木材-无机纳米复合体系中纳米粒子分散机制研究

发布时间：2018-06-11 19:38

本文选题：木材 + 无机纳米粒子　；参考：《中南林业科技大学》2015年硕士论文

【摘要】：木材作为一种天然可再生的重要有机高分子材料。以其独有的视觉、触觉、听觉以及环境友好等特性,受到人们的青睐。但是木材的低强度值、易腐朽、易燃烧等一些固有缺陷严重影响了木材的广泛使用,无机纳米粒子具有小尺寸效应、表面效应、宏观量子隧道效应等，有研究表明使用无机纳米粒子对木材进行改性,可以提高其力学性能,并可以使其具备一定的阻燃性,同时有研究发现无机纳米粒子对木材复合强化效果显著,但其表现出的规律与其对应的微米级粒子并不完全相同,分析原因主要在于无机纳米粒子能否打破其固有团聚特征,在基体内实现纳米级分散。因此有必要对无机纳米粒子在木材体系中的分散机制进行研究。基于此,本文选择纳米碳酸钙、纳米二氧化硅为代表的无机纳米粒子,增强木纤维/PP复合材料,作为木材-无机纳米复合材料体系,研究纳米粒子在木质基复合材料内的分散机制。在本研究中,先对纳米粒子进行改性分散,以纳米粒子可以达到纳米级别,保持纳米粒子纳米级分散不仅可以提高其与复合材料的界面相容性,还可以保证其在木纤维/PP中的良好分散,分别用激光粒度仪、傅里叶红外光谱分析仪、热重分析仪对改性前后的无机纳米粒子进行表征,再将两种无机纳米粒子通过不同的制备工艺制备纳米粒子增强木纤维/PP复合材料,对添加纳米粒子后的复合材料通过扫描电镜表征,并对扫描电镜图像进行分析与处理,引入无机纳米粒子在聚合物基中的分散模型,推导并修正,建立纳米粒子在木纤维/PP复合材料中的分散模型,并通过X衍射表征观察其均匀分散后其结构变化,测试复合材料的力学性能及吸水率来验证分散模型的准确性。本文主要研究结论如下：(1)采用硅烷偶联剂KH570与硬脂酸复合改性纳米碳酸钙,硅烷偶联剂KH570对纳米二氧化硅进行改性。结果表明：当KH570质量分数为10%时,纳米碳酸钙的分散改性效果最优,其吸油值最小,活化值最大,改性之后的纳米碳酸钙粒径主要集中在50-70nm, FTIR结果表明改性剂KH570、硬脂酸成功接枝于纳米碳酸钙粒子表面,热重结果表明改性剂在纳米碳酸钙表面接枝量大约为10%；当KH570的质量分数为5%时,纳米二氧化硅的分散效果最优,亲油化度值最大,经过改性之后的纳米二氧化硅粒径主要分布在40-60nm,FTIR结果表明改性剂硅烷偶联剂KH570成功接枝于纳米二氧化硅表面,热重结果表明改性剂KH570在纳米二氧化硅表面接枝量大约为23%；(2)经过不同表面改性处理方法的纳米碳酸钙及不同质量分数的纳米碳酸钙分别增强木纤维/PP复合材料,结果表明：分别当KH570的质量分数为10%、纳米碳酸钙质量分数为5%时,其对复合材料的力学性能提高量最显著,对吸水率的降低效果最明显,经过推导并修正之后的纳米碳酸钙在木纤维/PP复合材料中的分散模型与本试验结果相符；(3)经过不同表面改性处理方法的纳米二氧化硅及不同质量分数的纳米二氧化硅分别增强木纤维/PP复合材料,结果表明：分别当KH570的质量分数为5%、纳米二氧化硅质量分数为3%时,其对复合材料的力学性能提高量最显著,其对吸水率的降低效果最明显,经过推导并修正之后的纳米二氧化硅在木纤维/PP复合材料中的分散模型与本试验结果相符；(4)对比不同纳米粒子及不同制备工艺对纳米粒子在木纤维/PP复合材料中分散性影响,结果表明：纳米二氧化硅在木纤维/PP的分散性明显优于纳米碳酸钙,其对复合材料的力学性能提高、对吸水性能的降低,明显优于纳米碳酸钙对复合材料的影响。
[Abstract]:Wood is a natural and renewable important organic polymer material. It is favored by people for its unique characteristics of visual, tactile, hearing and environment friendly. However, wood's low strength, decaying, inflammable and other inherent defects seriously affect the wide use of wood. Inorganic nanoparticles have small size effect. Surface effect, macroscopic quantum tunneling effect and so on. Some studies have shown that the use of inorganic nanoparticles in the modification of wood can improve its mechanical properties, and can make it have a certain flame retardancy. At the same time, it has been found that the effect of inorganic nanoparticles on wood composite strengthening is remarkable, but its regularity and its corresponding micron grade particles are also found. It is not exactly the same, the main reason is that the inorganic nanoparticles can break the intrinsic agglomeration characteristics and realize the nanometer dispersion in the matrix. Therefore, it is necessary to study the dispersion mechanism of inorganic nanoparticles in the wood system. Based on this, this paper selects nano calcium carbonate and nano silica as the representative inorganic nanoparticles. The strong wood fiber /PP composite is used as a wood inorganic nanocomposite system to study the dispersion mechanism of nano particles in wood based composites. In this study, the nanoparticles are modified and dispersed first, and nanoparticles can reach the nanometer level. The nano particle dispersion can not only improve the nano particles and the composite materials. The interfacial compatibility can also ensure its good dispersion in the wood fiber /PP. The inorganic nanoparticles are characterized by laser particle size analyzer, Fu Liye infrared spectrum analyzer and thermogravimetric analyzer, and then two inorganic nanoparticles are prepared by different preparation processes to prepare the nano