【作者】 张仲凤；

【导师】 刘文金；

【作者基本信息】 中南林业科技大学 ， 木材科学与技术， 2007， 硕士

【摘要】 木材胀缩性研究是人工速生材高附加值加工利用的关键,是提高人工林木材产品质量的有力保证,是有效利用人工速生材、显著提高其商业价值的可靠方法。由于生产地和消费地大气含水率的差异,速生人工林木材制品常出现质量问题。尾巨桉是中国南方重要的速生林品种之一,研究尾巨桉木材在大气环境中的胀缩变化规律具有重要意义。通过模拟大气条件,探索尾巨桉木材含水率、弦向干缩率、弦向湿胀率随干燥和吸湿条件变化规律,建立尾巨桉实木胀缩规律的数学模型,并在应用中检验所建立的模型。傅立叶红外光谱显示,循环干燥后,干燥材的羟基吸光度降低；非共轭的醛、酮、羰基、酰或酯中的C=0强度减弱；共轭的醛、酮、羰基、酰或酯中的C=0波峰出现；积累双键或叁键由1个吸收峰变为2个或3个；酚醚键C—O—C、吡喃糖环上的C—O—C、酯基、饱和脂肪醚、醇的C—O吸收强度减弱,而苯环的吸收强度变化规律不一。循环干燥可以改变尾巨桉木材极性官能团的含量和亲水性。对试材进行循环干燥过程中,初含水率对含水率差和对尾巨桉木材弦向干缩率影响显著。干燥循环次数对尾巨桉木材含水率差影响显著,而对弦向干缩率影响不显著,且尾巨桉木材含水率差和弦向干缩率随着干燥循环次数呈下降趋势。在循环吸湿中,初含水率对含水率差的影响和对尾巨桉木材弦向湿胀率影响不显著；循环次数对尾巨桉木材含水率差、弦向湿胀率影响显著,且尾巨桉木材含水率差和弦向湿胀率随着循环次数呈先增大后减小趋势。尾巨桉木材在解吸和吸湿过程中,含水率对其弦向干缩率、弦向湿胀率影响显著,且弦向干缩率、弦向湿胀率随木材含水率的增大呈先增大后减小趋势。根据试验分析,结合一些经典模型,利用Origin技术通过非线性拟合,得到高度显著性的方程组,从而建立能准确反应含水率、干燥时间或吸湿时间、循环次数与弦向干缩率或湿胀率之间关系的尾巨桉实木胀缩规律的数学模型。经过模型检验,计算值与试验结果吻合较好,具有合理性和适用性。研究表明,采用循环干燥和吸湿工艺处理尾巨桉木材,可以有效降低尾巨桉木材弦向胀缩性,提高其木质耐侯性,延长尾巨桉实木制品的使用寿命。更多还原

【Abstract】 The research of wood swilling and shrinkage is the key of high- valued utilization of plantation wood, which products is a powerful guarantee to improve the quality of planted forest lumber, and is a reliable method of the effective use of fast-growing material and remarkably enhances its commercial value. The product made by the fast-growing planted forest lumber often has the quality problem because of the difference atmosphere moisture between produces and the expense. Mountain Gum×Flooded Gum wood is one of important fast-growing forest varieties in south China, which have the vital significance to study its bulking and shrinkage in the atmospheric environment.By simulating atmospheric conditions, we try to explore the moisture content, the tangential shrinkage, the tangential swilling with the wet and dry moisture conditions change of Mountain Gum×Flooded Gum wood, so that we can establish a mathematical model of the swell-shrink of Mountain Gum×Flooded Gum wood.As the FTIR spectrogram shows, after drying cycle, the drying of the wood-absorbance decrease, strength of the non-conjugated aldehydes, ketones,carbonyl, and Ester-C=O decline, peaks of conjugated aldehydes, ketones, carbonyl, and the ester carbonyl occurring. Following the accumulation of double bond or bond from a peak into two or three, absorption strength of the phenol ether bond starch, sugar pyran ring of C-O-C, ester, saturated fat ether, C-O alcohol weakened, and the absorption of the benzene ring intensity variation mixed. Drying cycle can change polar functional group content and hydrophilic of t Mountain Gum×Flooded Gum wood.In the drying cycle, the initial moisture content of the moisture content differential impact significantly, and the initial moisture content of the Timber Mountain Gum of the tangential direction significantly affect the moisture content. Drying cycle number has significantly impact on the difference of the moisture content of the Timber Mountain Gum, but the tangential shrinkage is not significantly affected, the difference of moisture content and tangential shrinkage of t Mountain Gum×Flooded Gum wood has decreased trend with the drying cycle number. when absorbing, the impact of the difference of the moisture content by first moisture content is not significant, and the first moisture content on the Mountain Gum x Flooded Gum wood tangential swilling impact was not significant. The impact of the difference of the moisture content and tangential swilling of Mountain Gum x Flooded Gum wood is significant with loop number, the moisture content and tangential swilling of Timber Mountain Gum×Flooded Gum wood has increased and then decreased trend with loop number.When the Timber Mountain Gum x Flooded Gum wood release and absorb water, the impact of the difference of the moisture content on tangential shrinkage and tangential swilling is significant, and the tangential shrinkage and tangential swilling has increased and then decreased trend with the increases of the moisture content.Based on the analysis, combining some classical model, the use of technology by Origin nonlinear fitting, be highly significant to the equation, so as to establish an accurated mathematical model of Mountain Gum×Flooded Gum wood response moisture content, drying or absorbing time, the relationship between the tangential shrinkage or tangential swilling with loop number. After testing model, the calculated and experimental results agree well with rationality and applicability.The research indicated that using the circulation to be dry and the moisture absorption craft processing Timber Mountain Gum×Flooded Gum wood, may effectively reduce its tangential shrinkage and swilling, improve its wood weathering, extended life of the products made of timber Mountain Gum wood.更多还原