聚合物分子刷负载催化剂的设计及催化乙烯聚合的研究

ETHYLENE POLYMERIZATION OF BRUSH-LIKED POLYMER SUPPORTED CATALYSTS

黄文俊

11649061

硕士

化学

陈忠仁

2018

2018.7.10

哈尔滨工业大学

深圳

双峰聚乙烯包含了高分子量与低分子量部分，可以提高材料本身的机械性能和加工性能，逐渐成为了高性能聚烯烃树脂的重要发展方向之一。目前生产双峰聚乙烯应用最为广泛的方法主要有串联反应器法和单反应器法，其中单反应器法不仅成本低、工艺简便，而且得到的双峰聚乙烯具有很好的混合效果，是发展生产双峰聚乙烯的重要工艺方法。本文以烯烃聚合负载化催化剂为出发点，合成设计了具有刷状拓扑结构的聚苯乙烯载体，通过对载体表面进行苯氧基亚胺功能化处理，设计了四种不同化学环境的配体并与钛、锆、镍配位合成相应的催化剂，应用于乙烯的催化聚合。研究发现，不同活性配体与金属配位聚合所得的聚乙烯分子量及活性有所差异，从而可以通过在同一载体上利用不同活性的混合配体实现双峰聚乙烯的调控与合成。具体工作及结论如下：1. 刷状拓扑结构聚苯乙烯载体的功能化修饰。本文通过文献综述调研，发现聚合物载体在烯烃聚合负载中的重要性，不仅可以减少对产品的污染，不造成反应釜堵塞，甚至可以作为填料进行补偿增强性能等。本文通过原子转移自由基聚合(ATRP) 的方法合成具有降冰片烯不饱和双键的聚苯乙烯，再通过开环易位聚合(ROMP) 实现刷状拓扑结构的设计合成，最后通过叠氮的点击化学反应以及醛胺缩合成功能化的分子刷载体，同时通过AFM/FT-IR/NMR 等表征方法证明了该方法的可行性。2. 苯氧基亚胺负载型钛、锆、镍催化剂的制备及其聚合性能研究。为了金属中心可以更好的进行负载以及催化烯烃聚合，经过探索发现，钛、锆金属中心具有较好的负载能力以及聚合活性，在乙烯聚合活性探索中我们发现钛、锆催化剂在乙烯聚合中活性较好，所得聚乙烯材料熔点在133℃左右。同时负载化后所得聚乙烯表面呈现出特殊的片层结构。3. 双峰聚乙烯的设计合成。本文在同一载体上用不同配体进行修饰，再与中心金属进行配位，实现活性位点的不同活性调控，实现双峰聚乙烯的合成与探究。高温GPC 测试中显示了双峰的性质，因此我们可以有选择性的合成特定分子量及比例可控的双峰聚乙烯。本文还探索了聚合物载体的形貌对聚乙烯产品的影响效果，从结果中可以看出，催化剂载体在聚合过程中起到了模板作用，实现了对聚合物形貌的干预作用。

Bimodal polyethylene, owing to the combination of high molecular weight fraction and low molecular weight fraction, can improve the mechanical properties and processing performance of the material itself, and has gradually become one of the important development of high-performance polyolefin resins. At present, the most widely used methods for producing bimodal polyethylene are mainly series reactor method and single-reactor method. The single-reactor method has a low cost and simple process, and the bimodal polyethylene obtained has a very good mixing effect. It is an important process in the development of bimodal polyethylene.The single-component in-situ loading of olefin polymerization catalyst has achieved commercial scale. Our work mainly focus on polystyrene supporter with a brush topology. Four different ligands coped with central metal are designed by phenoxy-imine functionalization of the brush arm. Then ethylene polymerization by supported catalysts were carried out. Regulation and synthesis of bimodal polyethylene were on the basis of these four types of ligands. The specific work and conclusions are as follows:(1) Functionalization of brush-liked polystyrene supporter.In this paper, polystyrenes with unsaturated double bonds were synthesized by atom transfer radical polymerization (ATRP), and the brush-like topology was developed and synthesized by Ring-Opening Metathesis Polymerization (ROMP). Finally, the click chemistry reaction of azide was carried out. The ultimate carrier is obtained by Aldehyde condensation. At the same time, AFM / FT-IR / NMR and other characterization methods have been demonstrated.(2) Preparation of phenoxy-imine supported titanium, zirconium, and nickel catalysts and their polymerization properties.In order to carry out the loading and olefin polymerization of metal catalysts, it has been found that the center of titanium and zirconium metal has a better loading capacity and polymerization activity. Then with the metal center for a single point coordination, we get the final polystyrene-supported catalyst.(3) Ethylene polymerization.We found that titanium/zirconium-derived polyethylene has good crystallization performance, and different catalysts have different activity. At the same time, GPC data found that the products obtained by one metal center with two different ligands on a brush supporter have bimodal properties, which mean the processing performance is more attractive. Therefore, the same method was utilized to modify the different active IIIsites by adjusting different salicylaldehyde ligands on the same carrier and then coordinating with the central metal to produce bimodal polyethylene.We also explored the effect of the supporter’s morphology on polyethylene. It can be observed that the shape of the catalyst carrier play a template role in the ethylene polymerization process, and the resulting product also has a similar appearance, which can direct the research of basic theory. It means that we can affect the polymer morphology through the intervention of Carrier-template-effect, and constitute a polymer similar to the catalyst morphology.

聚合物载体 乙烯聚合 双峰聚乙烯 多活性位点催化剂 模板效应

brush-like polymer supporter ethylene polymerization bimodal polyethylene multi-sites catalyst template effect

中文

联合培养

南方科技大学

黄文俊. 聚合物分子刷负载催化剂的设计及催化乙烯聚合的研究[D]. 深圳. 哈尔滨工业大学,2018.