Permanganic etching technique

The twisting lamellar structure of banded spherulites has been debated for decades without obtaining any satisfactory answer until recently. The nature of the isochiral (certain uniform handedness) lamellar twisting and the synchronic character of the twisting of a group of adjacent dominant lamellae both require an explanation. The permanganic etching technique provided... 

Several chemical etching techniques were tried by us on these materials [60]. Those based on alkaline reagents (whether potassium hydroxide in alkaline solution, or sodium ethoxide in ethanol) did not react enougheven to completely remove the smallest spurious features associated with the moulded surfaces. On the other hand, the permanganic reagent with phosphoric acid gave smooth and uniform attack over all the materials. In Fig. 2.23, etched surfaces of aU five materials are shown at three... 

Permanganic etching is a technique, introduced from this laboratory, which allows systematic study with the electron microscope of the... 

The potential applications of permanganic etching are very wide, as wide as the relationship of microstructure to properties." As befits a major new technique of broad relevance, the applications are increasing rapidly. It is not our intention to attempt to list all of these, for any such attempt would fail and be incomplete before publication. Rather, salient themes will be identified from the point of view of how... 

The technique of permanganic etching was applied in order to reveal the spherulitic structure and lamellar detail in polyolefines [46-49]. The samples were etched in order to remove the amorphous portions and optical microscopy was used to take images of the samples and measure the dimensions of the spherulites. 

Although several specific etchants have been devised [179-182], by far the most successful polymeric etching technique is permanganic etching [143, 183]. Initially reported in 1979, this approach to the study of polymer... 

Permanganic etching is frequently used to prepare surfaces for SEM examinations, notably of semicrystalline polymers and their blends and composites. In this case the etchant attacks the polymers destmctively and progressively removes the outer skin of the polymer, such that the loosely packed amorphous phase is preferentially etched out of the sample. This technique is especially useful for exposing the internal structural details of semicrystalline polymers. 

Figure 3.17 Top Application of different microscopic techniques to study the surface and interior of a hulk polymeric material. Bottom Comparison of the results from different microscopic techniques apphed to a - iPP (a) SEM image after permanganic etching, (b) TEM image of chemically stained ultrathin section, and (c) AFM tapping mode image.

The material for which melt-crystallized morphologies were first studied in detail was polyethylene, largely as a result of this being the system on which the techniques of chlorosulfonation and permanganic etching were developed. 

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