Premium
In Situ Polymerization of Olefins with Nanoparticles by Metallocene‐Catalysis
Author(s) -
Kaminsky Walter,
Funck Andreas
Publication year - 2008
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200751401
Subject(s) - tacticity , materials science , methylaluminoxane , metallocene , polymerization , polyethylene , nanocomposite , polymer , post metallocene catalyst , polymer chemistry , carbon nanotube , monomer , coordination polymerization , polypropylene , chemical engineering , in situ polymerization , nanoparticle , composite material , radical polymerization , nanotechnology , engineering
Exceptionally strong materials could be synthesized by filled polyolefins with nanosized, regid particles or fibers. Metallocene catalysts are excellent tools in the production of tailored microstructures as well as tacticities of polypropylenes. They are soluble in hydrocarbons and therefore can cover perfectly the surface of nano particles. Here multi‐walled carbon nanotubes (MWCNT) (diameter 15–25 nm, length up to 50 µm) were used as fillers. Before polymerization, the fillers were separated by ultra sound and then treated with methylaluminoxane (MAO). MAO reacts partially with defects and functional groups of oxidized MWCNT. Catalytically active centers are formed after adding the zirconocenes or other transition metal complexes directly on the CNT surface. The thickness of the polymer layer can be controlled by the monomer pressure and polymerization time. We obtained coatings of 5 to 100 nm. By this method carbon nanotubes can be covered also with isotactic or syndiotactic polypropylene, but also with polyethylene with any molecular mass. The nanocomposites obtained were especially investigated in regard to their crystallization behavior, which depended significantly on the matrix used.