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由木材剩余物杨木枝桠材为原料,制得杨木纤维的化学机械浆后,经直接烘干和溶剂置换两种不同的后续处理方法得到不同尺寸杨木纤维(PWF),再与环氧树脂E51经热压成型制备PWF增强环氧树脂(PWF/E51)复合材料。通过PWF微观形貌与尺寸分析,结合PWF/E51复合材料冲击断面微观形貌分析,探讨了PWF尺寸对PWF/E51复合材料力学性能的影响。研究结果表明:PWF尺寸对增强环氧树脂复合材料力学性能有较大影响,随PWF长径比增大,复合材料的冲击强度和弯曲强度均先增大后减小,其中溶剂置换处理的PWF/E51复合材料(长径比值14.8)力学强度最佳,冲击强度7.1 kJ/m2,弯曲强度68.2 MPa。此外,经溶剂置换处理的PWF/E51复合材料的力学强度较直接烘干处理有所提高。 相似文献
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研究了硫酸催化条件下,将恩茅松在苯酚中液化用于制备酚醛树脂的技术工艺,分析了各工艺参数对思茅松液化效率的影响,测定了由液化产物制备的液化木基酚醛树脂的物理化学性质和胶合强度。结论如下:1).液比、反应温度、时间和木粉目数是影响液化反应效率的重要因素,液化产物的残渣率均随上述工艺参数值的升高而降低。2).残渣含量对树脂物化性质和胶合强度均有影响,残渣含量降低,树脂粘度减小,聚合时间缩短,游离酚含量降低,胶合强度升高。3).甲醛/苯酚摩尔比对树脂的物化性质和胶合强度也有影响,甲醛/苯酚摩尔比增加,树脂粘度增加,聚合时间减少,游离酚含量减低,胶合强度升高。 相似文献
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Abasolo W. P. 《世界竹藤通讯》2009,7(3):45
对人工种植的棕榈藤和野生藤的力学特性进行对比。同时,评估了比重和纤维比对强度的变异性的影响,并评估了强度特性对藤龄的影响。人工种植和野生藤的断裂模数和弹性模数相似,由此证明人工种植藤的强度特性并不亚于野生藤的强度特性。这说明,人工藤可在工业上利用,且对藤产品的性能没有负面影响。绝干比重和纤维比也没有对其强度特性的变异性产生影响。同样,藤龄也不会对强度特性产生影响。很明显,幼龄藤也具有成熟藤秆相同的强度。 相似文献
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木材纤维的含量和形态特征,不仅影响木材的物理力学性质,而且是衡量木材利用价值的重要指标之一,木纤维的含量直接研究了木材的纸浆得浆率,对指导林木培育具有重要意义。本文对长江滩地推广的五个不同无性系的杂交柳树,从木材解剖性质,物理、力学性质的角度作较为系统的纤维特征及变异研究,为柳树杂交良种推广提供科学依据,也便于扩大杂交柳树在国民经济和人民生活中的利用范围。 相似文献
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用不同滤纸酶活力和羧甲基纤维素酶活力比(F/C)值的纤维素酶系处理轻量涂布纸二次纤维,研究了纤维素酶系组成对二次纤维性能的影响。随着F/C值从0增到2.5,长度小于0.2mm的纤维分布密度由23.55%降低到17.50%。纤维加权平均长度由1.067mm增加到1.168mm,纤维的卷曲系数由0.103下降到0.087;纤维的扭结强度由0.78个/mm增加到0.84个/mm。随着F/C值的增加,纤维素酶系外切酶的酶解作用增强,细小组分逐渐减少,二次纤维平均长度呈上升趋势,卷曲程度下降,有利于浆料滤水性能的改善,但纤维扭结强度上升对单根纤维强度和纸张强度产生不利影响。 相似文献
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Kouichi SETOYAMA 《中国林业科技(英文版)》2002,(4)
The effect of wood species (Chinese fir and Poplar), wood fiber content (10%, 25%, 40%) and wood fiber sizes (16 to 32 mesh, 32-65 mesh, above 65 mesh) on the properties of the wood fiber-Polypropylene composites were studied in this paper. The results indicate that the effect of wood fiber content and size in composite were more important than that of chosen wood species. Compared with polypropylene without wood fiber, the flexural strength of the composites increased when adding wood fiber into polypropylene, but the tensile and unnotched charpy impact strength decreased. And the above strength decreased with the wood fiber content increasing. When the wood fiber size becoming smaller (in higher mesh), the strength increased. In the comparison of wood species, the properties of composite using Chinese fir wood were better than that of Poplar, but not significant. The dynamic mechanical properties of the composites and PP were also tested and analyzed in this paper. 相似文献
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Heng Xu Tetsuya Nakao Chiaki Tanaka Masahiro Yoshinobu Hiroyuki Katayama 《Journal of Wood Science》1998,44(5):343-347
Short carbon fibers, a reinforced material in wood veneer composites, were used to investigate the effects of fiber length and orientation of fibers on the elasticity of plywood. The technical feasibility, elasticity, and strength of the reinforced plywood with short carbon fiber were evaluated. In a short fiber reinforcement system, the fiber length does not directly influence the reinforcement in Cox's theory when the fiber length exceeded a certain length. When the length of short carbon fiber is beyond 3 mm, the high reinforced result was obtained in the experiment. However, if fiber length was too long, the reinforced result was less owing to the bridge between fibers and the increase of holes. The optimum fiber length must be considered. The orientation of fibers has a strong influence on the reinforcement. Unidirectional, perpendicular, and random orientation displayed different influence on the elasticity. Experimental results were discussed with Cox's method. Reinforced plywood with short carbon fibers in random orientation has a higher shear modulus and bending strength than the controls, in addition to other mechanical properties. 相似文献
