This thesis focuses on the design, development, and evolution of a novel patent-pending
plastic processing technology entitled “Rapid Rotational Foam Molding” with special
emphasis on the processing of polyethylene (PE) integral-skin foamed core moldings.
Rapid Rotational Foam Molding is a technology deliberately designed to address the
intrinsic disadvantage of conventional rotational foam molding, i.e., its very long cycle
times. In this context, a physical system that exploits the positive synergistic effects of
innovatively combining extrusion melt compounding and rotational foam molding was
designed and built. The fundamental processing steps of this system comprise (i)
rotationally molding a non-foamable PE powder in a lab-scale oven while, (ii)
simultaneously melt compounding and foaming a pre-dry blended foamable PE and
chemical blowing agent (CBA) formulation in an on-line lab-scale extruder, and then (iii)
filling the newly created foaming material into the non-chilled hollow article thereby
created in the mold through a special interface.
Two varieties of PE resins ranging from linear low density PE (LLDPE) to high
density PE (HDPE) were selected for experimentation with melt flow rates (MFR)
ranging from 2.0 to 3.6 g/10min. The implemented CBA was Celogen OT. The
materials were characterized using thermal analysis techniques such as differential
scanning calorimetery (DSC) and thermogravimetric analysis (TGA) to ensure their
correct operating temperatures ranges. Scanning electron microscopy (SEM) was utilized
for characterizing the quality of the foam samples and achieved skin-foam interface for
the final moldings. Improvements to the achieved molding quality were accomplished
through various system and process modifications described throughout this research
work.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:OOSHDU.10155/35 |
| Date | 01 June 2009 |
| Creators | Christian, Kimberly Anne |
| Contributors | Pop-Iliev, Remon |
| Publisher | UOIT |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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