纳米黏土和多壁碳纳米管的载体化成型及其负载Ziegler-Natta催化剂的研究

Fabrication of Nano-Clay and Multi-Wall Carbon Nanotubes into Granular Support for the Immobilization of Ziegler-Natta Catalysts

通过喷雾干燥、SiO2纳米胶粒改性和造孔改性等手段制备形态和结构可控的成型纳米颗粒(纳米黏土颗粒和碳纳米管颗粒),并以其为载体负载Ziegler-Natta催化剂。采用SEM、TEM和比表面积测试等手段,对成型纳米颗粒及催化剂的形态、结构和性能进行表征。实验结果表明,通过调节喷雾干燥过程中料液固含量、进料速率、进气温度和进气压力等参数,可将纳米黏土或碳纳米管成型为球形颗粒;当SiO2纳米胶粒用量为5%(w)、碳酸氢铵用量为10%(w)时,可进一步改善成型纳米黏土颗粒的强度和孔结构;以成型纳米颗粒为载体负载Ziegler-Natta催化剂具有丙烯聚合活性高和立构规整控制能力强等特点,所得纳米复合聚丙烯颗粒具有良好的球形形态,且纳米颗粒在聚丙烯基体中均匀分散。

Nano-clay and multi-walled carbon nanotubes were modified by spray-drying and/or gelation,and the Ziegler-Natta catalysts were immbilized on the modified nano-particles as support.The particle morphology,structure and performance of the supports and corresponding catalysts were studied by means of SEM,TEM and specific surface area test.It was found that by adjusting the spray-drying parameters,namely solution solid content,feed rate,inlet temperature and inlet pressure,the nano-clay and multi-walled carbon nanotubes could be granulated into spherical particles.The particle strength and pore structure of the clay-based support could be further improved by addiing 5％（w） SiO2 and 10％（w） NH4HCO3.The Ziegler-Natta catalysts immobilized on the granular supports possessed high activity in propylene polymerization and controllability to the polypropylene isotacticity.The prepared polypropylene with good spherical mimicked the supported catalysts and the nano-particles were homogeneously dispersed inside the polypropylene matrix.