Effect of high temperature, biaxial stretching on the thermal and mechanical properties of HDPE/MWCNT sheet

Dong Xiang, Eileen Harkin-Jones, David Linton

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Citation (Scopus)

Abstract

High density polyethylene (HDPE)/multi-walled carbon nanotube (MWCNT) composites containing 4 wt% MWCNTs were prepared by melt mixing followed by compression moulding into sheet. Compression moulded sheets were heated to just below the melting temperature and biaxially stretched at ratios (SRs) of 2, 2.5 and 3.0. The effect of stretching on the thermal and mechanical properties of the sheet was studied by differential scanning calorimetry (DSC) and tensile testing. DSC results show that the crystallinity of all the stretched samples increases by approximately 13% due to strain induced crystallization. The melting temperature of the biaxially stretched samples increases only slightly while crystallization temperature is not affected. Tensile test results indicate that at a SR of 2.5 the elastic modulus of the stretched composites increases by 17.6% relative to the virgin HDPE, but the breaking strength decreases by 33%. While the elastic modulus and breaking strength of the HDPE/MWCNT samples continue to increase as SR increases they drop off after a SR of 2.5 for the virgin HDPE. This is probably due to the constraining influence of the nanotubes preventing the relaxation of polymer chains caused by adiabatic heating at high SRs. The addition of MWCNTs results in significant strain hardening during deformation. While this will lead to increased energy requirement in forming it will also result in a more stable process and the ability to produce deep draw containers with more uniform wall thickness.

Original languageEnglish
Title of host publicationProceedings of PPS-30
Subtitle of host publicationThe 30th International Conference of the Polymer Processing Society - Conference Papers
EditorsSadhan C. Jana
PublisherAmerican Institute of Physics Inc.
Volume1664
ISBN (Electronic)9780735413092
DOIs
Publication statusPublished - 22 May 2015
Event30th International Conference of the Polymer Processing Society, PPS 2014 - Cleveland, United States
Duration: 6 Jun 201412 Jun 2014

Conference

Conference30th International Conference of the Polymer Processing Society, PPS 2014
CountryUnited States
CityCleveland
Period6/06/1412/06/14

Keywords

  • Biaxial stretching
  • Carbon nanotubes
  • High density polyethylene
  • Manufacturing
  • Polymer composites
  • Processing

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  • Cite this

    Xiang, D., Harkin-Jones, E., & Linton, D. (2015). Effect of high temperature, biaxial stretching on the thermal and mechanical properties of HDPE/MWCNT sheet. In S. C. Jana (Ed.), Proceedings of PPS-30: The 30th International Conference of the Polymer Processing Society - Conference Papers (Vol. 1664). [700071] American Institute of Physics Inc.. https://doi.org/10.1063/1.4918442