Zhu Bangban, Liu Kan, Luo Liqiong, Zhang Ziyang, Xiao Yangke, Sun Minghao, Jie Suyun, Wang Wen-Jun, Hu Jijiang, Shi Shengbin, Wang Qingyue, Li Bo-Geng, Liu Pingwei
State Key Laboratory of Chemical Engineering, College of Chemical and Biological Engineering Zhejiang University, Hangzhou, 310027, P. R. China.
National-Certified Enterprise Technology Center, Kingfa Science and Technology Co., Ltd., Guangzhou, 510663, P. R. China.
Chemistry. 2023 Sep 26;29(54):e202300913. doi: 10.1002/chem.202300913. Epub 2023 Jul 27.
The loading of homogeneous catalysts with support can dramatically improve their performance in olefin polymerization. However, the challenge lies in the development of supported catalysts with well-defined pore structures and good compatibility to achieve high catalytic activity and product performance. Herein, we report the use of an emergent class of porous material-covalent organic framework material (COF) as a carrier to support metallocene catalyst-Cp ZrCl for ethylene polymerization. The COF-supported catalyst demonstrates a higher catalytic activity of 31.1×10 g mol h at 140 °C, compared with 11.2×10 g mol h for the homogenous one. The resulting polyethylene (PE) products possess higher weight-average molecular weight (M ) and narrower molecular weight distribution (Ð) after COF supporting, that is, M increases from 160 to 308 kDa and Ð drops from 3.3 to 2.2. The melting point (T ) is also increased by up to 5.2 °C. Moreover, the PE product possesses a characteristic filamentous microstructure and demonstrates an increased tensile strength from 19.0 to 30.7 MPa and elongation at break from 350 to 1400 % after catalyst loading. We believe that the use of COF carriers will facilitate the future development of supported catalysts for highly efficient olefin polymerization and high-performance polyolefins.
用载体负载均相催化剂可显著提高其在烯烃聚合反应中的性能。然而，挑战在于开发具有明确孔结构和良好相容性的负载型催化剂，以实现高催化活性和产品性能。在此，我们报道了使用一类新型多孔材料——共价有机框架材料（COF）作为载体来负载茂金属催化剂CpZrCl用于乙烯聚合。与均相催化剂在140℃下11.2×10³g·mol⁻¹·h⁻¹的催化活性相比，COF负载型催化剂在140℃下表现出31.1×10³g·mol⁻¹·h⁻¹的更高催化活性。负载COF后得到的聚乙烯（PE）产品具有更高的重均分子量（Mw）和更窄的分子量分布（Ð），即Mw从160 kDa增加到308 kDa，Ð从3.3降至2.2。熔点（Tm）也提高了5.2℃。此外，PE产品具有独特的丝状微观结构，负载催化剂后拉伸强度从19.0 MPa提高到30.7 MPa，断裂伸长率从350%提高到1400%。我们相信，COF载体的使用将有助于未来高效烯烃聚合负载型催化剂和高性能聚烯烃的发展。
