Calorimetry System Based on Polystyrene/MWCNT Nanocomposite for Electron Beam Dosimetry: A New Approach

A novel calorimetry system is presented to use in radiation processing facilities equipped with an electron accelerator. The calorimeter core was fabricated with polystyrene/multiwall carbon nanotube nanocomposite. The nanocomposite samples were made in different weight percentages of MWCNTs namely 0.05, 0.1, 0.28, 1, and 2 wt %. The SEM analysis was applied to demonstrate the dispersion state of the inclusions into the polymer matrix. The electrical percolation threshold was investigated and achieved at about 0.1 wt % of the inclusion. The electrical resistance of the samples was objected as the calorimeter response before and after the electron beam irradiation. A linear response of the resistance-dose curve was observed for all the nanocomposites having the 0.1 and 0.28 wt % of the inclusion at a dose range of ~8 to ~40 kGy. The results showed that the decrease of the MWCNT content leads to increasing the electrical resistance. Furthermore, the thicker sample showed better experimental results in comparison to the thinners. The best results were obtained for the nanocomposite sample containing 0.14 wt % of MWCNT and 5 mm of sample thickness.