Long-chain branching rheological properties

Keywords Siloxy-substituted metallocenes Long-chain branching Rheological properties ... 

Comonomers can be used to create a variety of polymer stmctures that can impart desirable properties. For example, even higher molecular weight PPS polymers can be produced by the copolymerization of a tri- or tetrafunctional comonomer (18). The resultant polymer molecules can have long-chain branching, which can be used to tailor the rheological response of the polymer to the appHcation. 

The final chapter develops the most modern insights in the relation between the rheological properties and the large scale architecture of polymers. Indeed, the largest effects of branching are encountered in their melt relaxation properties. In the absence of reptation, which dominates relaxation processes in Hnear polymers, a rich variety of other relaxation processes becomes apparent. The control ot the melt properties of polymers by means of their long-chain branch architecture will continue to lead to new industrial applications. 

Nam GJ, Yoo JH, Lee JW (2005) Effect of long-chain branches of polypropylene on rheological properties and foam-extrusion performances. J Appl Polym Sci 96 1793-1800... 

For high density polyethylene the MWD represents one of the basic parameters which, together with average molecular weight, density, short and long chain branching content, determines the physical, mechanical and rheological properties of the polymer and therefore its end uses (Table 1). 

The presence of long chain branches, which even in small quantities have a significant influence on rheological properties... 

Yan, D., W. J. Wang, and S. Zhu. 1999. Effect of long chain branching on rheological properties of metallocene polyethylene. Polymer 40 1737-1744. 

Jaewhan Kim, Dong Hak Kim, and Younggon Son, (2009). Rheological properties of long chain branched polyethylene melts at high shear rate. Polymer 49985001. 

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