Effect of chain structure on the processing stability of high-density polyethylene

Eszter Pock, C. Kiss, Ákos Janecska, Edina Epacher, B. Pukánszky

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Ethylene/1-hexene copolymers were prepared with various 1-hexene contents to introduce short-chain branches into the polymer chain for the study of their effect on processing stability. The polymer powder was characterised by various techniques. Its density, molecular weight, MFI and melting characteristics were determined by routine techniques, and its functional group content by DRIFT. Besides short-chain branching, the number of other functional groups also varied in the polymerisation reaction, but the vinyl group content of all samples was approximately the same. The inherent properties of the polymer were determined by its chain structure, the existence of branched structure was also proved by the decrease of melting temperature and crystallinity. The chemical structure of the polymer was further modified during processing, the dominating reaction being the addition of radicals to the vinyl groups, which resulted in long-chain branching. This proved that the most active weak site of the chain is the vinyl group; vinylidene and vinylene groups as well as short-chain branches do not take part to the same extent in degradation reactions during processing. The experiments revealed that the residual stability of the polymer is influenced, in fact determined, by another factor, or factors, which have not been investigated in this study. Preliminary experiments and some considerations indicate that traces of oxygen containing groups might determine stability, but further study is needed to verify this tentative explanation.

Original languageEnglish
Pages (from-to)1015-1021
Number of pages7
JournalPolymer Degradation and Stability
Volume85
Issue number3 SPEC. ISS.
DOIs
Publication statusPublished - Sep 2004

Fingerprint

Polyethylene
High density polyethylenes
polyethylenes
Polymers
Processing
polymers
Functional groups
hexenes
melting
Powders
Melting point
Ethylene
Melting
Copolymers
Experiments
Molecular weight
vinylidene
Polymerization
Oxygen
Degradation

Keywords

  • High-density polyethylene
  • Processing stability
  • Short and long chain branching
  • Vinyl group content
  • Weak sites

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics

Cite this

Effect of chain structure on the processing stability of high-density polyethylene. / Pock, Eszter; Kiss, C.; Janecska, Ákos; Epacher, Edina; Pukánszky, B.

In: Polymer Degradation and Stability, Vol. 85, No. 3 SPEC. ISS., 09.2004, p. 1015-1021.

Research output: Contribution to journalArticle

Pock, Eszter ; Kiss, C. ; Janecska, Ákos ; Epacher, Edina ; Pukánszky, B. / Effect of chain structure on the processing stability of high-density polyethylene. In: Polymer Degradation and Stability. 2004 ; Vol. 85, No. 3 SPEC. ISS. pp. 1015-1021.
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