Eby Thomas, Thachil; Renju, V S; Vidya Francis, K F; Ayswarya, E P(Elsevier, April , 2012)
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Abstract:
This paper presents the results of a study on the use of rice husk ash (RHA) for property modification of
high density polyethylene (HDPE). Rice husk is a waste product of the rice processing industry. It is used
widely as a fuel which results in large quantities of RHA. Here, the characterization of RHA has been done
with the help of X-ray diffraction (XRD), Inductively Coupled Plasma Atomic Emission Spectroscopy
(ICPAES), light scattering based particle size analysis, Fourier transform infrared spectroscopy (FTIR)
and Scanning Electron Microscope (SEM). Most reports suggest that RHA when blended directly with
polymers without polar groups does not improve the properties of the polymer substantially. In this
study RHA is blended with HDPE in the presence of a compatibilizer. The compatibilized HDPE-RHA blend
has a tensile strength about 18% higher than that of virgin HDPE. The elongation-at-break is also higher
for the compatibilized blend. TGA studies reveal that uncompatibilized as well as compatibilized HDPERHA
composites have excellent thermal stability. The results prove that RHA is a valuable reinforcing
material for HDPE and the environmental pollution arising from RHA can be eliminated in a profitable
way by this technique.
Expanded polystyrene (EPS) constitutes a considerable part of thermoplastic waste in the environment in
terms of volume. In this study, this waste material has been utilized for blending with silica-reinforced
natural rubber (NR). The NR/EPS (35/5) blends were prepared by melt mixing in a Brabender Plasticorder.
Since NR and EPS are incompatible and immiscible a method has been devised to improve compatibility.
For this, EPS and NR were initially grafted with maleic anhydride (MA) using dicumyl peroxide (DCP) to
give a graft copolymer. Grafting was confirmed by Fourier Transform Infrared Spectroscopy (FTIR) spectroscopy.
This grafted blend was subsequently blended with more of NR during mill compounding. Morphological
studies using Scanning Electron Microscopy (SEM) showed better dispersion of EPS in the
compatibilized blend compared to the noncompatibilized blend. By this technique, the tensile strength,
elongation at break, modulus, tear strength, compression set and hardness of the blend were found to be
either at par with or better than that of virgin silica filled NR compound. It is also noted that the thermal
properties of the blends are equivalent with that of virgin NR. The study establishes the potential of this
method for utilising waste EPS