Influence of Molecular Weight on the Creep Resistance of Almost Molten Polyethylene Blends
Journal article, 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.).

crosslink

low-density polyethylene (LDPE)

creep

tie chain

polyethylene blend

Author

Mattias Andersson

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

Roman Städler

Per Ola Hagstrand

Borealis AB

Thomas Gkourmpis

Borealis AB

Mats Andersson

University of South Australia

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Polymer Technology

Christian Müller

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Christian Müller Group

Macromolecular Chemistry and Physics

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

Vol. 219 3 1700072

Subject Categories

Polymer Chemistry

Polymer Technologies

Other Chemistry Topics

DOI

10.1002/macp.201700072

More information

Latest update

5/14/2018