侧链含芘聚芳醚酮的制备及其在修饰石墨纳米片上的研究

发布时间：2018-09-02 08:20

【摘要】：随着现代社会的发展,各行各业对于材料的要求越发多样化。与传统的金属材料或陶瓷材料相比,高分子材料有耐腐蚀、易加工且耐疲劳等诸多优点。因此,高分子材料是材料领域的重要研究方向。不可否认的是,高分子树脂自身的性能也具有局限性,单一的高分子树脂材料往往无法满足现代工业生产对材料力、热性能或光电等功能性要求。通过向高分子树脂材料中加入无机填料、纤维等对其进行复合改性无疑是目前解决上述问题最为有效的方式。这种物理改性方式操作简单,容易进行大规模的工业化生产。因此,大量的改性材料被研发出来并应用于日常的生产生活中。例如,碳纤维增强型树脂基复合材料被用作丰田汽车的骨架材料,使得汽车骨架重量降至420kg,从而降低了油耗。石墨纳米片(Graphite Nanoplatelets,GNPs)作为一种目前可实现量产的新型高性能无机填料逐渐进入研究人员们的视野。它在力、热、光电等性能上优于普通石墨,同时价格远低于石墨烯,具有优异的性价比,在制备防腐涂料、超级电容器以及摩擦材料中有着广泛的应用。但是,GNPs很难与高分子材料形成良好的界面相互作用,并且在制备GNPs/高分子复合材料的过程中,GNPs还会大量团聚进而形成缺陷,这二者均不利于复合材料性能的提升。但是,市面上常见的用来修饰无机填料的小分子分散剂、高分子分散剂或硅烷偶联剂的分解温度较低,在使用上述改性剂对GNPs进行分散时,无法避免其会在复合材料的热加工过程中分解,从而导致材料内部产生大量空洞缺陷,限制GNPs在复合材料中性能发挥。市面上耐高温高分子界面修饰剂的缺失导致的分散问题以及界面问题限制了GNPs在高性能聚合物体系,如聚醚醚酮体系中的应用。聚醚醚酮作为20世纪新发展起来的一类热塑性特种工程塑料,它具有较高的耐热等级、良好的力学性能、较好的耐化学腐蚀性以及优异的生物相容性。因此,本论文选择制备一种同样含有醚酮结构的耐高温高分子聚合物用以对GNPs进行表面修饰。修饰无机填料GNPs的方法主要分为两种,共价修饰和非共价修饰。共价修饰是通过化学反应将界面修饰剂以共价键链接在GNPs表面,这一方法会破坏GNPs的表面结构,进而影响GNPs的性能。非共价修饰则是利用GNPs具有大共轭结构的特点,凭借共轭基团之间的π-π相互作用这一分子间作用力使界面修饰剂吸附在GNPs表面,可以在保证GNPs的结构完整性即保持其优异的性能的同时,还可以提高GNPs在树脂基体中的分散程度。从作用力强弱角度分析,分子间作用力的强度远小于“共价键”,为了确保用于修饰的高分子聚合物与GNPs之间有足够强的相互作用,在高分子聚合物的分子设计中需要引入一定量的共轭基团。芘分子具有平面大共轭结构和良好的稳定性,因此,本论文利用Suzuki C-C偶联反应设计并制备了含有芘结构的双羟基单体,然后通过共聚反应得到芘含量可控的含芘侧基聚芳醚酮。经实验测试表明,含芘聚芳醚酮不仅具有良好的耐热等级和优异的力学性能,而且含芘聚芳醚酮在常见有机溶剂中的溶解性较好,便于在后续实验中对GNPs进行修饰。在相同处理条件下,经含芘聚合物修饰的GNPs在N-甲基吡咯烷酮中的分散度是未经修饰的GNPs的88倍。通过溶液共混的方法制备的GNPs/PEEK复合材料中,加入0.5 wt.%含芘聚合物修饰后的GNPs时,复合材料的弯曲强度提升12%、拉伸强度提升10%,与此同时断裂伸长率也提升一倍多。
[Abstract]:With the development of modern society, all walks of life have more and more diversified requirements for materials. Compared with traditional metal or ceramic materials, polymer materials have many advantages, such as corrosion resistance, easy processing and fatigue resistance. Due to its limitations, a single polymer resin material is often unable to meet the requirements of modern industrial production for its mechanical, thermal or photoelectric properties. As a result, a large number of modified materials have been developed and used in daily life. For example, carbon fiber reinforced resin matrix composites have been used as the skeleton materials of Toyota automobiles, reducing the weight of the car skeleton to 420 kg, thereby reducing fuel consumption. Platelets, GNPs, as a new type of high performance inorganic filler which can be produced in large quantities, have gradually come into the field of researchers. It is superior to ordinary graphite in mechanical, thermal, photoelectric and other properties, and its price is much lower than graphene. It has excellent performance-price ratio. It has a wide range of applications in the preparation of anticorrosive coatings, supercapacitors and friction materials. However, it is difficult for GNPs to form good interfacial interaction with polymer materials, and in the process of preparing GNPs/polymer composites, GNPs will agglomerate in large numbers and form defects, which are not conducive to the improvement of composite properties. The decomposition temperature of dispersant or silane coupling agent is low. When GNPs are dispersed by these modifiers, it is unavoidable that they will decompose during the hot working process of the composites, resulting in a large number of void defects in the interior of the composites, limiting the performance of GNPs in the composites. The dispersion and interfacial problems caused by GNPs restrict the application of GNPs in high performance polymer systems, such as polyether ether ketone systems. As a new type of thermoplastic engineering plastics developed in the 20th century, polyether ether ketone has high heat resistance, good mechanical properties, good chemical corrosion resistance and excellent biocompatibility. Therefore, a high temperature resistant polymer containing ether ketone structure was prepared to modify the surface of GNPs. There are two methods to modify the inorganic filler GNPs, covalent modification and non-covalent modification. Non-covalent modification is based on the large conjugate structure of GNPs and the intermolecular interaction between the conjugated groups, which makes the interfacial modifier adsorbed on the surface of GNPs. The structural integrity of GNPs can be guaranteed, i.e. the excellent properties can be maintained while the GNPs are kept. From the point of view of interaction strength, the intermolecular force is far less than the "covalent bond". In order to ensure the strong interaction between the modified polymer and GNPs, a certain amount of conjugated groups should be introduced into the molecular design of polymer. Pyrene molecule has planar macroconjugated structure and good stability. Therefore, in this paper, the dihydroxyl monomer containing pyrene structure was designed and prepared by Suzuki C-C coupling reaction, and then the pyrene content controllable poly (aryl ether ketone) containing pyrene side group was obtained by copolymerization. The dispersity of GNPs modified by pyrene-containing polymers in N-methylpyrrolidone was 88 times higher than that of unmodified GNPs under the same treatment conditions. The flexural strength and tensile strength of GNPs/PEEK composites modified with 0.5 wt.% pyrene-containing polymers were increased by 12% and 10% respectively, and the elongation at break was more than doubled.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ322.3;TQ127.11

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