Manufacturing and characterization of nanofilled epoxy
Hykkö, Eeva (2013)
2013
Materiaalitekniikan koulutusohjelma
Teknisten tieteiden tiedekunta - Faculty of Engineering Sciences
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Hyväksymispäivämäärä
2013-06-05
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:tty-201306071179
https://urn.fi/URN:NBN:fi:tty-201306071179
Tiivistelmä
Nanocomposites are a new field in the polymer industry offering improved mechanical, thermal, electrical and optical properties with low filler content. Nanocomposites have a huge potential in many applications, but the preparation methods are still under investigation. This is due to the tendency of nanoparticles to form large clusters during manufacturing due to their small size and high surface energy. Improved properties in composites cannot be achieved if the nanofiller dispersion is poor.
The scope of this study was to successfully manufacture epoxy composites with uniform nanofiller dispersion. Furthermore, the mechanical, thermal and rheological properties of the prepared samples were examined. Nanosized silicon dioxide (SiO2), organoclay and multi-walled carbon nanotubes (MWCNT) were incorporated into the epoxy resin by high shear mixing. Samples were prepared by moulding and the curing with a hardener was performed at elevated temperature.
Some difficulties were observed during manufacturing. A notable amount of air bubbles was formed on the resin during the mixing of the nanofillers and their removal slowed down the manufacturing process. Furthermore, viscosity of the nanofilled resin was strongly affected by the nanoparticles limiting the preparation of higher filler loadings. Small amounts (0.5 wt.%) of MWCNTs increased the viscosity of the resin significantly. In case of nano-SiO2 and nanoclay, concentration of 2 wt.% increased the viscosity so that the air bubble removal was extremely slow. Furthermore, the mixing of sample with 4 wt.% of nano-SiO2 was not possible anymore with the high shear mixer due to the markedly increased viscosity.
Improved properties in mechanical and thermal tests were not totally achieved. Scanning electron microscope (SEM) and field emission scanning electron microscope (FESEM) images indicated that the samples contained agglomerated nanoparticles indicating that the mixing may not have been effective enough.
Difficulties during manufacturing and the poor dispersion in the final composites require further research in terms of more effective preparation methods and matrix/filler compatibility. Other processing methods (such as ultrasonication or using solvents) in addition to high shear mixing are needed to achieve proper dispersion.
The scope of this study was to successfully manufacture epoxy composites with uniform nanofiller dispersion. Furthermore, the mechanical, thermal and rheological properties of the prepared samples were examined. Nanosized silicon dioxide (SiO2), organoclay and multi-walled carbon nanotubes (MWCNT) were incorporated into the epoxy resin by high shear mixing. Samples were prepared by moulding and the curing with a hardener was performed at elevated temperature.
Some difficulties were observed during manufacturing. A notable amount of air bubbles was formed on the resin during the mixing of the nanofillers and their removal slowed down the manufacturing process. Furthermore, viscosity of the nanofilled resin was strongly affected by the nanoparticles limiting the preparation of higher filler loadings. Small amounts (0.5 wt.%) of MWCNTs increased the viscosity of the resin significantly. In case of nano-SiO2 and nanoclay, concentration of 2 wt.% increased the viscosity so that the air bubble removal was extremely slow. Furthermore, the mixing of sample with 4 wt.% of nano-SiO2 was not possible anymore with the high shear mixer due to the markedly increased viscosity.
Improved properties in mechanical and thermal tests were not totally achieved. Scanning electron microscope (SEM) and field emission scanning electron microscope (FESEM) images indicated that the samples contained agglomerated nanoparticles indicating that the mixing may not have been effective enough.
Difficulties during manufacturing and the poor dispersion in the final composites require further research in terms of more effective preparation methods and matrix/filler compatibility. Other processing methods (such as ultrasonication or using solvents) in addition to high shear mixing are needed to achieve proper dispersion.