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采用热磨法研磨纤维,研究不同纤维目数(40~100目,20~120目,10~130目)对纤维板力学性能和成本的影响。在保证制作质量合格的纤维板试件基础上,对其进行力学性能试验,验证确定纤维目数区间的合理性,并利用确定的纤维目数区间进行密度和施胶量的单因素对比分析;分析其对力学性能和成本的影响。研究结果表明:纤维目数在40~100目时,可通过降低试件密度或减小施胶量,在保证制品较好力学性能的前提下降低制备成本,可实现优质优价经济效益最大化;从纤维板制品制备成本分析得出:采用上述三种纤维目数区间,在保证制品质量要求的前提下,可实现纤维目数区间与制品质量等级的合理匹配,达到合理利用原材料降低成本的效果。 相似文献
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Sasa Sofyan Munawar Kenji Umemura Fumio Tanaka Shuichi Kawai 《Journal of Wood Science》2008,54(1):28-35
This study focused on the effects of treatments of alkali, mild steam, and chitosan on the surface morphology, fiber texture,
and tensile properties of pineapple, ramie, and sansevieria fiber bundles. The fibers were treated with NaOH (2%), mild steam
(0.1 MPa), and chitosan solutions (4% and 8%). The properties of these treated fibers were characterized and compared with
the untreated fibers. Field emission scanning electron microscopy (FE-SEM) was used to observe the surface morphology of those
fibers. X-Ray diffraction (XRD) spectroscopy was used to observe the fiber textures. Tensile properties of the treated and
untreated fibers were also recorded. SEM micrographs showed that the surfaces of the NaOH-treated fibers were more damaged
than those of the steam-treated fibers. The 4% chitosan solution covered the fiber surface more uniformly than the 8% chitosan
solution. The steam-treated fibers had higher values of degree of crystallinity, crystallite orientation factor, and crystallite
size than the NaOHtreated fibers. Ramie fiber showed greater mechanical properties than the other fibers. The values of tensile
strength, Young’s modulus, and toughness of the steamtreated fibers, which were similar to those of the 4% chitosan-coated
fibers, were higher than those for the other treatments. 相似文献
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通过钻孔方法,研究了植物纤维穿孔板的孔隙率、穿孔排列方式、穿孔大小等对其静曲强度的影响,并建立了数学模型;提出检测穿孔板静曲强度时,要以试件构成单元理论宽度的倍数作为试件宽度的计算依据.试验结果表明:植物纤维穿孔板静曲强度的主要影响因子是孔隙率,其次是穿孔的排列方式,与孔径大小无关. 相似文献
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选取市场上具有代表性的两种商品针、阔叶木浆进行PFI打浆处理,研究在不同打浆度下浆料纤维质量、动态滤水性能、Zeta电位、微观结构等方面的变化,并对不同比例配抄条件下的成纸性能进行考察,结果表明:针、阔叶浆的打浆度与打浆转数之间的关系均符合线性分布:y=17.7503+0.0015x,R^2=0.9914(针叶浆);y=8.8986+0.00275x,R^2=0.9734(阔叶浆);经PFI打浆后,两种木浆纤维长度、宽度变化较小,细小组分含量变化明显;随着打浆度的升高,两者的滤水性能下降,Zeta电位先上升然后基本保持不变;初始打浆度下,随着针叶浆比例的减少、阔叶浆比例的增加,成纸的抗张强度先下降再增大,厚度逐渐下降至不变,定量逐渐增加,柔软度逐渐下降;随着打浆度的升高,成纸的抗张强度增大,厚度、定量逐渐下降,针叶浆成纸柔软度逐渐下降,阔叶浆成纸柔软度先升高再逐渐降低。 相似文献
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云南4种典型材用丛生竹宏观解剖结构与主要物理力学性质的关系 总被引:15,自引:0,他引:15
对云南4种典型的材用丛生竹(龙竹Dendrocalamusgiganteus,甜龙竹Dendrocalamusbrandisi,黄竹Dendrocalamusmembranaceus,油勒竹Bambusalapidea)的维管束密度、纤维比量、密度、含水率、干缩率、顺纹抗压强度和弦向抗弯强度的检测结果认为:4种竹材之间和同一竹种内径向、弦向和纵向上的结构和物理力学性质的分布存在着较大的差异。对结构指标与主要物理力学性质之间关系的分析结果认为:纤维比量比维管束密度与竹材物理力学性质的关系更为密切;4种竹材的纤维比量与密度、弦向抗弯强度和顺纹抗压强度呈正比关系,与饱湿含水率呈反比关系。 相似文献
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本文对长江滩地这一特定立地条件下经过人为耕作与未耕作模式下的杨树木材解剖性质及其变异的关系进行了比较研究。结果表明:林下耕作纤维长度变化范围在792.67-1114.33μm,属中等长度纤维,林下耕作杨树的纤维长度明显比未耕作的要长,两者纤维长度、宽度差异显著,长宽比差异极显著;林下耕作木材导管比量为29%,木纤维比量为54%,木射线比量为17%,变异系数分别为13.8%、7.4%、23.5%;低于对照木材,提高了材质均匀性;两者导管与木纤维组织比量轴向变化趋势一致,分别呈波动上升与下降的趋势,但木射线组织比量变异趋势存在较大的差别。林下耕作杨木导管比量自髓心向外呈上升趋势,木射线组织比量随着年龄的增加逐渐下降,并呈现一定的波动性:未经耕作的杨树木材组织比量径向变异规律性不明显。 相似文献