Polyolefin hybrids polypropylene

The concept of PO macroinitiators centers on the introduction of an initiation moiety into an olefinic polymer chain for polymerization. The most effective route for preparing PO macroinitiators is by employing functional polyolefins containing hydroxyl groups or other reactive groups. These functional POs are prepared by copolymerization of olefins with functional monomers and post-polymerization reaction, as mentioned above. In the case where an initiation moiety was at the chain-end of the polyolefins, a block type copolymer is produced. It has been reported that thiol-terminated PP was used as polymeric chain transfer agent in styrene and styrene/acrylonitrile polymerization to form polypropylene-b/odc-polystyrene (PP-b-PS) and polypropylene-btock-poly(styrene-co-acrylonitrile) (PP-b-SAN) block copolymer [19]. On the other hand, polymer hybrids with block and graft structures can be produced if initiation moieties are in the polymer chain. 

A nylon-clay hybrid (nanocomposite NCH) was originally developed by the authors and was the first polymer nanocomposite to be used practically. Since 1990, when it was first used, various studies and analyses of it have been reported. An excellent review was published in 2003 [1]. In the present review, which focuses on the authors studies, details on the NCH that we reported initially and further developments in polypropylene and polyethylene will be described. In Sect. 2, comprehensive classifications of the production methods developed previously will be described, according to the synthesis method employed. Thereafter, nylon will be discussed in Sect. 3, polyolefin in Sect. 4, and renewable polymer (green polymer) will be discussed in Sect. 5. 

Polypropylene (PP)-clay hybrids cannot be easily synthesized because PP is hydrophobic and has poor miscibility with clay silicates. Octadecyl ammonium ions were used as modifiers for the clay, and a polyolefin oligomer was used so that the clay became more compatible. Organophilic clay, a polyolefin oligomer and PP were blended using an extruder at 200 °C. It was confirmed by transmission electron microscopy (TEM) that the clay was dispersed in a monolayer state in the PP matrix. Thus, PP was directly intercalated into the clay gallery [15]. 

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