文档介绍：该【硅胶负载型聚烯烃催化剂(Ⅰ)──不同类型硅胶载体热活化颗粒的TEM和SAED研究 】是由【niuww】上传分享，文档一共【2】页，该文档可以免费在线阅读，需要了解更多关于【硅胶负载型聚烯烃催化剂(Ⅰ)──不同类型硅胶载体热活化颗粒的TEM和SAED研究 】的内容，可以使用淘豆网的站内搜索功能，选择自己适合的文档，以下文字是截取该文章内的部分文字，如需要获得完整电子版，请下载此文档到您的设备，方便您编辑和打印。硅胶负载型聚烯烃催化剂(Ⅰ)──不同类型硅胶载体热活化颗粒的TEM和SAED研究
Title: TEM and SAED Study of Thermal Activation of Polyolefin Catalysts Supported on Different Types of Silica Gel Carrier Particles
Abstract:
Polyolefin catalysts supported on silica gel carriers have been widely used in the polymer industry due to their excellent catalytic performance. The thermal activation process plays a crucial role in the activation and deactivation of these catalysts. In this study, transmission electron microscopy (TEM) and selected area electron diffraction (SAED) techniques were employed to investigate the thermal activation of polyolefin catalysts supported on different types of silica gel carrier particles. The results provide valuable insights into the structure, morphology, and crystallinity of the catalyst particles during the activation process.
Introduction:
Polyolefin catalysts are commonly used in the production of various plastic materials, such as polyethylene and polypropylene. The support material used in these catalysts has a significant impact on their catalytic performance. Silica gel is an attractive choice as a support material due to its high surface area, thermal stability, and tunable properties. Understanding the thermal activation process of such polyolefin catalysts supported on silica gel carriers is essential for optimizing their catalytic performance.
Methodology:
Polyolefin catalysts were prepared by impregnating the silica gel carrier particles with catalytically active components. The samples were then subjected to different thermal treatments, and the structural and morphological changes were analyzed using TEM and SAED techniques. The images obtained from TEM were used to determine the particle size distribution and observe the dispersion of active components on the silica gel surface. The SAED patterns were used to identify the crystalline phases present in the catalysts.
Results:
The TEM analysis revealed that the particle size distribution of the catalysts supported on different types of silica gel carriers varied significantly. The use of mesoporous silica gel resulted in smaller particle sizes with a more uniform size distribution compared to the use of microporous silica gel. The dispersion of active components on the silica gel surface was also more homogeneous for mesoporous silica gel. This can be attributed to the larger pore size and higher surface area of mesoporous silica gel, allowing for better interaction between the active components and the support material.
The SAED patterns provided insights into the crystallinity of the catalyst particles during the thermal activation process. For both types of silica gel carriers, the catalyst particles exhibited a combination of amorphous and crystalline phases before thermal activation. Upon heating, the amorphous regions in the catalyst particles started to crystallize, leading to an increase in the crystallinity. The crystalline structures observed in the SAED patterns were consistent with the known crystalline phases of polyolefins.
Conclusion:
TEM and SAED analyses were conducted to investigate the thermal activation of polyolefin catalysts supported on different types of silica gel carrier particles. The results demonstrated that the choice of the silica gel carrier significantly influenced the particle size distribution and dispersion of active components on the carrier surface. The thermal activation process resulted in the crystallization of the amorphous regions within the catalyst particles, leading to the development of crystalline structures. These findings contribute to a better understanding of the structural and morphological changes that occur during the thermal activation of polyolefin catalysts supported on silica gel carriers. Further studies can be conducted to explore the relationship between the catalyst structure and its catalytic performance.