The aim of this study was to improve the mechanical properties of a recycled grade
polypropylene. Polymer blends and nanocomposites were prepared by melt
compounding method in a twin screw extruder. Cloisite® / 15A, Cloisite® / 25A and
Cloisite® / 30B were used as organoclays, and ethylene-methyl acrylate-glycidyl
methacrylate (E-MA-GMA) and maleic anhydride grafted polypropylene (PP-MAH)
were used as compatibilizers. The effects of additive concentrations, types of
organoclays and compatibilizers, processing conditions, and the compatibilizer to
organoclay ratio on the morphology and mechanical, thermal and flow properties
were investigated.
Organoclay loading over 2 wt% prevented the intercalation mechanism and material
properties, even in the presence of compatibilizer, as a consequence of large clay
agglomerate formation. E-MA-GMA compatibilizer improved the intercalation ability of
the polymer / however a substantial increase in mechanical properties was not
obtained. PP-MAH is found to be a better compatibilizer.
Processing conditions significantly affected both mechanical properties and
morphology. When the processing temperature was decreased and screw speed was
increased simultaneously, tensile and impact properties were improved owing to
enhanced shear and dispersive forces.
TEM analysis revealed that intercalated and delaminated structures were formed with
the addition of PP-MAH compatibilizer. In addition to that, as the ratio of PP-MAH to
organoclay was increased, more effective dispersion of organoclay was observed
and hence resultant improvements in both tensile and impact properties were greater
at compatibilizer to organoclay ratio of three.
Cloisite® / 15A exhibited the highest improvements in mechanical properties, although
the degree of organoclay dispersion was better for Cloisite® / 25A and particularly for
Cloisite® / 30B. Melt flow index values were lower compared to pure recycled
polypropylene in the presence of organoclay and compatibilizers. DSC analysis
indicated no significant change in the melting behavior of the matrix materials.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/3/12609873/index.pdf |
| Date | 01 September 2008 |
| Creators | Cengiz, Filiz |
| Contributors | Yilmazer, Ulku |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | M.S. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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