number of WO3 particles/gram when compared to micro-sized WO3-
epoxy composites. Therefore, the distribution of the nano-sized WO3
in the resin should also be different from that presented by microsizedWO3,
thus resulting in a more uniform dispersion in the resin. As
a consequence, the chances of an X-ray photon with lower energy to interact
and be absorbed by WO3 particles may be higher in nano-sized
WO3-epoxy composites than in micro-sized WO3-epoxy composites.
Fig. 6 shows the back-scattered images of the same loading of WO3
(4 vol%) within nano-sized WO3-epoxy and micro-sized WO3-epoxy
composites using the Zeiss Evo 40XVP scanning electron microscope.
The WO3 particles were seen to be more closely dispersed in the
nano-sized WO3-epoxy composite (Fig. 6a) as compared to its microsized
counterpart (Fig. 6b). Thus, the probability for the lower energy
photons to interact with the WO3 particles and be absorbed is higher
for the nano-sized WO3-epoxy composite.