Influence of Molecular Weight on the Creep Resistance of Almost Molten Polyethylene Blends

Mattias G. Andersson, Roman Städler, Per Ola Hagstrand, Thomas Gkourmpis, Mats R. Andersson, Christian Müller

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)

Abstract

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, Tm ≈ 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 Mw 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.).

Original languageEnglish
Article number 1700072
Number of pages7
JournalMacromolecular Chemistry and Physics
Volume219
Issue number3
DOIs
Publication statusPublished - 1 Feb 2018
Externally publishedYes

Keywords

  • creep
  • crosslink
  • low‐density polyethylene (LDPE)
  • polyethylene blend
  • tie chain
  • low-density polyethylene (LDPE)

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