A staining method of polymeric powders for transmission electron microscope observation and its application to polyethylene single crystals

A new specimen preparation method for transmission electron microscope (TEM ) observation of polymeric powder samples is proposed. Powders were placed into a glass-fiber basket, and stained with RuO4 at 60 degrees C. Resultant stained powder; were embedded in epoxy resin and ultramicrotomed. This sam ple preparation for TEM observation was applied to single crystals of LLDPE and two HDPE's which have different molecular weight distributions. Obtain ed electron micrographs contained edge-on single crystalline lamellae, whic h have never been observed in Bat-on analysis by the common method. From th ese electron microscopic results, it was found that the single crystals of LLDPE and HDPE with a broad molecular weight distribution stacked with a nu mber of lamellae. On the other hand, HDPE with a narrower molecular weight distribution gives single lamellae without stacking. This method has advant ages that a specimen for observation can be prepared easily and gives bette r contrast on TEM micrographs. Compared with the results of the common shad owing method, it is clear that the stacked morphology of single crystal lam ellae can be investigated more quantitatively by this preparation/staining method.