The effects of polyethylene, (PE), type, compatibilizer type and organoclay type
on the morphology, rheological, thermal, and mechanical properties of ternary
low density polyethylene (LDPE), high density polyethylene (HDPE), and linear
low density polyethylene (LLDPE), matrix nanocomposites were investigated in
this study. Ethylene &ndash / Methyl acrylate &ndash / Glycidyl methacrylate terpolymer (E-MAGMA)
and Ethylene &ndash / Butyl acrylate- Maleic anhydrate terpolymer (E-BA-MAH)
were used as the compatibilizers. The organoclays selected for the study were
Cloisite 30B and Nanofil 8. Nanocomposites were prepared by means of melt
blending via co-rotating twin screw extrusion process. Extruded samples were
injection molded to be used for material characterization tests.
Optimum amounts of ingredients of ternary nanocomposites were determined
based on to the mechanical test results of binary blends of PE/Compatibilizer and
binary nanocomposites of PE/Organoclay. Based on the tensile test results, the
optimum contents of compatibilizer and organoclay were determined as 5 wt %
and 2 wt %, respectively.
XRD and TEM analysis results indicated that intercalated and partially exfoliated
structures were obtained in the ternary nanocomposites. In these
nanocomposites E-MA-GMA compatibilizer produced higher d-spacing in
comparison to E-BA-MAH, owing to its higher reactivity. HDPE exhibited the
highest basal spacing among all the nanocomposite types with E-MA-GMA/30B
system. Considering the polymer type, better dispersion was achieved in the
order of LDPE< / LLDPE< / HDPE, owing to the linearity of HDPE, and short
branches of LLDPE.
MFI values were decreased by the addition of compatibilizer and organoclay to
the matrix polymers. Compatibilizers imparted the effect of sticking the polymer
blends on the walls of test apparatus, and addition of organoclay showed the filler
effect and increased the viscosity.
DSC analysis showed that addition of compatibilizer or organoclay did not
significantly affect the melting behavior of the nanocomposites. Degree of
crystallinity of polyethylene matrices decreased with organoclay addition.
Nanoscale organoclays prevented the alignment of polyethylene chains and
reduced the degree of crystallinity.
Ternary nanocomposites had improved tensile properties. Effect of compatibilizer
on property enhancement was observed in mechanical results. Tensile strength
and Young&rsquo / s modulus of nanocomposites increased significantly in the presence
of compatibilizers.
| Identifer | oai:union.ndltd.org:METU/oai:etd.lib.metu.edu.tr:http://etd.lib.metu.edu.tr/upload/12613294/index.pdf |
| Date | 01 June 2011 |
| Creators | Isik Coskunses, Fatma |
| Contributors | Yilmazer, Ulku |
| Publisher | METU |
| Source Sets | Middle East Technical Univ. |
| Language | English |
| Detected Language | English |
| Type | Ph.D. Thesis |
| Format | text/pdf |
| Rights | To liberate the content for public access |
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