【摘要】 用电子显微镜研究了索尔维型β-TiCl₃,δ-TiCl₃的形态和结构,证实在制备过程中发生了由β-TiCl₃转变为δ-TiCl₃的晶形转化过程,计算了1克索尔维型δ-TiCl₃所能形成的活性中心数目,并发现在电子束的轰击下,β-TiCl₃会转化为δ-TiCl₃,δ-TiCl₃微晶粒会长大,此外还用超高压电镜观察了聚丙烯颗粒,提出了对聚丙烯颗粒形成过程的看法。更多还原

【Abstract】 The morphology and structures of Solvay type β-TiCl3 and vvvvv-TiCl3 were investigated directly by electron microscope. From electron microscopy it is revealed that in the process of catalyst preparation the products of first and second reaction steps (TiCl3 (Ⅰ) arid TiCl3 (Ⅱ)) are aggregates of needle-shaped crystallites which were shown to be β-TiCl3 from electron diffraction pattern Similarly, products of third reaction step (TiCl3 (Ⅲ)) are shown to be aggregates of microcrystallites with a size of - 100A and in the form of σ-TiCl3. The single crystal of σ-TiCl3 with rough edges was observed for the first time. Therefore, it is ascertained that transformation from β-TiCl3 to σ-TiCl3 took place in the third step. Moreover, the number of active center on the lateral faces of microcrystallites per gram of σ-TiCl3 was calculated and estimated to be 5 × 1020. It is very interesting that under the impingement of eleetron beam both transformation from β-TiCl3 to σ-TiCl3 and growth of σ-T’iCl3 microcrystallites were observed. Furthermore, it is proposed that during polymerization polypropylene chains would form around every β-TiCl3 mierocrystallite and therefore σ-TiCl3 microcrystallites would move apart from each other, thus they were actually observed as finely dispersed phase in the polymer mass.更多还原