高附加值应用提供有效途径。

As a rich forest resource, the effective utilization of Eucalyptus has attracted people’s attentions. In order to achieve the large-scale and high value-added application of Eucalyptus resources, Eucalyptus scrimbers with different densities and resin contents were prepared by the recombination technology, and its suitability manufacture process was studied to explore the effects of density and resin content on the bending properties and water resistance properties of scrimbers. Refer to GB/T 17657-2013 “The test method for physical and chemical properties of wood-based panels and veneer wood-based panels”, we examined the bending properties and water resistance properties of the scrimbers, and used the three-dimensional contour magnification observation system of the material surface to observe the end face cracking and surface warpage after the water resistance test. The results showed that the density had a significant impact on the bending properties and water resistance properties of the scrimber. For different densities under the test conditions(0.9-1.3 g/cm^(3)), the higher the density, the better the bending properties and water resistance properties of the scrimber. With the increase of density, MOR and MOE of the scrimber gradually increased, and the water absorption, width expansion and thickness expansion gradually decreased. At the same time, the end face cracking phenomenon is more and more obvious after the water resistance test, the end face crack increased from 73.510 μm(ρ=0.9 g/cm^(3)) to 206.821 μm(ρ=1.3 g/cm^(3)), counting an increase of 181.35%. Under experimental conditions, the bending properties of each density of the scrimber(from 0.9 to 1.3 g/cm^(3)) reached 160 E grade in GB/T 20241-2006 “Laminated veneer lumber”. For different resin contents(10%-30%) under the experimental conditions, the resin content had no significant effect on the bending properties of the scrimber, but had a significant effect on the water resistance properties of the scrimber. With the increase of the resin content, the bending properties of the scrimber had no obvious change trend, and the MOR and MOE fluctuated in a small range. The water absorption, width expansion and thickness expansion decreased gradually, and the surface warpage became less and less obvious, the sum of peaks and troughs of micro profile decreased from 718.7 μm(10%) to 281.7 μm(30%), counting a decrease of 60.80%. The properties of the scrimber could be regulated according to density and resin content to meet different application occasions. Structured Eucalyptus scrimber provided an effective way for the high value-added large-scale application of Eucalyptus.