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26 NORAAM MOAMAD , ANDANASTUT MUCATAR
2
, MARYAM JAMEELA GAZAL , DALAN MOD and CE USNA AZAR
1
Faculty of Manufacturing Engineering Universiti Teknikal Malaysia Melaka
Hang Tuah Jaya, 76100 Durian Tunggal, Melaka, MALAYSIA
1
noraihamutem.edu.my
2, 3, 5
Faculty of Engineering Universiti Kebangsaan Malaysia
43600 Bangi, Selangor, MALAYSIA
4
Malaysia Nuclear Agency 43600 Bangi, Selangor, MALAYSIA
1.0 I
NTRODUCTION
Much research has been carried out in the development of nano-filled composites through the incorporation of nano-scale materials such as ceramics and carbon in polymer matrix. For instance organoclays Teh et al.,
, carbon nanotubes Shanmugharaj et al.,
, alumina nanoparticles Siegel et al., and silica
nanoparticles Park et al., have been added to polymers. Polymer nanocomposites exhibit unique
properties even by the addition of a low weight percent nanofillers wt. , that cannot be obtained from conventional or micro-scale fillers López-Manchado et al.,
. The incorporation of nanofillers enhances mechanical, electrical, optical and other properties of polymer composites without sacrificing too much of the
needed properties such as toughness being traded for stiffness as that found in rubber filled carbon fibres Ajayan et al.,
. Several polymers have been used for preparing polymer nanocomposites such as elastomers natural rubber NR Peng et al.,
Vu et al., , epoxidized natural rubber ENR Teh et
al .,
Varghese et al., , styrene-butadiene rubber SBR Ahankari et al.,
Falco et al., ,
chloroprene rubber CR Das et al., , ethylene propylene diene monomer rubber EPDM Chang et al.,
etc. , thermoplastics nylon Ajayan et al., , polypropylene PP Kalaitzidou et al.,
asan et al
., , polyethylene terephthalate PET Bhimaraj et al.,
, polymetylmetacrylate PMMA Costache et al
., , polycarbonate Chandra et al.,
Eitan et al., etc. , and polymer blends Kontopoulou
et al .,
Arroyo et al., .
The development of polymer-ceramic nanocomposites has created a number of technologies and opportunities that can be applied to ENR. n a previous research by Teh et al.
, ENR was used as a compatibilizer in producing natural rubber-organoclay nanocomposites. Organoclay can be easily dispersed in
ABSTRACT
This paper examined the effect of alumina nanoparticles to the impact strength of ENR and emphasis on morphological characteristics of the materials. Epoxidized natural rubber-alumina
nanoparticle composites ENRAN was successfully prepared through direct melt compounding process using an internal mixer. It was cured by sulphur semi efficient curing system using a hot
press. Loading of alumina nanoparticles in the epoxidized natural rubber ENR matrix were varied from 10, 20, 30, 40, 50 to 60 phr. Izod impact test was performed on samples and fracture
surfaces were directly examined under Scanning Electron Microscope SEM. The impact strength decreased with increased filler loading. The composites were observed to fail in
moderately brittle fracture due to frozen state by liquid nitrogen and embrittlement effect of hard alumina as the ratio of filler to matrix increased. Energy absorption by filler pull-out suppressed
the mechanism of matrix yielding and matrix cracking. The decrease in matrix to filler ratio and the increase in agglomeration and crosslink density had contributed to the diminishing impact
strength of the composites. Keywords: Rubber, Alumina, Impact Fracture, Energy Absorption Mechanism, Morphology.
INVESTIGATION ON IMPACT FRACTURE OF EPOXIDIZED NATURAL RUBBER-ALUMINA NANOPARTICLE COMPOSITES
ENRAN
© 2011 GETview
Limited. All rights reserved
27 polar polymers when compared to non-polar polymers such as NR Teh et al.,
. ENR is miscible with more polar polymers smail et al.,
therefore offering unique properties such as good oil resistance, low gas permeability, a higher wet grip, rolling resistance, and a higher tensile strength. The oil resistance of ENR
vulcanizate is reported to almost meet the characteristics of medium-acrylonitrile-content nitrile rubber and also surpasses that of CR smail et al.,
. The resistance to air permeability of ENR is also claimed to be comparable to butyl rubber and medium-acrylonitrile-content nitrile rubber smail et al.,
. Alumina has been recognized as a structural material with an extremely high melting point
°C , a high degree of hardness, and is capable in taking on diverse shapes and functions Noboru,
. The potential of polymer filled alumina nanoparticle composites in wear and tribology, optical and
electrical have been studied by some researchers Bhimaraj et al., , Chandra et al.,
Gatos et al., . The incorporation of nano-scaled alumina in PP has improved the mechanical properties of the polymer
composites Jung et al., and increased the wear resistance of PET filled alumina nanoparticles by nearly
two times over the unfilled polymer Bhimaraj et al., . There have also been several reports of improved
ductility and toughness in brittle thermoset polymers due to the addition of alumina nanoparticles Ash et al., Ash et al.,
. n our previous study Mohamad et al., , the addition of alumina nanoparticles
