Polyvinyl alcohol and epoxy based composites for radiation shielding applications

Abstract

The present study has been focused towards designing efficient, non-toxic and cost-effective shielding materials with good mechanical strength for protection against radiations encountered in various environments like aerospace, hospitals, research and nuclear reactor establishments. From this perspective, to impart desired shielding properties, high Z filler dispersed polymer matrices such as Bi/WO3-polyvinyl alcohol (PVA), Ta2O5-epoxy, Ta2O5-Bi2O3-epoxy, micro Bi2O3-epoxy and nano Bi2O3-epoxy with varying filler contents have been synthesized. Structural characterizations were carried out using X-ray diffraction newline(XRD) and Fourier transform infrared (FT-IR) spectroscopy to reveal the interactions newlinebetween filler and polymer matrix. The morphological analyses were performed using newlinescanning electron microscopy (SEM) images. The AC conductivity measurements and newlineoptical studies revealed low conductivity property of the composites. The thermo newlinegravimetric analysis (TGA) and mechanical studies were conducted to ascertain thermal newlinestability and mechanical properties of the composites. With increase in filler concentration mechanical properties of Bi/WO3-PVA composites were found to be weakening. The TGA studies of Bi/WO3-PVA composites showed decrease in peak degradation temperature with increase in filler content. This prompted us to further design epoxy composites as epoxy matrix has good thermal stability and mechanical strength. Compared to neat epoxy, dispersion of varying wt% of Ta2O5 and Bi2O3 into epoxy matrix led to significant improvement in stiffness, storage modulus, glass transition temperature and thermal stability of the composites. Epoxy composites with 5 wt% of Ta2O5 and 30 wt% of Bi2O3 revealed better thermal and tensile properties when compared to same wt% Bi2O3 filled epoxy composites. The synergistic influence of micro and nano Bi2O3 filler on epoxy matrix composites showed similar thermal behaviour.