A combination of X-ray ptychography and X-ray fluorescence tomography (XRF) has been used to study the fragmentation behavior of an individual Ziegler–Natta catalyst particle, ∼40 μm in diameter, in the early stages of propylene polymerization with submicron spatial resolution. The electron density signal obtained from X-ray ptychography gives the composite phases of the Ziegler–Natta catalyst particle fragments and isotactic polypropylene, while 3-D XRF visualizes multiple isolated clusters, rich in Ti, of several microns in size. The radial distribution of Ti species throughout the polymer–catalyst composite particle shows that the continuous bisection fragmentation model is the main contributor to the fragmentation pathway of the catalyst particle as a whole. Furthermore, within the largest Ti clusters the fragmentation pathway was found to occur through both the continuous bisection and layer-by-layer models. The fragmentation behavior of polyolefin catalysts was for the first time visualized in 3-D by directly imaging and correlating the distribution of the Ti species to the polymer–catalyst composite phase.

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相关 X 射线 Ptychography 和荧光纳米断层扫描对单个催化剂颗粒在烯烃聚合早期阶段的碎裂行为的影响

X 射线 ptychography 和 X 射线荧光断层扫描 (XRF) 的组合已被用于研究单个齐格勒-纳塔催化剂颗粒（直径约 40 μm）在具有亚微米空间分辨率的丙烯聚合的早期阶段的碎裂行为. 从 X 射线 ptychography 获得的电子密度信号给出了齐格勒-纳塔催化剂颗粒碎片和全同立构聚丙烯的复合相，而 3-D XRF 则显示了多个孤立的簇，富含钛，大小为几微米。Ti 物质在整个聚合物-催化剂复合颗粒中的径向分布表明，连续二等分破碎模型是整个催化剂颗粒破碎路径的主要贡献者。此外，在最大的 Ti 簇中，通过连续二等分和逐层模型发现碎裂途径发生。通过直接成像并将 Ti 物质的分布与聚合物-催化剂复合相相关联，聚烯烃催化剂的碎裂行为首次在 3-D 中可视化。