Department of Chemistry, KAIST, Yuseong, Daejeon 305-751, Korea.
Macromol Rapid Commun. 2013 Mar 25;34(6):533-8. doi: 10.1002/marc.201200768. Epub 2013 Jan 25.
Catalytic natures of organometallic catalysts are modulated by coordinating organic ligands with proper steric and electronic properties to metal centers. Carbon-based nanomaterials such as graphene nanoplatelets are used with and without N-doping and multiwalled carbon nanotube as a ligand for ethylene polymerizations. Zirconocenes or titanocenes are immobilized on such nanomaterials. Polyethylenes (PEs) produced by such hybrids show a great increase in molecular weight relative to those produced by free catalysts. Specially, ultra-high-molecular-weight PEs are produced from the polymerizations at low temperature using the hybrid with N-doped graphene nanoplatelets. This result shows that such nanomaterials act a crucial role to tune the catalytic natures of metallocenes.
有机金属催化剂的催化性质可以通过与金属中心配位具有适当空间和电子性质的有机配体来调节。石墨烯纳米片等碳基纳米材料被用作配位体用于乙烯聚合，无论是否掺杂氮以及多壁碳纳米管。茂金属或钛金属被固定在这些纳米材料上。与自由催化剂相比，用这些杂化物制备的聚乙烯（PE）的分子量大大增加。特别是，使用具有氮掺杂石墨烯纳米片的杂化物在低温下聚合可以得到超高分子量的 PE。这一结果表明，此类纳米材料在调节茂金属的催化性质方面起着至关重要的作用。
