Use of metallocenes in the polymerization-filling technique with production of polyolefin-based composites

Development of a new synthetic method based on in situ strategies for polyethylene/clay composites

“…However, the polymerization activity is even worse if MAO/(nBuCp) 2 ZrCl 2 is supported on a traditional support like silica (REF and ISB+ISP[REF] samples). According to the literature, this higher activity may be related with a strong interaction between a Lewis acid like MAO with the basic clay's surface 32, 38. Also, it can be related with an easier access to the catalytic centers in the catalyst supported over sepiolite as they seem to be mainly located in the external surface.…”

“…These methods include the in situ polymerization (ISP) and the in situ blended (ISB) techniques. In the last one, the polyolefin is blended with the clay during the polymerization stage,35 whereas the ISP method is based on the intercalative polymerization of the monomer by immobilizing the catalytic system over the clay material 36–40. The ISP method is also addressed to the large‐scale applicability of metallocenes since heterogeneous polymerization conditions are needed in order to ensure good product morphology and avoid reactor fouling 41–43.…”

From carbon nanotube coatings to high‐performance polymer nanocomposites

“…Therefore, the non‐covalent surface modification of CNTs achieved recently by in situ (co)polymerization of olefins as catalysed directly from nanotubes previously surface‐treated by a highly active metallocene‐based complex represents an original and efficient method35, 44 to form homogeneously coated multiwalled carbon nanotubes (cMWNTs), finally leading to the complete destructuring of the native nanotube bundles 35, 44. This original process, called the polymerization‐filling technique (PFT), initially investigated in Ziegler–Natta polymerization,45, 46 then extended to metallocene catalysis,47, 48 consists firstly in anchoring methylaluminoxane (MAO), a well‐known co‐catalyst used in metallocene‐based olefin polymerization processes, onto the surface of carbon nanotubes. After high‐temperature treatment, most of the MAO (>98 mol%) remains anchored onto the carbon nanotube surface and cannot be removed, even by hot toluene washing.…”

Nanocellulose Aerogels for Supporting Iron Catalysts and In Situ Formation of Polyethylene Nanocomposites

“…While dispersing nanofillers in highly viscous polymer melts is rather difficult and energy‐intensive, it is much easier to disperse nanofillers in a low‐viscosity polymerization medium during polymerization, ideally in which the nanofiller serves as both catalyst support and reinforcement. Dubois and co‐workers pioneered this polymerization filling technique (PFT) by polymerizing olefins in the presence of catalysts supported on a wide variety of micron‐sized fillers like silicate, graphite, glass beads, and kaolin . Kaminsky treated cellulose and starch with methylaluminoxane (MAO) to produce carbohydrate‐supported single‐site catalysts for ethylene polymerization and formation of cellulose/polyethylene composites by PFT .…”