Influence of Molecular Weight on the Creep Resistance of Almost Molten Polyethylene Blends
Artikel i vetenskaplig tidskrift, 2018

The most common route to improve the creep resistance of low density polyethylene (LDPE) is crosslinking, which however results in volatile decomposition products that must be removed. Blends of LDPE and an additive-like amount of a linear polyethylene are found to offer improved creep resistance. Above the melting temperature of LDPE, T m ≈ 111 °C, a load-bearing network of higher-melting crystallites—connected through tie chains and trapped entanglements—provides additional form stability. The molecular weight of the linear polyethylene is found to be critical for the ability to arrest creep, which is correlated with the probability of tie chain formation as well as cocrystallization of the two polyethylenes. A number of high-density polyethylenes (HDPE) and one ultrahigh molecular weight polyethylene (UHMW-PE) are explored. For blends of LDPE and 2 wt% of the linear polyethylene, an HDPE with a weight-average molecular weight M w of 16 kg mol −1 is found to be sufficient to arrest creep at 115 °C. Further improvement in terms of creep resistance is obtained in case of UHMW-PE with creep fracture occurring only at a stress of 12 kPa at 115 °C. (Figure presented.).



polyethylene blend

low-density polyethylene (LDPE)

tie chain


Mattias Andersson

Chalmers, Kemi och kemiteknik, Tillämpad kemi

Roman Städler

Chalmers, Kemi och kemiteknik

Per Ola Hagstrand

Borealis GmbH

Thomas Gkourmpis

Borealis GmbH

Mats Andersson

Chalmers, Kemi och kemiteknik, Tillämpad kemi

University of South Australia

Christian Müller

Chalmers, Kemi och kemiteknik, Tillämpad kemi

Macromolecular Chemistry and Physics

1022-1352 (ISSN) 1521-3935 (eISSN)

Vol. 219 3 1700072




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