【作者】 张德荣；

【导师】 于志明；

【作者基本信息】 北京林业大学 ， 木材科学与技术， 2010， 博士

【摘要】 世界范围内日益重视对废弃物的处理与回收利用,随着我国城市化进程的加快和旧城改造项目的推进,每年产生大量的废旧木质材料；工业企业的生产以及日常生活也产生大量的废旧木质材料,将这些废旧木质材料回收和处理后重新使用,既可减少城市垃圾对环境带来的压力,同时又废物利用、变废为宝,缓解木材资源的紧缺。针对目前回收利用废旧刨花板时广泛使用的机械法制造再生刨花中出现的刨花形态损伤严重导致刨花板质量和加工性能差的问题,论文以废旧刨花板为研究对象,首次提出以爆破的方式处理废旧刨花板制造再生刨花,并对再生刨花的性质进行评价,同时使用再生刨花进行了刨花板制造实验,优化了热压工艺。实验选用不同的爆破工艺包括：蒸汽处理时间和蒸汽压力,通过电镜扫描(SEM)、傅立叶转换红外光谱(FTIR)、有机元素分析、化学成分分析、表面吸水率、筛分值等分析考察爆破处理对再生刨花微观构造、化学成分、物理性质的影响。采用正交试验设计,以刨花混合比例、施胶量、防水剂施加量、热压时间为因素,在不同的实验水平下进行再生刨花板制造,通过考察再生刨花板主要力学性能静曲强度(MOR)、弹性模量(MOE)、内结合强度(IB)、吸水厚度膨胀率(TS)衡量并优化工艺条件。以新旧刨花混合比例单因素为变量,通过对比的方法,考察机械法与爆破法对再生刨花板性能的影响。研究得到以下结论：1)爆破法处理废旧刨花板时,在保持刨花形态和产品质量方面具有明显优势,可以用于再生刨花的制造。2)对再生刨花性质的研究表明：爆破工艺对废旧刨花板产生两种效应：一是对胶粘剂的软化与破坏作用：从对再生刨花官能团以及有机元素含量的分析可以得出,爆破处理引起再生刨花中甲基、亚甲基、氨基数量的增减以及N元素含量变化,说明爆破处理对胶粘剂的分子结构产生很强的破坏作用。二是对木材产生影响,随爆破工艺的加剧,微观构造破坏加剧；在汽、热作用下,木材中的主要化学成分发生变化,半纤维素、木素含量降低,纤维素含量增加；纤维素结晶度相对增加。3)脲醛树脂胶粘剂的耐蒸汽处理能力远远低于木材,因此生产中可以实现蒸汽处理破坏胶粘剂并较好的保护原刨花形态。同时,对胶粘剂的破坏作用降低了再生刨花中甲醛含量,也有利于降低后期产品的甲醛含量。4)爆破法再生刨花制造刨花板时,产品的MOR、MOE、IB等优于机械法再生刨花制成的刨花板。再生刨花板优化工艺条件为：再生刨花比例：40%,施胶量：10%,石蜡乳液：0.7%,热压时间：35s／mm。更多还原

【Abstract】 More and more people are paying attention to the recycling and reusing of the used wood around the word. A large amount of waste wood is generated from many natural, commercial and domestic sources each year in China. The recycled wood can not only decrease the impact to the environment, but also can produce attractive products and relieve the scarcity of wood resources.The used particle board is always regenertated by the mechanic method which results in the serious damage to the shaving shape, the low quality and the poor process ability of the regenerated particle board. So the steam explosion technology of regenerating particle was studied in the paper, the characteristics of the regenerated particle were evaluated, and the optimization of the hot process are also discussed in the paper.Different technological conditions were selected including the time of steam treatment and the steam pressure. SEM, FTIR, elemental analysis, water absorption, and the analysis of the chemical component were used to evaluate the effect of explosion on the microscopic structure, chemical composition and physical properties to evaluate the properties of the regenerated particles. Orthogonal experiments were designed to prepare the regenerated particleboard. MOR, MOE, IB, TS of the board were examined to optimize the conditions, the array is designated by the Orthogonal Test L16 (45) involving four factors:the percent of regenerated particles(A), glue content (B), wax content (C) and hot pressing time (D). The effect of mechanical process and explosion process on the properties of regenerated particleboard was investigated by using the different ratios of recycled wood shavings and fresh shavings to produce the particleboard; and the significant findings were as follows:1) It was found that the regenerated wood shavings were better in maintaining the original shape and the quality of the following products after the explosion treatment than that after mechanical process. So explosion treatment is useful in the process of recycling of waste particleboard.2) The study on the characteristics of the regenerated wood shavings revealed that the explosion treatment caused two results to the used particleboard. On one hand, the adhesive was softened and destroyed, which can been seen from the amount changes of functional group including methyl, methylene and amino-group and the element N of the regenerated shavings; on the other hand, the explosion treatment had influence on the wood, the microscopic structure was destroyed with the increasing of the intensity of explosion. The content of semi-cellulose and lignin decreased, the content of cellulose and crystallinity of cellulose increased after the explosion treatment.3) The urea-formaldehyde resin of waste particle board could be destroyed and the shaving shapes could keep perfect under the certain explosion conditions because the stability of urea-formaldehyde resin to the steam was less than that of the wood. At the same time, the content of formaldehyde decreased with the damage of the urea-formaldehyde resin adhesive, which was benefit for the decreasing of the formaldehyde of the following products.4) The MOR, MOE and IB of the particleboard prepared from the recycled wood shavings using explosion process were better than that using mechanical process. The optimum conditions were as follows:the percent of regenerated particles 40%; adhesive content 10%; wax content 0.7% and hot pressing time:35s/mm.更多还原