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-  2018 

纳米碳酸钙改性处理桉木单板对胶合板弯曲性能的影响

DOI: 10.13360/j.issn.2096-1359.2018.05.008

Keywords: 纳米CaCO3, 桉木单板, 表面改性, 力学性能, 弯曲性能
nano-CaCO3
, eucalyptus veneer, surface modification, mechanical properties, bending property

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Abstract:

桉木因其材质疏松、易开裂、变形等缺陷而致其使用范围受限,为此,对桉木单板进行改性处理使其材性得到改善增强以扩大其用途。采用偶联剂KH-550对纳米CaCO3表面进行改性处理后,配制成质量分数分别为3.0%,5.0%,7.0%和9.0%的纳米CaCO3溶液,加压浸渍桉木单板,并以酚醛胶为胶黏剂热压成纳米CaCO3增强胶合板(5层),并采用FT-IR、SEM、万能力学实验机等对所获胶合板的结构与物理力学性能进行测试与表征分析。FT-IR分析表明,纳米CaCO3粒子表面上接枝了改性剂KH-550的特征官能团; SEM分析表明,改性的纳米CaCO3粒子均匀分散在桉木单板纤维上; 当纳米CaCO3质量分数为5.0%时,其处理后的质量增加率最大,达7.0%,胶合板的弹性模量、静曲强度最优,分别达到8 416和71.38 MPa,与未添加纳米CaCO3的相比分别提高了10.4%和27.1%。这是因为纳米CaCO3粒子经分散及KH-550改性后,比表面积增大,表面活性增强; 通过偶联剂的作用将纤维素和CaCO3粒子界面结合力提高,形成良好的界面结合,从而使胶合板的静曲强度、弹性模量增加。
The utilization of fast-growing wood is limited due to its major drawbacks, such as low density, poor mechanical properties, easy cracking and deformation. To promote the application of the fast-growing wood, it is necessary to address these drawbacks by developing cost-effective pre-treatment methods. The traditional wood treatment methods are not only time-consuming and labor-intensive, but also unable to significantly improve the wood properties. Emerging nanomaterials have broad application prospects. Through the screening of nanomaterials, nano-CaCO3 stands out in nanomaterials due to its superior properties and relatively inexpensive prices. However, there are a large number of active hydroxyl groups on the surface of nano-CaCO3 particles. The van der Waals forces generated between the hydroxyl groups make the particles unstable, resulting in particle agglomeration. The aim of this study, is to reduce the occurrence of this phenomenon and make the nano-characteristics of nano-particles of come into full play. The surface of nano-CaCO3 was modified with the coupling agent of KH-550, and the nano-CaCO3 solution with the mass fractions of 3.0%, 5.0%, 7.0%, and 9.0% was prepared and impregnated into eucalyptus veneers, respectively. The adhesive was hot-pressed into nano-CaCO3 reinforced plywood(five layers). The structure and physico-mechanical properties of the plywood obtained were characterized by the FT-IR, SEM, and universal test machine. The results of FT-IR analysis showed that the functional group of modifier KH-550 was grafted on the surface of nano-CaCO3 particles. The results of SEM analysis indicated that the modified nano-CaCO3 particles were uniformly dispersed on the eucalyptus veneer fibers. When the nano-CaCO3 content was 5.0%, the maximum weight gain after treatment was 7.0%. The elastic modulus and the static bending strength of the plywood were also examined, and the optimum values were 8 416 MPa and 71.38 MPa, respectively, which increased by 10.4% and 27.1%, respectively, compared with those without nano-CaCO3. It was because that the

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