Abstract
The thermoforming process involves a previously extruded sheet of material being reheated to a softened state below the melting temperature and then forced into a mould either by a plug, air pressure or a combination of both. Thermoplastics such as polystyrene (PS) and polypropylene (PP) are commonly processed via thermoforming for products in the packaging industry. However, high density polyethylene (HDPE) is generally not processed via thermoforming and yet HDPE is extensively processed throughout the packaging industry. The aim of this study was to investigate the potential of thermoforming HDPE. The objectives were to firstly investigate the mechanical response under comparable loading conditions and secondly, to investigate the final mechanical properties post-forming. Obtaining in-process stress-strain behavior during thermoforming is extremely challenging if not impossible. To overcome this limitation the processing conditions were replicated offline using the QUB biaxial stretcher. Typical processing conditions that the material will experience during the process are high strain levels, high strain rates between 0.1-10s-1 and high temperatures in the solid phase (1). Dynamic Mechanical Analysis (DMA) was used to investigate the processing range of the HDPE grade used in this study, a peak in the tan delta curve was observed just below the peak melting temperature and hence, a forming temperature was selected in this range. HPDE was biaxially stretched at 128°C at a strain rate of 4s-1, under equal biaxial deformation (EB). The results showed a level of biaxial orientation was induced which was accompanied by an increase in the modulus from 606 MPa in the non-stretched sample to 1212MPa in the stretched sample.
Original language | English |
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Title of host publication | Proceedings of the 20th International ESAFORM Conference on Material Forming (ESAFORM 2017) |
Editors | Dermot Brabazon, Inam Ul Ahad, Sumsun Naher |
Publisher | American Institute of Physics Inc. |
Volume | 1896 |
ISBN (Electronic) | 9780735415805 |
DOIs | |
Publication status | Published - 16 Oct 2017 |
Event | 20th International ESAFORM Conference on Material Forming, ESAFORM 2017 - Dublin, Ireland Duration: 26 Apr 2017 → 28 Apr 2017 |
Publication series
Name | AIP Conference Proceedings |
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Volume | 1896 |
ISSN (Print) | 0094-243X |
ISSN (Electronic) | 1551-7616 |
Conference
Conference | 20th International ESAFORM Conference on Material Forming, ESAFORM 2017 |
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Country/Territory | Ireland |
City | Dublin |
Period | 26/04/2017 → 28/04/2017 |
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Ecology
- Plant Science
- General Physics and Astronomy
- Nature and Landscape Conservation
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Dive into the research topics of 'Thermoforming of HDPE'. Together they form a unique fingerprint.Student theses
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Investigation into the mechanical response and microstructure evolution of high density polyethylene, under conditions applicable to the injection stretch blow moulding process
McKelvey, D. (Author), Menary, G. (Supervisor), Martin, P. (Supervisor) & Yan, S. (Supervisor), Dec 2018Student thesis: Doctoral Thesis › Doctor of Philosophy