particle reinforced wood fiber /PP composite. The composite material after adding nanoparticles was characterized by scanning electron microscope, and the scanning electron microscope images were analyzed and processed. The dispersion model of inorganic nanoparticles in the polymer matrix was introduced and modified. The dispersion model of the nano particles in the wood fiber /PP composite was established and the homogeneous dispersion was observed by the X diffraction. The main conclusions are as follows: (1) the modification of nano calcium carbonate with silane coupling agent KH570 and stearic acid modified nano calcium carbonate and silane coupling agent KH570 to nano silica. The results show that when the mass fraction of KH570 is 10%, nano carbon is used. The dispersion modification effect of calcium acid is the best, its oil absorption value is the smallest and the activation value is the largest. The particle size of nano calcium carbonate after modification is mainly concentrated in 50-70nm. FTIR results show that the modifier KH570, stearic acid is successfully grafted on the surface of nano calcium carbonate particles, and the thermal weight results show that the grafting amount of the modifier on the surface of nano calcium carbonate is about 10%; when KH570 When the mass fraction is 5%, the dispersing effect of nano silica is the best and the value of the affinity to oil is the largest. The size of nano silica particles after modification is mainly distributed in 40-60nm. FTIR results show that the modifier silane coupling agent KH570 is successfully grafted on the surface of nano silica, and the thermogravimetric results show that the modifier KH570 is connected to the surface of nano silica. The branch amount is about 23%. (2) the nano calcium carbonate and nano calcium carbonate with different mass fraction are respectively enhanced by different surface modification methods. The results show that when the mass fraction of KH570 is 10% and the mass fraction of nano calcium carbonate is 5%, the mechanical properties of the composites are the most significant, and the /PP composites are absorbed. The reduction effect of water rate is the most obvious. The dispersion model of nano calcium carbonate in wood fiber /PP composite after deduction and correction is in agreement with the experimental results. (3) the nano silica and the nano two silicon oxide with different mass fraction by different surface modification methods enhance the wood fiber /PP composite respectively. When the mass fraction of KH570 is 5% and the mass fraction of nano silica is 3%, the mechanical properties of the composite are the most significant, and the effect of reducing the water absorption is the most obvious. The dispersion model of nano silica in the wood fiber /PP composite after deduction and correction is in accordance with the experimental results; (4) comparison The effect of nano particles and different preparation processes on the dispersion of nano particles in wood fiber /PP composites shows that the dispersion of nano silica in wood fiber /PP is obviously better than that of nano calcium carbonate. The mechanical properties of the composites are improved and the water absorption property is lower, which is obviously better than that of nano calcium carbonate. Influence.
【学位授予单位】：中南林业科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TB383.1;TB33

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