Characterization of injection molded HDPE using SAXS and WAXS
Publicerad
Författare
Typ
Examensarbete för masterexamen
Program
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Plastic materials are used in many of our every day commodities. Its structure may
vary depending on which material it consists of and the applied process conditions.
The present work was carried out to contribute to the knowledge of the material
structure of a certain plastic material called high-density polyethylene, or HDPE,
produced through a manufacturing process called injection molding. The project
was carried out in collaboration with Tetra Pak® that uses HDPE as a component
in their packages.
The aim of the thesis was to characterize the structure of the material HDPE during
mechanical deformation. When the material is being produced the shearing
forces within the material in injection molding leads to a distribution of different
microstructures through the thickness of the material. The structures of the material’s
full thickness as well as the different layers, that were formed during molding,
were investigated. The structure of undeformed HDPE is relatively well-know, and
this work investigated how the structure changed after the material was subject to a
mechanical deformation. To get deeper insight into such changes, the material was
furthermore investigated with in-situ testing, of structural changes during mechanical
deformation.
The experimental characterization was performed by means of Small- and Wide-
Angle X-ray scattering (SAXS and WAXS) using both laboratory X-ray sources and
synchrotron X-ray sources. The scattering experiments showed different microstructures
of HDPE on different length-scales. The structures on different length-scales
could be distinguished before and after the material had been deformed. During the
uniaxial in-situ tensile tests, the deformation sequence of the structures could be
monitored, and give an explanation of material behavior under mechanical stress.
This information contributes to the general understanding of deformation of plastic
materials.
Beskrivning
Ämne/nyckelord
HDPE, Scanning SAXS/WAXS, in-situ SAXS WAXS, injection molded polyethylene