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The Properties on Bamboo Bundle Veneer and Bamboo-bundle Laminated Veneer Lumber

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Tutor: WangGe
School: Chinese Academy of Forestry
Course: Wood Science and Technology
Keywords: Bamboo bundle veneer,String connection,Precompressing densify,Lamina-ted bamboo-
CLC: TS653
Type: Master's thesis
Year:  2013
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As a new product of wood-based panel,the distinguished feature of bamboo scrimber isthe improvement of the utilization rate of bamboo which is high to90%and the variety of rawmaterials containing Moso bamboo and dwarf bamboo. Bamboo scrimber has advantages ofstability of mechanics¡¢high vertical strength. However,it has defects of uneven uniform ofdensity and high density,which hinder the further application in the building. The unevendensity is one of the problems in the research of bamboo scrimber in the stacking sequence stepand then manual operation makes it lower efficient and the slabbing no surface bondingstrength. Also,the overlapping of bamboo bundle lead to the slabbing uneven spread the qualityof spread of the slabbing determines the distribution of vertical density file and the uniform ofphysical and mechanical properties of bamboo scrimber.To solve this problem, on the base of the sheeted way in the process of laminated veneerlumber,the methods of line connection and densified bamboo bundle veneer on precompressedprocess are researched to make veneer one piece formation and the board high physical andmechanical properties at the same time.Dendrocalamus farinosus is taken as the research object which studied the effectof the processing of line connection and densified bamboo bundle veneer on precompre-ssed process on the properties of bamboo bundle and bamboo-bundle laminated veneerlumber.Main results are summarized as follows£º£¨1£©The methods of connection with sewing cotton and hot-melt plastic filament satisfiedthe requireements of a sheet of the bamboo bounding units.The line is2to3with300mmbamboo bundle. The method of sewing cotton had a little influence on the MOE and MOR ofbending and horizontal shearing strength of bamboo-bundle laminated veneer lumber. £¨2£©With the line connetion, the uniformity of physical and mechanical properties anddensity in both width and thickness direction of BLVL was superior to bamboo scrimber. Alsothe CV of BLVL with line was reduced as the increase of board density. The linear relationbetween the mechanical strength and density of BLVL with line connection was good. Then thedesign of mechanical properties was better than bamboo scrimber from0.7g/m3to1.1g/m3.£¨3£©The diffusion modelof Fick¡¯s law provided a good prediction of long-term h-ygroscopic behavior of BLVL.The equilibrium ratio of weight gain and thickness swelli-ng were enlarged with higher soaking temperature and density. The diffusion coefficientof BLVL was1.142.54£¨10-10/mm2/s£©.£¨4£©In the processing of densified bamboo bundle veneer with hot-pressing onprecompressed process, the tensile property of bamboo bundle increased with the increase ofhot pressing temperature from90¡æto150¡æand time from10min to15min. but the physicaland mechanical properties of board wad reduced. The merits of cold-pressing including:relatively simple operation, higher production efficiency, ower energy consumption. Amongcold-pressing, the board performance for the stacking sequence bamboo/poplar parallel to grainwas super than others.£¨5£©The impact performance for90¡æ£¬10min densification technology was fairlyequal with BLVL. The impact index of board decreased as the densification temperatureincreased. In the processing of densified bamboo bundle veneer with hot-pressing onprecompressed process. The overall impact performance for hot-pressing densificationwas better than that for cold-pressing technology.
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