Electron microscopy methods for studying polymer blends—comparison of scanning electron microscopy and transmission electron microscopy

Abstract The possibility of using a scanning electron microscope (SEM) for studying the morphology of mechanical polymer blends was investigated. Compounds of SBS/EPDM, and both filled and unfilled NBR/EPDM were tested. OsO 4 -stained thin-sections were also examined in a transmission electron microscope (TEM) and the results were compared. It seemed to be quite possible to use atomic number contrast detection in combination with OsO 4 staining for visualizing the morphology of the blends in SEM. Domains as small as 0·1 μm were clearly seen. This was done by means of a Robinson backscattered electron detector. Sample preparation was easy, 2 mm thick rubber plates were cut on dry ice to obtain a smooth surface. After staining, the samples were coated with a thin conductive carbon layer. The inner structures of SBS and the carbon black particles were not resolved in SEM but were easily seen in TEM.