【作者】 王蜜；

【导师】 李斌；

【作者基本信息】 东北林业大学 ， 高分子化学与物理， 2010， 硕士

【摘要】 自从Iijima发现碳纳米管(CNTs)以来,就引起人们的极大兴趣。碳纳米管拥有优异的力学性能、电性能、热稳定性等特性,并具有独特的一维纳米结构所特有的纳米效应,使其成为聚合物材料理想的增强体,并能赋予聚合物材料许多新的功能。为了有效地使具有这些优异性能的碳纳米管加强聚合物基体,两个主要问题必须解决：使碳纳米管均匀分散在聚合物基体和增强碳纳米管与基体聚合物之间的界面附着力。从而改善碳纳米管与基体聚合物之间的相容性。这是聚合物／碳纳米管复合材料发展的关键问题,化学功能化技术是解决这些问题的方法之一。聚硅氧烷(DMS)是主链由硅和氧组成的有机高分子合成材料。它的主要特征是Si-O-Si键较长,键角较大,这使得Si-O-Si键容易旋转,分子间作用力小及分子呈高柔顺态,基于以上特性,所以聚硅氧烷类高分子材料具有很多优异的物理、化学性能,如耐高低温性能、耐氧化性、耐候性、憎水性等。在最近的研究中人们发现将各种功能基团引入聚硅氧烷,不仅能保留聚硅氧烷的各种特性,还可赋予聚硅氧烷一些新的功能。本文将羧基多壁碳纳米管(MWNTs-COOH)和聚硅氧烷一步缩合,制得功能化碳纳米管。使用氨丙基双封端二甲基硅油(DPD)接枝碳纳米管,因为其高分子量更有助于形成多壁碳纳米管-多壁碳纳米管(MWNT-MWNT)网络结构。利用FTIR、XPS、TGA等测试手段对接枝后的碳纳米管结构进行表征。聚碳酸酯／羧基多壁碳纳米管(PC/MWNTs-COOH)和聚碳酸酯／氨丙基双封端二甲基硅油接枝多壁碳纳米管(PC/MWNTs-DPD)纳米复合材料采用了溶液和熔融两步法进行制备。利用力学性能、TEM、TGA、极限氧指数(LOI)、UL-94垂直燃烧性能和电学性能对复合材料的性能进行评估。实验结果表明,MWNTs-DPD能更好的分散在PC基体中,PC/MWNTs-DPD纳米复合材料的拉伸强度、弯曲强度、弯曲模量和阻燃性能都优于PC/MWNTs-COOH的。然而介电系数和介电损耗的结果表明PC／MWNTs-DPD纳米复合材料的导电性能比PC/MWNTs-COOH的差。将MWNTs-DPD应用于膨胀阻燃聚丙烯体系中,对其协效作用进行研究。复合材料采用熔融法制备。利用力学性能、TGA、极限氧指数(LOI)和UL-94垂直燃烧性能对复合材料的性能进行评估。实验结果表明,PP-IFR/MWNTs-DPD复合材料与PP-IFR/MWNTs-COOH复合材料相比阻燃性能较好,然而力学性能较差。热重分析数据表明,液态DPD柔顺的大分子链加入使PP-IFR体系的初始分解温度和最大热分解温度提前,成炭量下降,故PP-IFR/MWNTs-DPD复合材料的初始分解温度和最大热分解温度与PP-IFR比较提前,成炭量也下降。而PP-IFR/MWNTs-COOH复合材料的初始分解温度和最大热分解温度与PP-IFR比较却延后,成炭量也下降。更多还原

【Abstract】 Since Iijima discovered carbon nanotubes(CNTs), it has been drawn great attention. CNTs have excellent mechanical properties, predominant electrical, thermal stabilities and have the unique nano-effects of one dimensional nano-structure,which makes CNTs be the perfect reinforce for polymer materials, and give polymer materials many new functions. However, to effectively reinforce a matrix polymer with these outstanding properties of CNTs, two main issues have to be resolved:homogeneous dispersion of CNTs in matrix polymer; as well as strong interfacial adhesion between CNTs and matrix polymer. These requirements can be realized by improving the compatibility between CNTs and matrix polymer. In this regard, a key issue in development of polymer/CNTs composites is how to maximize the compatibility between CNTs and matrix polymer. Chemical functionalization technique is one of the methods for solving these problems.Siloxane(DMS) is composed by silicon and oxygen. Due to longer length and larger bond angle of Si-0 bond, it rotates easily. The intermolecular force gets weak, and the polymer is high elastic state. Polysiloxane has many outstanding physical, chemical performances, like oxidative resistance, the weathering resistance, hydrophobieity as well as physiological inert and so on.Various function groups are introduced into siloxane molecules to endow some new functions and retain DMS characteristics.In this study, functionalized MWNTs were fabricated through one-step condensation reaction of MWNTs-COOH with polysiloxane. Amino functionalization of the MWNTs was performed using diaminopropyl terminated dimethylpolysiloxane (DPD). DPD has a larger molecular weight and may form MWNT-MWNT network structure better. The FTIR, XPS and thermogravimetry analysis were used to study the surface chemical state of the modified multi-walled CNTs.Then PC/MWNTs-COOH and PC/MWNTs-DPD nanocomposites were prepared by the solution method and melt extrusion method. The mechanical properties, transmission electron microscopy (TEM), TGA, limiting oxygen index (LOI), UL-94 test, and permittivity test were used to evaluate the properties of the composites. The results showed that the MWNTs-DPD was dispersed well in the PC matrix; its tensile strength, flexual strength, flexural modulus, and flame retardancy were better than that of PC/MWNTs-COOH. However, the electrical properties of the PC/MWNTs-DPD nanocomposites based on pemittivity and dielectric loss result were worse than PC/MWNTs-COOH.The MWNTs-DPD were used in PP-IFR and to study their synergistic effect. The nanocomposites were prepared by the melt extrusion method. The mechanical properties, TGA, limiting oxygen index (LOI), UL-94 test were used to evaluate the properties of the composites. The experimental results discovered that the fire-retardant properties of PP-IFR/MWNTs-DPD was better than PP-IFR/MWNTs-COOH, but poor mechanical properties. TGA data show that the liquid DPD had macromolecular chain, which made the initial decomposition temperature and maximum decomposition temperature of PP-IFR advancing and carbon content decreasing. Therefore, the initial decomposition temperature and maximum decomposition temperature of PP-IFR/DPD were advanced and carbon content were decreased. But compared with PP-IFR, the initial decomposition temperature and maximum decomposition temperature of PP-IFR/ MWNTs-COOH were delayed and carbon content were also decreased.更多还原