Polypropylene metallocene-catalyzed

Figure 6 Loss tangent (<5) plotted as a function of complex modulus G for a series of syndiotactic and isotactic polypropylene. Reproduced with permission from Rojo et al. [32]. Copyright Wiley-VCH Verlag GmbH Co. KgaA. iPP, isotactic PP sPP, syndiotactic PP Met-iPP, metallocene-catalyzed PP (see Ref. [32] for full details).

Llinas GH, Dong SH, Mallin DT, Rausch MD, Lin YG, Winter HH, Chien JCW (1992) Crystalline-amorphous block polypropylene and nonsymmetric ansa-metallocene catalyzed polymerization. Macromolecules 25 1242-1253... 

Novolen A process for making polypropylene in the gas-phase, using a vertical stirred-bed reactor. Developed by BASF and engineered by Uhde. Eight plants had been licensed as of 1985. A metallocene-catalyzed version was introduced in 1996. The name is used also for the product. 

Metallocene-Catalyzed Polymerization of Propylene to Highly Isotactic Polypropylene in Organic Suspension... 

Block copolymers can be produced from terminally borane-containing polyolefins. These borane-containing POs can be synthesized by the metallocene-catalyzed (co)polymerization of olefin(s) monomer with 9-BBN as a chain transfer agent or by the metallocene catalyzed copolymerization of olefins with allyl-9-BBN [55,56], as referred to above. Alternatively, borane-containing POs were prepared by hydroboration of terminally unsaturated PO, for instance, terminally vinyl PE and terminally vinylidene PP [33-35,57]. Such method could produce diblock copolymers, such as polyethylene-block-poly(methyl methacrylate) (PE-fo-PMMA), polypropylene-foZock-poly(methyl methacrylate) (PP-fc-PMMA), polypropylene-foZock-poly(butyl methacrylate) (PP-fc-PBMA), and PP-fc-PS. 

The discovery of homogeneous metallocene catalysts in the 1980s was a very important milestone in polymer technology. With these catalysts the plastic industry is poised to move into an era of an entirely new range of polymeric materials with several specific advantages. From the initial discovery in the 1980s, close to five billion dollars is estimated to have been invested by several large chemical companies in research and development. In a relatively short time, this has resulted in approximately fifteen hundred patent applications Close to 0.5 million tons of metallocene-catalyzed polypropylene is expected to be manufactured by the year 2003. 

Dlubek et al [49] studied a series of metallocene-catalyzed poly a-olefins) with progressively longer chains as the pendant side groups from polypropylene to poly-l-eicosene (20 carbons). Their results show an interesting relationship between the o-Ps lifetime and intensity in the amorphous phase for this series of polymers. They found that the average hole size and o-Ps intensity from the amorphous phase, decreased from polyethylene to polypropylene, followed by a slight increase to poly-1-butene. There was a rapid rise in hole size and intensity to poly-l-dodecene. 

Shiomura, T. Uchikawa, N. Asanuma, T. Sugimoto, R. Fujio, I. Kimura, S. Harima, S. Akiyama, M. Kohno, M. Inoue, N. Metallocene-catalyzed Syndiotactic Polypropylene Preparation and Properties. In Metallocene-based Polyolefins Preparation, Properties and Technology, Scheirs, J., Kaminsky, W., Eds. Wiley Chichester, 2000 Vol. 1, p 467. 

Referring to Table 3.5, metallocene catalysts, as compared with Ziegler-Natta catalysts, consist only of single catalytic centers and therefore produce polymer chains having much more uniform chain length and distinctly lower atactic content than conventional polypropylene. Thus, metallocene-catalyzed polypropylene exhibits some good properties that are not attainable with Ziegler-Natta-catalyzed polypropylene, such as... 

Bond, E.B. Spruiell, J.E. Comparison of the crystallization behavior of Ziegler-Natta and metallocene catalyzed isotactic polypropylene, ANTEC, Europe, 1997, 388. 

Fas Fasce, L. A., Frontini, P. M., Wong, S.-C., Mai, Y.-W. Polypropylene modified with elastomeric metallocene-catalyzed polyolefin blends Fracture behavior and development of damage mechanisms. J. Polym. Sci. Part B - Polym. Phys. 42 (2004) 1075-1089. 

The MBS market is decreasing partially due to PVC bottles being replaced by PET. This trend is more evident in Europe due to widespread use of water bottles. In contrast, the film and sheet market remain strong. Overall, MBS sales are heavily dependent on the future of PVC, particularly flexible PVC. Flexible PVC, comprising 15% of the total PVC market, is vulnerable to penetration by metallocene catalyzed polyolefins (for example, super soft polypropylene ). 

Blown film is manufactured from metallocene-catalyzed polypropylene containing a-nucleating agent. The a-nucleating agent is a phosphate ester salt or a carboxylate salt added in quantity of 10 to 5000 ppm. The blown film has improved film forming properties and good optical and mechanical properties. ... 

Matyjaszewski, K. Saget, J. Pyun, J. Schlogl, M. Rieger, B. Synthesis of polypropylene-poly(meth)acrylate block copolymers using metallocene catalyzed processes and snbseqnent atom transfer radical polymerization. J. Macromol. ScL, PureAppl. Chem. 2002, A39, 901-913. 

Industrial use of an a-metallocenes for the production of isotactic polypropylene had to overcome not only technical hurdles, but has also been restricted by a complicated and scattered patent landscape. Basic patent rights like the activation of metallocene complexes by MAO, supported metallocenes [59, 62], silanediyl-bridges [49] and 2-methyl substitution [50], all of which were required for the use of awia-metallocenes in industrial polypropylene production, were owned by different companies such that no player had the freedom to move. Only in 1995,5 years after rac-dimethylsilylenbis(2-methylindenyl)zirconium dichloride had been described for the first time in a patent [50], did ExxonMobil and the former Hoechst AG announce independently their first commercial production of metallocene-catalyzed, isotactic polypropylene. Most likely, these 5 years were needed not only to solve technical problems, but also to gain access to all the necessary patent rights. 

The fourth type is metallocene catalyzed polypropylene and primarily aimed at the biaxially oriented polypropylene market. 

Metallocene-catalyzed polyolefins represent the latest wave of developments in the history of the polyolefin industry. These catalyst systems have been applied to a number of key product families across the chemical industry including polyethylene, polypropylene, cyclic olefins, styrenics, and specialty chemicals. Activity in the various metallocene technologies is proceeding on a global basis, with many participants already involved in alliance arrangements. 

There are two methods used to blend polypropylene and EPDM rubber to make a TPO. The original method, still used extensively, is to simply mechanically blend the two polymers together with high shear mixing at an elevated temperature. However, a newer procedure employs new catalyst technology to blend EPDM and PP in the polymer reactor itself. This newer technique lowers the TPO production costs however, this type of TPO can only be obtained from the polymer manufacturers themselves. Reactor-produced TPOs can also be made softer than the mechanically blended TPO types. Some TPOs are also based on polyethylene as well (such as metallocene-catalyzed polyethylene), see Figure 6.7. 

Lew C.Y., Murphy W.R., McNally G.M., Abe K., Yanai S., Metallocene-catalyzed polypropylene nanocomposite fibers the effect of melt spinning on the exfoliation of layered-silicates , Polymer Fibers 2004, Manchester 2004. 

TPO blends with the composition of a 70 wt% of polypropylene (PP) and a 30wt% of metallocene-catalyzed ethylene-octene copolymer (POE) were prepared using a corotating twin-screw extruder with a screw diameter of 30 mm (Werner Pfleiderer ZSK-30, L/D 38 1). Then 20... 

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