新型第四代负载型Ziegler-Natta聚丙烯催化剂的研究：催化剂结构与聚合性能的关系

本文详细研究了一种用于合成等规聚丙烯所用的新型Ziegler-Natta催化剂的结构，以及催化剂结构与聚合性能之间的关系。化学结构式为CH3CH2OMgOCH(CH2Cl)2的球形载体是在一种新的分散体系中合成的，这种载体被用于Ziegler-Natta催化剂的制备。X射线衍射表明催化剂中存在δ-MgCl2。远红外光谱分析进一步确定了催化剂中存在δ-MgCl2。该种催化剂具有多孔结构并且具有高的比表面积。催化剂得到充分的活化以及具有多孔结构是丙烯聚合时具有高活性的主要原因。扫描电镜能谱分析表明催化剂颗粒中具有均匀的钛分布。粒度分析显示催化剂颗粒具有较窄的粒径分布。催化剂颗粒完美的球形、均匀的钛分布以及较窄的粒径分布使得在聚合过程中产生较少的细粉。固体核磁碳谱分析表明邻苯二甲酸二异丁酯和MgCl2之间具有强烈的络合作用，这种络合作用是聚合物等规度较高的主要原因。

Study of a Novel Fourth-generation Supported Ziegler-Natta Catalyst for Propylene Polymerization: Relationship between Catalyst Structure and Polymerization Properties

The article presents a detailed structural study of a new spherical MgCl2-supported TiCl4 Ziegler-Natta catalyst for isotactic propylene polymerization, and researches on the relationship between catalyst structure and polymerization properties. The spherical support with chemical composition of CH3CH2OMgOCH(CH2Cl)2 has been synthesized from a new dispersion system and is used as supported material to prepare Ziegler-Natta catalyst. XRD analysis indicates the catalyst was fully activated and presented δ-MgCl2 in the active catalyst. Far-IR results confirm again the presence of δ-MgCl2 in the active catalyst. Textural property of the active catalyst exhibits high surface area with high porosity. The high activity in propylene polymerization is mainly due to the fully activation and the porous structure of the catalyst. Scanning electron microscope/energy dispersive spectrometer mapping results indicate a uniform titanium distribution throughout the particle. Particle size analysis shows that the catalyst owns a narrow particle size distribution. The perfect spherical shape, uniform titanium distribution and narrow particle size distribution of the catalyst confirm the production of polymers particles with less fines. 13C Solid state NMR and middle-IR analyses indicate that there exists strong complexation between diisobutyl phthalate and MgCl2, which leads to the high isotacticity of polypropylene.